Effects of different pneumoperitoneum pressures on the upper airway assessed by ultrasonography: a prospective, randomized, observer-blinded clinical study

BACKGROUND: This study aimed to evaluate the effects of low-pressure (10 mmHg) and standard-pressure (14 mmHg) pneumoperitoneum on upper airway dimensions during laparoscopic cholecystectomy performed in the reverse Trendelenburg position, using bedside ultrasonography. METHODS: In this prospective, randomized, observer-blinded study, 76 ASA I–II patients undergoing elective laparoscopic cholecystectomy were allocated to either 10 mmHg or 14 mmHg pneumoperitoneum. Upper airway parameters—including lateral pharyngeal wall (LPW) thickness, tongue thickness and width, parapharyngeal tissue thickness, and midsagittal tongue area—were measured at five time points (T0–T4). Perioperative data and postoperative respiratory complications (stridor, desaturation, re-intubation) were also assessed. RESULTS: Baseline characteristics were comparable between groups. All upper airway measurements increased over time, with significantly greater changes in the 14 mmHg group (mean LPW: 12.3 ± 1.1 mm vs. 11.2 ± 0.7 mm; p < 0.001). Group, time, and group*time interactions were significant for all sonographic parameters (all p < 0.001). Early postoperative respiratory complications were infrequent and similar between groups. CONCLUSIONS: In summary, standard-pressure pneumoperitoneum (14 mmHg) was associated with more pronounced ultrasonographic changes in upper airway anatomy compared with low pressure (10 mmHg). This was not accompanied by statistically significant differences in early postoperative respiratory complications between groups. TRIAL REGISTRATION: ClinicalTrials.gov (NCT07021482), registered on June 05, 2025.