Effect of Prophylactic Dexamethasone vs Placebo on Airway Dimensions Assessed by Ultrasonography in Patients Undergoing Laparoscopic Cholecystectomy

During laparoscopic surgery, the abdomen is inflated with carbon dioxide gas (pneumoperitoneum), which alters venous return and fluid distribution, potentially leading to swelling in the tissues of the upper airway. The placement of a breathing tube (endotracheal tube) under general anesthesia can also cause local airway irritation and edema. Although these airway dimension changes are frequently clinically silent, they can be accurately visualized and quantified at the bedside using non-invasive ultrasonography.

Dexamethasone is a corticosteroid with potent anti-inflammatory and anti-edematous actions commonly administered before surgery to alleviate postoperative nausea, vomiting, and sore throat. However, whether it helps prevent or attenuate measurable increases in airway wall thickness during and after laparoscopic surgery remains unclear.

The primary purpose of this randomized clinical trial is to evaluate whether a single preventive intravenous dose of dexamethasone attenuates upper-airway swelling, measured primarily by lateral pharyngeal wall thickness via ultrasound, in adult patients undergoing elective laparoscopic cholecystectomy.

Participants are randomly allocated into one of two groups:

• Dexamethasone Group: Receives an intravenous dose of dexamethasone (0.2 mg/kg) diluted in 10 mL normal saline prior to the induction of general anesthesia.
• Placebo Group: Receives an identical volume of 10 mL normal saline intravenously prior to the induction of general anesthesia.

Bedside ultrasound scans will be performed by a blinded assessor to evaluate lateral pharyngeal wall thickness, tongue thickness, and parapharyngeal space dimensions at five specific time points: before anesthesia induction, 30 minutes following pneumoperitoneum initiation, immediately prior to extubation, 1 hour after extubation, and 2 hours after extubation. Participants are also evaluated for any post-extubation airway complications or symptoms during their stay in the recovery unit.