Intraperitoneal Dexamethasone Spraying on Vagal Nerve-Rich Areas for Prevention of Hoarseness After Upper Abdominal Surgery

Overview

The goal of this clinical trial is to evaluate whether intraoperative spraying of dexamethasone onto the abdominal vagal nerve-rich areas can prevent postoperative hoarseness in patients undergoing elective upper abdominal surgery. The main questions it aims to answer are: * Does intraoperative topical dexamethasone spraying reduce the incidence of postoperative hoarseness after upper abdominal surgery? * Does postoperative intravenous dexamethasone accelerate recovery in patients who develop hoarseness? Researchers will compare a dexamethasone group (intraoperative spraying of 10 mg dexamethasone in 10 mL normal saline) to a placebo group (intraoperative spraying of 10 mL normal saline alone) to see if dexamethasone reduces the rate of postoperative hoarseness. Participants will: * Undergo voice assessment (GRBAS scale) and voice recording before surgery and daily for 10 days after surgery. * Be randomly assigned to receive either dexamethasone or placebo sprayed onto the surgical field at the end of the operation. * If hoarseness develops in the placebo group, be randomly assigned again to receive either intravenous dexamethasone (5 mg daily for 3 days) or placebo.

The mechanism of postoperative hoarseness remains unclear. It is traditionally attributed to direct injury to the recurrent laryngeal nerve or to endotracheal intubation. However, the surgical field in upper abdominal procedures is remote from the recurrent laryngeal nerve, yet the incidence of hoarseness is higher than in many other surgeries. Preclinical animal experiments by the research group have demonstrated that electrical or thermal stimulation of the subdiaphragmatic vagal nerve can induce vocal cord paralysis, and that immediate topical spraying of dexamethasone onto the affected area significantly reduces this effect. It is hypothesized that thermal injury to vagal nerve fibers in the upper abdomen triggers aberrant signaling through the solitary nucleus to the nucleus ambiguus, ultimately resulting in dysfunction of the recurrent laryngeal nerve. This trial is designed as a multi-center, prospective, randomized, double-blind, placebo-controlled study. A total of 584 adult patients scheduled for elective gastric, hepatobiliary, or pancreaticoduodenal surgery will be enrolled. At the end of the main surgical procedure and before abdominal closure, the surgeon will spray 10 mg of dexamethasone onto the vagal nerve-rich areas, such as the peritoneum around the esophageal hiatus, the lesser omental sac, and the surface of the hepatoduodenal ligament. Voice assessments will be conducted daily from postoperative day 1 through day 10 using the GRBAS scale by a trained evaluator blinded to group assignment. Patients will also undergo voice acoustic recording for Praat analysis. Those in the placebo group who develop hoarseness will be re-randomized to receive either intravenous dexamethasone 5 mg or placebo daily for 3 days.