[Determinants of survival in cardiopulmonary resuscitation]

Prognostic indices for survival after cardiopulmonary resuscitation (CPR) were investigated in 14 male Sprague-Dawley rats (500 +/- 50 g) and in 16 domestic pigs (25 +/- 4 kg). Arterial and venous blood gas and lactate measurements in association with the coronary perfusion pressure (CPP) and the end-expiratory CO2 concentration (ETCO2) were evaluated. Additional parameters in the porcine studies were coronary venous blood gas measurements and intramyocardial pH. Volume controlled ventilation was established and catheters were placed in the thoracic aorta and in the right atrium in both animal species. Additionally in the pigs, the pulmonary artery and the great cardiac vein were catheterized and intramyocardial pH was measured with a glass pH electrode placed in the diaphragmatic left ventricular myocardium. Ventricular fibrillation was induced with a direct current and external chest compression was initiated after four minutes in the rats and after three minutes in the pigs. Transthoracic DC defibrillation was attempted with 10J after two minutes of compression in the rats and with 300J after eight minutes of compression in the pigs. Eight of 14 rats and eight of 16 pigs were successfully resuscitated. Significant veno-arterial gradients for pH and pCO2 but not for lactate were observed during CPR in both animal species. With the exception of arterial pH in the pigs (p less than 0.05), neither arterial nor venous blood gas measurements nor intramyocardial pH separated resuscitated from non-resuscitated animals. However, CPP and ETCO2 significantly separated resuscitated from non-resuscitated animals.(ABSTRACT TRUNCATED AT 250 WORDS)