Deep breathing alleviates propofol-induced pain: a prospective, randomized, single-blind study

Purpose Propofol is commonly used to induce general anesthesia; however, the pain caused during propofol injection is a disadvantage. This study aimed to assess whether deep breathing attenuates propofol injection pain. Methods This prospective, single-blind, randomized controlled study included 200 patients who were scheduled to undergo elective surgery under general anesthesia and randomly and equally divided them into group D and group C. The observers were not blinded to the pain-relieving modality, but each patient was blinded. Group D patients were requested to repeatedly take deep breaths throughout general anesthesia induction with propofol. Group C patients were requested to breathe in the usual manner. The intensity of propofol injection pain was evaluated using the visual analog scale (VAS). Furthermore, we recorded the patients' pain expressions, including grimace or hand-withdrawal, and the recalled pain measured using a VAS in the post-anesthetic care units (PACU). Results Compared with patients in group C, those in group D showed significantly reduced VAS scores for propofol injection pain (20 [interquartile range (IQR): 0-48] vs. 37 [IQR 9-65], P = 0.017) and recalled pain in the PACU (16 [IQR 0-32] vs. 26 [IQR 0.5-51], P = 0.031). Further, the grimace incidence was significantly lower in group D (18%) than in group C (45%) (P < 0.001). There was no significant difference in the incidence of pain at induction, recalled pain, or hand-withdrawal. Conclusions Deep breathing could be an easy, safe, and inexpensive method for reducing pain during propofol injection.