Clinical And Basic Researches Of Intraoperative Hypothermia.

Background:Human as a constant temperature animals,the Tc(Core temperature) always maintained at 36.2～37.5℃.In the clinic we call it "Hypothermia" when the Tc is below 36℃,which is very common during major surgery. Hypothermia results from a variety of factors,and it will produce a great deal of adverse effects.Recently,studies have shown that intraoperative hypothermia will increase the rates of SSI (Surgical site infection) and become an important risk factor of SSI,which have been paid close attention by bose internal and abroad.However,it still lack of deeply and innovatively scientific researches in immune mechanisms, measures of regulation, means of intervention.Neutrophils,as a non-specific cellular component of the immune system,plays a critical role in the early stage of inflammation.Otherwise, cytokines are the effective components of the immune response.IL-8, secreted by the vein endothlial cells,has the regulative affect of PMN's response.Objective:To estimate the clinical effects of intraoperative hypothermia and try to identify the association between intraoperative hypothermia and the SSI. Moreover, we investigate the mechanisms of SSI that impaired by intraoperative hypothermia,and then illustrate the significance of warming techniques.Materials and Methods:General materials:Prospectively,86 gastric cancer patients concerning distal resection were selected from Mar.2009 to Feb.2010 in the First Affiliated Hospital of Dalian Medical University.They were randomly assigned to two temperature monitoring groups,woaming group(A group) and hypothermia group(B group).Methods:Gastric cancer patients were treated with general anesthesia and epidural anesthesia,undergoing opening radical resection of distal gastric cancer.Clinical parts:Monitoring and recording the Tc,blood loss,post-operative recovery,hospitalization,etc.T-tests is used to compared of the differences between the tow groups.P<0.05 was considered statistically significant.Monitoring of the occurrence of postoperative SSI.Linear equation was created with hypothermia and the rates of SSI by the Regression analysis.Basic parts:Venous blood samples wre tested the level of neutrophils, white blood cell count at different time points(preoperative,intraoperative and postoperative),laboratory detected by flow cytometry of whole blood neutrophil respiratory burst,ELISA method to measure IL-8 plasma concentration,analyze the correlation between the two groups,and regression analysis of IL-8 concentration and the incidence of SSI.Results:1.Clinical parts:The cases of the occurrence of intraoperative hypothermia in observed was 54.24%.The two groups were generally not significantly different, nevertheless, the changes of intraoperative Tc were significantly different. Patients usually suffer hypothermia after 1 hour in hypothermia group,their Tc were lower than 36℃,and then gradually decreased,while the Tc in worming group had no significant change during the whole operation.The values of blood loss,extraction of right drainage pipe under the hepatic,days to the first eating,days of suture removal,total hospitalizayion and postoperative hospital stay in hypothermia was significantly higher than worming group.And the same as the rate of SSI,the difference was statistically significant,and which assume a negative correlationship with the body temperature.2.Basic parts: In the range of 34℃～38℃we studied,the intensity of neutrophil respiratory burst and IL-8 levels were descented with decline of the intraoperative Tc.The rate of neutrophil activation and RB began to decreased during the operation,accompanied with the reduction of Tc,and there are significant differences compared with the values of preoperative inside and the corresponding points in warming group.The concentration of IL-8 also began to fall during the operation, and achieve to the minimum after 12h,meanwhile the differences was significant compared with the preoperative inside and the corresponding points in worming group.The change of IL-8 concentration was positive correlated with neutrophil respiratory burst intensity,on the contrary,negative correlation with the rate of SSI.Conclusions:1. Hypothermia is likely to increase blood loss,prolong hospital-lization, and can delay postoperative recovery by porlong the extraction of right drainage pipe under the liver,days to the first eating,days of suture removal,total hospitalizayion and postoperative hospital stay.2. Tc and the incidence of SSI are negative correlation,in other words, intraoperative hypothermia may increases the incidence of SSI.3. Intraoperative hypothermia can affect immune function by reducing the capacity of neutrophil respiratory burst intraoperative and the secretion of IL-8.4. It's likely to be one of the mechanisms that the changes of IL-8 and neutrophil respiratory burst capacity induced by intraoperative hypothermia lead to the increasing of SSI rate.5. Take systemic warming measures can effectively prevent the occurrence of intraoperative hypothermia,improve the postoperative recovery,and to some extent,reduce the incidence of SSI in patients undergoing distal resection of gastric cancer.