The American journal of emergency medicine
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Studies have shown that over 50% of cardiovascular deaths occur before hospitalization. A major factor associated with survival in cases of out-of-hospital cardiac arrest is the time from cardiovascular collapse to the initiation of cardiopulmonary resuscitation (CPR) or "downtime." The purpose of this study was to determine whether blood lactate levels could be used to predict downtime in the canine cardiac arrest model. Femoral arterial and Swan-Ganz catheters were placed in 22 mongrel dogs, and ventricular fibrillation was electrically induced. ⋯ Linear regression analysis revealed that 84% of the variability in serum lactate levels could be explained by downtime differences. In this model, blood lactate level is a reliable and objective measure of downtime and may be a useful indicator of the adequacy of CPR if levels decrease or remain stable. The clinical implications of this study lie with the use of blood lactate levels in the emergency department to guide the aggressiveness of resuscitative efforts.
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Despite the problems inherent in estimating blood flow from pressure, determination of systolic arterial pressure during cardiopulmonary resuscitation (CPR) is common and probably valuable as an indicator of potential systemic flow. The addition of interposed abdominal compression (IAC) to closed-chest CPR has been promoted because of its potential to increase systolic arterial pressure during CPR. ⋯ Two distinct methods of CPR were studied in conjunction with IAC. In six humans, there was no significant increase late in the resuscitative process in systolic arterial pressure or in DA-DCVP difference with IAC as compared with the two methods of CPR studied without IAC.
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This study was undertaken to characterize blood gas, pH, and lactate changes during and after cardiopulmonary resuscitation (CPR) in arterial and venous samples. Blood samples were withdrawn from the brachial artery, aortic arch, pulmonary artery, coronary sinus, and either the right or left cardiac ventricle of 24 anesthetized dogs. Ventricular fibrillation (VF) was induced electrically, and mechanical CPR was begun. ⋯ Lactate increased to 32 mg/dl during 9 minutes of CPR and did not significantly differ after defibrillation. Blood gases and pH returned to control values within an hour. This study suggests that arterial blood gases are sensitive to rapid changes occurring in the pulmonary capillary bed, while venous blood gases reflect changes occurring in the systemic capillary bed.
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Randomized Controlled Trial Comparative Study Clinical Trial
Pre-hospital IAC-CPR versus standard CPR: paramedic resuscitation of cardiac arrests.
Recent studies evaluating interposed abdominal compression cardiopulmonary resuscitation (IAC-CPR) have demonstrated a significant increase in cardiac output, mean arterial pressure, and cerebral perfusion, as compared with standard CPR. A clinical evaluation of IAC-CPR effectiveness on resuscitation outcome has not been reported. A prospective randomized study comparing IAC-CRP with standard CPR for resuscitation of prehospital cardiopulmonary arrest was undertaken using the Milwaukee County Paramedic System. ⋯ To determine whether abdominal compression increases regurgitation, the frequency of emesis before and after intubation was analyzed. No significant difference was found between the IAC-CPR and standard CPR groups. Thus, IAC-CPR applied by paramedics in the field to patients following intubation does not improve cardiac resuscitation rates.
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Comparative Study
Survival of out-of-hospital cardiac arrest with early initiation of cardiopulmonary resuscitation.
Records on 1,297 people with witnessed out-of-hospital cardiac arrest, caused by heart disease and treated by both emergency medical technicians (EMTs) and paramedics, were examined to determine whether or not early cardiopulmonary resuscitation (CPR) initiated by bystanders independently improved survival. Bystanders initiated CPR for 579 patients (bystander CPR); for the remaining 718 patients, CPR was delayed until the arrival of EMTs (delayed CPR). Survival was significantly better (P less than 0.05) in the bystander-CPR group (32%) than in the delayed-CPR group (22%). ⋯ The authors conclude that early initiation of CPR by bystanders significantly improves survival from out-of-hospital cardiac arrest, and they suggest that it may do so by prolonging the duration of VF after collapse and by increasing cardiac susceptibility to defibrillation. The benefit of this early CPR, however, appears to exist within a rather narrow window of effectiveness. It must be started within 4-6 minutes from the time of collapse and must be followed within 10-12 minutes of the collapse by advanced life support in order to be effective.