Salivary Cortisol as a Surrogate Marker of Stress Response in Children Undergoing Laparoscopic Surgery with Low-pressure versus Standard-pressure Pneumoperitoneum.

PURPOSE: Salivary cortisol is a validated, non-invasive biomarker of hypothalamic-pituitary-adrenal axis activity and surgical stress. Evidence on perioperative cortisol kinetics in children undergoing laparoscopic surgery is limited. This study evaluated temporal salivary cortisol trends and compared stress responses between low- and standard-pressure pneumoperitoneum (PP) in children undergoing laparoscopic surgery. METHODS: In this prospective randomized trial, 101 children scheduled for laparoscopic surgery were allocated to low-pressure PP (6-8 mmHg) or standard-pressure PP (9-11 mmHg) using block randomization. Salivary cortisol was measured preoperatively and at 6, 12, 24, 48, and 72 h postoperatively using enzyme-linked immunosorbent assay. Hemodynamic and respiratory parameters, pain scores, time to resume feeding, and hospital stay were recorded and analyzed. RESULTS: Ninety-three children completed the study (low-pressure: n = 47; standard-pressure: n = 46). Baseline cortisol levels were comparable (median: 5.94 vs. 4.96 nmol/L, P = 0.662). Across the cohort, cortisol showed a biphasic pattern: A rise peaking at 12 h, decline at 24 h, and secondary increase at 48 h, remaining above baseline at 72 h. No significant differences were observed between groups, though the low-pressure group had slightly higher cortisol at 12 h, and the standard-pressure group at 48 h. Hemodynamic and ventilatory parameters remained stable, and recovery outcomes - including pain, feed resumption, and hospital stay - were similar. CONCLUSION: Salivary cortisol is a reliable, noninvasive marker of perioperative stress in children undergoing laparoscopic surgery with a consistent postoperative trajectory. Within 6-11 mmHg, PP pressure did not influence stress response, intraoperative physiology, or short-term recovery.