Resuscitation
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Severe metabolic acidosis develops following prolonged periods of cardiopulmonary arrest (CPA), and excessive hydrogen ions derived from lactate and other noxious acids cause marked hyperkalemia in most CPA patients. This study investigated whether the serum electrolyte imbalance in resuscitated CPA patients is affected by the etiology of the CPA. Between 1999 and 2000, return of spontaneous circulation (ROSC) was achieved and serum electrolyte concentration measurements and blood gas analysis (BGA) were performed in 65 of 270 CPA patients treated. ⋯ The SAH group had significantly lower serum potassium concentrations than the other two groups and significantly higher glucose concentrations than the asphyxia group. Massive amounts of catecholamines are released into the systemic circulation of SAH patients and our results may indicate that the amount of catecholamines released in resuscitated SAH patients is greater than in heart attack or asphyxia patients, resulting in a lower serum potassium concentration despite the presence of severe metabolic acidosis. It should be clarified in a prospective study whether the presence of normokalemia and hyperglycemia in resuscitated CPA patients reliably predicts the presence of SAH.
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Transthoracic impedance and current flow are determinants of defibrillation success with monophasic shocks. Whether transthoracic impedance, either independently or via its association with body weight, is a determinant of biphasic waveform shock success has not been determined. ⋯ Body weight is a determinant of shock success with biphasic waveforms at low energy levels in this swine model.
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The recurrence rate of lethal cardiac events after the survival of a primary cardiac arrest in patients not having received an implantable cardioverter defibrillator (ICD) is investigated. ⋯ Cardiac arrest survivors without an apparent indication for an ICD have a high risk of suffering from a re-arrest of cardiac origin.
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We hypothesized that electrical shocks that defibrillate hearts successfully also produce myocardial injury, but only in settings in which the myocardium is underperfused. Myocardial function was measured in isolated, conventionally perfused or underperfused rat hearts during sinus rhythm and conventionally perfused or underperfused hearts during ventricular fibrillation (VF) after delivery of a sham, a 0.4 J, or a 0.7 J shock. ⋯ This contrasted with normally perfused hearts, whether in sinus rhythm or during VF, in which shocks resulted in no significant impairment. Electrical shocks therefore produce myocardial injury but only when myocardial perfusion is reduced.
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Comparative Study
Vasopressin with delayed combination of nitroglycerin increases survival rate in asphyxia rat model.
Recently, vasopressin has been reported as a more effective drug than epinephrine (adrenaline) for cardiopulmonary resuscitation (CPR). However, vasopressin decreases myocardial blood flow (MBF) because of its strong vasoconstriction, to maintain better coronary perfusion pressure (CPP) compared with epinephrine. Nitroglycerin is well known to be able to maintain MBF and increase survival rate. ⋯ Six min after asphyxia induced by obstructing the tracheal tube, CPR was performed in two ways. Three animals resuscitated in the V-Gr. (42%) and six/seven (84%) in the VN-Gr. (P<0.05). In the 6 min of asphyxia rat model, vasopressin combined with delayed nitroglycerin is more effective than vasopressin alone.