Theprotective effects of neck rapid induced hypothermia on brain of cardiopulmonary resuscitation rabbit

doi:10.3969/j.issn.1002-1949.2015.04.018

Abstract：Objective This study aims to investigate a new hypothermia treatment method of brain cooling at the begining of cardiopulmonary resuscitation ( CPR) recovery.and to determine whether this method has a better success rate of recovery, survival rate and nervous system function compared with the method which brain cooling is after CPR or method without brain cooling.Methods Twenty-four healthy male New Zealand rabbits, exposed to 4 minutes of ventricular fibrillation, were randomly divided into three groups with 8 rabbits in each group. A normal temperature recovery group (normothermia theat NT group): regular quiver recovery, no cooling intervention.A cooling during recovery group ( intra -arrest therapeutic hypothermia group IATH): at the begining of CPR, rapid cooling was run and the target brain temperature was 34 ℃, then maintain the target brain temperature unthil 4 hours after ROSC. Start cooling 1 hour after recovery group ( post -arrest therapeutic hypothermia group PATH):start rapid neck cooling 1 hour after CPR, target brain temperature is 34℃, other parameters are the same as group.The method was to observe the success rate of recovery and monitor the brain temperature, anus temperature, change of hemodynamics and respiratory function in 4 hours, NDS score 24 hours a day.Results There were 7 rabbits successfully recovered in the IATH group and only 4 in NT group and 5 in PATH group.There was no significant difference in anus temperature and brain temperature among all the groups, 4 mins after inducing ventricular fibrillation. After four minutes of CPR, the animal's brain temperature of IATH group, NT group, the PATH were (37.4 ±0.7)℃, (38.2 ±0.3)℃ and (38.1 ±0.5)℃, respectively, though the IATH group was statistically more significant compare to the other two groups (P<0.05).No obvious difference in anal temperature between the groups.4 minutes after CPR, the diastolic pressure of IATH group increased from 5.2 mm Hg to 32.0 mm Hg, NT group only increased from 5.7 mm Hg to 22.0 mm Hg and PATH group only increased from 5.4 mm Hg to 21.0 mm Hg (P<0.05).There was no significant difference in systolic blood pressure among the groups during recovery.48 hours survival rate of IATH group was obviously higher than that of NT group, and there was statistically significant between them (P<0.05). The recovery after 24 hours NDS rating of each group were all poor wtithout any significant differences among the groups, though the rating for neck cooling group was better than regular recovery group. Conclusion The neck cooling in the early CPR stage can lower brain temperature at early as possible and improve recovery diastolic blood pressure, followed by improved coronary perfusion pressure during recovery, improved the successful rate of CPR and 48-hour survival rate.