Airway pressure reliably predicts intra-abdominal pressure during laparoscopic surgery

BACKGROUND: Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) are life-threatening complications increasingly recognized in the surgical setting, particularly in complex abdominal wall surgery. Bladder pressure monitoring, although the gold standard, is limited intraoperatively due to constraints related to patient positioning, contamination risk, and procedural interruption. We evaluated the correlation between intra-abdominal pressure (IAP) and airway pressure (AWP) during laparoscopic cholecystectomy and the diagnostic accuracy of AWP for detecting intraoperative IAH. METHODS: Prospective observational cross-sectional study in ASA I-II patients undergoing elective laparoscopic cholecystectomy at a single tertiary center, Brazil. Data were collected between 2020 and 2021. Sample size was calculated using the Fleiss method (80% power, two-sided α = 0.05, assumed r = 0.30), requiring a minimum of 80 participants. Pneumoperitoneum was increased incrementally (baseline, 5, 10, 15, 20 mmHg). PIP and PLAT were recorded at each level. A linear mixed-effects model (REML) with patient as random intercept was used as the primary correlation analysis; Pearson correlation is reported as a descriptive secondary measure. ROC analyses were performed. RESULTS: Of 95 patients assessed, 78 completed the study. Both PIP and PLAT correlated significantly with IAP (p < 0.001). Linear mixed-effects model: PIP β = 0.439 cmH₂O/mmHg (95% CI: 0.410-0.468), p < 0.001, ICC = 0.640. PLAT β = 0.134 cmH₂O/mmHg (95% CI: 0.121-0.147), p < 0.001, ICC = 0.936. Pearson r (descriptive): PIP r = 0.670 (95% CI: 0.612-0.722); PLAT r = 0.253 (95% CI: 0.157-0.343). PIP increased by 6.99 cmH₂O at IAP 15 mmHg and 8.06 cmH₂O at IAP 20 mmHg. ROC analysis showed excellent diagnostic accuracy for PIP (AUC 0.905, 95% CI: 0.868-0.940), with an optimal cutoff of 24 cmH₂O (84.6% sensitivity, 87.2% specificity). PLAT showed poor diagnostic accuracy (AUC 0.695, 95% CI: 0.662-0.737) and is not a reliable clinical surrogate for IAP. CONCLUSION: PIP strongly correlates with IAP and accurately detects intraoperative IAH. PLAT is not recommended as a standalone diagnostic surrogate for IAP. Airway pressure monitoring may serve as a practical, real-time screening tool during abdominal surgery, with particular promise in complex abdominal wall reconstruction.