Blood flow velocity. Medical search

A value equal to the total volume flow divided by the cross-sectional area of the vascular bed.

The flow of BLOOD through or around an organ or region of the body.

A non-invasive technique using ultrasound for the measurement of cerebrovascular hemodynamics, particularly cerebral blood flow velocity and cerebral collateral flow. With a high-intensity, low-frequency pulse probe, the intracranial arteries may be studied transtemporally, transorbitally, or from below the foramen magnum.

The circulation of blood through the BLOOD VESSELS of the BRAIN.

The largest of the cerebral arteries. It trifurcates into temporal, frontal, and parietal branches supplying blood to most of the parenchyma of these lobes in the CEREBRAL CORTEX. These are the areas involved in motor, sensory, and speech activities.

Ultrasonography applying the Doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. (Stedman, 25th ed)

Artery originating from the internal carotid artery and distributing to the eye, orbit and adjacent facial structures.

The arterial blood vessels supplying the CEREBRUM.

Rhythmic, intermittent propagation of a fluid through a BLOOD VESSEL or piping system, in contrast to constant, smooth propagation, which produces laminar flow.

Ultrasonography applying the Doppler effect, with the superposition of flow information as colors on a gray scale in a real-time image. This type of ultrasonography is well-suited to identifying the location of high-velocity flow (such as in a stenosis) or of mapping the extent of flow in a certain region.

Ultrasonography applying the Doppler effect, with velocity detection combined with range discrimination. Short bursts of ultrasound are transmitted at regular intervals and the echoes are demodulated as they return.

The circulation of blood through the CORONARY VESSELS of the HEART.

PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.

The force that opposes the flow of BLOOD through a vascular bed. It is equal to the difference in BLOOD PRESSURE across the vascular bed divided by the CARDIAC OUTPUT.

A method of non-invasive, continuous measurement of MICROCIRCULATION. The technique is based on the values of the DOPPLER EFFECT of low-power laser light scattered randomly by static structures and moving tissue particulates.

The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.

Clinical manifestation consisting of a deficiency of carbon dioxide in arterial blood.

Three groups of arteries found in the eye which supply the iris, pupil, sclera, conjunctiva, and the muscles of the iris.

Central retinal artery and its branches. It arises from the ophthalmic artery, pierces the optic nerve and runs through its center, enters the eye through the porus opticus and branches to supply the retina.

Measurement of intracardiac blood flow using an M-mode and/or two-dimensional (2-D) echocardiogram while simultaneously recording the spectrum of the audible Doppler signal (e.g., velocity, direction, amplitude, intensity, timing) reflected from the moving column of red blood cells.

Use of reflected ultrasound in the diagnosis of intracranial pathologic processes.

The study of the deformation and flow of matter, usually liquids or fluids, and of the plastic flow of solids. The concept covers consistency, dilatancy, liquefaction, resistance to flow, shearing, thixotrophy, and VISCOSITY.

Specialized arterial vessels in the umbilical cord. They carry waste and deoxygenated blood from the FETUS to the mother via the PLACENTA. In humans, there are usually two umbilical arteries but sometimes one.

A pulmonary ventilation rate faster than is metabolically necessary for the exchange of gases. It is the result of an increased frequency of breathing, an increased tidal volume, or a combination of both. It causes an excess intake of oxygen and the blowing off of carbon dioxide.

The circulation of the BLOOD through the MICROVASCULAR NETWORK.

A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.

Post-systolic relaxation of the HEART, especially the HEART VENTRICLES.

The visualization of tissues during pregnancy through recording of the echoes of ultrasonic waves directed into the body. The procedure may be applied with reference to the mother or the fetus and with reference to organs or the detection of maternal or fetal disease.

Artery formed by the bifurcation of the internal carotid artery (CAROTID ARTERY, INTERNAL). Branches of the anterior cerebral artery supply the CAUDATE NUCLEUS; INTERNAL CAPSULE; PUTAMEN; SEPTAL NUCLEI; GYRUS CINGULI; and surfaces of the FRONTAL LOBE and PARIETAL LOBE.

The presence of an increased amount of blood in a body part or an organ leading to congestion or engorgement of blood vessels. Hyperemia can be due to increase of blood flow into the area (active or arterial), or due to obstruction of outflow of blood from the area (passive or venous).

The number of times the HEART VENTRICLES contract per unit of time, usually per minute.

The visualization of deep structures of the body by recording the reflections or echoes of ultrasonic pulses directed into the tissues. Use of ultrasound for imaging or diagnostic purposes employs frequencies ranging from 1.6 to 10 megahertz.

Theoretical representations that simulate the behavior or activity of the cardiovascular system, processes, or phenomena; includes the use of mathematical equations, computers and other electronic equipment.

The vessels carrying blood away from the heart.

The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.

Pressure within the cranial cavity. It is influenced by brain mass, the circulatory system, CSF dynamics, and skull rigidity.

Period of contraction of the HEART, especially of the HEART VENTRICLES.

The heart rate of the FETUS. The normal range at term is between 120 and 160 beats per minute.

The arterial trunk that arises from the abdominal aorta and after a short course divides into the left gastric, common hepatic and splenic arteries.

The veins and arteries of the HEART.

The processes whereby the internal environment of an organism tends to remain balanced and stable.

The physiological widening of BLOOD VESSELS by relaxing the underlying VASCULAR SMOOTH MUSCLE.

One of the CARBONIC ANHYDRASE INHIBITORS that is sometimes effective against absence seizures. It is sometimes useful also as an adjunct in the treatment of tonic-clonic, myoclonic, and atonic seizures, particularly in women whose seizures occur or are exacerbated at specific times in the menstrual cycle. However, its usefulness is transient often because of rapid development of tolerance. Its antiepileptic effect may be due to its inhibitory effect on brain carbonic anhydrase, which leads to an increased transneuronal chloride gradient, increased chloride current, and increased inhibition. (From Smith and Reynard, Textbook of Pharmacology, 1991, p337)

The age of the conceptus, beginning from the time of FERTILIZATION. In clinical obstetrics, the gestational age is often estimated as the time from the last day of the last MENSTRUATION which is about 2 weeks before OVULATION and fertilization.

Drugs used to cause dilation of the blood vessels.

The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)

Changes in the observed frequency of waves (as sound, light, or radio waves) due to the relative motion of source and observer. The effect was named for the 19th century Austrian physicist Johann Christian Doppler.

The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.

Elements of limited time intervals, contributing to particular results or situations.

An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.

A large vessel supplying the whole length of the small intestine except the superior part of the duodenum. It also supplies the cecum and the ascending part of the colon and about half the transverse part of the colon. It arises from the anterior surface of the aorta below the celiac artery at the level of the first lumbar vertebra.

The failure of a FETUS to attain its expected FETAL GROWTH at any GESTATIONAL AGE.

The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.

A polygonal anastomosis at the base of the brain formed by the internal carotid (CAROTID ARTERY, INTERNAL), proximal parts of the anterior, middle, and posterior cerebral arteries (ANTERIOR CEREBRAL ARTERY; MIDDLE CEREBRAL ARTERY; POSTERIOR CEREBRAL ARTERY), the anterior communicating artery and the posterior communicating arteries.

Echocardiography applying the Doppler effect, with the superposition of flow information as colors on a gray scale in a real-time image.

Branch of the common carotid artery which supplies the anterior part of the brain, the eye and its appendages, the forehead and nose.

The circulation of BLOOD, of both the mother and the FETUS, through the PLACENTA.

Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.

Maintenance of blood flow to an organ despite obstruction of a principal vessel. Blood flow is maintained through small vessels.

The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.

The deformation and flow behavior of BLOOD and its elements i.e., PLASMA; ERYTHROCYTES; WHITE BLOOD CELLS; and BLOOD PLATELETS.

A standard and widely accepted diagnostic test used to identify patients who have a vasodepressive and/or cardioinhibitory response as a cause of syncope. (From Braunwald, Heart Disease, 7th ed)

The heart of the fetus of any viviparous animal. It refers to the heart in the postembryonic period and is differentiated from the embryonic heart (HEART/embryology) only on the basis of time.

Artery formed by the bifurcation of the BASILAR ARTERY. Branches of the posterior cerebral artery supply portions of the OCCIPITAL LOBE; PARIETAL LOBE; inferior temporal gyrus, brainstem, and CHOROID PLEXUS.

The neural systems which act on VASCULAR SMOOTH MUSCLE to control blood vessel diameter. The major neural control is through the sympathetic nervous system.

A significant drop in BLOOD PRESSURE after assuming a standing position. Orthostatic hypotension is a finding, and defined as a 20-mm Hg decrease in systolic pressure or a 10-mm Hg decrease in diastolic pressure 3 minutes after the person has risen from supine to standing. Symptoms generally include DIZZINESS, blurred vision, and SYNCOPE.

Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic.

The circulation of blood through the BLOOD VESSELS supplying the abdominal VISCERA.

A clinical manifestation of abnormal increase in the amount of carbon dioxide in arterial blood.

Technique using an instrument system for making, processing, and displaying one or more measurements on individual cells obtained from a cell suspension. Cells are usually stained with one or more fluorescent dyes specific to cell components of interest, e.g., DNA, and fluorescence of each cell is measured as it rapidly transverses the excitation beam (laser or mercury arc lamp). Fluorescence provides a quantitative measure of various biochemical and biophysical properties of the cell, as well as a basis for cell sorting. Other measurable optical parameters include light absorption and light scattering, the latter being applicable to the measurement of cell size, shape, density, granularity, and stain uptake.

The internal resistance of the BLOOD to shear forces. The in vitro measure of whole blood viscosity is of limited clinical utility because it bears little relationship to the actual viscosity within the circulation, but an increase in the viscosity of circulating blood can contribute to morbidity in patients suffering from disorders such as SICKLE CELL ANEMIA and POLYCYTHEMIA.

The circulation of the BLOOD through the LUNGS.

Determination of the shortest time interval between the injection of a substance in the vein and its arrival at some distant site in sufficient concentration to produce a recognizable end result. It represents approximately the inverse of the average velocity of blood flow between two points.

The position or attitude of the body.

Volume of circulating BLOOD. It is the sum of the PLASMA VOLUME and ERYTHROCYTE VOLUME.

The pressure that would be exerted by one component of a mixture of gases if it were present alone in a container. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

An alkaloid found in opium but not closely related to the other opium alkaloids in its structure or pharmacological actions. It is a direct-acting smooth muscle relaxant used in the treatment of impotence and as a vasodilator, especially for cerebral vasodilation. The mechanism of its pharmacological actions is not clear, but it apparently can inhibit phosphodiesterases and it may have direct actions on calcium channels.

The blood vessels which supply and drain the RETINA.

The hollow thick-walled muscular organ in the female PELVIS. It consists of the fundus (the body) which is the site of EMBRYO IMPLANTATION and FETAL DEVELOPMENT. Beyond the isthmus at the perineal end of fundus, is CERVIX UTERI (the neck) opening into VAGINA. Beyond the isthmi at the upper abdominal end of fundus, are the FALLOPIAN TUBES.

Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues using a transducer placed in the esophagus.

The physiological narrowing of BLOOD VESSELS by contraction of the VASCULAR SMOOTH MUSCLE.

Echocardiography applying the Doppler effect, with velocity detection combined with range discrimination. Short bursts of ultrasound are transmitted at regular intervals and the echoes are demodulated as they return.

The volume of BLOOD passing through the HEART per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with STROKE VOLUME (volume per beat).

A nucleoside that is composed of ADENINE and D-RIBOSE. Adenosine or adenosine derivatives play many important biological roles in addition to being components of DNA and RNA. Adenosine itself is a neurotransmitter.

The circulation of the BLOOD through the vessels of the KIDNEY.

Either of the two principal arteries on both sides of the neck that supply blood to the head and neck; each divides into two branches, the internal carotid artery and the external carotid artery.

The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)

The valve between the left atrium and left ventricle of the heart.

The hemodynamic and electrophysiological action of the left HEART VENTRICLE. Its measurement is an important aspect of the clinical evaluation of patients with heart disease to determine the effects of the disease on cardiac performance.

Symptoms of cerebral hypoperfusion or autonomic overaction which develop while the subject is standing, but are relieved on recumbency. Types of this include NEUROCARDIOGENIC SYNCOPE; POSTURAL ORTHOSTATIC TACHYCARDIA SYNDROME; and neurogenic ORTHOSTATIC HYPOTENSION. (From Noseworthy, JH., Neurological Therapeutics Principles and Practice, 2007, p2575-2576)

An infant during the first month after birth.

Small uniformly-sized spherical particles, of micrometer dimensions, frequently labeled with radioisotopes or various reagents acting as tags or markers.

The unborn young of a viviparous mammal, in the postembryonic period, after the major structures have been outlined. In humans, the unborn young from the end of the eighth week after CONCEPTION until BIRTH, as distinguished from the earlier EMBRYO, MAMMALIAN.

A human infant born before 37 weeks of GESTATION.

The volume of packed RED BLOOD CELLS in a blood specimen. The volume is measured by centrifugation in a tube with graduated markings, or with automated blood cell counters. It is an indicator of erythrocyte status in disease. For example, ANEMIA shows a low value; POLYCYTHEMIA, a high value.

A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.

The movement of the BLOOD as it is pumped through the CARDIOVASCULAR SYSTEM.

Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)

A fetal blood vessel connecting the pulmonary artery with the descending aorta.

Unstable isotopes of xenon that decay or disintegrate emitting radiation. Xe atoms with atomic weights 121-123, 125, 127, 133, 135, 137-145 are radioactive xenon isotopes.

Recording of change in the size of a part as modified by the circulation in it.

The vessels carrying blood away from the capillary beds.

Ultrasonography applying the Doppler effect combined with real-time imaging. The real-time image is created by rapid movement of the ultrasound beam. A powerful advantage of this technique is the ability to estimate the velocity of flow from the Doppler shift frequency.

Radiography of the vascular system of the heart muscle after injection of a contrast medium.

The failure by the observer to measure or identify a phenomenon accurately, which results in an error. Sources for this may be due to the observer's missing an abnormality, or to faulty technique resulting in incorrect test measurement, or to misinterpretation of the data. Two varieties are inter-observer variation (the amount observers vary from one another when reporting on the same material) and intra-observer variation (the amount one observer varies between observations when reporting more than once on the same material).

Pathological processes which result in the partial or complete obstruction of ARTERIES. They are characterized by greatly reduced or absence of blood flow through these vessels. They are also known as arterial insufficiency.

The rhythmical expansion and contraction of an ARTERY produced by waves of pressure caused by the ejection of BLOOD from the left ventricle of the HEART as it contracts.

The hemodynamic and electrophysiological action of the LEFT ATRIUM.

The two principal arteries supplying the structures of the head and neck. They ascend in the neck, one on each side, and at the level of the upper border of the thyroid cartilage, each divides into two branches, the external (CAROTID ARTERY, EXTERNAL) and internal (CAROTID ARTERY, INTERNAL) carotid arteries.

In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.

Freedom from activity.

The artery formed by the union of the right and left vertebral arteries; it runs from the lower to the upper border of the pons, where it bifurcates into the two posterior cerebral arteries.

A spectrum of pathological conditions of impaired blood flow in the brain. They can involve vessels (ARTERIES or VEINS) in the CEREBRUM, the CEREBELLUM, and the BRAIN STEM. Major categories include INTRACRANIAL ARTERIOVENOUS MALFORMATIONS; BRAIN ISCHEMIA; CEREBRAL HEMORRHAGE; and others.

The posture of an individual lying face up.

The circulation of BLOOD through the LIVER.

Non-invasive method of vascular imaging and determination of internal anatomy without injection of contrast media or radiation exposure. The technique is used especially in CEREBRAL ANGIOGRAPHY as well as for studies of other vascular structures.

External decompression applied to the lower body. It is used to study orthostatic intolerance and the effects of gravitation and acceleration, to produce simulated hemorrhage in physiologic research, to assess cardiovascular function, and to reduce abdominal stress during childbirth.

An imbalance between myocardial functional requirements and the capacity of the CORONARY VESSELS to supply sufficient blood flow. It is a form of MYOCARDIAL ISCHEMIA (insufficient blood supply to the heart muscle) caused by a decreased capacity of the coronary vessels.

The innermost layer of the three meninges covering the brain and spinal cord. It is the fine vascular membrane that lies under the ARACHNOID and the DURA MATER.

A phosphodiesterase inhibitor that blocks uptake and metabolism of adenosine by erythrocytes and vascular endothelial cells. Dipyridamole also potentiates the antiaggregating action of prostacyclin. (From AMA Drug Evaluations Annual, 1994, p752)

Central retinal vein and its tributaries. It runs a short course within the optic nerve and then leaves and empties into the superior ophthalmic vein or cavernous sinus.

A branch of the abdominal aorta which supplies the kidneys, adrenal glands and ureters.

Forced expiratory effort against a closed GLOTTIS.

A volatile vasodilator which relieves ANGINA PECTORIS by stimulating GUANYLATE CYCLASE and lowering cytosolic calcium. It is also sometimes used for TOCOLYSIS and explosives.

The organ of sight constituting a pair of globular organs made up of a three-layered roughly spherical structure specialized for receiving and responding to light.

Narrowing or stricture of any part of the CAROTID ARTERIES, most often due to atherosclerotic plaque formation. Ulcerations may form in atherosclerotic plaques and induce THROMBUS formation. Platelet or cholesterol emboli may arise from stenotic carotid lesions and induce a TRANSIENT ISCHEMIC ATTACK; CEREBROVASCULAR ACCIDENT; or temporary blindness (AMAUROSIS FUGAX). (From Adams et al., Principles of Neurology, 6th ed, pp 822-3)

Manometric pressure of the CEREBROSPINAL FLUID as measured by lumbar, cerebroventricular, or cisternal puncture. Within the cranial cavity it is called INTRACRANIAL PRESSURE.

Pathophysiological conditions of the FETUS in the UTERUS. Some fetal diseases may be treated with FETAL THERAPIES.

Plethysmographic determination in which the intensity of light reflected from the skin surface and the red cells below is measured to determine the blood volume of the respective area. There are two types, transmission and reflectance.

The main artery of the thigh, a continuation of the external iliac artery.

The use of ultrasound to guide minimally invasive surgical procedures such as needle ASPIRATION BIOPSY; DRAINAGE; etc. Its widest application is intravascular ultrasound imaging but it is useful also in urology and intra-abdominal conditions.

Abnormally low BLOOD PRESSURE that can result in inadequate blood flow to the brain and other vital organs. Common symptom is DIZZINESS but greater negative impacts on the body occur when there is prolonged depravation of oxygen and nutrients.

Pathological conditions of intracranial ARTERIES supplying the CEREBRUM. These diseases often are due to abnormalities or pathological processes in the ANTERIOR CEREBRAL ARTERY; MIDDLE CEREBRAL ARTERY; and POSTERIOR CEREBRAL ARTERY.

A sympathomimetic agent with specificity for alpha-1 adrenergic receptors. It is used to maintain BLOOD PRESSURE in hypotensive states such as following SPINAL ANESTHESIA.

The hollow, muscular organ that maintains the circulation of the blood.

A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.

Relatively complete absence of oxygen in one or more tissues.

Analysis based on the mathematical function first formulated by Jean-Baptiste-Joseph Fourier in 1807. The function, known as the Fourier transform, describes the sinusoidal pattern of any fluctuating pattern in the physical world in terms of its amplitude and its phase. It has broad applications in biomedicine, e.g., analysis of the x-ray crystallography data pivotal in identifying the double helical nature of DNA and in analysis of other molecules, including viruses, and the modified back-projection algorithm universally used in computerized tomography imaging, etc. (From Segen, The Dictionary of Modern Medicine, 1992)

The first branch of the SUBCLAVIAN ARTERY with distribution to muscles of the NECK; VERTEBRAE; SPINAL CORD; CEREBELLUM; and interior of the CEREBRUM.

Procedures in which placement of CARDIAC CATHETERS is performed for therapeutic or diagnostic procedures.

A method of computed tomography that uses radionuclides which emit a single photon of a given energy. The camera is rotated 180 or 360 degrees around the patient to capture images at multiple positions along the arc. The computer is then used to reconstruct the transaxial, sagittal, and coronal images from the 3-dimensional distribution of radionuclides in the organ. The advantages of SPECT are that it can be used to observe biochemical and physiological processes as well as size and volume of the organ. The disadvantage is that, unlike positron-emission tomography where the positron-electron annihilation results in the emission of 2 photons at 180 degrees from each other, SPECT requires physical collimation to line up the photons, which results in the loss of many available photons and hence degrades the image.

Contractile activity of the MYOCARDIUM.

Benzenesulfonate derivative used as a systemic hemostatic.

The condition of an anatomical structure's being constricted beyond normal dimensions.

The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (= OXYGEN CONSUMPTION) or cell respiration (= CELL RESPIRATION).

The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs.

The middle third of a human PREGNANCY, from the beginning of the 15th through the 28th completed week (99 to 196 days) of gestation.

Measurement of oxygen and carbon dioxide in the blood.

The amount of BLOOD pumped out of the HEART per beat, not to be confused with cardiac output (volume/time). It is calculated as the difference between the end-diastolic volume and the end-systolic volume.

Anesthesia caused by the breathing of anesthetic gases or vapors or by insufflating anesthetic gases or vapors into the respiratory tract.

A subfield of acoustics dealing in the radio frequency range higher than acoustic SOUND waves (approximately above 20 kilohertz). Ultrasonic radiation is used therapeutically (DIATHERMY and ULTRASONIC THERAPY) to generate HEAT and to selectively destroy tissues. It is also used in diagnostics, for example, ULTRASONOGRAPHY; ECHOENCEPHALOGRAPHY; and ECHOCARDIOGRAPHY, to visually display echoes received from irradiated tissues.

Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.

Veins draining the cerebrum.

Localized reduction of blood flow to brain tissue due to arterial obstruction or systemic hypoperfusion. This frequently occurs in conjunction with brain hypoxia (HYPOXIA, BRAIN). Prolonged ischemia is associated with BRAIN INFARCTION.

The minute vessels that connect the arterioles and venules.

A noble gas with the atomic symbol Xe, atomic number 54, and atomic weight 131.30. It is found in the earth's atmosphere and has been used as an anesthetic.

Tomography using radioactive emissions from injected RADIONUCLIDES and computer ALGORITHMS to reconstruct an image.

Bleeding into the intracranial or spinal SUBARACHNOID SPACE, most resulting from INTRACRANIAL ANEURYSM rupture. It can occur after traumatic injuries (SUBARACHNOID HEMORRHAGE, TRAUMATIC). Clinical features include HEADACHE; NAUSEA; VOMITING, nuchal rigidity, variable neurological deficits and reduced mental status.

A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.

A stable, non-explosive inhalation anesthetic, relatively free from significant side effects.

Increased pressure within the cranial vault. This may result from several conditions, including HYDROCEPHALUS; BRAIN EDEMA; intracranial masses; severe systemic HYPERTENSION; PSEUDOTUMOR CEREBRI; and other disorders.

Posture while lying with the head lower than the rest of the body. Extended time in this position is associated with temporary physiologic disturbances.

Persons with no known significant health problems who are recruited to participate in research to test a new drug, device, or intervention as controls for a patient group. (from http://clinicalcenter.nih.gov/recruit/volunteers.html, accessed 2/14/2013)

A vertical distance measured from a known level on the surface of a planet or other celestial body.

The inferior part of the lower extremity between the KNEE and the ANKLE.

Constriction of arteries in the SKULL due to sudden, sharp, and often persistent smooth muscle contraction in blood vessels. Intracranial vasospasm results in reduced vessel lumen caliber, restricted blood flow to the brain, and BRAIN ISCHEMIA that may lead to hypoxic-ischemic brain injury (HYPOXIA-ISCHEMIA, BRAIN).

A powerful vasodilator used in emergencies to lower blood pressure or to improve cardiac function. It is also an indicator for free sulfhydryl groups in proteins.

A phenethylamine found in EPHEDRA SINICA. PSEUDOEPHEDRINE is an isomer. It is an alpha- and beta-adrenergic agonist that may also enhance release of norepinephrine. It has been used for asthma, heart failure, rhinitis, and urinary incontinence, and for its central nervous system stimulatory effects in the treatment of narcolepsy and depression. It has become less extensively used with the advent of more selective agonists.

The constant checking on the state or condition of a patient during the course of a surgical operation (e.g., checking of vital signs).

Substances used to allow enhanced visualization of tissues.

The continuation of the axillary artery; it branches into the radial and ulnar arteries.

The venous trunk which receives blood from the lower extremities and from the pelvic and abdominal organs.

Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.

The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.

A noninvasive technique that uses the differential absorption properties of hemoglobin and myoglobin to evaluate tissue oxygenation and indirectly can measure regional hemodynamics and blood flow. Near-infrared light (NIR) can propagate through tissues and at particular wavelengths is differentially absorbed by oxygenated vs. deoxygenated forms of hemoglobin and myoglobin. Illumination of intact tissue with NIR allows qualitative assessment of changes in the tissue concentration of these molecules. The analysis is also used to determine body composition.

The pressure of the fluids in the eye.

The excision of the thickened, atheromatous tunica intima of a carotid artery.

Loss of consciousness due to a reduction in blood pressure that is associated with an increase in vagal tone and peripheral vasodilation.

The period following a surgical operation.

The determination of oxygen-hemoglobin saturation of blood either by withdrawing a sample and passing it through a classical photoelectric oximeter or by electrodes attached to some translucent part of the body like finger, earlobe, or skin fold. It includes non-invasive oxygen monitoring by pulse oximetry.

The motion of fluids, especially noncompressible liquids, under the influence of internal and external forces.

Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.

Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components.

Nitrogen oxide (N2O). A colorless, odorless gas that is used as an anesthetic and analgesic. High concentrations cause a narcotic effect and may replace oxygen, causing death by asphyxia. It is also used as a food aerosol in the preparation of whipping cream.

The valve consisting of three cusps situated between the right atrium and right ventricle of the heart.

Narrowing or constriction of a coronary artery.

The condition of an anatomical structure's being dilated beyond normal dimensions.

Studies to determine the advantages or disadvantages, practicability, or capability of accomplishing a projected plan, study, or project.

The continuous measurement of physiological processes, blood pressure, heart rate, renal output, reflexes, respiration, etc., in a patient or experimental animal; includes pharmacologic monitoring, the measurement of administered drugs or their metabolites in the blood, tissues, or urine.

The main trunk of the systemic arteries.

Persistently high systemic arterial BLOOD PRESSURE. Based on multiple readings (BLOOD PRESSURE DETERMINATION), hypertension is currently defined as when SYSTOLIC PRESSURE is consistently greater than 140 mm Hg or when DIASTOLIC PRESSURE is consistently 90 mm Hg or more.

Statistical models in which the value of a parameter for a given value of a factor is assumed to be equal to a + bx, where a and b are constants. The models predict a linear regression.

Interruption of sympathetic pathways, by local injection of an anesthetic agent, at any of four levels: peripheral nerve block, sympathetic ganglion block, extradural block, and subarachnoid block.

A class of compounds that reduces the secretion of H+ ions by the proximal kidney tubule through inhibition of CARBONIC ANHYDRASES.

The thoracolumbar division of the autonomic nervous system. Sympathetic preganglionic fibers originate in neurons of the intermediolateral column of the spinal cord and project to the paravertebral and prevertebral ganglia, which in turn project to target organs. The sympathetic nervous system mediates the body's response to stressful situations, i.e., the fight or flight reactions. It often acts reciprocally to the parasympathetic system.

Dilation of an occluded coronary artery (or arteries) by means of a balloon catheter to restore myocardial blood supply.

A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.

Studies comparing two or more treatments or interventions in which the subjects or patients, upon completion of the course of one treatment, are switched to another. In the case of two treatments, A and B, half the subjects are randomly allocated to receive these in the order A, B and half to receive them in the order B, A. A criticism of this design is that effects of the first treatment may carry over into the period when the second is given. (Last, A Dictionary of Epidemiology, 2d ed)

Injections made into a vein for therapeutic or experimental purposes.

The veins that return the oxygenated blood from the lungs to the left atrium of the heart.

Radiography of the vascular system of the brain after injection of a contrast medium.

Physical activity which is usually regular and done with the intention of improving or maintaining PHYSICAL FITNESS or HEALTH. Contrast with PHYSICAL EXERTION which is concerned largely with the physiologic and metabolic response to energy expenditure.

The effect of cardiac contraction on collateral resistance in the canine heart. (1/7943)

We determined whether the coronary collateral vessels develop an increased resistance to blood flow during systole as does the cognate vascular bed. Collateral resistance was estimated by measuring retrograde flow rate from a distal branch of the left anterior descending coronary artery while the main left coronary artery was perfused at a constant pressure. Retrograde flow rate was measured before and during vagal arrest. We found that in 10 dogs the prolonged diastole experienced when the heart was stopped caused no significant change in the retrograde flow rate, which indicated that systole has little effect on the collateral resistance. However, when left ventricular end-diastolic pressure was altered by changing afterload or contractility, a direct relationship between end-diastolic pressure and collateral resistance was noted. (+info)

Investigation of the theory and mechanism of the origin of the second heart sound. (2/7943)

To investigate further the origin of the second heart sound we studied human subjects, dogs, and a model in vitro of the cardiovascular system. Intra-arterial sound, pressure, and, where possible, flow and high speed cine (2,000 frames/sec) were utilized. The closure sound of the semilunar valves was of higher amplitude in be ventricles than in their respective arterial cavities. The direction of inscription of the main components of intra-arterial sound were opposite in direction to the components of intraventricular sound. Notches, representative of pressure increments, were noted on the ventricular pressure tracings and were coincident with the components of sound. The amplitude of the closure sound varied with diastolic pressure, but remained unchanged with augmentation of forward and retrograde aortic flow. Cines showed second sound to begin after complete valvular closure, and average leaflet closure rate was constant regardless of pressure. Hence, the semilunar valves, when closed, act as an elastic membrane and, when set into motion, generate compression and expansion of the blood, producing transient pressure changes indicative of sound. The magnitude of the initial stretch is related to the differential pressure between the arterial and ventricular chambers. Sound transients which follow the major components of the second sound appear to be caused by the continuing stretch and recoil of the leaflets. Clinically unexplained findings such as the reduced or absent second sound in calcific aortic stenosis and its paradoxical presence in congenital aortic stenosis may be explained by those observations. (+info)

Flow-mediated vasodilation and distensibility of the brachial artery in renal allograft recipients. (3/7943)

BACKGROUND: Alterations of large artery function and structure are frequently observed in renal allograft recipients. However, endothelial function has not yet been assessed in this population. METHODS: Flow-mediated vasodilation is a useful index of endothelial function. We measured the diameter and distensibility of the brachial artery at rest using high-resolution ultrasound and Doppler frequency analysis of vessel wall movements in the M mode. Thereafter, changes in brachial artery diameter were measured during reactive hyperemia (after 4 min of forearm occlusion) in 16 cyclosporine-treated renal allograft recipients and 16 normal controls of similar age and sex ratio. Nitroglycerin-mediated vasodilation was measured to assess endothelium-independent vasodilation. Brachial artery blood pressure was measured using an automatic sphygmomanometer, and brachial artery flow was estimated using pulsed Doppler. RESULTS: Distensibility was reduced in renal allograft recipients (5.31 +/- 0. 74 vs. 9.10 +/- 0.94 x 10-3/kPa, P = 0.003, mean +/- sem), while the brachial artery diameter at rest was higher (4.13 +/- 0.14 vs. 3.25 +/- 0.14 mm, P < 0.001). Flow-mediated vasodilation was significantly reduced in renal allograft recipients (0.13 +/- 0.08 vs. 0.60 +/- 0.08 mm or 3 +/- 2 vs. 19 +/- 3%, both P < 0.001). However, nitroglycerin-mediated vasodilation was similar in renal allograft recipients and controls (0.76 +/- 0.10 vs. 0.77 +/- 0.09 mm, NS, or 19 +/- 3 vs. 22 +/- 2%, NS). There were no significant differences in brachial artery flow at rest and during reactive hyperemia between both groups. The impairments of flow-mediated vasodilation and distensibility in renal allograft recipients remained significant after correction for serum cholesterol, creatinine, parathyroid hormone concentrations, end-diastolic diameter, as well as blood pressure levels, and were also present in eight renal allograft recipients not treated with cyclosporine. Flow-mediated vasodilation was not related to distensibility in either group. CONCLUSIONS: The results show impaired endothelial function and reduced brachial artery distensibility in renal allograft recipients. The impairments of flow-mediated vasodilation and distensibility are not attributable to a diminished brachial artery vasodilator capacity, because endothelium-independent vasodilation was preserved in renal allograft recipients. (+info)

Profile of neurohumoral agents on mesenteric and intestinal blood flow in health and disease. (4/7943)

The mesenteric and intestinal blood flow is organized and regulated to support normal intestinal function, and the regulation of blood flow is, in part, determined by intestinal function itself. In the process of the development and adaptation of the intestinal mucosa for the support of the digestive processes and host defense mechanisms, and the muscle layers for propulsion of foodstuffs, a specialized microvascular architecture has evolved in each tissue layer. Compromised mesenteric and intestinal blood flow, which can be common in the elderly, may lead to devastating clinical consequences. This problem, which can be caused by vasospasm at the microvascular level, can cause intestinal ischaemia to any of the layers of the intestinal wall, and can initiate pathological events which promote significant clinical consequences such as diarrhea, abdominal angina and intestinal infarction. The objective of this review is to provide the reader with some general concepts of the mechanisms by which neurohumoral vasoactive substances influence mesenteric and intestinal arterial blood flow in health and disease with focus on transmural transport processes (absorption and secretion). The complex regulatory mechanisms of extrinsic (sympathetic-parasympathetic and endocrine) and intrinsic (enteric nervous system and humoral endocrine) components are presented. More extensive reviews of platelet function, atherosclerosis, hypertension, diabetes mellitus, the carcinoid syndrome, 5-hydroxytryptamine and nitric oxide regulation of vascular tone are presented in this context. The possible options of pharmacological intervention (e.g. vasodilator agonists and vasoconstrictor antagonists) used for the treatment of abnormal mesenteric and intestinal vascular states are also discussed. (+info)

Venous ulceration and continuous flow in the long saphenous vein. (5/7943)

OBJECTIVE: To determine the clinical significance of continuous flow in the long saphenous vein in limbs with venous ulceration. DESIGN: Retrospective review. PATIENTS AND METHODS: Review of 1608 consecutive limbs undergoing colour duplex scanning for venous disease over a 43 month period. RESULTS: Continuous flow in the long saphenous vein is seen in 8% of limbs with venous ulceration and in 37% of limbs with deep venous obstruction. Sixty-six per cent of ulcerated limbs with continuous flow in the long saphenous vein had deep venous obstruction, 27% had deep venous reflux with cellulitis and 7% had lymphoedema in addition to venous ulceration. CONCLUSION: Continuous flow in the long saphenous vein in patients with venous ulceration should alert the clinician to the possibility of deep venous obstruction. Such limbs should be treated by compression bandaging with extreme caution. (+info)

Brightness alters Heidelberg retinal flowmeter measurements in an in vitro model. (6/7943)

PURPOSE: The Heidelberg Retinal Flowmeter (HRF), a laser Doppler flowmetry device, has captured interest as a research and clinical tool for measurement of ocular blood flow. Concerns remain about the range and accuracy of the values that it reports. METHODS: An in vitro blood-flow model was constructed to provide well-controlled laminar flow through a glass capillary for assessment by HRF. A change in material behind the glass capillary was used to simulate changing brightness conditions between eyes. RESULTS: Velocities reported by the HRF correlated linearly to true velocities below 8.8 mm/sec. Beyond 8.8 mm/sec, HRF readings fluctuated randomly. True velocity and HRF reported velocities were highly correlated, with r = 0.967 (P < 0.001) from 0.0 mm/sec to 2.7 mm/sec mean velocity using a light background, and r = 0.900 (P < 0.001) from 2.7 mm/sec to 8.8 mm/sec using a darker background. However, a large change in the y-intercept occurred in the calibration curve with the background change. CONCLUSIONS: The HRF may report velocities inaccurately because of varying brightness in the fundus. In the present experiment, a darker background produced an overreporting of velocities. An offset, possibly introduced by a noise correction routine, apparently contributed to the inaccuracies of the HRF measurements. Such offsets vary with local and global brightness. Therefore, HRF measurements may be error prone when comparing eyes. When used to track perfusion in a single eye over time, meaningful comparison may be possible if meticulous care is taken to align vessels and intensity controls to achieve a similar level of noise correction between measurements. (+info)

Analysis of blood flow in the long posterior ciliary artery of the cat. (7/7943)

PURPOSE: Experiments were undertaken to use a new technique for direct on-line measurement of blood flow in the long posterior ciliary artery (LPCA) in cats and to evaluate possible physiological mechanisms controlling blood flow in the vascular beds perfused by this artery. METHODS: Blood flow in the temporal LPCA was measured on a continuous basis using ultrasonic flowmetry in anesthetized cats. Effects of acute sectioning of the sympathetic nerve and changes in LPCA and cerebral blood flows in response to altered levels of inspired CO2 and O2 were tested in some animals. In others, the presence of vascular autoregulatory mechanisms in response to stepwise elevations of intraocular pressure was studied. RESULTS: Blood flow in the temporal LPCA averaged 0.58+/-0.03 ml/min in 45 cats anesthetized with pentobarbital. Basal LPCA blood flow was not altered by acute sectioning of the sympathetic nerve or by changes in low levels of inspired CO2 and O2, although 10% CO2 caused a modest increase. Stepwise elevations of intraocular pressure resulted in comparable stepwise decreases of LPCA blood flow, with perfusion pressure declining in a linear manner throughout the perfusion-pressure range. CONCLUSIONS: Ultrasonic flowmetry seems to be a useful tool for continuous on-line measurement of LPCA blood flow in the cat eye. Blood flow to vascular beds perfused by this artery does not seem to be under sympathetic neural control and is refractory to modest alterations of blood gas levels of CO2 and O2. Blood vessels perfused by the LPCA show no clear autoregulatory mechanisms. (+info)

Demonstration of rapid onset vascular endothelial dysfunction after hyperhomocysteinemia: an effect reversible with vitamin C therapy. (8/7943)

BACKGROUND: Hyperhomocysteinemia is a major and independent risk factor for vascular disease. The mechanisms by which homocysteine promotes atherosclerosis are not well understood. We hypothesized that elevated homocysteine concentrations are associated with rapid onset endothelial dysfunction, which is mediated through oxidant stress mechanisms and can be inhibited by the antioxidant vitamin C. METHODS AND RESULTS: We studied 17 healthy volunteers (10 male and 7 female) aged 33 (range 21 to 59) years. Brachial artery diameter responses to hyperemic flow (endothelium dependent), and glyceryltrinitrate (GTN, endothelium independent) were measured with high resolution ultrasound at 0 hours (fasting), 2 hours, and 4 hours after (1) oral methionine (L-methionine 100 mg/kg), (2) oral methionine preceded by vitamin C (1g/day, for 1 week), and (3) placebo, on separate days and in random order. Plasma homocysteine increased (0 hours, 12.8+/-1.4; 2 hours, 25.4+/-2.5; and 4 hours, 31. 2+/-3.1 micromol/l, P<0.001), and flow-mediated dilatation fell (0 hours, 4.3+/-0.7; 2 hours, 1.1+/-0.9; and 4 hours, -0.7+/-0.8%) after oral L-methionine. There was an inverse linear relationship between homocysteine concentration and flow-mediated dilatation (P<0. 001). Pretreatment with vitamin C did not affect the rise in homocysteine concentrations after methionine (0 hours, 13.6+/-1.6; 2 hours, 28.3+/-2.9; and 4 hours, 33.8+/-3.7 micromol/l, P=0.27), but did ameliorate the reduction in flow-mediated dilatation (0 hours, 4. 0+/-1.0; 2 hours, 3.5+/-1.2 and 4 hours, 2.8+/-0.7%, P=0.02). GTN-induced endothelium independent brachial artery dilatation was not affected after methionine or methionine preceded by vitamin C. CONCLUSIONS: We conclude that an elevation in homocysteine concentration is associated with an acute impairment of vascular endothelial function that can be prevented by pretreatment with vitamin C in healthy subjects. Our results support the hypothesis that the adverse effects of homocysteine on vascular endothelial cells are mediated through oxidative stress mechanisms. (+info)

When the body's CO2 levels are too low, it can cause a range of symptoms including:

1. Dizziness and lightheadedness
2. Headaches
3. Fatigue and weakness
4. Confusion and disorientation
5. Numbness or tingling in the hands and feet
6. Muscle twitching
7. Irritability and anxiety
8. Increased heart rate and blood pressure
9. Sleep disturbances
10. Decreased mental performance and concentration

Hypocapnia can be diagnosed through a series of tests, including blood gas analysis, electroencephalography (EEG), and imaging studies such as computed tomography (CT) or magnetic resonance imaging (MRI). Treatment options vary depending on the underlying cause of hypocapnia, but may include breathing exercises, oxygen therapy, medication, and addressing any underlying conditions.

In severe cases, hypocapnia can lead to seizures, coma, and even death. Therefore, it is important to seek medical attention if symptoms persist or worsen over time.

There are several potential causes of hyperventilation, including anxiety, panic attacks, and certain medical conditions such as asthma or chronic obstructive pulmonary disease (COPD). Treatment for hyperventilation typically involves slowing down the breathing rate and restoring the body's natural balance of oxygen and carbon dioxide levels.

Some common signs and symptoms of hyperventilation include:

* Rapid breathing
* Deep breathing
* Dizziness or lightheadedness
* Chest pain or tightness
* Shortness of breath
* Confusion or disorientation
* Nausea or vomiting

If you suspect that someone is experiencing hyperventilation, it is important to seek medical attention immediately. Treatment may involve the following:

1. Oxygen therapy: Providing extra oxygen to help restore normal oxygen levels in the body.
2. Breathing exercises: Teaching the individual deep, slow breathing exercises to help regulate their breathing pattern.
3. Relaxation techniques: Encouraging the individual to relax and reduce stress, which can help slow down their breathing rate.
4. Medications: In severe cases, medications such as sedatives or anti-anxiety drugs may be prescribed to help calm the individual and regulate their breathing.
5. Ventilation support: In severe cases of hyperventilation, mechanical ventilation may be necessary to support the individual's breathing.

It is important to seek medical attention if you or someone you know is experiencing symptoms of hyperventilation, as it can lead to more serious complications such as respiratory failure or cardiac arrest if left untreated.

In some cases, hyperemia can be a sign of a more serious underlying condition that requires medical attention. For example, if hyperemia is caused by an inflammatory or infectious process, it may lead to tissue damage or organ dysfunction if left untreated.

Hyperemia can occur in various parts of the body, including the skin, muscles, organs, and other tissues. It is often diagnosed through physical examination and imaging tests such as ultrasound, computed tomography (CT), or magnetic resonance imaging (MRI). Treatment for hyperemia depends on its underlying cause, and may include antibiotics, anti-inflammatory medications, or surgery.

In the context of dermatology, hyperemia is often used to describe a condition called erythema, which is characterized by redness and swelling of the skin due to increased blood flow. Erythema can be caused by various factors, such as sun exposure, allergic reactions, or skin infections. Treatment for erythema may include topical medications, oral medications, or other therapies depending on its underlying cause.

There are several possible causes of orthostatic hypotension, including:

1. Deconditioning: This is a common cause of orthostatic hypotension in older adults who have been bedridden or hospitalized for prolonged periods.
2. Medication side effects: Certain medications, such as beta blockers and vasodilators, can cause orthostatic hypotension as a side effect.
3. Heart conditions: Conditions such as heart failure, arrhythmias, and structural heart defects can lead to orthostatic hypotension.
4. Neurological disorders: Certain neurological disorders, such as Parkinson's disease, multiple sclerosis, and stroke, can cause orthostatic hypotension.
5. Vasomotor instability: This is a condition where the blood vessels constrict or dilate rapidly, leading to a drop in blood pressure.
6. Anemia: A low red blood cell count can lead to a decrease in oxygen delivery to the body's tissues, causing orthostatic hypotension.
7. Dehydration: Dehydration can cause a drop in blood volume and lead to orthostatic hypotension.
8. Hypovolemia: This is a condition where there is a low volume of blood in the body, leading to a drop in blood pressure.
9. Sepsis: Sepsis can cause vasodilation and lead to orthostatic hypotension.
10. Other causes: Other causes of orthostatic hypotension include adrenal insufficiency, thyroid disorders, and certain genetic conditions.

Symptoms of orthostatic hypotension may include:

* Dizziness or lightheadedness
* Fainting
* Blurred vision
* Nausea and vomiting
* Headaches
* Fatigue
* Weakness
* Confusion

If you experience any of these symptoms, it is important to seek medical attention as soon as possible. Your healthcare provider can perform a physical examination and order diagnostic tests to determine the underlying cause of your orthostatic hypotension. Treatment will depend on the specific cause, but may include medications to raise blood pressure, fluid replacement, and addressing any underlying conditions.

Hypercapnia is a medical condition where there is an excessive amount of carbon dioxide (CO2) in the bloodstream. This can occur due to various reasons such as:

1. Respiratory failure: When the lungs are unable to remove enough CO2 from the body, leading to an accumulation of CO2 in the bloodstream.
2. Lung disease: Certain lung diseases such as chronic obstructive pulmonary disease (COPD) or pneumonia can cause hypercapnia by reducing the ability of the lungs to exchange gases.
3. Medication use: Certain medications, such as anesthetics and sedatives, can slow down breathing and lead to hypercapnia.

The symptoms of hypercapnia can vary depending on the severity of the condition, but may include:

1. Headaches
2. Dizziness
3. Confusion
4. Shortness of breath
5. Fatigue
6. Sleep disturbances

If left untreated, hypercapnia can lead to more severe complications such as:

1. Respiratory acidosis: When the body produces too much acid, leading to a drop in blood pH.
2. Cardiac arrhythmias: Abnormal heart rhythms can occur due to the increased CO2 levels in the bloodstream.
3. Seizures: In severe cases of hypercapnia, seizures can occur due to the changes in brain chemistry caused by the excessive CO2.

Treatment for hypercapnia typically involves addressing the underlying cause and managing symptoms through respiratory support and other therapies as needed. This may include:

1. Oxygen therapy: Administering oxygen through a mask or nasal tubes to help increase oxygen levels in the bloodstream and reduce CO2 levels.
2. Ventilation assistance: Using a machine to assist with breathing, such as a ventilator, to help remove excess CO2 from the lungs.
3. Carbon dioxide removal: Using a device to remove CO2 from the bloodstream, such as a dialysis machine.
4. Medication management: Adjusting medications that may be contributing to hypercapnia, such as anesthetics or sedatives.
5. Respiratory therapy: Providing breathing exercises and other techniques to help improve lung function and reduce symptoms.

It is important to seek medical attention if you suspect you or someone else may have hypercapnia, as early diagnosis and treatment can help prevent complications and improve outcomes.

In individuals with orthostatic intolerance, the body has difficulty adjusting to the change in position from lying down or sitting to standing, leading to a sudden drop in blood pressure and heart rate. This can cause symptoms such as dizziness, lightheadedness, fainting, and fatigue.

Orthostatic intolerance can be caused by a variety of factors, including dehydration, hypovolemia (low blood volume), certain medications, and medical conditions such as heart failure, anemia, and adrenal insufficiency. Treatment for orthostatic intolerance typically involves addressing the underlying cause, increasing fluid and electrolyte intake, and in some cases, medication to help regulate blood pressure and heart rate.

In summary, orthostatic intolerance is a condition where an individual experiences symptoms due to their body's inability to maintain stable blood pressure and heart rate when changing positions. It can be caused by various factors and treated with addressing the underlying cause, fluid and electrolyte replacement, and medication if necessary.

Types of Arterial Occlusive Diseases:

1. Atherosclerosis: Atherosclerosis is a condition where plaque builds up inside the arteries, leading to narrowing or blockages that can restrict blood flow to certain areas of the body.
2. Peripheral Artery Disease (PAD): PAD is a condition where the blood vessels in the legs and arms become narrowed or blocked, leading to pain or cramping in the affected limbs.
3. Coronary Artery Disease (CAD): CAD is a condition where the coronary arteries, which supply blood to the heart, become narrowed or blocked, leading to chest pain or a heart attack.
4. Carotid Artery Disease: Carotid artery disease is a condition where the carotid arteries, which supply blood to the brain, become narrowed or blocked, leading to stroke or mini-stroke.
5. Renal Artery Stenosis: Renal artery stenosis is a condition where the blood vessels that supply the kidneys become narrowed or blocked, leading to high blood pressure and decreased kidney function.

Symptoms of Arterial Occlusive Diseases:

1. Pain or cramping in the affected limbs
2. Weakness or fatigue
3. Difficulty walking or standing
4. Chest pain or discomfort
5. Shortness of breath
6. Dizziness or lightheadedness
7. Stroke or mini-stroke

Treatment for Arterial Occlusive Diseases:

1. Medications: Medications such as blood thinners, cholesterol-lowering drugs, and blood pressure medications may be prescribed to treat arterial occlusive diseases.
2. Lifestyle Changes: Lifestyle changes such as quitting smoking, exercising regularly, and eating a healthy diet can help manage symptoms and slow the progression of the disease.
3. Endovascular Procedures: Endovascular procedures such as angioplasty and stenting may be performed to open up narrowed or blocked blood vessels.
4. Surgery: In some cases, surgery may be necessary to treat arterial occlusive diseases, such as bypass surgery or carotid endarterectomy.

Prevention of Arterial Occlusive Diseases:

1. Maintain a healthy diet and lifestyle
2. Quit smoking and avoid exposure to secondhand smoke
3. Exercise regularly
4. Manage high blood pressure, high cholesterol, and diabetes
5. Avoid excessive alcohol consumption
6. Get regular check-ups with your healthcare provider

Early detection and treatment of arterial occlusive diseases can help manage symptoms, slow the progression of the disease, and prevent complications such as heart attack or stroke.

1. Stroke: A stroke occurs when the blood supply to the brain is interrupted, either due to a blockage or a rupture of the blood vessels. This can lead to cell death and permanent brain damage.
2. Cerebral vasospasm: Vasospasm is a temporary constriction of the blood vessels in the brain, which can occur after a subarachnoid hemorrhage (bleeding in the space surrounding the brain).
3. Moyamoya disease: This is a rare condition caused by narrowing or blockage of the internal carotid artery and its branches. It can lead to recurrent transient ischemic attacks (TIs) or stroke.
4. Cerebral amyloid angiopathy: This is a condition where abnormal protein deposits accumulate in the blood vessels of the brain, leading to inflammation and bleeding.
5. Cavernous malformations: These are abnormal collections of blood vessels in the brain that can cause seizures, headaches, and other symptoms.
6. Carotid artery disease: Atherosclerosis (hardening) of the carotid arteries can lead to a stroke or TIAs.
7. Vertebrobasilar insufficiency: This is a condition where the blood flow to the brain is reduced due to narrowing or blockage of the vertebral and basilar arteries.
8. Temporal lobe dementia: This is a type of dementia that affects the temporal lobe of the brain, leading to memory loss and other cognitive symptoms.
9. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL): This is a rare genetic disorder that affects the blood vessels in the brain, leading to recurrent stroke-like events.
10. Moyamoya disease: This is a rare condition caused by narrowing or blockage of the internal carotid artery and its branches, leading to decreased blood flow to the brain and increased risk of stroke.

It's important to note that this list is not exhaustive and there may be other causes of stroke and TIAs that are not included here. A proper diagnosis can only be made by a qualified medical professional after conducting a thorough examination and reviewing the individual's medical history.

Coronary disease is often caused by a combination of genetic and lifestyle factors, such as high blood pressure, high cholesterol levels, smoking, obesity, and a lack of physical activity. It can also be triggered by other medical conditions, such as diabetes and kidney disease.

The symptoms of coronary disease can vary depending on the severity of the condition, but may include:

* Chest pain or discomfort (angina)
* Shortness of breath
* Fatigue
* Swelling of the legs and feet
* Pain in the arms and back

Coronary disease is typically diagnosed through a combination of physical examination, medical history, and diagnostic tests such as electrocardiograms (ECGs), stress tests, and cardiac imaging. Treatment for coronary disease may include lifestyle changes, medications to control symptoms, and surgical procedures such as angioplasty or bypass surgery to improve blood flow to the heart.

Preventative measures for coronary disease include:

* Maintaining a healthy diet and exercise routine
* Quitting smoking and limiting alcohol consumption
* Managing high blood pressure, high cholesterol levels, and other underlying medical conditions
* Reducing stress through relaxation techniques or therapy.

There are two main types of carotid stenosis:

1. Internal carotid artery stenosis: This type of stenosis occurs when the internal carotid artery, which supplies blood to the brain, becomes narrowed or blocked.
2. Common carotid artery stenosis: This type of stenosis occurs when the common carotid artery, which supplies blood to the head and neck, becomes narrowed or blocked.

The symptoms of carotid stenosis can vary depending on the severity of the blockage and the extent of the affected area. Some common symptoms include:

* Dizziness or lightheadedness
* Vertigo (a feeling of spinning)
* Blurred vision or double vision
* Memory loss or confusion
* Slurred speech
* Weakness or numbness in the face, arm, or leg on one side of the body

If left untreated, carotid stenosis can lead to a stroke or other serious complications. Treatment options for carotid stenosis include medications to lower cholesterol and blood pressure, as well as surgical procedures such as endarterectomy (removing plaque from the artery) or stenting (placing a small mesh tube in the artery to keep it open).

In conclusion, carotid stenosis is a serious medical condition that can lead to stroke and other complications if left untreated. It is important to seek medical attention if symptoms persist or worsen over time.

Examples of fetal diseases include:

1. Down syndrome: A genetic disorder caused by an extra copy of chromosome 21, which can cause delays in physical and intellectual development, as well as increased risk of heart defects and other health problems.
2. Spina bifida: A birth defect that affects the development of the spine and brain, resulting in a range of symptoms from mild to severe.
3. Cystic fibrosis: A genetic disorder that affects the respiratory and digestive systems, causing thick mucus buildup and recurring lung infections.
4. Anencephaly: A condition where a portion of the brain and skull are missing, which is usually fatal within a few days or weeks of birth.
5. Clubfoot: A deformity of the foot and ankle that can be treated with casts or surgery.
6. Hirschsprung's disease: A condition where the nerve cells that control bowel movements are missing, leading to constipation and other symptoms.
7. Diaphragmatic hernia: A birth defect that occurs when there is a hole in the diaphragm, allowing organs from the abdomen to move into the chest cavity.
8. Gastroschisis: A birth defect where the intestines protrude through a opening in the abdominal wall.
9. Congenital heart disease: Heart defects that are present at birth, such as holes in the heart or narrowed blood vessels.
10. Neural tube defects: Defects that affect the brain and spine, such as spina bifida and anencephaly.

Early detection and diagnosis of fetal diseases can be crucial for ensuring proper medical care and improving outcomes for affected babies. Prenatal testing, such as ultrasound and blood tests, can help identify fetal anomalies and genetic disorders during pregnancy.

There are several causes of hypotension, including:

1. Dehydration: Loss of fluids and electrolytes can cause a drop in blood pressure.
2. Blood loss: Losing too much blood can lead to hypotension.
3. Medications: Certain medications, such as diuretics and beta-blockers, can lower blood pressure.
4. Heart conditions: Heart failure, cardiac tamponade, and arrhythmias can all cause hypotension.
5. Endocrine disorders: Hypothyroidism (underactive thyroid) and adrenal insufficiency can cause low blood pressure.
6. Vasodilation: A condition where the blood vessels are dilated, leading to low blood pressure.
7. Sepsis: Severe infection can cause hypotension.

Symptoms of hypotension can include:

1. Dizziness and lightheadedness
2. Fainting or passing out
3. Weakness and fatigue
4. Confusion and disorientation
5. Pale, cool, or clammy skin
6. Fast or weak pulse
7. Shortness of breath
8. Nausea and vomiting

If you suspect that you or someone else is experiencing hypotension, it is important to seek medical attention immediately. Treatment will depend on the underlying cause of the condition, but may include fluids, electrolytes, and medication to raise blood pressure. In severe cases, hospitalization may be necessary.

Types of cerebral arterial diseases include:

1. Cerebral vasospasm: A temporary constriction of the blood vessels in the brain, often seen after subarachnoid hemorrhage (bleeding in the space surrounding the brain).
2. Moyamoya disease: A rare condition caused by narrowing or blockage of the internal carotid artery and its branches, leading to decreased blood flow to the brain.
3. Cerebral amyloid angiopathy: A condition in which abnormal protein deposits accumulate in the walls of blood vessels supplying the brain, leading to inflammation and damage.
4. Cerebral infarction (stroke): The loss of brain tissue due to reduced blood flow or a blockage in an artery supplying the brain.
5. Cerebral hemorrhage: Bleeding in the brain, often due to rupture of a blood vessel or aneurysm.

Symptoms of cerebral arterial diseases can vary depending on the location and severity of the affected blood vessels, but may include headache, confusion, weakness or numbness in the face or limbs, difficulty speaking or understanding speech, and vision problems.

Diagnosis of cerebral arterial diseases typically involves a combination of physical examination, medical history, neuroimaging studies (such as CT or MRI scans), and angiography (a test that uses dye and X-rays to visualize the blood vessels in the brain).

Treatment options for cerebral arterial diseases depend on the underlying cause and severity of the condition, but may include medications to control blood pressure, cholesterol levels, or inflammation, as well as surgical interventions such as endarterectomy (removing plaque from the affected blood vessel) or aneurysm repair. In some cases, cerebral arterial diseases may be treated with a combination of medical and surgical therapies.

Complications of cerebral arterial diseases can include stroke, seizures, and cognitive decline. With prompt and appropriate treatment, however, many individuals with cerebral arterial diseases can experience significant improvement in symptoms and quality of life.

There are different types of anoxia, including:

1. Cerebral anoxia: This occurs when the brain does not receive enough oxygen, leading to cognitive impairment, confusion, and loss of consciousness.
2. Pulmonary anoxia: This occurs when the lungs do not receive enough oxygen, leading to shortness of breath, coughing, and chest pain.
3. Cardiac anoxia: This occurs when the heart does not receive enough oxygen, leading to cardiac arrest and potentially death.
4. Global anoxia: This is a complete lack of oxygen to the entire body, leading to widespread tissue damage and death.

Treatment for anoxia depends on the underlying cause and the severity of the condition. In some cases, hospitalization may be necessary to provide oxygen therapy, pain management, and other supportive care. In severe cases, anoxia can lead to long-term disability or death.

Prevention of anoxia is important, and this includes managing underlying medical conditions such as heart disease, diabetes, and respiratory problems. It also involves avoiding activities that can lead to oxygen deprivation, such as scuba diving or high-altitude climbing, without proper training and equipment.

In summary, anoxia is a serious medical condition that occurs when there is a lack of oxygen in the body or specific tissues or organs. It can cause cell death and tissue damage, leading to serious health complications and even death if left untreated. Early diagnosis and treatment are crucial to prevent long-term disability or death.

Some examples of pathologic constrictions include:

1. Stenosis: A narrowing or constriction of a blood vessel or other tubular structure, often caused by the buildup of plaque or scar tissue.
2. Asthma: A condition characterized by inflammation and constriction of the airways, which can make breathing difficult.
3. Esophageal stricture: A narrowing of the esophagus that can cause difficulty swallowing.
4. Gastric ring constriction: A narrowing of the stomach caused by a band of tissue that forms in the upper part of the stomach.
5. Anal fissure: A tear in the lining of the anus that can cause pain and difficulty passing stools.

Pathologic constrictions can be caused by a variety of factors, including inflammation, infection, injury, or genetic disorders. They can be diagnosed through imaging tests such as X-rays, CT scans, or endoscopies, and may require surgical treatment to relieve symptoms and improve function.

The term ischemia refers to the reduction of blood flow, and it is often used interchangeably with the term stroke. However, not all strokes are caused by ischemia, as some can be caused by other factors such as bleeding in the brain. Ischemic stroke accounts for about 87% of all strokes.

There are different types of brain ischemia, including:

1. Cerebral ischemia: This refers to the reduction of blood flow to the cerebrum, which is the largest part of the brain and responsible for higher cognitive functions such as thought, emotion, and voluntary movement.
2. Cerebellar ischemia: This refers to the reduction of blood flow to the cerebellum, which is responsible for coordinating and regulating movement, balance, and posture.
3. Brainstem ischemia: This refers to the reduction of blood flow to the brainstem, which is responsible for controlling many of the body's automatic functions such as breathing, heart rate, and blood pressure.
4. Territorial ischemia: This refers to the reduction of blood flow to a specific area of the brain, often caused by a blockage in a blood vessel.
5. Global ischemia: This refers to the reduction of blood flow to the entire brain, which can be caused by a cardiac arrest or other systemic conditions.

The symptoms of brain ischemia can vary depending on the location and severity of the condition, but may include:

1. Weakness or paralysis of the face, arm, or leg on one side of the body
2. Difficulty speaking or understanding speech
3. Sudden vision loss or double vision
4. Dizziness or loss of balance
5. Confusion or difficulty with memory
6. Seizures
7. Slurred speech or inability to speak
8. Numbness or tingling sensations in the face, arm, or leg
9. Vision changes, such as blurred vision or loss of peripheral vision
10. Difficulty with coordination and balance.

It is important to seek medical attention immediately if you experience any of these symptoms, as brain ischemia can cause permanent damage or death if left untreated.

Symptoms of intracranial hypertension can include headache, nausea and vomiting, confusion, seizures, and loss of consciousness. Treatment options depend on the underlying cause, but may include medications to reduce pressure, draining excess CSF, or surgery to relieve obstruction.

Intracranial hypertension can be life-threatening if left untreated, as it can lead to permanent brain damage and even death. Therefore, prompt medical attention is essential for proper diagnosis and management of this condition.

If you suspect vasospasm, it is essential to seek medical attention immediately. A healthcare professional will perform a physical examination and order imaging tests, such as CT or MRI scans, to confirm the diagnosis. Treatment options may include medications to dilate blood vessels, surgery to relieve pressure on affected areas, or other interventions depending on the severity of the condition.

Preventing vasospasm can be challenging, but some measures can reduce the risk of developing this condition. These include managing underlying conditions such as high blood pressure, diabetes, or high cholesterol levels; avoiding head injuries by wearing protective gear during sports and other activities; and adopting a healthy lifestyle that includes regular exercise and a balanced diet.

Early diagnosis and treatment are critical in managing vasospasm and preventing long-term damage to the brain tissue. If you experience any symptoms suggestive of vasospasm, seek medical attention promptly to receive appropriate care and improve outcomes.

The exact cause of vasovagal syncope is not fully understood, but it is thought to be related to an imbalance in the autonomic nervous system (which controls involuntary functions such as heart rate and blood pressure). It can be triggered by a variety of factors, including:

* Strong emotions such as fear or anxiety
* Pain or discomfort
* Intense physical activity
* Dehydration or low blood sugar
* Certain medications

During a vasovagal syncope episode, the person may experience symptoms such as:

* Dizziness or lightheadedness
* Blurred vision
* Nausea or vomiting
* Sweating
* Feeling of impending doom or loss of control
* Eventually, fainting or falling to the ground

Diagnosis of vasovagal syncope is typically made based on a combination of symptoms and physical examination findings. Tests such as an electrocardiogram (ECG) or blood tests may be ordered to rule out other conditions that may be causing the symptoms. Treatment for vasovagal syncope usually involves addressing any underlying triggers, such as managing stress or avoiding certain stimuli that may cause the episodes. In some cases, medications such as beta blockers or antidepressants may be prescribed to help regulate the heart rate and blood pressure.

The severity of coronary stenosis can range from mild to severe, with blockages ranging from 15% to over 90%. In mild cases, lifestyle changes and medication may be enough to manage symptoms. However, more severe cases typically require interventional procedures such as angioplasty or bypass surgery to improve blood flow to the heart.

There are many different causes of pathological dilatation, including:

1. Infection: Infections like tuberculosis or abscesses can cause inflammation and swelling in affected tissues, leading to dilatation.
2. Inflammation: Inflammatory conditions like rheumatoid arthritis or Crohn's disease can cause dilatation of blood vessels and organs.
3. Heart disease: Conditions like heart failure or coronary artery disease can lead to dilatation of the heart chambers or vessels.
4. Liver or spleen disease: Dilatation of the liver or spleen can occur due to conditions like cirrhosis or splenomegaly.
5. Neoplasms: Tumors can cause dilatation of affected structures, such as blood vessels or organs.

Pathological dilatation can lead to a range of symptoms depending on the location and severity of the condition. These may include:

1. Swelling or distension of the affected structure
2. Pain or discomfort in the affected area
3. Difficulty breathing or swallowing (in the case of dilatation in the throat or airways)
4. Fatigue or weakness
5. Pale or clammy skin
6. Rapid heart rate or palpitations
7. Shortness of breath (dyspnea)

Diagnosis of pathological dilatation typically involves a combination of physical examination, imaging studies like X-rays or CT scans, and laboratory tests to identify the underlying cause. Treatment depends on the specific condition and may include medications, surgery, or other interventions to address the underlying cause and relieve symptoms.

There are two types of hypertension:

1. Primary Hypertension: This type of hypertension has no identifiable cause and is also known as essential hypertension. It accounts for about 90% of all cases of hypertension.
2. Secondary Hypertension: This type of hypertension is caused by an underlying medical condition or medication. It accounts for about 10% of all cases of hypertension.

Some common causes of secondary hypertension include:

* Kidney disease
* Adrenal gland disorders
* Hormonal imbalances
* Certain medications
* Sleep apnea
* Cocaine use

There are also several risk factors for hypertension, including:

* Age (the risk increases with age)
* Family history of hypertension
* Obesity
* Lack of exercise
* High sodium intake
* Low potassium intake
* Stress

Hypertension is often asymptomatic, and it can cause damage to the blood vessels and organs over time. Some potential complications of hypertension include:

* Heart disease (e.g., heart attacks, heart failure)
* Stroke
* Kidney disease (e.g., chronic kidney disease, end-stage renal disease)
* Vision loss (e.g., retinopathy)
* Peripheral artery disease

Hypertension is typically diagnosed through blood pressure readings taken over a period of time. Treatment for hypertension may include lifestyle changes (e.g., diet, exercise, stress management), medications, or a combination of both. The goal of treatment is to reduce the risk of complications and improve quality of life.

The symptoms of altitude sickness can vary in severity and may include:

* Headache
* Dizziness and lightheadedness
* Nausea and vomiting
* Fatigue and weakness
* Shortness of breath
* Coughing and chest tightness
* Swelling of the hands, feet, and face

In severe cases, altitude sickness can lead to more serious complications such as:

* High-altitude pulmonary edema (HAPE): fluid buildup in the lungs that can be life-threatening
* High-altitude cerebral edema (HACE): fluid buildup in the brain that can be life-threatening

To prevent altitude sickness, it is recommended to ascend gradually and give your body time to acclimate to the higher altitude. This can be done by spending a few days at a lower altitude before ascending to a higher altitude. It is also important to stay hydrated by drinking plenty of water and avoid alcohol and sedatives, which can increase the risk of altitude sickness.

If you experience any symptoms of altitude sickness, it is important to descend to a lower altitude as soon as possible. Medications such as acetazolamide (Diamox) can also be used to help prevent and treat altitude sickness. In severe cases, hospitalization may be necessary to receive oxygen therapy and other medical treatment.

Other definitions:

* Premature birth: A birth that occurs before 37 completed weeks of gestation.
* Preterm birth: A birth that occurs before 37 completed weeks of gestation, but not necessarily before 22 weeks.
* Very preterm birth: A birth that occurs before 28 completed weeks of gestation.
* Extremely preterm birth: A birth that occurs before 24 completed weeks of gestation.

Diseases associated with premature infants:

1. Respiratory distress syndrome (RDS): A condition in which the baby's lungs do not produce enough surfactant, a substance that helps the air sacs in the lungs expand and contract properly.
2. Bronchopulmonary dysplasia (BPD): A chronic lung disease that can develop in premature infants who have RDS.
3. Intraventricular hemorrhage (IVH): Bleeding in the brain that can occur in premature infants, particularly those with RDS or BPD.
4. Retinopathy of prematurity (ROP): A condition that can cause blindness in premature infants due to abnormal blood vessel growth in the retina.
5. Necrotizing enterocolitis (NEC): A condition that can cause damage to the intestines and other parts of the digestive system in premature infants.
6. Intracranial hemorrhage (ICH): Bleeding in the brain that can occur in premature infants, particularly those with RDS or BPD.
7. Gastrointestinal problems: Premature infants are at risk for gastroesophageal reflux disease (GERD), necrotizing enterocolitis (NEC), and other gastrointestinal problems.
8. Feeding difficulties: Premature infants may have difficulty feeding, which can lead to weight gain issues or the need for a feeding tube.
9. Respiratory infections: Premature infants are at increased risk for respiratory infections, such as pneumonia and bronchiolitis.
10. Developmental delays: Premature infants may be at risk for developmental delays or learning disabilities, particularly if they experienced significant health problems or required oxygen therapy.

It is important to note that not all premature infants will develop these complications, and the severity of the conditions can vary depending on the individual baby's health and the level of care they receive. However, it is essential for parents and caregivers to be aware of the potential risks and seek prompt medical attention if they notice any signs of distress or illness in their premature infant.

Types of Fetal Distress:

1. Hypoxia (lack of oxygen): This is one of the most common causes of fetal distress, which can occur due to placental insufficiency, umbilical cord compression, or other issues that restrict the flow of oxygen and nutrients to the fetus.
2. Acidosis: When the fetus's blood becomes too acidic, it can lead to fetal distress, as this can cause damage to the baby's organs and tissues.
3. Heart rate variability: Abnormal heart rate patterns in the fetus can indicate distress and may require closer monitoring or medical interventions.
4. Decreased movements: A decrease in fetal movement can be a sign of distress, particularly if it occurs suddenly or accompanied by other signs such as decreased heart rate or changes in fetal position.
5. Meconium staining: The presence of meconium in the amniotic fluid can indicate fetal distress, as it may be a sign of a prolonged or difficult labor.
6. Cephalopelvic disparity: When the fetus's head is too large to pass through the mother's pelvis, it can cause fetal distress and may require assisted delivery methods such as vacuum extraction or cesarean section.
7. Prolonged labor: A prolonged labor can lead to fetal distress due to decreased blood flow and oxygen supply to the fetus.
8. Maternal complications: Maternal complications such as high blood pressure, preeclampsia, or infection can also cause fetal distress.

Signs and Symptoms of Fetal Distress:

1. Changes in fetal heart rate: An abnormal heart rate pattern may indicate fetal distress, including tachycardia (rapid heart rate), bradycardia (slow heart rate), or variability in heart rate.
2. Decreased fetal movement: A decrease in fetal movement or lack of response to movement can be a sign of fetal distress.
3. Changes in fetal position: Abnormal fetal position, such as breech presentation or shoulder dystocia, can cause fetal distress.
4. Decreased muscle tone: Weak or floppy muscles in the fetus can indicate fetal distress.
5. Cyanosis (blue skin): A bluish tint to the skin may indicate that the fetus is not getting enough oxygen.
6. Acidosis (high blood acidity): An increase in blood acidity can lead to fetal distress and may require immediate medical intervention.
7. Respiratory distress: Difficulty breathing or rapid breathing can be a sign of fetal distress.
8. Umbilical cord issues: Problems with the umbilical cord, such as a prolapsed cord or a cord that is wrapped around the fetus's neck, can cause fetal distress.

Treatment and Management of Fetal Distress:

1. Oxygen supplementation: Providing oxygen to the fetus through a mask or nasal tubes may help improve oxygenation.
2. Intravenous (IV) fluids and medications: Administering IV fluids and medications can help stabilize the fetus and manage symptoms such as low blood pressure, low heart rate, or high acidity in the blood.
3. Fetal heart rate monitoring: Close monitoring of the fetus's heart rate may help identify signs of distress early on.
4. Uterine massage: Gentle massage of the uterus may help improve blood flow to the fetus.
5. Delivery: In some cases, delivery may be necessary to immediately address fetal distress.
6. Neonatal care: If the baby is born with signs of distress, immediate neonatal care may be necessary to ensure proper respiratory and cardiac function.

Prevention of Fetal Distress:

1. Proper prenatal care: Regular check-ups with a healthcare provider can help identify potential issues before they become critical.
2. Avoiding smoking, alcohol, and drug use during pregnancy: These substances can increase the risk of fetal distress.
3. Maintaining a healthy diet and weight gain during pregnancy: A balanced diet and appropriate weight gain can help ensure proper fetal growth and development.
4. Managing chronic medical conditions such as high blood pressure and diabetes: Proper management of these conditions can reduce the risk of fetal distress.
5. Avoiding excessive exercise and heat exposure during pregnancy: Overexertion and overheating can increase the risk of fetal distress.
6. Proper use of medications: Some medications can increase the risk of fetal distress, so it is important to discuss any medications with a healthcare provider before taking them during pregnancy.

Hyperoxia can cause damage to the body's tissues and organs, particularly the lungs and brain. In severe cases, hyperoxia can lead to respiratory failure, seizures, and even death.

There are several ways to diagnose hyperoxia, including:

1. Blood tests: These can measure the levels of oxygen in the blood.
2. Arterial blood gas (ABG) analysis: This is a test that measures the amounts of oxygen and carbon dioxide in the blood.
3. Pulse oximetry: This is a non-invasive test that measures the amount of oxygen in the blood by shining a light through the skin.

Treatment for hyperoxia depends on the underlying cause, but may include:

1. Oxygen therapy: This involves administering oxygen to the patient through a mask or nasal tubes.
2. Medications: These may be used to treat any underlying conditions that are causing hyperoxia.
3. Mechanical ventilation: In severe cases, this may be necessary to support the patient's breathing.

In summary, hyperoxia is a condition where there is too much oxygen in the body, and it can cause damage to the body's tissues and organs. Diagnosis is typically made through blood tests or other tests, and treatment may involve oxygen therapy, medications, or mechanical ventilation.

Patent ductus arteriosus (PDA) is a condition in which the DA fails to close after birth. This can result in excessive blood flow to the lungs and put extra strain on the heart. PDA is relatively common, occurring in about 1 in every 2000 live births.

Symptoms of PDA may include:

* Fast breathing (tachypnea)
* Shortness of breath (dyspnea)
* Fatigue
* Sweating during feedings
* Frequent respiratory infections

If left untreated, PDA can lead to long-term complications such as:

* Increased risk of respiratory infections
* Heart failure
* Developmental delays
* Cognitive impairments

Treatment for PDA may include:

* Medications to reduce blood pressure in the lungs and improve oxygenation
* Surgery to close the ductus arteriosus, either through a catheter or open-heart surgery

In some cases, PDA may be treated with medication alone. However, if the condition is not treated promptly, surgical intervention may be necessary to prevent long-term complications.

Some common causes of syncope include:

1. Vasovagal response: This is the most common cause of syncope and is triggered by a sudden drop in blood pressure, usually due to sight of blood or injury.
2. Cardiac arrhythmias: Abnormal heart rhythms can lead to a decrease in blood flow to the brain, causing syncope.
3. Heart failure: When the heart is unable to pump enough blood to meet the body's needs, syncope can occur.
4. Anemia: A low red blood cell count can cause decreased oxygen delivery to the brain, leading to syncope.
5. Dehydration: Lack of fluids and electrolytes can lead to a decrease in blood pressure, causing syncope.
6. Medication side effects: Certain medications can cause syncope as a side effect, such as vasodilators and beta-blockers.
7. Neurological disorders: Syncope can be a symptom of neurological conditions such as seizures, migraines, and stroke.
8. Psychological factors: Stress, anxiety, and panic attacks can also cause syncope.

Diagnosis of syncope is based on a thorough medical history and physical examination, as well as diagnostic tests such as electrocardiogram (ECG), echocardiogram, and blood tests. Treatment of syncope depends on the underlying cause and may include lifestyle modifications, medication, and in some cases, surgical intervention.

In summary, syncope is a symptom of a wide range of medical conditions that can be caused by cardiovascular, neurological, and psychological factors. A thorough diagnosis and appropriate treatment are necessary to determine the underlying cause and prevent complications.

There are several types of ischemia, including:

1. Myocardial ischemia: Reduced blood flow to the heart muscle, which can lead to chest pain or a heart attack.
2. Cerebral ischemia: Reduced blood flow to the brain, which can lead to stroke or cognitive impairment.
3. Peripheral arterial ischemia: Reduced blood flow to the legs and arms.
4. Renal ischemia: Reduced blood flow to the kidneys.
5. Hepatic ischemia: Reduced blood flow to the liver.

Ischemia can be diagnosed through a variety of tests, including electrocardiograms (ECGs), stress tests, and imaging studies such as CT or MRI scans. Treatment for ischemia depends on the underlying cause and may include medications, lifestyle changes, or surgical interventions.

The most common carotid artery disease is atherosclerosis, which is the buildup of plaque in the inner lining of the arteries. This buildup can lead to a narrowing or blockage of the arteries, reducing blood flow to the brain and increasing the risk of stroke. Other conditions that can affect the carotid arteries include:

1. Carotid artery stenosis: A narrowing of the carotid arteries caused by atherosclerosis or other factors.
2. Carotid artery dissection: A tear in the inner lining of the arteries that can cause bleeding and blockage.
3. Carotid artery aneurysm: A bulge in the wall of the arteries that can lead to rupture and stroke.
4. Temporal bone fracture: A break in the bones of the skull that can cause damage to the carotid arteries and result in stroke or other complications.

Carotid artery diseases are typically diagnosed using imaging tests such as ultrasound, computed tomography (CT) angiography, or magnetic resonance angiography (MRA). Treatment options for carotid artery diseases depend on the underlying condition and its severity, but may include lifestyle changes, medications, surgery, or endovascular procedures.

Prevention of carotid artery diseases is key to reducing the risk of stroke and other complications. This includes managing risk factors such as high blood pressure, high cholesterol, smoking, and diabetes, as well as maintaining a healthy lifestyle and getting regular check-ups with your doctor.

There are several types of hydrocephalus, including:

1. Aqueductal stenosis: This occurs when the aqueduct that connects the third and fourth ventricles becomes narrowed or blocked, leading to an accumulation of CSF in the brain.
2. Choroid plexus papilloma: This is a benign tumor that grows on the surface of the choroid plexus, which is a layer of tissue that produces CSF.
3. Hydrocephalus ex vacuo: This occurs when there is a decrease in the volume of brain tissue due to injury or disease, leading to an accumulation of CSF.
4. Normal pressure hydrocephalus (NPH): This is a type of hydrocephalus that occurs in adults and is characterized by an enlarged ventricle, gait disturbances, and cognitive decline, despite normal pressure levels.
5. Symptomatic hydrocephalus: This type of hydrocephalus is caused by other conditions such as brain tumors, cysts, or injuries.

Symptoms of hydrocephalus can include headache, nausea, vomiting, seizures, and difficulty walking or speaking. Treatment options for hydrocephalus depend on the underlying cause and may include medication, surgery, or a shunt to drain excess CSF. In some cases, hydrocephalus can be managed with lifestyle modifications such as regular exercise and a balanced diet.

Prognosis for hydrocephalus varies depending on the underlying cause and severity of the condition. However, with timely diagnosis and appropriate treatment, many people with hydrocephalus can lead active and fulfilling lives.

1) They share similarities with humans: Many animal species share similar biological and physiological characteristics with humans, making them useful for studying human diseases. For example, mice and rats are often used to study diseases such as diabetes, heart disease, and cancer because they have similar metabolic and cardiovascular systems to humans.

2) They can be genetically manipulated: Animal disease models can be genetically engineered to develop specific diseases or to model human genetic disorders. This allows researchers to study the progression of the disease and test potential treatments in a controlled environment.

3) They can be used to test drugs and therapies: Before new drugs or therapies are tested in humans, they are often first tested in animal models of disease. This allows researchers to assess the safety and efficacy of the treatment before moving on to human clinical trials.

4) They can provide insights into disease mechanisms: Studying disease models in animals can provide valuable insights into the underlying mechanisms of a particular disease. This information can then be used to develop new treatments or improve existing ones.

5) Reduces the need for human testing: Using animal disease models reduces the need for human testing, which can be time-consuming, expensive, and ethically challenging. However, it is important to note that animal models are not perfect substitutes for human subjects, and results obtained from animal studies may not always translate to humans.

6) They can be used to study infectious diseases: Animal disease models can be used to study infectious diseases such as HIV, TB, and malaria. These models allow researchers to understand how the disease is transmitted, how it progresses, and how it responds to treatment.

7) They can be used to study complex diseases: Animal disease models can be used to study complex diseases such as cancer, diabetes, and heart disease. These models allow researchers to understand the underlying mechanisms of the disease and test potential treatments.

8) They are cost-effective: Animal disease models are often less expensive than human clinical trials, making them a cost-effective way to conduct research.

9) They can be used to study drug delivery: Animal disease models can be used to study drug delivery and pharmacokinetics, which is important for developing new drugs and drug delivery systems.

10) They can be used to study aging: Animal disease models can be used to study the aging process and age-related diseases such as Alzheimer's and Parkinson's. This allows researchers to understand how aging contributes to disease and develop potential treatments.

There are several types of intracranial embolism, including:

1. Cerebral embolism: This occurs when a blood clot or other foreign matter becomes lodged in the brain, blocking the flow of blood and oxygen to brain tissue.
2. Pulmonary embolism: This occurs when a blood clot forms in the lungs and travels to the brain, causing blockage of blood vessels.
3. Aortic embolism: This occurs when a blood clot or other foreign matter becomes lodged in the aorta, the main artery that carries oxygenated blood from the heart to the rest of the body.
4. Atrial myxoma embolism: This occurs when a tumor in the heart, known as an atrial myxoma, breaks loose and travels to the brain, causing blockage of blood vessels.

Intracranial embolism can be diagnosed through various imaging tests such as CT or MRI scans, angiography, and Doppler ultrasound. Treatment options for intracranial embolism depend on the underlying cause and may include medications to dissolve blood clots, surgery to remove the blockage, or endovascular procedures such as stenting or coiling.

Preventive measures for intracranial embolism include managing risk factors for cardiovascular disease, such as high blood pressure, high cholesterol, and smoking cessation, as well as avoiding long periods of immobility during long-distance travel. Early diagnosis and treatment are critical in preventing long-term cognitive and neurological damage.

1. Ischemic stroke: This is the most common type of stroke, accounting for about 87% of all strokes. It occurs when a blood vessel in the brain becomes blocked, reducing blood flow to the brain.
2. Hemorrhagic stroke: This type of stroke occurs when a blood vessel in the brain ruptures, causing bleeding in the brain. High blood pressure, aneurysms, and blood vessel malformations can all cause hemorrhagic strokes.
3. Transient ischemic attack (TIA): Also known as a "mini-stroke," a TIA is a temporary interruption of blood flow to the brain that lasts for a short period of time, usually less than 24 hours. TIAs are often a warning sign for a future stroke and should be taken seriously.

Stroke can cause a wide range of symptoms depending on the location and severity of the damage to the brain. Some common symptoms include:

* Weakness or numbness in the face, arm, or leg
* Difficulty speaking or understanding speech
* Sudden vision loss or double vision
* Dizziness, loss of balance, or sudden falls
* Severe headache
* Confusion, disorientation, or difficulty with memory

Stroke is a leading cause of long-term disability and can have a significant impact on the quality of life for survivors. However, with prompt medical treatment and rehabilitation, many people are able to recover some or all of their lost functions and lead active lives.

The medical community has made significant progress in understanding stroke and developing effective treatments. Some of the most important advances include:

* Development of clot-busting drugs and mechanical thrombectomy devices to treat ischemic strokes
* Improved imaging techniques, such as CT and MRI scans, to diagnose stroke and determine its cause
* Advances in surgical techniques for hemorrhagic stroke
* Development of new medications to prevent blood clots and reduce the risk of stroke

Despite these advances, stroke remains a significant public health problem. According to the American Heart Association, stroke is the fifth leading cause of death in the United States and the leading cause of long-term disability. In 2017, there were over 795,000 strokes in the United States alone.

There are several risk factors for stroke that can be controlled or modified. These include:

* High blood pressure
* Diabetes mellitus
* High cholesterol levels
* Smoking
* Obesity
* Lack of physical activity
* Poor diet

In addition to these modifiable risk factors, there are also several non-modifiable risk factors for stroke, such as age (stroke risk increases with age), family history of stroke, and previous stroke or transient ischemic attack (TIA).

The medical community has made significant progress in understanding the causes and risk factors for stroke, as well as developing effective treatments and prevention strategies. However, more research is needed to improve outcomes for stroke survivors and reduce the overall burden of this disease.

Myocardial ischemia can be caused by a variety of factors, including coronary artery disease, high blood pressure, diabetes, and smoking. It can also be triggered by physical exertion or stress.

There are several types of myocardial ischemia, including:

1. Stable angina: This is the most common type of myocardial ischemia, and it is characterized by a predictable pattern of chest pain that occurs during physical activity or emotional stress.
2. Unstable angina: This is a more severe type of myocardial ischemia that can occur without any identifiable trigger, and can be accompanied by other symptoms such as shortness of breath or vomiting.
3. Acute coronary syndrome (ACS): This is a condition that includes both stable angina and unstable angina, and it is characterized by a sudden reduction in blood flow to the heart muscle.
4. Heart attack (myocardial infarction): This is a type of myocardial ischemia that occurs when the blood flow to the heart muscle is completely blocked, resulting in damage or death of the cardiac tissue.

Myocardial ischemia can be diagnosed through a variety of tests, including electrocardiograms (ECGs), stress tests, and imaging studies such as echocardiography or cardiac magnetic resonance imaging (MRI). Treatment options for myocardial ischemia include medications such as nitrates, beta blockers, and calcium channel blockers, as well as lifestyle changes such as quitting smoking, losing weight, and exercising regularly. In severe cases, surgical procedures such as coronary artery bypass grafting or angioplasty may be necessary.

Symptoms of cerebral hemorrhage may include sudden severe headache, confusion, seizures, weakness or numbness in the face or limbs, and loss of consciousness. The condition is diagnosed through a combination of physical examination, imaging tests such as CT or MRI scans, and laboratory tests to determine the cause of the bleeding.

Treatment for cerebral hemorrhage depends on the location and severity of the bleeding, as well as the underlying cause. Medications may be used to control symptoms such as high blood pressure or seizures, while surgery may be necessary to repair the ruptured blood vessel or relieve pressure on the brain. In some cases, the condition may be fatal, and immediate medical attention is essential to prevent long-term damage or death.

Some of the most common complications associated with cerebral hemorrhage include:

1. Rebleeding: There is a risk of rebleeding after the initial hemorrhage, which can lead to further brain damage and increased risk of death.
2. Hydrocephalus: Excess cerebrospinal fluid can accumulate in the brain, leading to increased intracranial pressure and potentially life-threatening complications.
3. Brain edema: Swelling of the brain tissue can occur due to the bleeding, leading to increased intracranial pressure and potentially life-threatening complications.
4. Seizures: Cerebral hemorrhage can cause seizures, which can be a sign of a more severe injury.
5. Cognitive and motor deficits: Depending on the location and severity of the bleeding, cerebral hemorrhage can result in long-term cognitive and motor deficits.
6. Vision loss: Cerebral hemorrhage can cause vision loss or blindness due to damage to the visual cortex.
7. Communication difficulties: Cerebral hemorrhage can cause difficulty with speech and language processing, leading to communication difficulties.
8. Behavioral changes: Depending on the location and severity of the bleeding, cerebral hemorrhage can result in behavioral changes, such as irritability, agitation, or apathy.
9. Infection: Cerebral hemorrhage can increase the risk of infection, particularly if the hemorrhage is caused by a ruptured aneurysm or arteriovenous malformation (AVM).
10. Death: Cerebral hemorrhage can be fatal, particularly if the bleeding is severe or if there are underlying medical conditions that compromise the patient's ability to tolerate the injury.

There are several different types of brain injuries that can occur, including:

1. Concussions: A concussion is a type of mild traumatic brain injury that occurs when the brain is jolted or shaken, often due to a blow to the head.
2. Contusions: A contusion is a bruise on the brain that can occur when the brain is struck by an object, such as during a car accident.
3. Coup-contrecoup injuries: This type of injury occurs when the brain is injured as a result of the force of the body striking another object, such as during a fall.
4. Penetrating injuries: A penetrating injury occurs when an object pierces the brain, such as during a gunshot wound or stab injury.
5. Blast injuries: This type of injury occurs when the brain is exposed to a sudden and explosive force, such as during a bombing.

The symptoms of brain injuries can vary depending on the severity of the injury and the location of the damage in the brain. Some common symptoms include:

* Headaches
* Dizziness or loss of balance
* Confusion or disorientation
* Memory loss or difficulty with concentration
* Slurred speech or difficulty with communication
* Vision problems, such as blurred vision or double vision
* Sleep disturbances
* Mood changes, such as irritability or depression
* Personality changes
* Difficulty with coordination and balance

In some cases, brain injuries can be treated with medication, physical therapy, and other forms of rehabilitation. However, in more severe cases, the damage may be permanent and long-lasting. It is important to seek medical attention immediately if symptoms persist or worsen over time.

Examples of acute diseases include:

1. Common cold and flu
2. Pneumonia and bronchitis
3. Appendicitis and other abdominal emergencies
4. Heart attacks and strokes
5. Asthma attacks and allergic reactions
6. Skin infections and cellulitis
7. Urinary tract infections
8. Sinusitis and meningitis
9. Gastroenteritis and food poisoning
10. Sprains, strains, and fractures.

Acute diseases can be treated effectively with antibiotics, medications, or other therapies. However, if left untreated, they can lead to chronic conditions or complications that may require long-term care. Therefore, it is important to seek medical attention promptly if symptoms persist or worsen over time.

There are several potential causes of LVD, including:

1. Coronary artery disease: The buildup of plaque in the coronary arteries can lead to a heart attack, which can damage the left ventricle and impair its ability to function properly.
2. Heart failure: When the heart is unable to pump enough blood to meet the body's needs, it can lead to LVD.
3. Cardiomyopathy: This is a condition where the heart muscle becomes weakened or enlarged, leading to impaired function of the left ventricle.
4. Heart valve disease: Problems with the heart valves can disrupt the normal flow of blood and cause LVD.
5. Hypertension: High blood pressure can cause damage to the heart muscle and lead to LVD.
6. Genetic factors: Some people may be born with genetic mutations that predispose them to developing LVD.
7. Viral infections: Certain viral infections, such as myocarditis, can inflame and damage the heart muscle, leading to LVD.
8. Alcohol or drug abuse: Substance abuse can damage the heart muscle and lead to LVD.
9. Nutritional deficiencies: A diet lacking essential nutrients can lead to damage to the heart muscle and increase the risk of LVD.

Diagnosis of LVD typically involves a physical exam, medical history, and results of diagnostic tests such as electrocardiograms (ECGs), echocardiograms, and stress tests. Treatment options for LVD depend on the underlying cause, but may include medications to improve cardiac function, lifestyle changes, and in severe cases, surgery or other procedures.

Preventing LVD involves taking steps to maintain a healthy heart and reducing risk factors such as high blood pressure, smoking, and obesity. This can be achieved through a balanced diet, regular exercise, stress management, and avoiding substance abuse. Early detection and treatment of underlying conditions that increase the risk of LVD can also help prevent the condition from developing.

Sickle cell anemia is caused by mutations in the HBB gene that codes for hemoglobin. The most common mutation is a point mutation at position 6, which replaces the glutamic acid amino acid with a valine (Glu6Val). This substitution causes the hemoglobin molecule to be unstable and prone to forming sickle-shaped cells.

The hallmark symptom of sickle cell anemia is anemia, which is a low number of healthy red blood cells. People with the condition may also experience fatigue, weakness, jaundice (yellowing of the skin and eyes), infections, and episodes of severe pain. Sickle cell anemia can also increase the risk of stroke, heart disease, and other complications.

Sickle cell anemia is diagnosed through blood tests that measure hemoglobin levels and the presence of sickle cells. Treatment typically involves managing symptoms and preventing complications with medications, blood transfusions, and antibiotics. In some cases, bone marrow transplantation may be recommended.

Prevention of sickle cell anemia primarily involves avoiding the genetic mutations that cause the condition. This can be done through genetic counseling and testing for individuals who have a family history of the condition or are at risk of inheriting it. Prenatal testing is also available for pregnant women who may be carriers of the condition.

Overall, sickle cell anemia is a serious genetic disorder that can significantly impact quality of life and life expectancy if left untreated. However, with proper management and care, individuals with the condition can lead fulfilling lives and manage their symptoms effectively.

In this condition, the heart chambers become rigid and cannot expand and contract properly, which reduces the heart's ability to pump blood effectively. This can lead to a decrease in the amount of blood that reaches the body's tissues and organs, causing symptoms such as fatigue, shortness of breath, and swelling in the legs and feet.

There are several types of restrictive cardiomyopathy, including:

1. Idiopathic RCM: This type of RCM has no known cause.
2. Amyloidosis-related RCM: This type of RCM is caused by the buildup of abnormal proteins called amyloid in the heart tissue.
3. Hypertensive RCM: This type of RCM is caused by high blood pressure, which can damage the heart muscle and make it stiff.
4. Drug-induced RCM: This type of RCM is caused by certain medications that can damage the heart muscle.
5. Infiltrative RCM: This type of RCM is caused by the infiltration of the heart muscle by abnormal substances, such as inflammatory cells or tumors.

Treatment for restrictive cardiomyopathy usually involves managing symptoms and addressing any underlying causes, such as high blood pressure or amyloidosis. Medications may include diuretics to reduce fluid buildup, blood thinners to prevent clots, and medications to manage high blood pressure. In severe cases, a heart transplant may be necessary.

There are different types of myocardial infarctions, including:

1. ST-segment elevation myocardial infarction (STEMI): This is the most severe type of heart attack, where a large area of the heart muscle is damaged. It is characterized by a specific pattern on an electrocardiogram (ECG) called the ST segment.
2. Non-ST-segment elevation myocardial infarction (NSTEMI): This type of heart attack is less severe than STEMI, and the damage to the heart muscle may not be as extensive. It is characterized by a smaller area of damage or a different pattern on an ECG.
3. Incomplete myocardial infarction: This type of heart attack is when there is some damage to the heart muscle but not a complete blockage of blood flow.
4. Collateral circulation myocardial infarction: This type of heart attack occurs when there are existing collateral vessels that bypass the blocked coronary artery, which reduces the amount of damage to the heart muscle.

Symptoms of a myocardial infarction can include chest pain or discomfort, shortness of breath, lightheadedness, and fatigue. These symptoms may be accompanied by anxiety, fear, and a sense of impending doom. In some cases, there may be no noticeable symptoms at all.

Diagnosis of myocardial infarction is typically made based on a combination of physical examination findings, medical history, and diagnostic tests such as an electrocardiogram (ECG), cardiac enzyme tests, and imaging studies like echocardiography or cardiac magnetic resonance imaging.

Treatment of myocardial infarction usually involves medications to relieve pain, reduce the amount of work the heart has to do, and prevent further damage to the heart muscle. These may include aspirin, beta blockers, ACE inhibitors or angiotensin receptor blockers, and statins. In some cases, a procedure such as angioplasty or coronary artery bypass surgery may be necessary to restore blood flow to the affected area.

Prevention of myocardial infarction involves managing risk factors such as high blood pressure, high cholesterol, smoking, diabetes, and obesity. This can include lifestyle changes such as a healthy diet, regular exercise, and stress reduction, as well as medications to control these conditions. Early detection and treatment of heart disease can help prevent myocardial infarction from occurring in the first place.

Anatomy52

Organisms2

Diseases36

Chemicals and Drugs25

Analytical, Diagnostic and Therapeutic Techniques and Equipment78

Psychiatry and Psychology1

Phenomena and Processes64

Disciplines and Occupations2

Anthropology, Education, Sociology and Social Phenomena2

Information Science6

Named Groups3

Health Care17

The effect of cardiac contraction on collateral resistance in the canine heart. (1/7943)

Investigation of the theory and mechanism of the origin of the second heart sound. (2/7943)

Flow-mediated vasodilation and distensibility of the brachial artery in renal allograft recipients. (3/7943)

Profile of neurohumoral agents on mesenteric and intestinal blood flow in health and disease. (4/7943)

Venous ulceration and continuous flow in the long saphenous vein. (5/7943)

Brightness alters Heidelberg retinal flowmeter measurements in an in vitro model. (6/7943)

Analysis of blood flow in the long posterior ciliary artery of the cat. (7/7943)

Demonstration of rapid onset vascular endothelial dysfunction after hyperhomocysteinemia: an effect reversible with vitamin C therapy. (8/7943)

No images available that match "blood flow velocity"

Blood Flow Velocity

Regional Blood Flow

Ultrasonography, Doppler, Transcranial

Cerebrovascular Circulation

Middle Cerebral Artery

Ultrasonography, Doppler

Ophthalmic Artery

Cerebral Arteries

Pulsatile Flow

Ultrasonography, Doppler, Color

Ultrasonography, Doppler, Pulsed

Coronary Circulation

Blood Pressure

Vascular Resistance

Laser-Doppler Flowmetry

Hemodynamics

Hypocapnia

Ciliary Arteries

Retinal Artery

Echocardiography, Doppler

Echoencephalography

Rheology

Umbilical Arteries

Hyperventilation

Microcirculation

Carbon Dioxide

Diastole

Ultrasonography, Prenatal

Anterior Cerebral Artery

Hyperemia

Heart Rate

Ultrasonography

Models, Cardiovascular

Arteries

Reference Values

Intracranial Pressure

Systole

Heart Rate, Fetal

Celiac Artery

Coronary Vessels

Homeostasis

Vasodilation

Acetazolamide

Gestational Age

Vasodilator Agents

Dogs

Doppler Effect

Pregnancy

Time Factors

Oxygen

Mesenteric Artery, Superior

Fetal Growth Retardation

Brain

Circle of Willis

Echocardiography, Doppler, Color

Carotid Artery, Internal

Placental Circulation

Prospective Studies

Collateral Circulation

Reproducibility of Results

Hemorheology

Tilt-Table Test

Fetal Heart

Posterior Cerebral Artery

Vasomotor System

Hypotension, Orthostatic

Echocardiography

Splanchnic Circulation

Hypercapnia

Flow Cytometry

Blood Viscosity

Pulmonary Circulation

Blood Circulation Time

Posture

Blood Volume

Partial Pressure

Papaverine

Retinal Vessels

Uterus

Echocardiography, Transesophageal