Effects of hypertonic saline on myocardial blood flow in a porcine model of prolonged cardiac arrest

Objective: To evaluate the effects of hypertonic saline (HS) on myocardial reperfusion pressure (MPP) and blood flow (MBF), and cardiac index (CI) during and after cardiopulmonary resuscitation (CPR). Methods: In 21 domestic swine (16-23 kg) open chest cardiac massage was initiated after 10 min of ventricular fibrillation. With the onset of CPR animals randomly received HS (7.2%; 2 ml/kg per 10 min or 4 ml/kg per 20 min) or normal saline ((NS); 2 ml/kg per 10 min). Haemodynamic variables were monitored continuously, and coloured microspheres were used to measure MBF and CI before cardiac arrest (CA), during CPR and 5, 30 and 120 min after the return of spontaneous circulation. Results: During CPR HS significantly increased MPP, MBF, and CI in comparison to NS (P < 0.05, resp., MANOVA). Doubling the volume of HS did not improve the haemodynamic effects seen after application of 2 ml/kg per 10 min. HS-infusion significantly increased the survival rate at 120 min, 6/7 and 5/7 animals receiving 2 ml/kg per 10 min or 4 ml/kg per 20 min versus 2/7 after NS-infusion (P < 0.05, chi(2)-test). Conclusions: HS applied during open chest cardiac massage enhanced MBF and CI, and significantly increased resuscitation success and survival rate. The positive effects of this promising new approach need to be confirmed in clinical studies. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.