Prehospital emergency care : official journal of the National Association of EMS Physicians and the National Association of State EMS Directors
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The amount of myocardial perfusion required for successful defibrillation after prolonged cardiac arrest is not known. Coronary perfusion pressure (CPP) is a surrogate for myocardial perfusion. One limited clinical study reported that a threshold of 15 mmHg was necessary for return of spontaneous circulation (ROSC), and that CPP was predictive of ROSC. A distinction between threshold and dose of CPP has not been reported. ⋯ Higher CPP threshold and dose are associated with and predictive of ROSC.
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Comparative Study
Comparison of low-energy versus high-energy biphasic defibrillation shocks following prolonged ventricular fibrillation.
Since the initial development of the defibrillator, there has been concern that, while delivery of a large electric shock would stop fibrillation, it would also cause damage to the heart. This concern has been raised again with the development of the biphasic defibrillator. ⋯ Biphasic 360-J shocks do not cause more cardiac damage than biphasic 150-J shocks in this animal model of prolonged VF and resuscitation.
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To determine whether the number of advanced life support-trained personnel at the scene of an out-of-hospital cardiac arrest (OHCA) was associated with return of spontaneous circulation (ROSC) or survival to hospital discharge. ⋯ The presence of three or more paramedics at the scene of OHCA was not associated with improved survival to hospital discharge when compared to crews with two paramedics. Additional research is needed to determine the potential cause of this finding.
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Comparative Study
The effect of physical exertion in chemical and biological personal protective equipment on physiological function and reaction time.
The primary objective of this study was to describe and compare changes in heart rate, venous pH, venous partial pressure of carbon dioxide (pCO(2)), venous bicarbonate level, lactate level, oxygen saturation (SpO(2)), and tympanic membrane (TM) temperature occurring in a group of healthy volunteers during 20 minutes of physical exertion, both with and without chemical and biological personal protective equipment (PPE). A further aim was to establish whether any significant prolongation of reaction time occurred after physical exertion in chemical and biological PPE, compared to baseline values without the protective equipment. ⋯ This study did not identify any effect of 20 minutes of heavy exercise in highly fit volunteers wearing level C chemical and biological PPE on reaction time. Heart rate response and TM temperature were higher during exertion in PPE. These differences, along with other physiological alterations observed, were not of clinical relevance. Further studies using arterial blood gas analysis and a more accurate measure of core body temperature are needed to better assess the physiological effect of this level and duration of exercise on subjects wearing similar PPE. Other aspects of cognition also require investigation under these conditions, in order to assess their effect on patient and rescuer safety.