Tight control of prehospital ventilation by capnography in major trauma victims.
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BACKGROUND: Tracheal intubation combined with controlled ventilation of the lungs is an important part of the prehospital management of major trauma victims, but gauging the adequacy of ventilation remains a major problem. METHODS: Ninety-seven major trauma victims who underwent tracheal intubation in the field and controlled ventilation of the lungs during prehospital treatment by a Helicopter Emergency Medical Service were assigned randomly to one of two groups: (1) monitor group (n=57) and (2) monitor-blind group (n=40), according to whether the anaesthetist could or could not see an attached capnograph screen. In the monitor-blind group ventilation was set by using a tidal-volume of 10 ml kg(-1) estimated body weight and an age-appropriate ventilatory frequency. In the monitor group, ventilation was adjusted to achieve target end-tidal carbon dioxide values determined by the 'physiological state' of the trauma victim. Arterial blood gases were measured upon hospital admission while maintaining the ventilation initiated in the field and the Pa(CO(2)) value obtained was used as the determinant of the adequacy of prehospital ventilation. RESULTS: The incidence of 'normoventilation' was significantly higher (63.2 vs 20%; P<0.0001) and the incidence of 'hypoventilation' upon hospital admission was significantly lower (5.3 vs 37.5%; P<0.0001) in the monitor group; patients with severe head and chest trauma and haemodynamically unstable patients and those with a high injury severity score were significantly more likely to be 'normoventilated' upon hospital admission in the monitor group than in the monitor-blind group. CONCLUSIONS: The data support the routine use of prehospital capnographic monitoring using target end-tidal carbon dioxide values adapted to the physiological state of the patient in major trauma victims requiring tracheal intubation in the field. (+info)
Towards evidence based emergency medicine: best BETs from the Manchester Royal Infirmary. Colourimetric CO(2) detector compared with capnography for confirming ET tube placement.
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A short cut review was carried out to establish whether colourimetric carbon dioxide detectors are as reliable as capnometry at verifying tracheal placement of endotracheal tubes after emergency intubation. A total of 69 papers were found using the reported search, of which four presented the best evidence to answer the clinical question. The author, date and country of publication, patient group studied, study type, relevant outcomes, results, and study weaknesses of these best papers are tabulated. A clinical bottom line is stated. (+info)
The PEP respiratory monitor: a validation study.
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The search for a reliable and accurate respiratory rate monitor for use in non-intubated patients has proved to be a long and fruitless one. A new device fulfilling the criteria for such a monitor has recently been described. The pyroelectric polymer (PEP) device is safe, non-invasive, and cheap. In this study the PEP device, transthoracic impedance, and standard observer counting were all compared with the existing gold standard of capnography in 12 healthy adult volunteers. Using a standard statistical technique it was shown that the PEP device performed as well as a capnograph and was more accurate than the other currently available methods of monitoring respiratory rate. (+info)
Accuracy of pulse oximetry and capnography in healthy and compromised horses during spontaneous and controlled ventilation.
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The objective of this prospective clinical study was to evaluate the accuracy of pulse oximetry and capnography in healthy and compromised horses during general anesthesia with spontaneous and controlled ventilation. Horses anesthetized in a dorsal recumbency position for arthroscopy (n = 20) or colic surgery (n = 16) were instrumented with an earlobe probe from the pulse oximeter positioned on the tip of the tongue and a sample line inserted at the Y-piece for capnography. The horses were allowed to breathe spontaneously (SV) for the first 20 min after induction, and thereafter ventilation was controlled (IPPV). Arterial blood, for blood gas analysis, was drawn 20 min after induction and 20 min after IPPV was started. Relationships between oxygen saturation as determined by pulse oximetry (SpO2), arterial oxygen saturation (SaO2), arterial carbon dioxide partial pressure (PaCO2), and end tidal carbon dioxide (P(et)CO2), several physiological variables, and the accuracy of pulse oximetry and capnography, were evaluated by Bland-Altman or regression analysis. In the present study, both SpO2 and P(et)CO2 provided a relatively poor indication of SaO2 and PaCO2, respectively, in both healthy and compromised horses, especially during SV. A difference in heart rate obtained by pulse oximetry, ECG, or palpation is significantly correlated with any pulse oximeter inaccuracy. If blood gas analysis is not available, ventilation to P(et)CO2 of 35 to 45 mmHg should maintain the PaCO2 within a normal range. However, especially in compromised horses, it should never substitute blood gas analysis. (+info)
Comparison of propofol and sevoflurane for laryngeal mask airway insertion.
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In this study, we compared haemodynamic changes, laryngeal mask airway (LMA) insertion time, and complications in patients anesthetized by inhalation of sevoflurane with those of intravenous induction with propofol. One hundred patients, aged between 20-40 years were enrolled in this study. Group 1 received propofol (2.5 mg/kg i.v.) and group 2 received sevoflurane (6%+50% N2O+50% O2) by inhalation using the tidal volume technique. LMA insertion time was found to be significantly longer in sevoflurane group than in propofol group. Mean arterial blood pressure was significantly lower within each group after induction in comparison to before induction values. In both groups, the LMA was successfully inserted in all patients. The quality of anaesthesia according to patients was significantly higher in the propofol group (80%) than in sevoflurane group (30%). Odor perception was significantly higher in sevoflurane group (84%) than in propofol group (38%). Apnoea was significantly higher in propofol group (40%) than in sevoflurane group (0%). Sevoflurane is an alternative to propofol for induction of anaesthesia and has a lower incidence of apnoea. Other complication rates are not higher than which propofol but the longer duration of induction time is a disadvantage. (+info)
Difference in end-tidal CO2 between asphyxia cardiac arrest and ventricular fibrillation/pulseless ventricular tachycardia cardiac arrest in the prehospital setting.
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INTRODUCTION: There has been increased interest in the use of capnometry in recent years. During cardiopulmonary resuscitation (CPR), the partial pressure of end-tidal carbon dioxide (PetCO2) correlates with cardiac output and, consequently, it has a prognostic value in CPR. This study was undertaken to compare the initial PetCO2 and the PetCO2 after 1 min during CPR in asphyxial cardiac arrest versus primary cardiac arrest. METHODS: The prospective observational study included two groups of patients: cardiac arrest due to asphyxia with initial rhythm asystole or pulseless electrical activity, and cardiac arrest due to acute myocardial infarction or malignant arrhythmias with initial rhythm ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT). The PetCO2 was measured for both groups immediately after intubation and then repeatedly every minute, both for patients with and without return of spontaneous circulation (ROSC). RESULTS: We analyzed 44 patients with asphyxial cardiac arrest and 141 patients with primary cardiac arrest. The first group showed no significant difference in the initial value of the PetCO2, even when we compared those with and without ROSC. There was a significant difference in the PetCO2 after 1 min of CPR between those patients with ROSC and those without ROSC. The mean value for all patients was significantly higher in the group with asphyxial arrest. In the group with VF/VT arrest there was a significant difference in the initial PetCO2 between patients without and with ROSC. In all patients with ROSC the initial PetCO2 was higher than 10 mmHg. CONCLUSIONS: The initial PetCO2 is significantly higher in asphyxial arrest than in VT/VF cardiac arrest. Regarding asphyxial arrest there is also no difference in values of initial PetCO2 between patients with and without ROSC. On the contrary, there is a significant difference in values of the initial PetCO2 in the VF/VT cardiac arrest between patients with and without ROSC. This difference could prove to be useful as one of the methods in prehospital diagnostic procedures and attendance of cardiac arrest. For this reason we should always include other clinical and laboratory tests. (+info)
Prehospital determination of tracheal tube placement in severe head injury.
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OBJECTIVES: The aim of this prospective study in the prehospital setting was to compare three different methods for immediate confirmation of tube placement into the trachea in patients with severe head injury: auscultation, capnometry, and capnography. METHODS: All adult patients (>18 years) with severe head injury, maxillofacial injury with need of protection of airway, or polytrauma were intubated by an emergency physician in the field. Tube position was initially evaluated by auscultation. Then, capnometry and capnography was performed (infrared method). Emergency physicians evaluated capnogram and partial pressure of end tidal carbon dioxide (EtCO(2)) in millimetres of mercury. Determination of final tube placement was performed by a second direct visualisation with laryngoscope. Data are mean (SD) and percentages. RESULTS: There were 81 patients enrolled in this study (58 with severe head injury, 6 with maxillofacial trauma, and 17 politraumatised patients). At the first attempt eight patients were intubated into the oesophagus. Afterwards endotracheal intubation was undertaken in all without complications. The initial capnometry (sensitivity 100%, specificity 100%), capnometry after sixth breath (sensitivity 100%, specificity 100%), and capnography after sixth breath (sensitivity 100%, specificity 100%) were significantly better indicators for tracheal tube placement than auscultation (sensitivity 94%, specificity 66%, p<0.01). CONCLUSION: Auscultation alone is not a reliable method to confirm endotracheal tube placement in severely traumatised patients in the prehospital setting. It is necessary to combine auscultation with other methods like capnometry or capnography. (+info)
Lung cancer pulse oximetry and capnography in lung function laboratories.
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OBJECTIVE: To compare values reflecting oxyhemoglobin saturation obtained by pulse oximetry (SpO2) and values for end-tidal carbon dioxide pressure (PETCO2) obtained by capnography with direct measures of gas saturation values and pressures (PaO2 and PaCO2) in arterial blood gas samples. PATIENTS AND METHODS: We studied 57 consecutive patients ranging in age from 34 to 83 years--16 of whom were smokers--who presented for lung function testing. RESULTS: The mean (SD) SpO2 was 95% (2.4%), and oxygen saturation measured directly in arterial blood samples was 95.1% (2.3%) (P=NS). The mean PETCO2 was 37.9 (5.3) mm Hg and PaCO2 by arterial blood gas analysis was 40.6 (5.4) mm Hg (P<.0001). The correlation between the 2 measurements of oxygen saturation (SpO2 and direct assessment) was 0.806 (P<.0001), and the correlation between PETCO2 and PaCO2 was 0.845 (P<.0001). The mean difference between the 2 expressions of oxygen saturation was 0.08% (1.46%) and between PETCO2 and PaCO2 was 2.7 (2.9) mm Hg. CONCLUSION: Both measurement devices (pulse oximeter and capnograph) are appropriate for use in a lung function laboratory. The difference between PETCO2 and the PaCO2 should be kept in mind. (+info)