Effects of postoperative environmental noise on surgery induced pain: Evidence based on a prospective observational study

Many patients recovering from surgery in wards are disturbed by environmental noise. However, the effects of environmental noise on postoperative pain are unclear. This study aimed to assess the association between postoperative noise and pain. This prospective study included 182 women who underwent cesarean sections. Postoperative noise was continuously recorded, and pain intensity at rest was assessed using a numerical rating scale (NRS) for 0–6, 6–12, 12–18, and 18–24 h after the patients were returned to the ward. Cumulative pain scores were calculated by summing the NRS scores at each time point and comprised the primary outcome. The maximum pain NRS score and analgesic consumption during the 24 h after surgery were also recorded. Mean environmental noise intensity during the daytime was an independent factor for cumulative pain scores, maximum pain scores, and analgesic use during the first postoperative 24 h (β, 0.37; 95% CI, 0.21–0.53 and β, 0.12; 95% CI, 0.07–0.17; P < 0.001 for both; β, 0.86; 95% CI, 0.25–1.46; P = 0.006). Cumulative and maximum NRS pain scores as well as the incidence of NRS ≥ 4 were significantly higher in patients under mean daytime environmental noise of ≥58, than <58 dB (dB) (8.0 [6.0–11.3] vs. 6.0 (5.0–7.0); 3.0 [2.0–4.0] vs. 2.0 [2.0–2.0, and 25.6% vs. 11.0%; RR, 2.32; 95% CI, 1.19–4.54, respectively; P < 0.001 for all). Higher-level postoperative noise exposure was associated with more severe postoperative pain and increased analgesic needs, as well as a higher incidence of moderate-to-severe pain in patients recovering from cesarean delivery. Our findings indicate that reducing environmental ward noise might benefit for postoperative pain management.