Resuscitation
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To assess the safety and the accuracy of a 4 h stepwise diagnostic approach relying on clinical judgement in unselected patients with acute chest pain. ⋯ The 4 h stepwise approach guided by clinical judgement was safe for ruling out impending cardiac events in unselected patients with acute chest pain. However, more extensive evaluation is necessary for accurate rule-in of coronary chest pain.
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To explore the effects of alkaline buffers on cerebral perfusion and cerebral acidosis during and after cardiopulmonary resuscitation (CPR), 45 anaesthetized piglets were studied. The animals were subjected to 5 min non-interventional circulatory arrest followed by 7 min closed chest CPR and received either 1 mmol/kg of sodium bicarbonate, 1 mmol/kg of tris buffer mixture, or the same volume of saline (n=15 in all groups), adrenaline (epinephrine) boluses and finally external defibrillatory shocks. Systemic haemodynamic variables, cerebral cortical blood flow, arterial, mixed venous, and internal jugular bulb blood acid-base status and blood gases as well as cerebral tissue pH and PCO(2) were monitored. ⋯ After restoration of spontaneous circulation, during and after temporary arterial hypotension, pH in internal jugular bulb blood and in cerebral tissue as well as cerebral cortical blood flow was lower after saline than in animals receiving alkaline buffer. Buffer administration during CPR promoted cerebral cortical reperfusion and mitigated subsequent post-resuscitation cerebral acidosis during lower blood pressure and flow in the reperfusion phase. The arterial alkalosis often noticed during CPR after the administration of alkaline buffers was caused by low systemic blood flow, which also results in poor outcome.
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Defibrillation is essential for victims of sudden cardiac arrest (SCA) with ventricular fibrillation (VF), yet it does not terminate the underlying causes of VF. Prior to more definitive interventions, these same causes may result in recurrence of VF following defibrillation (refibrillation). The incidence and course of refibrillation, and its relation to patient outcomes, has not been previously described in the context of treatment of out-of-hospital SCA with biphasic waveform automated external defibrillators (AEDs). ⋯ One hundred and sixteen of 128 shocks delivered under BLS care to 49 patients with witnessed cardiac arrests presenting with VF terminated VF. Most patients (61%) refibrillated while under BLS care, many (35%) more than once. Occurrence of and time to refibrillation were unrelated to achievement of return of spontaneous circulation (ROSC) under BLS care (BLS ROSC), to survival to hospital discharge and to neurologically intact survival.
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The pupils dilate following cardiac arrest but the mechanism is unknown. If pupillary dilation represents inadequate blood supply to the midbrain, pupil size might be a rough guide to the adequacy of the resuscitation effort. The brain dead organ harvest patient presents a unique opportunity to study pupillary activity in the absence of an intact midbrain and to examine the effects of asphyxia on the pupil. ⋯ Time to peak dilation was 4.3+/-1.4 min and latency of dilation was 1.4+/-1.2 min. Dapiprazole eye drops prevented the pupillary dilation in contralateral eye of the five cases in which it was used. The cause of this sympathetic activity is either a short burst of neuronal activity in the peripheral sympathetic system innervating the dilator muscle, or release of stored norepinephine from the presynaptic terminals, as asphyxia intervenes.