Agreement between intra-bladder and insufflation pressure readings during laparoscopic surgery

Following the recognition of intra-abdominal pressure (IAP) as a vital sign in critically ill patients, substantial research has focused on improving IAP monitoring techniques and devices. The Abdominal Compartment Society’s guidelines state that any novel IAP measurement method must be validated against a reference method. Literature shows that insufflators are commonly used during laparoscopic surgeries as a reference, although their use poses challenges and requires several precautions. This research aims to investigate the agreement between IAP measurements via the bladder and insufflators during laparoscopic surgeries and to address whether insufflators can be used as a reference method to examine new IAP measurement techniques via the bladder. A prospective observational study was conducted in patients undergoing laparoscopic surgery. A total of 202 paired IAP measurements were performed in 18 patients. Patients were stratified into two study groups according to the baseline IAP (IAP0 < 12 mmHg or IAP0 ≥ 12 mmHg). The agreement between IAP measurement via the TraumaGuard bladder catheter (IAPTG) and IAP obtained via Stryker or Conmed insufflator (IAPinsuf) was assessed using correlation, concordance, Bland–Altman, and error-grid analyses. The average IAP0 was 7.5 ± 1.9 mmHg and 15.4 ± 2.6 mmHg in patients without and with IAH. We found a two-way mixed-effects absolute agreement intraclass correlation coefficient of 0.7 for patients without baseline IAH and –0.3 for the patients with baseline IAH, indicating moderate agreement between bladder and insufflation pressures only in patients without baseline IAH. Nevertheless, Pearson’s correlation coefficient revealed a high linear relationship between the measured variables in both groups. Bland and Altman’s analysis showed a bias of 2.8 ± 2.7 mmHg, with ± 5.3 mmHg as the limits of agreement for patients without IAH. In contrast, patients with IAH had a bias of 10.6 ± 5.3 and limits of agreement of ± 10.4 mmHg. The findings support not using insufflation pressure as a gold standard reference for future validation studies due to its inherent limitations.