Background: General pathophysiological mechanisms regarding associations between fluid administration and intra-abdominal hypertension (IAH) are evident, but specific effects of type, amount, and timing of fluids are less clear. Objectives: This review aims to summarize current knowledge on associations between fluid administration and intra-abdominal pressure (IAP) and fluid management in patients at risk of intra-abdominal hypertension and abdominal compartment syndrome (ACS). Methods: We performed a structured literature search from 1950 until May 2021 to identify evidence of associations between fluid management and intra-abdominal pressure not limited to any specific study or patient population. Findings were summarized based on the following information: general concepts of fluid management, physiology of fluid movement in patients with intra-abdominal hypertension, and data on associations between fluid administration and IAH. Results: We identified three randomized controlled trials (RCTs), 38 prospective observational studies, 29 retrospective studies, 18 case reports in adults, two observational studies and 10 case reports in children, and three animal studies that addressed associations between fluid administration and IAH. Associations between fluid resuscitation and IAH were confirmed in most studies. Fluid resuscitation contributes to the development of IAH. However, patients with IAH receive more fluids to manage the effect of IAH on other organ systems, thereby causing a vicious cycle. Timing and approach to de-resuscitation are of utmost importance, but clear indicators to guide this decision-making process are lacking. In selected cases, only surgical decompression of the abdomen can stop deterioration and prevent further morbidity and mortality. Conclusions: Current evidence confirms an association between fluid resuscitation and secondary IAH, but optimal fluid management strategies for patients with IAH remain controversial.

This review presents an overview of previously reported non-invasive intra-abdominal pressure (IAP) measurement techniques. Each section covers the basic physical principles and methodology of the various measurement techniques, the experimental results, and the advantages and disadvantages of each method. The most promising non-invasive methods for IAP measurement are microwave reflectometry and ultrasound assessment, in combination with an applied external force.

Intra-abdominal hypertension, defined as an intra-abdominal pressure (IAP) equal to or above 12 mmHg is one of the major risk-factors for increased morbidity (organ failure) and mortality in critically ill patients. Therefore, IAP monitoring is highly recommended in intensive care unit (ICU) patients to predict development of abdominal compartment syndrome and to provide a better care for patients hospitalized in the ICU. The IAP measurement through the bladder is the actual reference standard advocated by the abdominal compartment society; however, this measurement technique is cumbersome, non-continuous, and carries a potential risk for urinary tract infections and urethral injury. Using microwave reflectometry has been proposed as one of the most promising IAP measurement alternatives. In this study, a novel radar-based method known as transient radar method (TRM) has been used to monitor the IAP in an in vitro model with an advanced abdominal wall phantom. In the second part of the study, further regression analyses have been done to calibrate the TRM system and measure the absolute value of IAP. A correlation of –0.97 with a p-value of 0.0001 was found between the IAP and the reflection response of the abdominal wall phantom. Additionally, a quadratic relation with a bias of −0.06 mmHg was found between IAP obtained from the TRM technique and the IAP values recorded by a pressure gauge. This study showed a promising future for further developing the TRM technique to use it in clinical monitoring.

Introduction: Increased intra-abdominal pressure (IAP) has an important impact on morbidity and mortality in critically ill patients. The SERENNO Sentinel system (Serenno Medical, Yokne’am Illit, Israel) is a novel device that allows automatic and continuous IAP measurements. Aims: Pre-clinical validation in a bench model study comparing the new device with the gold standard method and two other continuous IAP measurement devices. Methods: IAP measurement with the novel SERENNO device (IAP_SER) was compared with the gold standard IAP_H2O (water column height) and two other automatic and continuous IAP measurement devices: IAP_CiM measured via the CiMON device (Pulsion Medical Systems, Munich, Germany) and IAP_SPIE measured using the Spiegelberg device (Spiegelberg, Hamburg, Germany), which previously received the CE mark for clinical applications. The IAP measurement was performed six times (n = 6) at each pressure value (between 0 and 35 mmHg) with different methods and the height of the water column in a bench-top phantom was used as the reference IAP for further interpretations. In addition to the quadruple comparisons, intra- and inter-observer variability of IAP measurements were also calculated. Correlation studies and Bland and Altman’s analyses were performed in addition to the concordance study. Results: The CiMON and Spiegelberg devices showed a greater dynamic range and standard deviation when recording IAP_CiM and IAP_SPIE compared with IAP_SER. In general, the maximum and minimum values of IAP recorded with each device (at each level of IAP_H2O) were significantly different from each other. However, the average values were in very good agreement. The highest correlation was observed between IAP_SER and IAP_H2O, and IAP_SER and IAP_SPIE (R = 0.99, p = 0.001 for both comparisons and intra- and inter-observer measurements). Although the CiMON and SERENNO systems were in very good agreement with each other, a slightly smaller correlation coefficient was found between them (R = 0.95, p = 0.001, and R = 0.96, p = 0.001 for intra- and inter-observer measurements, respectively). When compared to the gold standard (IAP_H2O), Bland and Altman’s analysis showed a mean difference of +0.44, −0.25, and −0.04 mmHg for the intra-observer measurements and +0.18, −0.75, and −0.58 mmHg for the inter-observer measurements for IAP_SER, IAP_CiM, and IAP_SPIE, respectively. IAP_SER showed a small positive bias (overestimation), while IAP_CiM and IAP_SPIE showed a negative bias (underestimation) when compared to IAP_H2O. Further statistical analysis showed a concordance coefficient of 100% with an excellent ability of the SERENNO system in tracking IAP_H2O changes. Conclusions: Pre-clinical validation of a new IAP monitoring device (SERENNO) showed very promising results when compared with the gold standard and other continuous techniques; however, clinical trials should be followed as the next stage of the validation process. Based on the actual research guidelines, the SERENNO system can be used interchangeably with the gold standard.

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.