Effect of noise isolation during general anaesthesia on the incidence of moderate-to-severe pain after major abdominal surgery: multicentre randomized clinical study.

BACKGROUND

Postoperative pain remains a major challenge following major abdominal surgery. Noise in the operating room is a modifiable stressor, and the efficacy of targeted noise isolation requires prospective investigation. This study investigated the effects of intraoperative noise isolation on the incidence of moderate-to-severe postoperative pain.

METHODS

This multicentre randomized clinical trial assessed patients who underwent elective major abdominal surgery under general anaesthesia in four medical centres in China between April, 2024 and May, 2025. Following anaesthesia induction, patients were randomized to either wear noise-cancelling headphones or not (control). The primary outcome of this study was the incidence of moderate-to-severe pain (numeric rating scale (NRS) score ≥ 4) within the 24-hour (h) period after surgery. Secondary outcomes included the incidence of moderate-to-severe pain, cumulative postoperative pain NRS scores within 48 h after surgery, and the consumption of analgesic drugs within 24 and 48 h after surgery.

RESULTS

In all, 304 patients were enrolled and randomized; 302 patients were included in the final analysis (150 in the noise isolation group, 152 in the control group). The incidence of moderate-to-severe pain was higher in the control than noise isolation group within 24 h after surgery (49 versus 23%, respectively; relative risk (RR) 0.47; 95% confidence interval (c.i.) 0.33 to 0.65; P  < 0.001) and within 48 h after surgery (51 versus 25%, respectively; RR 0.48; 95% c.i. 0.35 to 0.66; P < 0.001). During the 24-h and 48-h periods after surgery, the number of patient-controlled intravenous analgesia boluses was significantly higher in the control group, which also had a higher extra analgesia requirement and increased total analgesic consumption compared with the noise isolation group. The cumulative and maximum rest and movement pain scores were higher in the control than noise isolation group during the 48-h period after surgery.

CONCLUSIONS

Intraoperative noise isolation was found to be an effective, safe, and non-invasive preventive intervention that significantly lowered the incidence of moderate-to-severe pain after major abdominal surgery, arguing for its integration into standard multimodal analgesic strategies. Registration number: NCT06316440 (http://www.clinicaltrials.gov).