The effect of mild hypothermia and induced hypertension on long term survival rate and neurological outcome after asphyxial cardiac arrest in rats

Study objective: we studied the long-term effect of a combined treatment wi th resuscitative mild hypothermia and induced hypertension on survival rate and neurological outcome after asphyxial cardiac arrest (CA) in rats. Meth ods: 36 male Wistar rats, were randomised into three groups: Group I (n = 1 0): anaesthetised with halothane and N2O/O-2 (70/30%) had vessel cannulatio n but no asphyxial CA; mechanical ventilation was continued to 1 h. Group I I (n = 13). under the same anaesthetic conditions and vessel cannulation. w as subjected to asphyxial CA of 8 min, reversed by brief external heart mas sage and followed by mechanical ventilation to 1 h post restoration of spon taneous circulation (ROSC). Group III (n = 13). received the same insult an d resuscitation as described in group II, but in contrast to the previous g roup, a combination treatment of hypothermia (34 degreesC) and induced hype rtension was started immediately after ROSC and maintained fur 60 min ROSC. Survival rate and neurological deficit (ND) scores were determined before arrest, at 3 and 24 h, and each 24-h up to 4 weeks after ROSC. Results: Bas eline variables were the same in the three groups. Comparison of the asphyx ial CA groups groups II and III), show ed an increased. although not statis tically significant, survival rate at 72 h after ROSC in group III, and it became highly significant at 4 weeks after ROSC. The ND scores were the sam e in both asphyxial CA groups (groups II and III). Conclusions: Resuscitati ve mild hypothermia and induced hypertension after asphyxial CA in rats is associated with a better survival rate. This beneficial effect persisted fo r 4 weeks after ROSC. (C) 2001 Elsevier Science Ireland Ltd. All rights res erved.