Abstract 254: Comparison of Cold Crystalloid and Colloid Infusions for Induction of Therapeutic Hypothermia in a Porcine Model of Cardiac Arrest
Introduction: Cold crystalloids have been used for induction of therapeutic hypothermia after cardiac arrest but so far the effectiveness of cold colloids has not been evaluated. This prospective study investigates the cooling effect of rapid intravenous infusion of cold crystalloid compared to colloid in a porcine model of ventricular fibrillation (VF).
Methods: VF was electrically induced in twenty-two anesthetized domestic pigs (33 ± 2 kg). Defibrillation was attempted after 15 min CPR using the AutoPulse (Zoll Medical, USA) and artificial ventilation. After spontaneous circulation was restored, the animals were randomized to receive either 1500 mL of 1°C cold Voluven [6% hydroxyethyl starch 130/0.4 in 0.9% NaCl] within 25 min using a Zoll Power Infuser (group A; n = 9), or 1500 mL of 1°C cold normal saline (group B; n = 9), or no infusion (group C; n = 4). The animals were observed for 90 min following infusion. Cerebral, rectal, intramuscular, pulmonary artery, and subcutaneous fat body temperatures (BT) were continuously recorded using GES 130 temperature probes and GMH 3250 digital thermometers with logger function (Greisinger Electronic, Germany). Data were analyzed with JMP 3.2 software (SAS Institute, USA) and are expressed as a mean ± SD. P < 0.05 was considered statistically significant.
Results: 45.6 ± 2.7 mL·kg-1 of cold colloid was infused in group A, and 46.8 ± 3.1 mL·kg-1 of crystalloid in group B. The animals treated with cold fluids achieved a significant decrease of BT in all measurement sites while there was a spontaneous increase in group C. At the time of finishing infusion there was a greater decrease in cerebral and pulmonary artery temperatures in group B compared to group A (-1.7 ± 0.4 vs. -1.1 ± 0.3 °C, P < 0.05, and -2.1 ± 0.3 vs. -1.6 ± 0.2 °C, P < 0.05 respectively). Area under the curve (AUC) analysis of the decrease in intra-cerebral BT revealed a more vigorous cooling effect in group B compared to A (-91 ± 30 vs. -62 ± 32 °C·min, P = 0.06). There was also a higher calculated amount of absorbed heat for crystalloids compared to colloids (33.9 ± 5.7 vs. 26.6 ± 3.4 cal, P < 0.05).
Conclusion: Cold crystalloid infusions resulted in a more intense cooling effect than colloid infusions of the same temperature and infusion rate in this porcine model of cardiac arrest.
- © 2011 by American Heart Association, Inc.