Hip Arthroscopy and Hypothermia

PurposeTo determine the incidence of and factors that contribute to the development of hypothermia during hip arthroscopic surgery.MethodsAn analytic observational study was carried out in a cohort of 73 consecutive patients. All patients underwent hip arthroscopy for the treatment of femoroacetabular impingement. The patients' core temperature (esophageal) was measured throughout the surgery. Relevant information was collected on the patients (age, gender, body mass index, blood pressure) and on the procedure (volume and temperature of saline solution, pressure of fluid pump, surgery time, room temperature). The corresponding statistical analysis was performed with Stata 10.0 (StataCorp, College Station, TX), by use of a repeated-measures generalized estimating equations model.ResultsThe patients' mean age was 33 years, and there were 39 female and 34 male patients. The mean body mass index was 23.9; systolic blood pressure, 97.5 mm Hg; and diastolic blood pressure, 52.2 mm Hg. The incidence of hypothermia below 35°C (95°F) was 2.7%. The multivariate statistical analysis of the results showed a direct relation between hypothermia and surgery time of more than 120 minutes (P < .001). There was an inverse relation between core body temperature and surgery time (P < .001), with a drop of 0.19°C/h (32.342°F/h). Of the patients, 68.22% had a decrease in temperature of more than 0.5°C (32.9°F) until the end of surgery. There was also a direct relation between core body temperature and saline solution temperature (P < .001), body mass index (P < .01), and diastolic blood pressure (P < .03).ConclusionsThe incidence of hypothermia below 35°C (95°F) in patients who underwent hip arthroscopy for the treatment of femoroacetabular impingement is 2.7%. The factors that contribute toward the development of hypothermia during hip arthroscopic surgery are prolonged surgery time, low body mass index, low blood pressure during the procedure, and low temperature of the arthroscopic irrigation fluid.Level of EvidenceLevel II, development of diagnostic criteria on the basis of consecutive patients with a universally applied reference gold standard.