INTRAOPERATIVE HYPOTHERMIA ASSOCIATED WITH LOWER-EXTREMITY TOURNIQUETDEFLATION

Study Objective: To determine the rapidity and extent of core temperat ure decrease following release of a lower extremity pneumatic tourniqu et. Design: Prospective study. Setting: Inpatient surgery in a univers ity trauma center. Patients: 11 ASA status I and II adults; undergoing unilateral lower extremity fracture fixation in which a tourniquet wa s used, with general anesthesia. Interventions: Temperature was measur ed in the esophagus before and after lower extremity tourniquet releas e. Measurements and Main Results: Tourniquet times ranged from 41 to 1 29 minutes (mean 98.5 +/- 9.1 minutes). Following tourniquet deflation core temperature decreased in all patients, with a maximal decline at 10 minutes, the termination of measurements, although trending downwa rd. Esophageal temperature decreased an average of 0.46 degrees C +/- 0.2 degrees C at 5 minutes, and 0.67 degrees C +/- 0.2 degrees C at 10 minutes following tourniquet release respectively. Temperature change s were significant (p = 0.0001) at both time intervals. Conclusion: Co re temperature drops significantly immediately following release of th e tourniquet at the esophageal temperature monitoring site. This decre ase is the result of cooling of systemic blood reperfusing the hypothe rmic limb, and mixing of cool, ''washed out'' blood with the systemic circulation. As the consequences of hypothermia are well-known we reco mmend core temperature monitoring in all patients having lower extremi ty tourniquet placed during general anesthesia, as well as vigilant mo nitoring for prolonged effects of anesthetics in the postoperative per iod.