Circulating-Water Mattress Enhances Thermal Comfort and Patient Satisfaction but Shows Non-Superiority in Temperature Maintenance in Ophthalmic Day-Case Surgery: A Randomized Controlled Trial

Abstract

Purpose: Perioperative hypothermia, a common complication of general anesthesia, is associated with adverse outcomes. While active warming methods are recommended, the effectiveness of circulating-water mattresses during ophthalmic surgeries remains understudied. This randomized controlled trial assessed whether a circulating-water mattress combined with a cotton quilt (Group W) was superior to a cotton quilt alone (Group C) in maintaining patient body temperature during ophthalmic day-case surgery. Patients and Methods: Group W patients (n=39) used a preheated circulating-water mattress (38°C) on the operating table and were covered with a cotton quilt (from their entry to the operating room until they returned to the ward). Group C patients (n=38) lay on an unheated table and were covered with a cotton quilt. The axillary temperature in the surgical waiting area served as the baseline. Axillary temperature, ambient temperature, heart rate, and mean arterial pressure were documented at anesthesia induction (T0), start of surgery (T1), every 5 min for the first hour (T2–T13), and end of surgery (T14). Satisfaction and thermal comfort scores were assessed at baseline in the waiting area, 5 min before anesthesia induction (t0), 15 min after entering the post-anesthesia care unit (PACU) (t1), and upon leaving the PACU (t2). The primary outcome measure was the axillary temperature at T14. Results: At T14, Group W had a higher axillary temperature than Group C (36.40±0.06°C vs 36.18±0.06°C, P=0.011), with the mean difference 0.22°C, which did not exceed the predefined superiority threshold of 0.30°C, indicating that the warming effect in Group W was not superior to that in Group C. However, thermal comfort and satisfaction scores were significantly enhanced at t0 and t1 (P<0.05). Conclusion: During ophthalmic day-case surgeries, a circulating-water mattress plus a cotton quilt was not superior, regarding their warming effect, but they significantly enhanced patients’ thermal comfort and satisfaction.