Preventing hypothermia in elective arthroscopic shoulder surgery patients: a protocol for a randomised controlled trial

The trial will employ a randomised 2 x 2 factorial design. Eligible patients will be stratified by anaesthetist and block randomised into one of four groups: Group one will receive preoperative warming with a forced air warming device; group two will receive warmed intraoperative irrigation solutions; group three will receive both preoperative warming and warmed intraoperative irrigation solutions; and group four will receive neither intervention. Participants in all four groups will receive active intraoperative warming with a forced air warming device. The primary outcome measures are postoperative temperature, thermal comfort, and total recovery time. Primary outcomes will undergo a two-way analysis of variance controlling for covariants such as operating room ambient temperature and volume of intraoperative irrigation solution.This trial is designed to confirm the effectiveness of these interventions at maintaining perioperative normothermia and to evaluate if this translates into improved patient outcomes.ACTRN12610000591055Inadvertent perioperative hypothermia, defined as a core temperature below 36°C [1], is a common, yet widely under-acknowledged adverse clinical consequence of surgery [1-3]. Patients undergoing arthroscopic shoulder surgery are particularly at risk, with the average patient experiencing a core temperature heat loss of between 1°C and 3°C [4-6]. Three principle factors are said to contribute to this problem: Reduced metabolic heat production due to the anaesthetic; heat loss due to the cold perioperative environment and the use of large quantities of surgical irrigation solution; and impaired thermoregulation which results in a core to periphery thermal redistribution [7].Although hypothermia is a common perioperative problem, it is not a benign one: The consequences are both physiological and psychological in nature and are far more serious than patients just ‘feeling uncomfortably cold’. Research has demonstrated a clear link between inadv