Annals of emergency medicine
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Electromechanical dissociation (EMD) in patients in cardiac arrest is associated with a poor prognosis. Pressor agents, particularly alpha-agonists, have proven to be useful in resuscitation from asphyxial and fibrillatory arrest in the animal model. Beta-agonists, such as isoproterenol, have not been shown to improve the resuscitation rate. ⋯ One study demonstrated methoxamine's superiority in raising the aortic diastolic pressure and resuscitating animals from ventricular fibrillation. No significant advantage of norepinephrine use is evident in the literature. Controlled experiments in the animal model and in human patients must be done to determine whether methoxamine or epinephrine is superior in resuscitation from EMD and other forms of cardiac arrest.
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While rapid intervention with basic cardiac life support and prompt delivery of prehospital care using advanced cardiac life support (ACLS) have yielded impressive results in the resuscitation of other arrest rhythms, very little improvement has been shown in the rates of resuscitation from asystole. Anecdotal reports list instances in which patients in asystole have had normal cardiac activity restored after defibrillation. Current ACLS protocols for initial evaluation recommend a single-lead "quick-look" interpretation of cardiac rhythm using portable defibrillator paddles. ⋯ For an eight-month period 119 patients were entered into the study and compared to system controls of asystolic patients presenting in the previous year. While ten patients (8.4%) showed an immediate rhythm change after initial countershock and six of ten reached the hospital with a rhythm and a pulse, no statistically significant comparison could be made regarding improved resuscitation or survival rates. The finding of no statistically significant deterioration of resuscitation or survival rates, however, justifies the continuation of the study.
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Comparative Study
Differences in cerebral and myocardial perfusion during closed-chest resuscitation.
Substantial differences in cerebral and myocardial blood flow occur during cardiac arrest and artificial circulatory support using closed-chest techniques. This inequality can be explained by differences in generated driving pressures across the cerebral resistance vessels and the coronary vascular bed. ⋯ Contemporary cardiopulmonary resuscitation investigations are addressing this problem. Cardiac and cerebral resuscitation techniques must develop in parallel before clinically meaningful results can be obtained.
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Transthoracic cardiac pacing historically has been relegated to the role of the technique of last resort in treating cardiac arrest. Recent studies have shown that this technique has a high rate of successful electrical capture, but often without mechanical activity. Survival rates have been shown to be dismal when the technique is used late in cardiac arrest. ⋯ Survivors generally have been treated early in their arrest and have had hemodynamically ineffective bradycardias. These findings suggest that rapid initiation of transcutaneous pacing in patients with Stokes-Adams attacks, increasing heart block associated with myocardial ischemia, postdefibrillation asystole, or pulseless bradycardia may improve survival. However, victims of a prolonged cardiac arrest whose myocardium has irreversibly ceased to function mechanically are unlikely to benefit from any pacing technique.
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Historical Article
Cardiopulmonary resuscitation research 1960-1984: discoveries and advances.
The 24-year history of cardiopulmonary resuscitation (CPR) can be divided into four eras. The first (1960-1962) was the era of serendipitous discovery and description of "closed-chest cardiac massage" by Kouwenhoven and colleagues. Closed-chest heart massage was combined with artificial ventilation, and became known as CPR. ⋯ The effectiveness had become established through widespread use in coronary care units, catheterization laboratories, and prehospital emergency systems, and open-chest cardiac massage was completely supplanted by CPR in virtually every resuscitation effort. The current era (1976-present) is the era of rediscovery and refinement, beginning with the observation that blood flow and pressure can be generated during cardiac arrest by coughing ("cough CPR"), without actual compression of the chest or heart, and that augmentation of arterial pressure and carotid blood flow resulted from simultaneous compression and ventilation (SCV-CPR or "new CPR"). The current era has provided a new explanation of the mechanism of blood flow during CPR and alternative methods of maintaining perfusion during cardiac arrest.(ABSTRACT TRUNCATED AT 250 WORDS)