Variation and accuracy of intra-abdominal pressure measurement in different body positions: a prospective study

Recent studies confirm that intra-abdominal hypertension (IAH) frequently develops in critically ill patients, posing a significant risk of organ failure and increased mortality. Accurate intra-abdominal pressure (IAP) measurement is essential for effective diagnosis, prevention, and treatment. Previous studies indicate that accurate IAP measurement using traditional Foley catheters requires the bladder to be filled with a maximum of 25 mL of sterile saline solution after clamping the catheter, restricting the ability to monitor IAP continuously due to variations in the bladder fill volume. The TraumaGuard catheter enables continuous IAP measurement irrespective of bladder fill volume. The primary objective was the validation of the TraumaGuard catheter (Sentinel Medical Technologies, Jacksonville, Florida, USA), a new continuous bladder pressure monitoring device. ICU patients were studied across different body positions to assess measurement accuracy by comparing the correlation, bias, precision, and agreement between IAP readings obtained using the TraumaGuard catheter and the FoleyManometer measurement method (SecurMeter, Deltamed, Viadana, Italy), which serves as the gold standard. The secondary endpoint of this study was to investigate the impact of different body positions on IAP. Adult ICU patients (≥ 18 years) requiring bladder catheterisation were enrolled. IAP was measured using a TraumaGuard catheter (IAPTG) and FoleyManometer method (IAPFM) across multiple positions to have a broad range of IAP values and to study the impact of body position on IAP measurement. Pairwise analysis of IAPTG and IAPFM in the supine, reverse Trendelenburg (15°, 30°, and 45°), and head-of-bed (HOB) elevation positions (15°, 30°, and 45°) was performed using correlation, concordance, and Bland-Altman analyses. The error-grid analysis assessed the risk associated with inaccurate measurements at each body position. The robustness of the TraumaGuard catheter as a detection system for IAH detection system was evaluated by receiver operating characteristic (ROC) curve. The IAP variation as a function of body position was investigated and compared with the reviewed literature. Gender, age, body mass index (BMI), and sequential organ failure assessment (SOFA) score were also recorded for each participant. Twenty-five adult ICU patients with a mean age of 63.6 ± 11.6 years and BMI of 28.3 ± 3.7 kg/m2 were included. The mean IAP increased from 9.8 ± 1.7 mmHg in supine to 10.4 ± 1.5 mmHg in reverse Trendelenburg and 14.9 ± 1.6 mmHg in HOB elevation positions. The correlation coefficients were 0.9, 0.9, and 0.8 for supine, reverse Trendelenburg, and HOB elevation positions. The supine positions showed a bias and precision of 0.8 and 1.7 mmHg according to Bland-Altman analysis. Reverse Trendelenburg and HOB elevation positions showed a bias of − 0.3 and 1.5 mmHg with a precision of 1.5 and 1.6 mmHg, respectively. The lower and upper limits of agreement were − 2.5–4.2 mmHg, − 3.2–2.6 mmHg, and − 1.6–4.6 mmHg for supine, reverse Trendelenburg, and HOB elevation positions with a percentage error of 35%, 28%, and 21%, respectively. Concordance coefficients were highest in reverse Trendelenburg positions (100.0%) compared to supine (95.3%) and HOB elevation (92.1%) positions. The error-grid analysis indicated no medium/high-risk errors for supine and reverse Trendelenburg and a 2.7% medium-risk error at HOB elevation positions. The results of this validation of a new continuous IAP monitoring device in ICU patients showed excellent results when compared to the gold standard. Changing the body position from supine to reverse Trendelenburg or HOB elevation increases the IAP.