Effect of preoperative warming on intraoperative hypothermia and postoperative functional recovery in total hip arthroplasty: a randomized clinical trial.

Background: Intraoperative hypothermia is associated with increased morbidity and impaired postoperative recovery. Direct anterior-approached total hip arthroplasty (ATHA) may lead to significant thermal loss. We aimed to assess whether preoperative warming had an impact on intraoperative hypothermia and postoperative functional recovery after ATHA.

Methods: In this prospective randomized controlled clinical trial 40 patients scheduled for ATHA were randomly divided into two groups of 20 patients each. Group W received, prior to the induction of general anesthesia, a 30 minutes 43 °C forced-air preoperative warming. Group C did not receive any preoperative warming. A blinded observer noted the core body temperature at the time of induction and at fixed time points, i.e. every five minutes during the first hour of surgery. The evolution of postoperative patient perceived thermal comfort (TC) and functional recovery (QoR-15) was assessed 24, 48 and 72 hours after surgery. Length of stay in the post-anesthesia care unit (PACU) was noted.

Results: The temperature drop was significantly faster and of higher amplitude in group C than in group W, during first hour of surgery (P<0.001). Evolution of QoR-15 and TC was significantly better in group W than in group C (P<0.001 for QoR-15 and P<0.001 for thermal comfort), with shorter length of stay (median [IQR]) in the PACU (minutes; 73 [61-79] for group C and 98 [83-129] for group W, P<0.001).

Conclusions: In ATHA, pre-warming delays and reduces intraoperative heat loss, impacting patient comfort and postoperative functional recovery.