Abstract 111: Effects of Target Temperature of Hypothermia on Outcomes of CPR in a Rat Model of VF
Therapeutic hypothermia has been recommended by AHA as one of the standards of post-resuscitation management. However, the optimal target body temperature remains unknown. In this study, we investigated the effects of different target body temperatures (35°C, 33°C and 28°C) on the outcomes of CPR in a rat model of VF. We hypothesized that milder hypothermia (35°C) would yield equal improvement in outcomes of CPR as 33°C and yield significantly better outcomes when compared with normothermia and deep hypothermia (28°C). VF was induced in 24 male Sprague-Dawley rats and untreated for 8 min. Animals were then randomized into four groups (n=6 each): 1. 37°C group; 2. 35°C group; 3. 33°C group; 4. 28°C group. CPR, including mechanical chest compression with ventilation was performed for 8 min prior to defibrillation. Hypothermia was immediately induced following successful resuscitations and continued for 4 hours before rewarming. Temperature and myocardial function were continuously monitored during hypothermia and after rewarming, duration of survival was recorded. Cardiac output (CO) was significantly better in the 33°C and 35°C groups when compared with the 28°C and 37°C groups, no difference was observed between the 33°C and 35°C groups. However, a significantly better CO was observed in the 35°C group after rewarming (Table). Duration of survival was significantly longer in both the 33°C and 35°C groups (Table). Milder hypothermia significantly improved the outcomes of CPR when compared with normothermia and deep hypothermia. Hypothermia at 35°C was equally protective as 33°C, with better CO after rewarming.
- © 2011 by American Heart Association, Inc.