Use of intraoperative mild hyperventilation to decrease the incidence of postoperative shoulder pain after laparoscopic gastric sleeve surgery: A prospective randomised controlled study

BACKGROUND AND AIMS: Post-laparoscopic shoulder pain (PLSP) is a common problem. It is a referred type of pain resulting from irritation of phrenic nerve endings. Multiple manoeuvres were used to decrease its incidence with varying success rates. In this study, we tested the use of mild intraoperative hyperventilation to reduce PLSP in patients undergoing laparoscopic sleeve gastrectomy surgery (LSG). METHODS: Consenting American Society of Anesthesiologists-I and II patients undergoing LSG under general anaesthesia were randomly assigned to two groups. Group A (53 patients) received intraoperative mild hyperventilation with target end-tidal carbon dioxide (ETCO(2)) of 30–32 mmHg. Group B (51 patients) received conventional ventilation (ETCO(2) of 35–40 mmHg). Incidence and severity of PLSP, cumulative analgesic requirements and incidence of nausea and vomiting were recorded at 12 and 24 hours postoperatively and then followed up after discharge over the phone at 48 hours, 1 week, 1 month and 3 months. Statistical significance of differences between the two groups was defined at P < 0.05. RESULTS: Incidence of PLSP was comparable between the two groups in the first 24 hours. The intervention group had a significantly lower incidence of PLSP throughout the remaining assessment points (56.6% vs. 80.4%, 30.2% vs. 78.4%, 15.1% vs. 70.6%, 3.8% vs. 35.3% at 36 hours, 48 hours, 1 week and 1 month, respectively, P < 0.05). The average PLSP pain score was significantly lower in the mild hyperventilation group at all assessment time points. Nausea and vomiting were non-significantly lower in the mild hyperventilation group. CONCLUSION: Mild intraoperative hyperventilation could be beneficial in reducing the incidence and severity of PLSP after LSG surgery.