The American journal of emergency medicine
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This study was undertaken to determine the effect of interposed abdominal compressions (IAC) during cardiopulmonary resuscitation (CPR) on gastric insufflation when the airway is not secured with an endotracheal tube. A canine model was used in which a common ventilation pressure was applied to separate cuffed esophageal and tracheal tubes. Gas entering the stomach was collected by a pre-placed gastrostomy tube leading to a bell spirometer. ⋯ During standard CPR, measurable gastric gas volume was collected in 28 of 30 trials (mean 215 +/- 93 ml/ventilation). During IAC-CPR, in which abdominal pressure was maintained during ventilation after every 5th chest compression, measurable gastric gas was collected in 15 of 30 trials (mean 40 +/- 11 ml/ventilation). Interposed abdominal compressions as an adjunct to standard CPR may not only be of hemodynamic benefit, but may also reduce the incidence of gastric insufflation and attendant complications.
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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 Blood samples were withdrawn from the brachial artery, aortic arch, pulmonary artery, coronary sinus, and either the right or left cardiac ventricle of 24 anesthetized dogs.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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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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Previous studies have shown that pulmonary edema occurs in half of all pre-hospital cardiac arrest victims who cannot be successfully resuscitated and is a major cause of hypoxemia and poor lung compliance during resuscitation. Pulmonary vascular hypertension and elevation of pulmonary capillary wedge pressure have been observed during cardiac resuscitation in humans. To further define the time course of the pulmonary hemodynamic changes, pulmonary artery diastolic pressure (PAd) was measured on a computerized trend recorder prior to, during, and immediately after arrest in three adult patients. ⋯ In both patients who were resuscitated successfully, the PADP returned to baseline within 5 minutes of effective spontaneous circulation. The finding that such hemodynamic changes occur rapidly during resuscitation and can reverse quickly with resumption of effective spontaneous circulation is consistent with the time course for the early development of pulmonary edema. Development of pulmonary edema many hours following successful resuscitation likely involves other mechanisms.