Twenty-four hour survival in a canine model of cardiac arrest comparing three methods of manual cardiopulmonary resuscitation.

Two new modifications of manual cardiopulmonary resuscitation, high impulse compression at a rate of 120/min and interposed abdominal compression at a rate of 60/min, have been reported to produce better hemodynamic responses than standard cardiopulmonary resuscitation at 60/min. However, the effect of these two new methods on initial resuscitation success and 24 hour survival is unknown. In this study, 30 mongrel dogs were divided into three equal groups, each treated with one of three types of manual cardiopulmonary resuscitation. Ventricular fibrillation was induced electrically in morphinized, endotracheally intubated dogs emerging from halothane anesthesia. After 3 minutes of circulatory arrest without intervention, one of the three techniques of manual cardiopulmonary resuscitation was begun, and continued for 17 minutes. Defibrillation was performed at 20 minutes. Successful resuscitation was defined as a mean arterial blood pressure of at least 60 mm Hg, without chest compressions, 10 minutes after the initial defibrillation attempt. Intensive care was provided for 2 hours, including hemodynamic and respiratory monitoring, and drug intervention when required. Twenty-four hour survival and neurologic deficit were used as critical measures of outcome. Ten of 30 animals survived 24 hours with a mean neurologic deficit score of 5% (normal = 0, brain dead = 100). There was no difference in initial resuscitation success, 24 hour survival or neurologic deficit of the survivors among the three manual cardiopulmonary resuscitation methods. Aortic diastolic and calculated coronary perfusion pressures were similar for all three methods. Well performed standard manual cardiopulmonary resuscitation is as effective as these modified versions (high impulse compression and interposed abdominal compression) when compared in the same animal model.

Comparison of mechanical techniques of cardiopulmonary resuscitation: survival and neurologic outcome in dogs.

Three currently available mechanical devices for cardiopulmonary resuscitation (CPR) were compared using a canine cardiac arrest model. Twenty-four-hour survival without neurologic deficit was the goal. A group of 30 large mongrel dogs was divided equally among Thumper CPR, simultaneous compression and ventilation (SCV) CPR, and vest CPR. Ventricular fibrillation was induced electrically, and after 3 minutes of no intervention, one of the three types of mechanical CPR was performed for 17 minutes. SCV CPR and vest CPR produced significantly greater aortic and right atrial systolic pressures than Thumper CPR (P less than .03). The SCV CPR technique also produced significantly higher aortic diastolic pressure and right atrial diastolic pressure than either of the other methods (P less than .03). However, coronary perfusion pressure was not different among the three mechanical methods. No differences in immediate resuscitation, 24-hour survival, or neurologic deficit scores at 24 hours were found. Neither SCV nor the vest techniques of CPR appear better for survival or neurologic outcome than standard cardiopulmonary resuscitation performed with the Thumper.

CPR-induced trauma: comparison of three manual methods in an experimental model.

Cardiopulmonary resuscitation (CPR) often results in traumatic injury to the patient. Differences in CPR-induced trauma among various forms of manual, external CPR, however, are unknown. We compared CPR-induced trauma among manual standard (STD) CPR at 60 compressions per minute; high-impulse compression (HIC) CPR at 120 compressions per minute; and interposed abdominal compression (IAC) CPR at 60 compressions per minute. A large (24 +/- 3 kg) mongrel canine model was used. Ten animals were assigned to each type of CPR. Each received 17 minutes of CPR, applied to produce the best possible coronary perfusion pressure without obviously damaging the dog. Defibrillation was attempted at 20 minutes. Necropsy was performed at the time of death or after sacrifice at 24 hours. Careful postmortem examination of the thorax, lungs, heart, abdomen, and great vessels was performed. A semiquantitative trauma score of 0 to 5 was assigned to each area with a possible maximal score of 25. There was no difference in trauma scores among STD (6.4 +/- 1.5), HIC (9.4 +/- 1.4), and IAC (8.1 +/- 1.3) methods. No significant correlation was found between the method of CPR and the different types of trauma. Specifically, IAC did not produce an increase in liver lacerations nor did HIC produce a significant increase in thoracic or pulmonary injuries. Six of 20 initially resuscitated animals expired during the 24-hour follow-up period due to CPR-induced injuries. Four of these six had extensive pulmonary trauma, including pulmonary hemorrhage or edema. Liver lacerations were the second most lethal injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Manual versus mechanical cardiopulmonary resuscitation in an experimental canine model.

Manual and mechanical chest compressions during CPR were compared in the canine model. Endpoints were hemodynamics produced during CPR, resuscitation success at 30 min, 24-h survival, neurologic function of survivors, and CPR-produced trauma. Ten animals in each group underwent 20 min of ventricular fibrillation, during which CPR was performed for 17 min. Hemodynamics produced with manual and mechanical chest compressions were similar. Seven of ten animals in each group were resuscitated. Five animals from the manual group and four animals from the mechanical group survived for 24 h. Neurologic function of survivors was excellent and similar in each group. There was no significant difference in trauma between the two types of chest compression. The similar results for manual and mechanical chest compression in this canine model suggest that different experimental CPR studies can be compared regardless or whether manual or mechanical chest compressions were performed.