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

BACKGROUND: Patients having arthroscopic shoulder surgery frequently experience periods of inadvertent hypothermia. This common perioperative problem has been linked to adverse patient outcomes such as myocardial ischaemia, surgical site infection and coagulopathy. International perioperative guidelines recommend patient warming, using a forced air warming device, and the use of warmed intraoperative irrigation solutions for the prevention of hypothermia in at-risk patient groups. This trial will investigate the effect of these interventions on patients' temperature, thermal comfort, and total recovery time. METHOD/DESIGN: 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. DISCUSSION: 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. AUSTRALIAN NEW ZEALAND CLINICAL TRIALS REGISTRY NUMBER: ACTRN12610000591055.

Preventing inadvertent hypothermia: comparing two protocols for preoperative forced-air warming.

Preoperative forced-air warming is one way of preventing inadvertent perioperative hypothermia. There is scant evidence, however, on the best warming method or the acceptability of these methods to patients. This pilot study compared two warming protocols: one that commenced at maximum temperature and was titrated down as requested (A) and one that commenced at near body temperature and was titrated up as tolerated (B). A crossover design was used in which each participant (n=10) received both protocols sequentially. The mean device temperature and length of time spent at maximum settings were greater for protocol A (43°C±0°C vs 41°C±1°C, P=.003; and 60±0 vs 41.5±2.8 minutes, P=.004). There was no difference in thermal comfort scores, participant temperature, or sweating between the two protocols. When asked, participants preferred protocol A to B (70% to 30%). Starting at higher device settings appears the more favorable of the two approaches.