Nitrous oxide inhalation combined with lidocaine local anesthesia on the comfort of plastic surgery outpatient procedures: A randomized, controlled, single-blind trial

Yidan Su¹Jiefeng Zou²Jingwen Guo²Yan Qi²Yonghua Li³Bing Nie^4*Ziying Dong^5*Wenjun Zhang^6*

• ¹Department of Plastic and Aesthetic Surgery, Qingdao Hospital, University of Health and Rehabilitation Sciences (Qingdao Municipal Hospital), Qingdao Municipal Hospital Group, Qingdao, China
• ²Shanghai Changzheng Hospital, Shanghai, China
• ³Department of Anesthesiology, Shanghai Changzheng Hospital, Shanghai, China
• ⁴Shanghai Skin Diseases Hospital, Shanghai, China
• ⁵Department of Plastic and Aesthetic Surgery, Qingdao Hospital, University of Health and Rehabilitation Sciences (Qingdao Municipal Hospital), Qingdao, Qingdao Municipal Hospital Group, Qingdao, China
• ⁶Department of Burn and Plastic Surgery, Shanghai Changzheng Hospital, Shanghai, China

Background: The use of infiltration injection of lidocaine with adrenaline in outpatient plastic surgeries has certain limitations, such as injection pain, increased blood pressure, and heart rate fluctuations. Nitrous oxide has good analgesic and anti-anxiety effects. However, its application in outpatient plastic surgery is relatively limited. This study aimed to investigate the advances following combined nitrous oxide inhalation and local anesthesia to provide a new anesthesia option for improving surgical comfort. Methods: This study adopted a randomized, single-blind grouping method. After the preoperative assessment, patients inhaled nitrous oxide (up to 50% concentration) or air through a nasal mask. Before and during surgery, the patients' basic information and vital signs were recorded. Follow-up was performed three days after surgery. Results: A total of 82 patients were randomized, with 41 in each group (Group A: N₂O/O₂; Group B: Air/O₂). Group A showed significantly better outcomes across multiple measures: maximum pain score was lower (1.9 ± 0.7 vs. 3.1 ± 0.9; mean difference: -1.2, 95% CI: -1.6 to -0.8; p=0.0039), hemodynamic parameters were more stable, and anxiety reduction was greater (mean difference in BSTAI change: -0.6, 95% CI: -1.1 to -0.1; p=0.018) compared to Group B. Conclusions: This combined anesthesia method significantly reduced the pain experienced during surgery, stabilized blood pressure and heart rate, reduced anxiety, and improved surgical comfort in outpatient plastic surgery patients. Trial registration: This study was registered with the Chinese Clinical Trial Registry (ChiCTR) under the registration number ChiCTR2400080612 on February 2024.