Maximal Expiratory Flow-Volume Curves
Maximal Expiratory Flow Rate
Lung Volume Measurements
Forced Expiratory Flow Rates
Peak Expiratory Flow Rate
Respiratory Function Tests
Residual Volume
Vital Capacity
Forced Expiratory Volume
Measure of the maximum amount of air that can be expelled in a given number of seconds during a FORCED VITAL CAPACITY determination . It is usually given as FEV followed by a subscript indicating the number of seconds over which the measurement is made, although it is sometimes given as a percentage of forced vital capacity.
Total Lung Capacity
The volume of air contained in the lungs at the end of a maximal inspiration. It is the equivalent to each of the following sums: VITAL CAPACITY plus RESIDUAL VOLUME; INSPIRATORY CAPACITY plus FUNCTIONAL RESIDUAL CAPACITY; TIDAL VOLUME plus INSPIRATORY RESERVE VOLUME plus functional residual capacity; or tidal volume plus inspiratory reserve volume plus EXPIRATORY RESERVE VOLUME plus residual volume.
Lung
Airway Resistance
Forced expiratory wheezes in a patient with dynamic expiratory narrowing of central airways and an oscillating pattern of the flow-volume curve. (1/53)
Forced expiratory wheezes (FEW) are common and the pathogenesis of this phenomenon might involve fluttering of the airways, but this theory has not been confirmed in patients. We report a case of a patient with FEW and a normal FEV1 that showed a bronchoscopically confirmed collapse of the trachea and main stem bronchi during forced expiration. Superimposed to the flow-volume curve was an oscillating pattern with a frequency that corresponded well with the wheeze generated during forced expiration. The oscillating pattern in the flow-volume curve and the collapse of the major airways supports the theory of wheezes generated by fluttering airways during forced expiration. Although FEW may be found also in healthy subjects, flow limitation is essential for the generation of FEW. The inclusion of a forced expiratory maneuver in the clinical examination might therefore be helpful in guiding the diagnosis towards airways obstruction. (+info)The shape of the maximum expiratory flow-volume curve reflects exposure in farming. (2/53)
The objective of the study was to examine the effect of farming exposure, respiratory symptoms and smoking on the shape of the MEFV-curve in 1,691 male farming students and 407 male controls and to relate the slope ratio with FEV(1) and FEV(1) /FVC. Each subject underwent a medical interview and the slope ratios from the MEFV-curve at 75 (SR75), 50 (SR50) and 25 (SR25) %FVC together with FEV1 and FVC were recorded. Histamine bronchial reactivity (Yan method) was measured and skin prick test with inhalant allergens was performed. In smokers, SR75 increased with increasing exposure to: general farming, swine and dairy cattle (p< or =0.020). SR50 increased with increasing exposure to farming (p=0.015). In non-smokers, SR25 increased with increasing exposure to swine and dairy cattle (p=0. 021) and increased SR25 was associated with sensitisation to house dust mite (p=0.017). Data revealed an interaction between smoking and exposure to farming. FEV(1) and FEV(1)/FVC was not associated with farming exposure or production animals. FEV1 and FEV(1)/FVC (p< or =0.003) were lower among subjects wi bronchial hyperresponsiveness and asthma (FEV(1) and asthma only in smokers). SR75 (p=0.037) and SR50 (p=0.024) were increased in subjects with asthma and SR75 was increased in subjects with bronchial hyperresponsiveness, but only in smokers (p=0.002). In conclusion, exposure to farming seems to influence the shape of the MEFV-curve and there are indications of interaction between exposure to organic dust and smoking. These changes are seen only in the slope ratios and not in FEV(1) and FEV(1)/FVC. However, FEV(1) and FEV(1)/FVC are superior to slope ratios in differentiating healthy subjects from those with respiratory symptoms. (+info)An isoflow-volume technique for assessing airway dynamics in children and adults. (3/53)
BACKGROUND: We propose a new approach to the measurement of small airway function as an alternative to recordings of maximal expiratory flow-volume (MEFV) curves. OBJECTIVES: A newly developed technique to record isoflow-volume (IFV) curves to be tested against maximal respiratory flow curves. METHODS: An isoflow whistle (IFW; Iflopen) measures the length of a constant expiration after full inspiration. The note of the whistle enables a subject to generate an even expiration, and the isoflow maintenance times at 1 l x s(-1) (IFMT1) and 2 l x s(-1) (IFMT2) are recorded. The accuracy and reproducibility of the IFV technique were evaluated in 17 healthy adults (age 17-55 years) and in 14 asthmatic children (age 6-14 years). Comparisons with standard lung function parameters, such as forced expiratory volume in 1 s (FEV1), maximal expiratory flow at 50% (MEF50) and 25% (MEF25) vital capacity and peak expiratory flow (PEF), obtained with a Wright Peakflow Meter were undertaken in 102 healthy (aged 8-14 years) and 101 asthmatic children (aged 6-17 years). A bronchial challenge test was performed in 13 asthmatic children. RESULTS: The expired volume measured by the IFW showed an acceptable agreement with that of a pneumotachograph (mean error of 4.32% for IFMT1 and 5.93% for IFMT2). In healthy and in asthmatic children, the correlations between FEV1 and IFMT1 or IFMT2 (r = 0.92 and 0.94, respectively) were found to be greater than that between FEV1 and PEF (r = 0.68). During bronchial challenge tests in 13 asthmatic children, the FEV1 decreased to 69% of baseline and IFMT1 to 58% of baseline. CONCLUSIONS: The IFV technique accurately measured airway obstruction and closely followed changes in standard parameters of the MEFV curve. (+info)The short-term repeatability of histamine bronchial testing in young males. The SUS study. (4/53)
We have measured bronchial responsiveness (BR) to histamine on two occasions between 5 and 24 h apart, to determine if conventional and new indices of BR are repeatable. A random sample of 29 healthy male subjects with a mean age of 19 (SD 3.44) years from a larger study repeated a Yan method test of BR, recording both partial and maximal expiratory flow volume (PEFV and MEFV) curves. From the MEFV curves log-dose slopes (LDS) for forced expiratory volume in 1 sec (FEV1), forced expiratory flow between 25% and 75% of forced vital capacity (FVC) (FEF(25-75%)), mean expiratory flow at 30% and 40% of FVC (MEF30, MEF40), and the first moment of the spirogram (alpha1) truncated at 75% and 90% of FVC were calculated, as well as the provocative dose that induces a 20% fall in FEV1 (PD20FEV1). From the PEFV curves LDS for alpha(1)75% and alpha(1)90%, and MEF30 and MEF40 were derived. Apart from MEF30 and alpha(1)90% the second test was significantly lower (P<0.05) than the first when measuring the repeatability of spirometric indices, whereas the LDS of the indices showed no significant change. The repeatability expressed as intra-class correlation coefficient (ICC) was highest for LDS FEV1 (0.87), second highest for LDS MEF40 (0.67) and LDS MEF30 (0.65). The LDS for moment indices were much less repeatable and the lowest ICC was found in all LDS indices derived from PEFV curves. Within-subject variance was not influenced by atopic status, smoking habits or recordable PD20FEV1. As tests for bronchial hyper-responsiveness (BHR) the LDS of FEV1, MEF40 and MEF30 seem to be acceptable for use in population studies. (+info)Can asthma treatment in sports be doping? The effect of the rapid onset, long-acting inhaled beta2-agonist formoterol upon endurance performance in healthy well-trained athletes. (5/53)
Inhaled beta2-agonists have been subject to restrictions in relationship to sports due to fear of possible improvement in endurance performance. According to the international doping regulations only inhaled salbutamol, terbutaline and salmeterol are allowed for use in sports. Formoterol is a recently introduced rapid onset-long-acting inhaled beta2-agonist. The main aim of the present randomized, double-blind placebo-controlled study was to investigate possible improvement in endurance performance of inhaled formoterol in 24 healthy well-trained competitive male athletes, 21-29 years old. Lung function (flow-volume loops) was measured before, 15 min after each inhaled study drug and before and repeatedly after exercise. On day 1, maximum oxygen uptake (VO2max), peak ventilation (VEpeak) and running time till exhaustion were measured and used to determine the exercise load on days 2 and 3. On days 2 and 3 the subjects inhaled the study drugs, rested for 1 h, then exercised, and VO2max, VEpeak and running time until exhaustion were determined. Inhaled formoterol did not improve any parameter of endurance performance. On the other hand a statistically significant, although not clinically significant (0.05 ml(-1) min kg(-1)), change was found in estimated difference of VO2max between formoterol and placebo in favour of placebo. Lung function increased significantly after inhaled formoterol, and after exercise also for placebo, but without differences between the beta2-agonist and placebo after exercise. In conclusion, inhaled formoterol did not improve endurance performance compared to placebo. (+info)The body weight-walking distance product as related to lung function, anaerobic threshold and peak VO2 in COPD patients. (6/53)
The product of walking distance and body weight (D x W) mimics the work of walking. We hypothesized the superiority of D x W to walking distance (D) alone in any correlation with lung function, anaerobic threshold (AT) and maximal oxygen uptake (VO2max). We further hypothesized that the D x W product for a 6-min walk test (6 MWT) would correlate with the AT and VO2max because all three are markers of exercise ability. Thirty-three male chronic obstructive pulmonary disease (COPD) patients with mean forced expiratory volume in 1 sec (FEV1) of 1.2+/-0.4 l (range 0.58-1.86 l) were enrolled. Six patients were excluded due to inability to achieve a maximal test. Lung function and self-assessed every-day activities using a oxygen-cost diagram were evaluated before entry of the study. A maximal effort ramp-pattern cardiopulmonary exercise test (CPET) and a 6 MWT were conducted in random order. Borg score, heart rate, and O2 saturation with pulse oximetry (SpO2) were measured during both exercise tests. VO2 AT and minute ventilation were also measured during the CPET. Correlations were sought between the distance covered in the 6 MWT, and the D x W product with AT, VO2max and other variables. The average D and D x W were 456 m and 27.5 kg km(-1), respectively. D x W was superior to D alone when correlated with the VO2max and AT determined from the CPET, while modestly correlated with the change (delta) in Borg score and delta SpO2 in the 6 MWT and self-assessed every-day activities. Distance x weight product was correlated with the AT and VO2max. In addition, D x W was better correlated with diffusing capacity for carbon monoxide and vital capacity than D alone. We conclude that D x W mimics the work of walking better than D and is suggested as a parameter for evaluation of patients' fitness if gas exchange measurements are not available. (+info)Forced expiratory manoeuvres in children: do they meet ATS and ERS criteria for spirometry? (7/53)
The aim of this study was to evaluate the applicability of American Thoracic Society and European Respiratory Society criteria for spirometry in children. Maximal expiratory flow/volume (MEFV) measurements from 446 school-age children, experienced in performing MEFV manoeuvres, were studied and acceptability (start-of-test (backward extrapolated volume as a percentage of forced vital capacity (FVC) ([Vbc%FVC) or as an absolute value (Vbe), end-of-test (forced expiratory time (FET)) and reproducibility criteria (absolute and percentage difference between best and second-best FVC and forced expiratory volume in one second (FEV1) (deltaFVC, deltaFVC %, deltaFEV1 and deltaFEV1 %)) were applied to these manoeuvres. The Vbe%FVC criterion was met by 91.5%, the Vbe <0.15 L criterion by 94.8% and the Vbe <0.10 L by 60.1% of children. Vbe <0.15 L appeared to be a more useful parameter than Vbe%FVC. The FET criterion was met by only 15.3% of children. deltaFVC <0.2 L and deltaFEV1 <0.2 L were met by 97.1% and 98.4%, and deltaFVC <0.1 L and deltaFEV1 <0.1 L by 79.8% and 84.3% of the children, respectively. These criteria appeared to be less useful compared to percentage criteria (deltaFVC % and deltaFEV1 %). Even experienced children did not meet all international criteria for spirometry. However, most of their MEFV curves are useful for interpretation. Based on the performance of these children, a re-evaluation of criteria for maximal expiratory flow/volume measurements in children is proposed. (+info)Screening tests for pulmonary function abnormality. (8/53)
Simple tests based on a voluntary forced expiration can detect pulmonary impairment of occupational or environmental origin earlier than can be done using clinical or radiographic examination. These tests are easily performed and repeated, require little time and can be readily set up in the field. Flow impairment ("obstructive") has conventionally been measured by the forced expiratory volume--1 sec (FEV1); earlier changes, in the small airways are more likely to be detected by the maximal mid-expiratory flow (MMF) and the maximum expiratory flow-volume (MEFV) curve at low lung volumes. Volume impairment ("restrictive") is detected by the forced vital capacity (FVC) from which the preceding measurements are made. (+info)Maximal Expiratory Flow-Volume (MEFV) curves are graphic representations of the maximum flow rates achieved during a forced expiration, starting at total lung capacity and ending at residual volume, used to assess pulmonary function and identify obstructive ventilatory defects.
Maximal expiratory flow-volume (MEFV) curves are a graphical representation of the maximum volume of air that can be exhaled during a forced breath, measured at different lung volumes. It is a pulmonary function test used to assess obstructive lung diseases such as asthma or chronic obstructive pulmonary disease (COPD).
The MEFV curve is created by having the patient take a deep breath in and then exhale as forcefully and quickly as possible into a spirometer, which measures the volume and flow of air. The test is repeated multiple times to ensure accurate results.
The MEFV curve provides information on the degree of obstruction in the airways, the location of the obstruction (central or peripheral), and the severity of the disease. It can also be used to monitor the effectiveness of treatment and disease progression over time.
Maximal Expiratory Flow Rate (MEFR) is the maximum volume of air that can be exhaled during a forced expiration starting from full inspiration, typically measured in liters per second, and used to assess pulmonary function and obstructive lung diseases such as asthma or COPD.
Maximal Expiratory Flow Rate (MEFR) is a measure of how quickly a person can exhale air from their lungs. It is often used in pulmonary function testing to assess the degree of airflow obstruction in conditions such as chronic obstructive pulmonary disease (COPD) or asthma.
The MEFR is typically measured by having the person take a deep breath and then exhale as forcefully and quickly as possible into a device that measures the volume and flow of air. The MEFR is calculated as the maximum flow rate achieved during the exhalation maneuver, usually expressed in liters per second (L/s) or seconds (L/sec).
MEFR can be measured at different lung volumes, such as at functional residual capacity (FRC) or at total lung capacity (TLC), to provide additional information about the severity and location of airflow obstruction. However, MEFR is not as commonly used in clinical practice as other measures of pulmonary function, such as forced expiratory volume in one second (FEV1) or forced vital capacity (FVC).
'Lung Volume Measurements' refer to the various techniques used to determine the total amount of air inhaled or exhaled from the lungs at different points during the respiratory cycle, providing valuable information about lung function and disease.
Lung volume measurements are clinical tests that determine the amount of air inhaled, exhaled, and present in the lungs at different times during the breathing cycle. These measurements include:
1. Tidal Volume (TV): The amount of air inhaled or exhaled during normal breathing, usually around 500 mL in resting adults.
2. Inspiratory Reserve Volume (IRV): The additional air that can be inhaled after a normal inspiration, approximately 3,000 mL in adults.
3. Expiratory Reserve Volume (ERV): The extra air that can be exhaled after a normal expiration, about 1,000-1,200 mL in adults.
4. Residual Volume (RV): The air remaining in the lungs after a maximal exhalation, approximately 1,100-1,500 mL in adults.
5. Total Lung Capacity (TLC): The total amount of air the lungs can hold at full inflation, calculated as TV + IRV + ERV + RV, around 6,000 mL in adults.
6. Functional Residual Capacity (FRC): The volume of air remaining in the lungs after a normal expiration, equal to ERV + RV, about 2,100-2,700 mL in adults.
7. Inspiratory Capacity (IC): The maximum amount of air that can be inhaled after a normal expiration, equal to TV + IRV, around 3,500 mL in adults.
8. Vital Capacity (VC): The total volume of air that can be exhaled after a maximal inspiration, calculated as IC + ERV, approximately 4,200-5,600 mL in adults.
These measurements help assess lung function and identify various respiratory disorders such as chronic obstructive pulmonary disease (COPD), asthma, and restrictive lung diseases.
'Forced Expiratory Flow Rates' in the context of pulmonary function tests, refer to the speed of airflow expelled from the lungs during various parts of a forced exhalation, measured at specific points after starting to blow out forcefully following a full inspiration, providing valuable information about the caliber and elasticity of the bronchial tubes and the efficiency of the gas exchange process in the lungs.
Forced expiratory flow rates (FEFR) are measures of how quickly and efficiently air can be exhaled from the lungs during a forced breath maneuver. These measurements are often used in pulmonary function testing to help diagnose and monitor obstructive lung diseases such as asthma or chronic obstructive pulmonary disease (COPD).
FEFR is typically measured during a forced expiratory maneuver, where the person takes a deep breath in and then exhales as forcefully and quickly as possible into a mouthpiece connected to a spirometer. The spirometer measures the volume and flow rate of the exhaled air over time.
There are several different FEFR measurements that can be reported, including:
* Forced Expiratory Flow (FEF) 25-75%: This is the average flow rate during the middle half of the forced expiratory maneuver.
* Peak Expiratory Flow Rate (PEFR): This is the maximum flow rate achieved during the first second of the forced expiratory maneuver.
* Forced Expiratory Volume in 1 Second (FEV1): This is the volume of air exhaled in the first second of the forced expiratory maneuver.
Abnormal FEFR values can indicate obstruction in the small airways of the lungs, which can make it difficult to breathe out fully and quickly. The specific pattern of abnormalities in FEFR measurements can help doctors differentiate between different types of obstructive lung diseases.
Peak Expiratory Flow Rate (PEFR) is the maximum speed at which an individual can forcefully exhale air from their lungs after fully inhaling, measured in liters per minute, used as a quick assessment of breathing capacity and obstructive lung disorders like asthma.
Peak Expiratory Flow Rate (PEFR) is a measurement of how quickly a person can exhale air from their lungs. It is often used as a quick test to assess breathing difficulties in people with respiratory conditions such as asthma or chronic obstructive pulmonary disease (COPD). PEFR is measured in liters per minute (L/min) and the highest value obtained during a forceful exhalation is recorded as the peak expiratory flow rate. Regular monitoring of PEFR can help to assess the severity of an asthma attack or the effectiveness of treatment.
Respiratory Function Tests (RFTs) are a group of clinical tests that measure various lung volumes, flows and gas exchange to evaluate pulmonary function and detect presence, severity or progression of respiratory diseases or conditions.
Respiratory Function Tests (RFTs) are a group of medical tests that measure how well your lungs take in and exhale air, and how well they transfer oxygen and carbon dioxide into and out of your blood. They can help diagnose certain lung disorders, measure the severity of lung disease, and monitor response to treatment.
RFTs include several types of tests, such as:
1. Spirometry: This test measures how much air you can exhale and how quickly you can do it. It's often used to diagnose and monitor conditions like asthma, chronic obstructive pulmonary disease (COPD), and other lung diseases.
2. Lung volume testing: This test measures the total amount of air in your lungs. It can help diagnose restrictive lung diseases, such as pulmonary fibrosis or sarcoidosis.
3. Diffusion capacity testing: This test measures how well oxygen moves from your lungs into your bloodstream. It's often used to diagnose and monitor conditions like pulmonary fibrosis, interstitial lung disease, and other lung diseases that affect the ability of the lungs to transfer oxygen to the blood.
4. Bronchoprovocation testing: This test involves inhaling a substance that can cause your airways to narrow, such as methacholine or histamine. It's often used to diagnose and monitor asthma.
5. Exercise stress testing: This test measures how well your lungs and heart work together during exercise. It's often used to diagnose lung or heart disease.
Overall, Respiratory Function Tests are an important tool for diagnosing and managing a wide range of lung conditions.
Residual Volume (RV) is the amount of air that remains in the lungs after a forced maximal expiration, representing the minimum volume of air that cannot be exhaled from the lungs and can only be measured with specialized equipment.
Residual Volume (RV) is the amount of air that remains in the lungs after a forced exhale, also known as the "expiratory reserve volume." It is the lowest lung volume that can be reached during a forced exhalation and cannot be completely emptied due to the presence of alveoli that are too small or too far from the airways. This volume is important for maintaining the structural integrity of the lungs and preventing their collapse. Any additional air that enters the lungs after this point will increase the total lung capacity. The normal residual volume for an average adult human is typically around 1 to 1.5 liters.
'Vital Capacity' is the total volume of air that can be forcibly exhaled from the lungs after a maximum inspiration, typically measured in liters.
Vital capacity (VC) is a term used in pulmonary function tests to describe the maximum volume of air that can be exhaled after taking a deep breath. It is the sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume. In other words, it's the total amount of air you can forcibly exhale after inhaling as deeply as possible. Vital capacity is an important measurement in assessing lung function and can be reduced in conditions such as chronic obstructive pulmonary disease (COPD), asthma, and other respiratory disorders.
Forced Expiratory Volume (FEV) is the volume of air forcefully exhaled from a person's lungs during the first few seconds (usually 1, 2, or 3 seconds) of a forced expiration maneuver, which is commonly used in pulmonary function tests to assess obstructive lung diseases.
Forced Expiratory Volume (FEV) is a medical term used to describe the volume of air that can be forcefully exhaled from the lungs in one second. It is often measured during pulmonary function testing to assess lung function and diagnose conditions such as chronic obstructive pulmonary disease (COPD) or asthma.
FEV is typically expressed as a percentage of the Forced Vital Capacity (FVC), which is the total volume of air that can be exhaled from the lungs after taking a deep breath in. The ratio of FEV to FVC is used to determine whether there is obstruction in the airways, with a lower ratio indicating more severe obstruction.
There are different types of FEV measurements, including FEV1 (the volume of air exhaled in one second), FEV25-75 (the average volume of air exhaled during the middle 50% of the FVC maneuver), and FEV0.5 (the volume of air exhaled in half a second). These measurements can provide additional information about lung function and help guide treatment decisions.
Airway obstruction is a medical condition characterized by the partial or complete blockage of the respiratory tract, preventing the normal flow of air into and out of the lungs, which can lead to respiratory distress, hypoxia, and potentially death if not promptly treated.
Airway obstruction is a medical condition that occurs when the normal flow of air into and out of the lungs is partially or completely blocked. This blockage can be caused by a variety of factors, including swelling of the tissues in the airway, the presence of foreign objects or substances, or abnormal growths such as tumors.
When the airway becomes obstructed, it can make it difficult for a person to breathe normally. They may experience symptoms such as shortness of breath, wheezing, coughing, and chest tightness. In severe cases, airway obstruction can lead to respiratory failure and other life-threatening complications.
There are several types of airway obstruction, including:
1. Upper airway obstruction: This occurs when the blockage is located in the upper part of the airway, such as the nose, throat, or voice box.
2. Lower airway obstruction: This occurs when the blockage is located in the lower part of the airway, such as the trachea or bronchi.
3. Partial airway obstruction: This occurs when the airway is partially blocked, allowing some air to flow in and out of the lungs.
4. Complete airway obstruction: This occurs when the airway is completely blocked, preventing any air from flowing into or out of the lungs.
Treatment for airway obstruction depends on the underlying cause of the condition. In some cases, removing the obstruction may be as simple as clearing the airway of foreign objects or mucus. In other cases, more invasive treatments such as surgery may be necessary.
Total Lung Capacity (TLC) is the maximum volume of air that can be contained within the lungs at the end of a maximal inspiration, including all functional residual capacity and residual volume.
Total Lung Capacity (TLC) is the maximum volume of air that can be contained within the lungs at the end of a maximal inspiration. It includes all of the following lung volumes: tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume. TLC can be measured directly using gas dilution techniques or indirectly by adding residual volume to vital capacity. Factors that affect TLC include age, sex, height, and lung health status.
The lung is a paired, spongy organ within the thoracic cavity that functions primarily in the gas exchange process, enabling the body to extract oxygen from the atmosphere and release carbon dioxide with every breath.
A lung is a pair of spongy, elastic organs in the chest that work together to enable breathing. They are responsible for taking in oxygen and expelling carbon dioxide through the process of respiration. The left lung has two lobes, while the right lung has three lobes. The lungs are protected by the ribcage and are covered by a double-layered membrane called the pleura. The trachea divides into two bronchi, which further divide into smaller bronchioles, leading to millions of tiny air sacs called alveoli, where the exchange of gases occurs.
'Airway Resistance' is the opposition to airflow during breathing, resulting from the frictional forces between the gas and the walls of the respiratory tract, often quantified as the pressure difference per unit flow rate.
Airway resistance is a measure of the opposition to airflow during breathing, which is caused by the friction between the air and the walls of the respiratory tract. It is an important parameter in respiratory physiology because it can affect the work of breathing and gas exchange.
Airway resistance is usually expressed in units of cm H2O/L/s or Pa·s/m, and it can be measured during spontaneous breathing or during forced expiratory maneuvers, such as those used in pulmonary function testing. Increased airway resistance can result from a variety of conditions, including asthma, chronic obstructive pulmonary disease (COPD), bronchitis, and bronchiectasis. Decreased airway resistance can be seen in conditions such as emphysema or after a successful bronchodilator treatment.
Spirometry is a common type of pulmonary function test (PFT) that measures how well the lungs exchange air and how effectively they can be expelled by the patient, providing valuable information for diagnosing and monitoring various respiratory conditions such as asthma, COPD, and restrictive lung diseases.
Spirometry is a common type of pulmonary function test (PFT) that measures how well your lungs work. This is done by measuring how much air you can exhale from your lungs after taking a deep breath, and how quickly you can exhale it. The results are compared to normal values for your age, height, sex, and ethnicity.
Spirometry is used to diagnose and monitor certain lung conditions, such as asthma, chronic obstructive pulmonary disease (COPD), and other respiratory diseases that cause narrowing of the airways. It can also be used to assess the effectiveness of treatment for these conditions. The test is non-invasive, safe, and easy to perform.
Pulmonary ventilation is the process of moving air into and out of the lungs, thereby providing oxygen to the body and removing carbon dioxide, which is accomplished by the actions of inspiration (breathing in) and expiration (breathing out).
Pulmonary ventilation, also known as pulmonary respiration or simply ventilation, is the process of moving air into and out of the lungs to facilitate gas exchange. It involves two main phases: inhalation (or inspiration) and exhalation (or expiration). During inhalation, the diaphragm and external intercostal muscles contract, causing the chest volume to increase and the pressure inside the chest to decrease, which then draws air into the lungs. Conversely, during exhalation, these muscles relax, causing the chest volume to decrease and the pressure inside the chest to increase, which pushes air out of the lungs. This process ensures that oxygen-rich air from the atmosphere enters the alveoli (air sacs in the lungs), where it can diffuse into the bloodstream, while carbon dioxide-rich air from the bloodstream in the capillaries surrounding the alveoli is expelled out of the body.
Peak expiratory flow
Knudson, RJ (1983). "Changes in the normal maximal expiratory flow-volume curve with growth and aging". Am Rev Respir Dis. 127 ... The peak expiratory flow (PEF), also called peak expiratory flow rate (PEFR) and peak flow measurement, is a person's maximum ... Peak expiratory flow is typically measured in units of liters per minute (L/min). Peak flow readings are higher when patients ... It is important to use the same peak flow meter every time. To interpret the significance of peak expiratory flow measurements ...
List of MeSH codes (E01)
... maximal expiratory flow rate MeSH E01.370.386.700.660.225.505 - maximal expiratory flow-volume curves MeSH E01.370.386.700. ... peak expiratory flow rate MeSH E01.370.386.700.660.230 - forced expiratory volume MeSH E01.370.386.700.660.500 - maximal ... expiratory reserve volume MeSH E01.370.386.700.485.750.275.650 - residual volume MeSH E01.370.386.700.485.750.900 - vital ... expiratory reserve volume MeSH E01.370.386.700.485.750.900.350 - inspiratory capacity MeSH E01.370.386.700.485.750.900.350.350 ...
List of MeSH codes (G09)
... maximal expiratory flow rate MeSH G09.772.765.650.300.630 - maximal expiratory flow-volume curves MeSH G09.772.765.650.300.670 ... peak expiratory flow rate MeSH G09.772.765.650.430 - forced expiratory volume MeSH G09.772.765.650.630 - maximal voluntary ... expiratory reserve volume MeSH G09.772.765.850.390.820 - residual volume MeSH G09.772.765.850.970 - vital capacity MeSH G09.772 ... renal blood flow, effective MeSH G09.330.582.163.812.740 - renal plasma flow MeSH G09.330.582.163.812.750 - renal plasma flow, ...
Pulmonary function testing
... vital capacity to be considered accurate it has to be conducted three times where the peak is sharp in the flow-volume curve ... Maximal expiratory pressure (MEP) is the maximal pressure measured during forced expiration (with cheeks bulging) through a ... The lung volumes are tidal volume (VT), inspiratory reserve volume (IRV), expiratory reserve volume (ERV), and residual volume ... Reproducibility of the PFT is determined by comparing the values of forced vital capacity (FVC) and forced expiratory volume at ...
Spirometry
... a volume-time curve, showing volume (litres) along the Y-axis and time (seconds) along the X-axis a flow-volume loop, which ... forced expiratory flow 25-75% (FEF 25-75) and maximal voluntary ventilation (MVV), also known as Maximum breathing capacity. ... Spirometry generates pneumotachographs, which are charts that plot the volume and flow of air coming in and out of the lungs ... Ciprandi, Giorgio; Cirillo, Ignazio (1 February 2011). "Forced expiratory flow between 25% and 75% of vital capacity may be a ...
Freediving blackout
At 30 msw (4 bar), 2% by volume oxygen in the lung gas gives a pO2 of 60 millimetres of mercury (80 mbar). At 10 msw (2 bar), ... Ischaemic hypoxia is caused by reduced blood flow to the brain arising from cerebral vasoconstriction brought on by low carbon ... Positive end-expiratory pressure will generally improve oxygenation. Freediving - Underwater diving without breathing apparatus ... Lindholm P, Lundgren CE (2006). "Alveolar gas composition before and after maximal breath-holds in competitive divers". ...
Peak expiratory flow - Wikipedia
Knudson, RJ (1983). "Changes in the normal maximal expiratory flow-volume curve with growth and aging". Am Rev Respir Dis. 127 ... The peak expiratory flow (PEF), also called peak expiratory flow rate (PEFR) and peak flow measurement, is a persons maximum ... Peak expiratory flow is typically measured in units of liters per minute (L/min). Peak flow readings are higher when patients ... It is important to use the same peak flow meter every time. To interpret the significance of peak expiratory flow measurements ...
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The effect of organic dust exposure on long-term change in lung function: a systematic review and meta-analysis | Occupational ...
Changes in the normal maximal expiratory flow-volume curve with growth and aging. Am Rev Respir Dis 1983;127:725-34.doi:10.1164 ... as argued by Burrows et al in a study on changes in the normal flow-volume curve with growth and ageing,44 and by an official ... Aging-related considerations when evaluating the forced expiratory volume in 1 second (FEV1) over time. J Gerontol A Biol Sci ... Meta-analysis revealed an overall small significant excess loss in forced expiratory volume in the 1st s for exposed compared ...
Multi-ethnic reference values for spirometry for the 3-95-yr age range: the global lung function 2012 equations | European...
Changes in the normal maximal expiratory flow-volume curve with growth and aging. Am Rev Respir Dis 1983; 127: 725-734. ... Predicted values for a, b) forced expiratory volume in 1 s (FEV1), c, d) forced vital capacity (FVC) and e, f) FEV1/FVC by sex ... The lower limit of normal (LLN), based on the 5th centile (-1.64 z-scores), values for forced expiratory volume in 1 s (FEV1) ... a) Age-related cross-sectional annual change in forced expiratory volume in 1 s (FEV1) is larger in tall subjects rather than ...
Multi-ethnic reference values for spirometry for the 3-95-yr age range: the global lung function 2012 equations | European...
Changes in the normal maximal expiratory flow-volume curve with growth and aging. Am Rev Respir Dis 1983; 127: 725-734. ... Predicted values for a, b) forced expiratory volume in 1 s (FEV1), c, d) forced vital capacity (FVC) and e, f) FEV1/FVC by sex ... The lower limit of normal (LLN), based on the 5th centile (-1.64 z-scores), values for forced expiratory volume in 1 s (FEV1) ... a) Age-related cross-sectional annual change in forced expiratory volume in 1 s (FEV1) is larger in tall subjects rather than ...
A double-blind placebo controlled trial with oral ambroxol and N-acetylcysteine for mucolytic treatment in cystic fibrosis
PDF) Acoustic analysis of snoring sound in patients with simple snoring and obstructive sleep apnea
Maximal expiratory flow-volume (MEFV) curves were measured in 1044 healthy nonsmoking volunteers living in the Barcelona area, ... forced maximal mid-expiratory flow (FEF25-75%), peak expiratory flow rate (PEF) and maximal expiratory flow at 50 and 75% of ... Maximal flow during snoring was less (p less than 0.05) in OSA (0.18 +/- 0.07 liter/second) than in HS (0.36 +/- 0.06 liter/ ... FEV1: forced expiratory volume in one second; Pa,O2: arterial ... is always preceded by flow limitation [9]. Flow limita-. tion ...
Early COPD Diagnosis in Family Medicine Practice: How to Implement Spirometry?
R. J. Knudson, M. D. Lebowitz, C. J. Holberg, and B. Burrows, "Changes in the normal maximal expiratory flow-volume curve with ... For the low volume clinic, the minimal exposure and the small number of patients may limit the possibility of having a ... Private clinics also have the support of a nurse and they are usually taking care of the largest volume of patients. ... The service of a trained and designated healthcare professional should be targeted to the high volume clinics. ...
NIOSHTIC-2 Search Results - Full View
Lung function was recorded using maximal (MEFV) and partial expiratory flow volume (PEFV) curves, measuring MEF at 60% of ... There were 18 responders to CBE and 17 responders to CDE.The average maximal falls in MEF(40%)(P) were 70 +/- 4.9 and 70 +/- ... baseline vital capacity below total lung capacity [MEF(40%)(P)] on the PEFV curve. Responders were subjects who developed a 20 ...
Spirometric Reference Values from a Sample of the General U.S. Population | American Journal of Respiratory and Critical Care...
Knudson R. J., Lebowitz M. D., Holberg C. J., Burrows B.Changes in the normal maximal expiratory flow-volume curve with growth ... At the completion of each maneuver, a display was provided of all the flow-volume curves, the FVC, FEV1, PEF, and expiratory ... During the performance of the FVC maneuver, real-time displays of flow-volume and volume-time curves were provided to the ... In addition, the raw flow-volume and volume-time curves were reviewed by a senior technician and the subjects performance was ...
Indoor air pollution and its association with poor lung function, microalbuminuria and variations in blood pressure among...
The maximal expiratory flow-volume curve in normal subjects in India. Chest. 1986;89(6):852-56. ... Peak expiratory flow rate (PEFR), forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and forced ... FEV1, FEV6, PEFR and predicted FEV6% among kitchen workers with MAU in south India were lower in terms of volumes and flow ... expiratory volume in six seconds (FEV6) were measured for the study subjects using a spirometer (PIKO-1 and PIKO-6, Ferraris ...
Department of Bio-Medical Engineering - Research output
- Tel Aviv University
Maximal Expiratory Flow-Volume Curves 80% * Residual Volume 54% * Lung 48% * Trachea 47% ... STEADY COMPRESSIBLE FLOW IN COLLAPSIBLE TUBES.. Elad, D., Kamm, R. D. & Shapiro, A. H., 1987, p. 139-140. 2 p.. Research output ... Sensing volume and biasing corrections for dual counter LDA processors. Shemer, L. & Einav, S., 1979, In: Review of Scientific ... Steady compressible flow in collapsible tubes: Application to forced expiration. Elad, D., Kamm, R. D. & Shapiro, A. H., Jun ...
Occupational health hazards of stone quarry workers of Nagaland,
India
Subhashini, A. S./Satchidhanandam, N. (2002). Maximal expiratory flow volume curve in quarry workers. Indian Journal of ... Panwar, B. R./Vyas, A./Singh, S. K. (2016). Effect of reduction in peak expiratory flow rate on blood pressure of sand stone ... Tiwari, R. R./Sharma, Y. K./Saiyed, H. N. (2005). Peak expiratory flow and respiratory morbidity: a study among silica-exposed ... 2018) with a significant reduction of forced vital capacity (FVC) and forced expiratory volume (FEV) (Gholami et al. 2020). The ...
组合预测模型在女性呼气高峰
Measurements of maximal expiratory flow- volume curves in 134 normal adults. Journal of Bengbu Medical College, 10(2): 114-117 ... Study on different altitude of 506 healthy peoples maximal expiratory flow volume curve. Medical Journal of National Defending ... Determination of Hohhot healthy adults maximal expiratory flow volume curve. Inner Mongolia Medical Journal, 8 (3): 154-155.] ... Measurement of maximum expiratory flow-volume curve in 272 healthy subjects and influence of aging on ventilatory function. ...
Physiotherapy improves symptoms of exercise-induced laryngeal obstruction in young elite athletes: a case series | BMJ Open...
Lung function was measured by maximal expiratory flow-volume curves (MasterScreen Pneumo spirometer; CareFusion, Hochberg, ... lung function was measured by flow-volume curves, and non-specific bronchial hyper-responsiveness was measured by a ... and forced expiratory volume in 1 s (FEV1) were measured. Predicted values are according to Quanjer et al.36 ... The maximal oxygen uptake (VO2max) was stable in all cases pretreatment and post-treatment, except for case 2 where VO2max and ...
Plus it
Changes in the normal maximal expiratory flow-volume curve with growth and aging. Am Rev Respir Dis 1983;127(6):725-734. ... Continuing lung growth in children, which has been correlated with improvements in maximal expiratory flow and upstream airway ... Effect of dry powder inhaler resistance on the inspiratory flow rates and volumes of cystic fibrosis patients of six years and ... researchers demonstrated that even a low inspired flow of 30 L/min and volume of 0.6 L could empty a TIP capsule in 2 efforts, ...
Article|International Journal of Current Research and Review
Subhashini AS, Satchidhanandam N. Maximal expiratory flow volume curve in quarry workers. Indian J Physiol Pharmacol 2002 Jan; ... forced expiratory volume in 1 second (FEV1-lit), peak expiratory flow rate (PEFR -lit/sec), maximum expiratory flow rate (FEF25 ... Then each subject was asked to perform forced Expiratory manoeuvre and maximum Ventilation volume manoeuvre .(8,9) For forced ... For maximum Ventilation volume manoeuvre workers were asked to take a maximum inspiration then pinch his nose and expire as ...
Pesquisa | Portal Regional da BVS
BACKGROUND: Parameters from maximal expiratory flow-volume curves (MEFVC) have been linked to CT-based parameters of COPD. ... INTERPRETATION: The shape of the maximal expiratory flow-volume curve as analyzed with PCA is not an appropriate screening tool ... Principal component analysis of flow-volume curves in COPDGene to link spirometry with phenotypes of COPD. ... Methods: Volumes and densities of the lung/lobes of three COVID-19 patients were assessed using follow-up in vivo CT and ex ...
Detection of Airway Obstruction in Exercise-Induced Asthma Observations
The peak flow meter is less reliable when the maximal expiratory flow-volume curve shows a steeper slope than normal. The ... asthmatic patients show a maximum expiratory flow-volume curve with a very steep rise and a conspicuous decline. This sharp ... It was reported that both Raw and lung volumes (TLC and Vtg) were increased after EIA. Our data failed to show any significant ... In the assessment of early changes in airway flow in our patients, the relative insensitivity of PEFR may also be inherent to ...
S-EPMC8047618 - Normal Routine Spirometry Can Mask COPD/Emphysema in Symptomatic Smokers. - OmicsDI
... maximal expiratory flow at 25%-75% of FVC (MEF25-75) only 4 of 16, residual volume (RV) 4 of 16, and RV to total lung capacity ... Methods Expiratory airflow at high and low lung volumes post-bronchodilator were measured and correlated with lung computed ... Results Despite normal routine spirometry, all16 patients had isolated, abnormal forced expiratory flow at 75% of FVC (FEF75) ... requires analysis of expiratory airflow at low lung volumes, including FEF75. Dependence upon normal routine spirometry may ...
EurekaMag Full Text Articles Chapter 28199
Vincken, W. 1987: Effects of acute weight loss on the maximal expiratory flow volume mefv curve of obese subjects. Clinical ... Gervin, C.A.; Harris, T.R.; Katz, M.A. 1982: Effects of acute changes in coronary blood flow on protein transport in the dog. ... Batten, J.J.; L.K.; Sidebotham, R.L.; Spencer, J.; Baron, J.H. 1988: Effects of acid pepsin volume of secretion and mucus ... Flaim, S.F.; Fields, R.H.; Peuler, J.D.; Harrison, T.S. 1980: Effects of acute and chronic volume overload on plasma and ...
average+flow+rate - с английского на все языки
See also forced expiratory f. Called also maximal midexpiratory f. and maximal or maximum midexpiratory flow rate … Medical ... Flow can be measured in a variety of ways. Positive displacement flow meters acumulate a fixed volume of fluid and then count ... inflow performance curve, reservoir curve, tubing curve, outflow curve, system graph, pressure loss ... Plug flow reactor model - The plug flow reactor (PFR) model is used to describe chemical reactions in continuous, flowing ...
List of Figures | COPD-X
Random variation of inspiratory lung function parameters in patients with COPD: a diagnostic accuracy study | BMC Pulmonary...
The forced inspiratory volume in 1 second (FIV1), inspiratory capacity (IC), maximal inspiratory flow at 50% (MIF50) and peak ... Inspiratory parameters like the forced inspiratory volume in 1 second (FIV1) and inspiratory capacity (IC) can be responsive to ... inspiratory flow (PIF) were measured five times in one day and again within two weeks of the first measurement. The values of ... the response of the forced expiratory volume in 1 second (FEV1) after bronchodilator application is weak. ...
Spirometric assessment in asthma in children
... peak expiratory flow (maximum flow during forced expulsion) and maximal voluntary volume (the maximum amount of air that can be ... using both flow-volume curves and volume-time curves, as well as active symptoms or history of symptoms such as coughing, ... representing volume and flow, respectively. The resulting graph is aptly termed the flow-volume curve. ... When viewing flow-volume curve of a supposed normal person, the area of the curve that is descending will normally reach a peak ...
average flow rate | Перевод average flow rate?
See also forced expiratory f. Called also maximal midexpiratory f. and maximal or maximum midexpiratory flow rate … Medical ... Flow can be measured in a variety of ways. Positive displacement flow meters acumulate a fixed volume of fluid and then count ... usually calculated as an average flow over a given portion of the expiratory curve; the portion between 25 and 75 per cent of ... Plug flow reactor model - The plug flow reactor (PFR) model is used to describe chemical reactions in continuous, flowing ...
Drager Babylog 8000 Plus Ventilator | Teaching Unit
Expiratory Block, Flow Sensor, Sensor Insert, Flow Sensor Cable, Stand, and Air & O2 Hoses.. Configuration:. Contact us to see ... Trigger: Flow/volume trigger, leak adapted. - Trigger delay: approx. 40-60 ms ... Real-time curves: Flow and pressure, integrated. *Inspiratory oxygen concentration: 21-100 vol.% oxygen ... Maximal frequency: 200 bpm. *Inspiratory time: 0.1 to 2 seconds. *Expiratory time: 0.2 to 30 seconds ...
FEV1PulmonaryResidualPeakTidal volumeExpiratoire maximalVital capacitySpirometryThoracicAirwayAirflow limitationExpirationInspirationMeasurementLung functionPressuresInspiratory volumeTypicallyOxygenBaselineVentilationMeasuresReserve volumeMeasurementsAlveoliAdultsContinuousParametersDiseasesChestCapacitiesTimeAssessmentPressureStroke volumePatientsReductionCannot be measuredArterial diameterDecreaseIncreases
FEV110
- FEV1) and peak expiratory flow rate (PEFR) than those of African ethnicity. (who.int)
- Measures of expiratory airflow are preserved and airway resistance is normal and the forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) ratio is increased. (medscape.com)
- In chronic obstructive pulmonary disease (COPD), the response of the forced expiratory volume in 1 second (FEV1) after bronchodilator application is weak. (biomedcentral.com)
- These authors found that in patients with severe COPD (FEV1 mean was 38% of the predicted normal value), the reduction in dyspnea after the inhalation of a beta (2)-adrenoreceptor agonist was closely correlated to the change in parameters of forced inspiration, particularly for the forced inspiratory volume in 1 second (FIV1), but not with changes in parameters of forced expiration. (biomedcentral.com)
- The forced expiratory flow averaged over the time during which 25 to 75% of the FVC is exhaled may be a more sensitive marker of mild, small airway airflow limitation than the FEV1, but the reproducibility of this variable is poor. (msdmanuals.com)
- This is defined in spirometry as a reduction in the ratio of the expiratory volume measured in the 1st second of a forceful exhalation (FEV1) to the total volume of air exhaled in the forced expiration (FVC), the FVC being an estimate of the individual's effective lung volume. (cdc.gov)
- The first step when interpretin… The decrease in lung volumes causes a decrease in airflow (reduced FEV1-see Figure: Flow-volume loops B). However, spirometry is not widely available and spirometric test results are not always optimally recorded or interpreted except when performed by … Common obstructive lung diseases are asthma, bronchitis, bronchiectasis and chronic obstructive pulmonary disease (COPD). (maymoitruong.com)
- It measures the forced vital capacity (FVC), the forced exhaled volume in 1 second (FEV1), total lung capacity, and residual volume. (wikidoc.org)
- Forced expiratory volume in one second (FEV1): Forced expiratory volume in one second measures the total amount of air that can be forcibly exhaled in the first second of the FVC test.Healthy people generally expel around 75% … Objective To determine whether low-tidal-volume ventilation compared with conventional ventilation during major surgery decreases postoperative pulmonary complications. (annarborbonsaisociety.org)
- Forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) were significantly higher in males than females. (who.int)
Pulmonary14
- Patients were assessed clinically and by extensive pulmonary function techniques (body-plethysmography, maximal expiratory flow-volume curves, trapped air determination). (nih.gov)
- The severity of chronic obstructive pulmonary disease (COPD) is defined by the degree of expiratory airflow limitation. (biomedcentral.com)
- Airflow and lung volume measurements can be used to differentiate obstructive from restrictive pulmonary disorders, to characterize severity, and to measure responses to therapy. (msdmanuals.com)
- Studies have found that unadjusted flow and volume values are more predictive of patient outcomes than ethnically adjusted values, suggesting that these adjustments may result in under-recognition (and thus undertreatment) of true decreases in pulmonary function in non-White individuals. (msdmanuals.com)
- 11 During the early phase of inspiration, the positive pressure in the alveolus moves blood from the pulmonary circulation to the heart, resulting in an increase in left ventricular preload, a rise in stroke volume and blood pressure. (vin.com)
- 12 As inspiration continues, the pulmonary vascular bed is depleted of blood and the pulmonary vascular resistance rises, a decrease in left ventricular preload occurs, and stroke volume and blood pressure decrease. (vin.com)
- 12 The decrease in stroke volume is particularly obvious if the pulmonary vascular bed is hypovolaemic. (vin.com)
- Spirometry (meaning the measuring of breath ) is the most common of the Pulmonary Function Tests (PFTs), measuring lung function, specifically the measurement of the amount (volume) and/or speed (flow) of air that can be inhaled and exhaled. (wikidoc.org)
- Pressure (P)-volume (V) relationships of the total respiratory system a) in normal and b) in chronic obstructive pulmonary disease (COPD).Tidal P-V curves during rest ( ) and exercise ( ) are shown. (annarborbonsaisociety.org)
- Analysis from 1,019 patients undergoing one-lung ventilation indicated that low tidal volume in the presence of low positive end-expiratory pressure is associated with increased pulmonary complications. (annarborbonsaisociety.org)
- There are 3 main ways auto-PEEP occurs: 1) High minute ventilation - high respiratory rates or high tidal volumes Similar to pulmonary function tests, these will include tidal breathing (the normal breathing volume), respiratory rate, and vital capacity (breathing volume during a deep breath). (annarborbonsaisociety.org)
- Modest declines in maximal pulmonary function with VATS-I were seen when comparing all curve types together but not when comparing Lenke 1 curves alone. (vermaspine.com)
- The model may also be used to predict maximal pulmonary function recovery. (vermaspine.com)
- Taken together the results of these assessments suggest a restrictive pulmonary function impairment without expiratory flow limitation. (ersjournals.com)
Residual5
- Measuring airflow at FEF 50 detected only 8 of 16 patients, maximal expiratory flow at 25%-75% of FVC (MEF 25-75 ) only 4 of 16, residual volume (RV) 4 of 16, and RV to total lung capacity ratio only 2 of 16. (omicsdi.org)
- a Residual volume. (medscape.com)
- Although an accurate diagnoses of total lung volume is not possible with spirometry (residual lung volume cannot be measured with a spirometer) spirometry results can be very suggestive for a restrictive lung disease. (maymoitruong.com)
- 1,9-13 Many surgical patients undergo short-term ventilation with large V T (>10 ml/kg predicted body … There are a number of different measurements and terms which are often used to describe this including tidal volume, inspiratory reserve volume, residual volume, vital … Lung volumes and exercise. (annarborbonsaisociety.org)
- Maximal inspiratory and expiratory pressures were performed from residual volume and total lung capacity, respectively. (bvsalud.org)
Peak21
- The peak expiratory flow (PEF), also called peak expiratory flow rate (PEFR) and peak flow measurement, is a person's maximum speed of expiration, as measured with a peak flow meter, a small, hand-held device used to monitor a person's ability to breathe out air. (wikipedia.org)
- Peak expiratory flow is typically measured in units of liters per minute (L/min). (wikipedia.org)
- Peak flow readings are higher when patients are well, and lower when the airways are constricted. (wikipedia.org)
- Due to the wide range of 'normal' values and the high degree of variability, peak flow is not the recommended test to identify asthma. (wikipedia.org)
- A small portion of people with asthma may benefit from regular peak flow monitoring. (wikipedia.org)
- When peak flow is being monitored regularly, the results may be recorded on a peak flow chart. (wikipedia.org)
- It is important to use the same peak flow meter every time. (wikipedia.org)
- To interpret the significance of peak expiratory flow measurements, a comparison is made to reference (normal, predicted) values based on measurements taken from the general population. (wikipedia.org)
- More recently, medical calculators have been developed to calculate predicted values for peak expiratory flow. (wikipedia.org)
- There are a number of non-equivalent scales used in the interpretation of peak expiratory flow. (wikipedia.org)
- These formulas have also been trended over time in both rural and metropolitan areas both as air quality studies and as studies on asthma due to the Peak Flow measurement's accuracy as a predictor of mortality and poor prognosis. (wikipedia.org)
- Electronic devices will sample the flow and multiply the sample volume(Litres) by 60, divided by the sample time(seconds) for a result measured in L/minute : sample volume × 60 sample time {\displaystyle {\frac {{\text{sample volume}}\times 60}{\text{sample time}}}} The highest of three readings is used as the recorded value of the Peak Expiratory Flow Rate. (wikipedia.org)
- It may be plotted out on graph paper charts together with a record of symptoms or using peak flow charting software. (wikipedia.org)
- The measurement of peak expiratory flow was pioneered by Martin Wright, who produced the first meter specifically designed to measure this index of lung function. (wikipedia.org)
- Since the original design of instrument was introduced in the late 1950s, and the subsequent development of a more portable, lower cost version (the "Mini-Wright" peak flow meter), other designs and copies have become available across the world. (wikipedia.org)
- 1989. New regression equations for predicting peak expiratory flow in adults. (wikipedia.org)
- As a first step, correlation analysis was used to analyze the relationship between peak expiratory flow value of adult women and the selected 25 indicators of geographical factors. (progressingeography.com)
- Based on the result, seven geographic indicators (latitude, altitude, average temperature, annual average relative humidity, annual rainfall, topsoil gravel percentage, and topsoil reference capacity) that have significant correlation with peak expiratory flow reference value were extracted for further analysis. (progressingeography.com)
- The output of this study indicates that the relationship between geographical factors and healthy adult Chinese women's lung peak expiratory flow rate should not be overlooked. (progressingeography.com)
- The forced inspiratory volume in 1 second (FIV1), inspiratory capacity (IC), maximal inspiratory flow at 50% (MIF50) and peak inspiratory flow (PIF) were measured five times in one day and again within two weeks of the first measurement. (biomedcentral.com)
- The peak expiratory flow (PEF) is the peak flow occurring during exhalation. (msdmanuals.com)
Tidal volume10
- Improved respiratory efficiency, increased minute ventilation and tidal volume. (bmj.com)
- Sometimes, the test will be preceded by a period of quiet breathing in and out from the sensor (tidal volume), or the rapid breath in (forced inspiratory part) will come before the forced exhalation. (wikidoc.org)
- This was a RCT of low vs. traditional tidal volume ventilation in 861 patients with acute lung injury. (annarborbonsaisociety.org)
- In case you missed it, that trial showed that low tidal volume ventilation (6 ml/kg IBW) improved mortality from 40% to 31% in patients with established lung … The chart above shows volume of the lungs as a function of time. (annarborbonsaisociety.org)
- Figure 1- Effect of lung mechanics and inspiratory time on tidal volume (V T) delivery during high-frequency oscillatory ventilation.a) Maximum potential V T is determined by lung compliance (C L) and inspiratory time (t I), while the rate of V T delivery is determined by lung mechanics. (annarborbonsaisociety.org)
- To further investigate the tidal volume (VT) response to exercise in severe COPD, nine patients were … In COPD individuals, there is a resetting of the respiratory system's relaxation volume to a higher level than in the healthy individuals. (annarborbonsaisociety.org)
- To the Editor The inherent physiological rationale for lowering tidal volume during mechanical ventilation is to decrease strain on the lung tissue to avoid ventilator-induced lung injury. (annarborbonsaisociety.org)
- It can be assessed with the negative expiratory pressure (NEP) technique and is expressed as either the percentage of the tidal volume over which EFL occurs (EFL%Vt) or according to more detailed three-point or five-point scoring systems. (annarborbonsaisociety.org)
- Importance In patients who undergo mechanical ventilation during surgery, the ideal tidal volume is unclear. (annarborbonsaisociety.org)
- The tidal volume is the total amount of air inhaled or exhaled during regular respiration or relaxed breathing. (annarborbonsaisociety.org)
Expiratoire maximal2
- Les Soudanais d'origine arabe avaient une capacité vitale, un volume expiratoire maximal seconde et un débit expiratoire de pointe nettement supérieurs à ceux des Soudanais d'origine africaine. (who.int)
- Le volume expiratoire maximal par seconde (VEMS) et la capacité vitale forcée (CVF) étaient nettement supérieurs chez les garçons que chez les filles. (who.int)
Vital capacity7
- Forced expiratory value in 1 s (FEV 1 ) and forced vital capacity (FVC) between ethnic groups differed proportionally from that in Caucasians, such that FEV 1 /FVC remained virtually independent of ethnic group. (ersjournals.com)
- On the latter we measured the maximal expiratory flow 60% of baseline vital capacity below total lung capacity (MEF40%(P)). Responders (R) were defined as subjects who developed a 20% or greater fall in MEF40%(P) following extract challenge. (cdc.gov)
- Some of the factors responsible for the abnormal nitrogen washout tracings in the other 19 patients, which produced no sudden change in the "alveolar" plateau could be as follows: nonuniform distribution of ventilation, abnormal respiratory flow patterns, local changes in lung compliance which can be accentuated even more during exercise, and the inability of the patients (especially after exercise ) to hold their breaths at vital capacity. (onlineasthmainhalers.com)
- This includes post-bronchodilator normal forced expiratory volume in 1 second (FEV 1 )(L)≥80% predicted, forced vital capacity (FVC)(L)≥80% predicted, and FEV 1 /FVC ≥70% or greater than age corrected lower limit of normal (LLN). (omicsdi.org)
- maximum midexpiratory flow - the average rate of airflow measured between exhaled volumes of 25 and 75 per cent of the vital capacity during a forced exhalation. (academic.ru)
- The static lung volumes/capacities are further subdivided into four standard volumes (tidal, inspiratory … Forced vital capacity (FVC): Forced vital capacity measures the amount of air you can breathe out forcefully after taking as deep a breath as possible. (annarborbonsaisociety.org)
- During baseline assessments, upright forced vital capacity (FVC) was 60% of predicted, while the ratio between forced expiratory volume in 1 s and FVC (FEV 1 /FVC) was 80% [ 2 ]. (ersjournals.com)
Spirometry8
- In 1994, as NHANES III was completing data collection, the ATS revised its 1987 spirometry recommendations ( 11 ), which included changes in both the extrapolated volume and the reproducibility criteria. (atsjournals.org)
- Expiratory airflow at high and low lung volumes post-bronchodilator were measured and correlated with lung computed tomography (CT) and lung pathology (6 patients) in 16 symptomatic, treated smokers, and all with normal routine spirometry. (omicsdi.org)
- Despite normal routine spirometry, all16 patients had isolated, abnormal forced expiratory flow at 75% of FVC (FEF 75 ) using data from Knudson et al, Hankinson et al NHAMES III, and Quanjer et al and the Global Lung Function Initiative. (omicsdi.org)
- This study confirms our earlier observations that detection of small airways obstruction and/or emphysema, in symptomatic smokers with normal routine spirometry, requires analysis of expiratory airflow at low lung volumes, including FEF 75 . (omicsdi.org)
- Assessing functional res-pi-ra-tory parameters is often challenging, especially in children, where spirometry requires the full collaboration in order to cor-rectly aquire and interpret flows and volumes. (medichub.ro)
- Quantitative measures of inspiratory and expiratory flow are obtained by forced spirometry. (msdmanuals.com)
- The expiratory volume-time graph should also be smooth and free from abnormalities caused by: Typical spirometry findings in obstructive lung disease include: It can be useful to assess reversibility with a bronchodilator if considering asthma as a cause of obstructive airway disease. (maymoitruong.com)
- Other tests used for restrictive lung patterns along with spirometry are helium lung volumes and diffusing capacity of carbon monoxide. (wikidoc.org)
Thoracic3
- Restrictive lung diseases are characterized by a reduction in FRC and other lung volumes because of pathology in the lungs, pleura, or structures of the thoracic cage. (medscape.com)
- We read with extreme interest the recently published work by O'Donnell and colleagues (May 2010).1 Comparing lung volumes obtained using different techniques in a sample of patients with severe airflow limitation, the authors conclude that plethysmography systematically overestimates lung volumes with regard to gas dilution and thoracic imaging techniques. (annarborbonsaisociety.org)
- VATS procedures for thoracic scoliosis and open approaches for thoracolumbar curve types were associated with minimal to no permanent defi cits. (vermaspine.com)
Airway1
- The expected sudden change in the slope of the "alveolar" plateau (phase 3) of the nitrogen washout curve which signals airway closure, did not appear despite the fact that the test in each instance was repeated three to five times. (onlineasthmainhalers.com)
Airflow limitation1
- In the presence of airflow limitation, the patient exhales air slowly, while the total volume of air exhaled is generally not affected. (wikidoc.org)
Expiration1
- The flow-volume loop is typically flattened during inspiration and expiration. (maymoitruong.com)
Inspiration1
- The total lung capacity (TLC) is the volume of gas that is contained in the lungs at the end of maximal inspiration. (annarborbonsaisociety.org)
Measurement2
- Flow measurement - is the quantification of bulk fluid movement. (academic.ru)
- The measurement of maximal static researches with different samples in order to respiratory pressures (MRP) at the mouth compare values found with predicted ones in provides subsidies to direct the preoperative and previous studies, or to present new predicted postoperative therapeutic goals1, assess the equations2,7-11. (bvsalud.org)
Lung function6
- It shows limited evidence of a causal association between exposure to organic dust and change in lung function, with a small significant excess decline in only forced expiratory volume in the 1st s of 4.92 mL/year (95% CI 0.14 to 9.69) among exposed compared with controls. (bmj.com)
- Lung function was recorded using maximal and partial flow volume curves. (cdc.gov)
- Inappropriate laryngeal movements during exercise were measured by the continuous laryngoscopy exercise test, lung function was measured by flow-volume curves, and non-specific bronchial hyper-responsiveness was measured by a methacholine provocation test. (bmj.com)
- All athletes had less respiratory distress, improved lung function at rest and reduced inappropriate laryngeal movements during maximal exercise. (bmj.com)
- Measurements are typically reported as absolute flows and volumes and as percentages of predicted values using data derived from large populations of people presumed to have normal lung function. (msdmanuals.com)
- Origin for lung function decline is the maximal point of lung function within 2.5 years after start of treatment. (ersjournals.com)
Pressures4
- 4 The haemodynamic measurements of filling pressures, urine output and biochemical indicators are misleading and poor indicators of central blood volume. (vin.com)
- Maximal respiratory pressures were assessed by a digital manometer with the adolescents in the seated position and wearing a nose clip. (bvsalud.org)
- were not successful in predicting the values for maximal respiratory pressures in the population studied, indicating the necessity of using in clinical practice reference values from a healthy population of the same ethnicity. (bvsalud.org)
- The maximal inspiratory ( P Imax ) and expiratory pressures ( P Emax ) were −108 cmH 2 O (97% predicted) and 213 cmH 2 O (176% predicted), respectively ( table 2 ) [ 4 , 5 ]. (ersjournals.com)
Inspiratory volume1
- Inspiratory parameters like the forced inspiratory volume in 1 second (FIV1) and inspiratory capacity (IC) can be responsive to bronchodilators. (biomedcentral.com)
Typically1
- These diseases are typically characterized by a reduction in expiratory air flow rates. (cdc.gov)
Oxygen2
- It is well established that for an individual athlete training or competing at altitude maximal oxygen uptake (VO 2 max) will be impaired. (bmj.com)
- VO 2max , Maximal oxygen uptake. (biomedcentral.com)
Baseline4
- The average maximal response to CBE was a fall of MEF40%(P) to 68 +/- 9.1% of baseline compared to 68 +/- 6.8 for CDE (NS). (cdc.gov)
- Maternal blood volume increases progressively, peaking at a value of approximately 40% above baseline by the third trimester. (medscape.com)
- The increased blood volume is associated with elevated cardiac output, which increases by 30-50% above baseline levels by 25 weeks. (medscape.com)
- The heart rate increases and reaches a maximal value of 10-30% above baseline values by 32 weeks. (medscape.com)
Ventilation4
- i Maximal voluntary ventilation. (medscape.com)
- however, during heavy exercise, many athletes demonstrate limitations to expiratory flow and are unable to increase ventilation in hypoxia. (bmj.com)
- One prevalent approach is ventilation with large tidal volumes. (annarborbonsaisociety.org)
- LARGE tidal volumes (V T) contribute to and worsen the acute respiratory distress syndrome (ARDS) in intensive care unit (ICU) patients after hours or days of ventilation. (annarborbonsaisociety.org)
Measures2
- Endothelial function can be assessed non-invasively using the technique of flow mediated dilatation (FMD), where endothelium-dependent dilatation in the brachial artery is assessed during reactive hyperaemia in response to 5 minute arterial occlusion and endothelium-independent dilatation in response to sublingual glyceryl trinitrate, using high-resolution vascular ultrasound and a real-time analyser that measures arterial diameter and Doppler flow. (cam.ac.uk)
- Pulse pressure variation (PPV) and stroke volume variation (SVV) are the most famous dynamic measures. (biomedcentral.com)
Reserve volume4
- jExpiratory reserve volume. (medscape.com)
- j Expiratory reserve volume. (medscape.com)
- Inspiratory reserve volume is … Respiratory volumes are the amount of air inhaled, exhaled and stored within the lungs at any given time. (annarborbonsaisociety.org)
- decreased expiratory reserve volume definitely changes. (medscape.com)
Measurements1
- Measurements may be based on 1 second or less but are usually reported as a volume per minute. (wikipedia.org)
Alveoli1
- Air flows to and from the alveoli as lungs inflate and deflate during each respiratory cycle. (medscape.com)
Adults1
- For example, historical cohorts of primarily American and European adults showed lower lung volumes in multiple non-White ethnic groups (eg, Blacks, Hispanics, Asians) than in Whites. (msdmanuals.com)
Continuous2
- A reduction in inappropriate laryngeal movements during maximal effort, according to continuous laryngoscopy exercise tests prephysiotherapy and postphysiotherapy treatment. (bmj.com)
- Plug flow reactor model - The plug flow reactor (PFR) model is used to describe chemical reactions in continuous, flowing systems. (academic.ru)
Parameters2
- In contrast, no correlations were observed between exercise parameters and LA volumes or any other echocardiographic indices. (fortunepublish.com)
- Less-invasive dynamic parameters include plethysmographic-derived parameters, variation in blood flow in large arteries, and variation in the diameters of central veins. (biomedcentral.com)
Diseases1
- Restrictive lung diseases are characterized by reduced lung volumes, either because of an alteration in lung parenchyma or because of a disease of the pleura, chest wall, or neuromuscular apparatus. (medscape.com)
Chest2
- The volume of FRC is determined by the balance of the inward elastic recoil of the lungs and the outward elastic recoil of the chest wall. (medscape.com)
- In cases of intrinsic lung disease, the physiological effects of diffuse parenchymal disorders reduce all lung volumes by the excessive elastic recoil of the lungs, relative to the outward recoil forces of the chest wall. (medscape.com)
Capacities1
- Static lung volumes and capacities were also decreased [ 3 ]. (ersjournals.com)
Time3
- Most currently used devices measure only airflow and integrate time to estimate the expired volume. (msdmanuals.com)
- This article gives a brief explanation about volume-time curves which are used to assist the distinction between obstructive and restrictive lung disease. (maymoitruong.com)
- This results in a linear increase in forearm volume over time, and this is proportional to arterial blood inflow until venous pressure rises towards the occluding pressure. (cam.ac.uk)
Assessment2
- The assessment of adequate intravascular volume in critically ill patients and patients undergoing anaesthesia is vital in ensuring an adequate circulation. (vin.com)
- Assessment of patient response to volume expansion presents a daily challenge for acute care physicians. (biomedcentral.com)
Pressure5
- Compliance is the volume change produced by a change in the distending pressure. (medscape.com)
- This law relates to the delivery of blood (blood flow, ml/kg/min) than to pressure. (vin.com)
- Poiseuille's equation tells us that flow is directly proportional to the pressure difference and the radius to the fourth power, and inversely proportional to the length of the tube and the viscosity. (vin.com)
- Cardiac output and stroke volume are assessed non-invasively using inert gas rebreathing technique and blood pressure measured using specialised BP monitor. (cam.ac.uk)
- Transdiaphragmatic pressure ( P di ) obtained during maximal voluntary sniff manoeuvres (sniff P di ) was 74 cmH 2 O (51% predicted) ( table 2 and figure 1a ) [ 5 ]. (ersjournals.com)
Stroke volume2
- Fluid responsiveness is defined as a positive increase in stroke volume in response to a fluid bolus. (vin.com)
- Fluid responsiveness (FR) is defined as the ability of the left ventricle to increase its stroke volume (SV) in response to fluid administration. (biomedcentral.com)
Patients3
- In inspiratory flow and volume assessments, patients exhale as completely as possible, then forcibly inhale. (msdmanuals.com)
- p-value represents difference in annual ICS adherence between not-controlled and controlled patients as defined by area under the curve method and independent-samples t-test. (ersjournals.com)
- 10 Fluid responsive patients are on the preload-dependent portion of the Frank-Starling curve, while nonresponsive patients are on the preload load-independent portion of the curve. (vin.com)
Reduction1
- The many disorders that cause reduction or restriction of lung volumes may be divided into two groups based on anatomical structures. (medscape.com)
Cannot be measured1
- this volume cannot be measured, only calculated. (annarborbonsaisociety.org)
Arterial diameter1
- Changes in arterial diameter produces little change in circulating volume space but do affect left heart cardiac output and hence venous return to the right heart, while changes in venous capacitance has dramatic effects on circulating volume space. (vin.com)
Decrease1
- In healthy children neither the total lung capacity (TLC) nor Vtg significantly changed after exercise, but they may decrease slightly as a result of an increase in intrathoracic blood volume. (onlineasthmainhalers.com)
Increases3
- Additionally, increasing ventilatory work in hypoxia may actually be negative for performance, if dyspnoea increases or muscle blood flow is reduced secondary to an increased sympathetic outflow (eg, the muscle metaboreflex response). (bmj.com)
- In active labor, hyperventilation increases and tachypnea caused by pain and anxiety might result in marked hypocapnia and respiratory alkalosis, adversely affecting fetal oxygenation by reducing uterine blood flow. (medscape.com)
- Plasma volume increases by 45-50%, and red cell mass increases by 20-30%, resulting in anemia of pregnancy. (medscape.com)
