comparison the effects of different temperatures on the core temperature and the concentrations of lactate in patients who were candidate for posterior spine fusion surgery under general intravenous anesthesia

background: long surgery causes hypothermia and increased bleeding and can increase the arterial blood lactate levels during anesthesia. it causes cellular hypoxia and its complications. considering the core temperature of the patient during surgery it can prevent hypoxia. this study aimed to compare the effects of different temperatures on the core temperature and the concentrations of lactate in patients who were candidate for posterior spine fusion surgery under general intravenous anesthesia. methods: in this clinical trial study, 60 patients with asa ii risk undergoing spine fusion surgery referred to rasoul akram hospital from 2015 were studied. patients were divided in two groups of receiving temperature of 36 ° and 40 ° c during operation. demographic data as well as information before anesthesia, after surgery, as well as recovery was gathered in the check list. data then were entered to the statistical software spss v. 16 and analyzed. results: the mean age of patients was 49.14 (sd= 12.97) years. pre-operation o2 saturation had significant difference between the two groups (p value = 0.015). trend of hb, hct, hr, sbp, o2 sat, operating room temperature, ph, arterial hco3, arterial o2 pressure, arterial blood lactate, degree of arterial blood saturation and arterial access base in 36ºc group (p value <0.05). trend of hb, hct, hr, sbp, o2 sat, operating room temperature, ph, hco3 level of arterial pressure, arterial o2, arterial co2 pressure, degree of saturation of arterial blood and arterial access was statistically significant in 40ºc group (p value <0.05). conclusion: in bleeding and low blood pressure and hypothermia, the level of serum lactate is more than 3.5 meq/l, which is caused by cellular hypoxia. in our study in two temperatures during operation lactate level was low because of longer time of operation that shows loss of hypoxia and high level of consciousness and less complication. also time of waking up was more rapid. so as lactate level was low, prophylaxis of hypoxia is more.