Effects of mild hypothermia on cardiac function in early stage of post-resuscitation in rabbits

Abstract

Objective To observe the effects of mild hypothermia on post-resuscitation myocardial dysfunction in rabbits in order to elucidate the underlying mechanism of hypothermia.Methods After setting up rabbit model of cardiopulmonary resuscitation,20 rabbits were randomly ( random number)divided into two groups,namely normothermic resuscitation group (group A,n =10 ) and post-ROSC hypothermia group ( group B,n =10).In the group A,animals wore treated with standard CPR after cardiac arrest.In post-ROSC hypothermia group,the body temperature of animals was cooled to 32 ～ 34°C after successful ROSC.The left ventricular end-diastolic pressure (LVEDP),left ventricular pressure rise and fall rates ( ± dp/dtmax,serum concentrations of heart-type fatty acid-binding protein (H-FABP) and 8-isoprostaglandin F2a (8-iso-PGF2a) and Cyclooxygenase-2 (COX-2) were observed. Results Compared with the A group,the B group had significantly better hemodynamics,and lower serum H-FABP,8-isoPGF2a and COX-2 levels in the early stage of post-resuscitation ( both P ＜ 0.05 ).Conclusions Mild hypothermia attenuated post-resuscitation myocardial dysfunction during the early period of postresuscitation.The cryoprotective effect on myooardium is likely associated with the reduction of 8-iso-PGF2a and COX-2. Key words: Cardiopulmonary resuscitation; Mild hypothermia; Postresuscitation myocardial dysfunction; Serum concentrations of heate-type fatty acid-binding protein ; 8-iso-prostaglandin F2a; Cyclooxygenase-2