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Objective To evaluate the effect of intracarotid cold saline infusion (ICSI) on neurological outcomes in canines with cardiac arrest (CA) introduced by severe hypothermia.Methods Restoration of spontaneous circulation (ROSC) after hypothermic CA was induced in 10 Beagle dogs.These 10 dogs were randomly divided into 2 groups (5 each).Dogs in control group were rewarmed using warn water bath,and dogs in experimental group received the bath rewarming plus ICSI for 6 hours to maintain the brain temperature ＜36℃.In both groups,the Neurologic Disability Scores (NDS) were recorded at 24h after the ROSC,and their brains were removed for pathologic analysis using hematoxylin and eosin stain.The brain water content and sl00β of serum level were also measured.Results The water content (79.43％ ± 0.72％ vs.80.79％ ± 1.06％,P＜0.05) and serum level of s100β (119.83 ± 42.93pg/ml vs.329.82 ± 190.39pg/ml,P＜0.05) were significantly lower in experimental group than in the control group.Control group presented obvious pathological damage of the hippocampal pyramidal cells.There was no significant difference in NDS between the two groups.Conclusion ICSI could reduce the production of s100β and pathological brain damage in postarrest hypothermic canines.
RESUMO
Objective To investigate the safety and therapeutic effect of intra-carotid infusion with cold sa line in rats with acute focal cerebral ischemia-reperfusion injury.Methods 60 rats were randomly divided into six groups:sham operated group,normal infusion group,stroke group,local hypothermic group,local normothermic group,and systemic infusion group.Brain infarct volume and cerebral water content were analyzed 48 h after ischemia.Neurological deficits were assessed using the mNSS 24 h and 48 h after infarction.Results In the local hypothermic group,brain temperature was reduced to 33 to 34 ℃ within 5 to 10 minutes,and this significantly low temperature maintained to nearly 60 minutes after infusion continued.Physiological variables were not significantly different among each time point (P ＞ 0.05).No significant morphological abnormality was found in brain sections stained with TTC and HE.Animals receiving local cold infusion significantly decreased infarct volume and brain water content compared to stroke group (P ＜ 0.05).Both 24 h and 48 h mNSS in local hypothermic group was significantly lower than those in other groups (P ＜ 0.05).Conclusions Intra-carotid infusion with cold saline can quickly and effectively reduce brain temperature and is a relatively safe cooling method.Local hypothermia significantly reduced brain infarct volume,decreased brain water content and improved neurological functional outcomes after brain ischemia.