Effect of limb ischemic post-conditioning in combination with hypothermia on brain injury after cardiopulmonary resuscitation in swine

Abstract

Objective To evaluate the effect of limb ischemic post-conditioning (LIPC) in combination with hypothermia on brain injury after cardiopulmonary resuscitation (CPR) in swine. Methods Eighteen adult male white swine, weighing 35-40 kg, were used.The swine model of brain injury was established by inducing ventricular fibrillation for 10 min followed by 5 min of CPR.The animals were randomly divided into 3 groups (n=6 each) using a random number table: cardiac arrest-CPR group (group CA-CPR), group LIPC, and LIPC combined with hypothermia group (group LIPC+ H). In LIPC and LIPC+ H groups, LIPC was performed at the onset of CPR.In addition, the body temperature was cooled down to 32-34 ℃ by using a cooling blanket after successful resuscitation, and then maintained at this level until 4 h after resuscitation, followed by 4 h of re-warming at a rate of 1 ℃/h in group LIPC+ H.At 24, 48 and 72 h after resuscitation (T1-3), neurologic deficit score (NDS) and neurologic alertness score (NAS) were evaluated.Blood samples were collected from the auricular vein for determination of the concentrations of neuron-specific enolase (NSE) and S100B protein in serum by enzyme-linked immunosorbent assay. Results Compared with group CA-CPR, the NDS was significantly decreased, and the NAS was increased at T1-3, and the concentrations of NSE and S100B protein in serum were decreased at T2, 3 in LIPC and LIPC+ H groups (P<0.05). Compared with group LIPC, the NDS was significantly decreased, and the NAS was increased at T1-3, and the concentrations of NSE and S100B protein in serum were decreased at T3 in group LIPC+ H (P<0.05). Conclusion The combination of LIPC and hypothermia provides better efficacy than either alone in reducing brain injury after CPR in swine. Key words: Hypothermia, induced; Ischemic postconditioning; Extremities; Heart arrest; Cardiopulmonary resuscitation; Reperfusion injury; Brain