Mild hypothermia does not increase blood loss during total hip arthroplasty

Background: The effects of mild hypothermia on blood loss are little known. Methods: Patients, undergoing primary prosthetic hip surgery under spinal anaesthesia, were randomised to the operative procedure, with (n=25) or without (n=25) forced air warming. Core temperature was repeatedly measured from the tympanic membrane. The blood loss was calculated by three different methods; the intraoperative loss was estimated visually. The loss during and after the operation was obtained by determination of lost haemoglobin (the Hb‐method). The blood loss during hospital stay was also calculated from the haemoglobin balance. Results: Among controls, core temperature decreased by 1.3±0.6°C (mean±SD) and in the warmed patients 0.5±0.4°C (P