IAP Monitoring: Fast Facts


Intra-abdominal hypertension (IAH), or its more severe form, Abdominal Compartment Syndrome (ACS), is a common, life-threatening complication associated with substantial morbidity and mortality among critically ill adults. IAH occurs in 30-50% of critically ill patients [1].

These conditions have also been linked with acute and chronic renal failure, multi-organ dysfunction syndrome (MODS), increased lengths of intensive care unit (ICU) and hospital stay [2].

Who is at risk for IAH and ACS?

All patients who are edematous, critically ill or who have abdominal distension for any reason are at risk for IAH or ACS [4]. Abdominal surgery, high-volume fluid resuscitation, ileus, and pulmonary, renal, or liver dysfunction predict IAH. More extensive lists are provided by the WSACS (World Society of Abdominal Compartment Syndrome) and the London Health Sciences Centre [4, 5].

How does IAH or ACS develop?

The pressure inside the abdominal compartment can increase due to the accumulation of intravascular fluid and interstitial edema.  As this fluid accumulates, the pressure in the abdomen begins to increase. Untreated IAH can progress to ACS, multiple organ failure, and ultimately death [1].

When should Intra Abdominal Pressure (IAP) be measured?

The WSACS recommends that patients be screened for IAH/ACS risk factors upon ICU admission and in the presence of new or progressive organ failure. If two or more risk factors are present, a baseline IAP measurement should be obtained. If IAH is present, IAP monitoring should be performed throughout the patient’s critical illness [3].


IAP Monitoring

How is IAP measured?

Intra-bladder pressure (IBP) monitoring is considered the method of choice for indirect IAP monitoring due to its accuracy, relative ease, and cost-effectiveness [5]. IAP is measured through the patient’s indwelling urinary Foley catheter, utilizing the bladder wall as a passive transducing membrane [6].

There are currently several IAP monitoring devices on the market, designed to be used with Foley catheters.


The Clarity RMS™ is compatible with these devices, enabling on-the-spot deployment at any time for optimal clinical care and cost-effectiveness.



[1] Malbrain ML, Chiumello D, Pelosi P, et al. Incidence and prognosis of intra-abdominal hypertension in a mixed population of critically ill patients: A multiple-center epidemiological study. Crit Care Med. 2005;33 (2):315-322.

[2] Holodinsky JK, Roberts DJ, Ball CG, Blaser AR, et al. Risk factors for intra-abdominal hypertension and abdominal compartment syndrome among adult intensive care unit patients: a systematic review and meta-analysis. Crit Care. 2013; 17(5): R249.

[3] WSACS Consensus Guidelines Summary 2021. https://www.wsacs.org/education/436/wsacs-consensus-guidelines-summary/

[4] London Health Sciences Centre. Critical Care Trauma Centre. Information and Procedure: Intra-Abdominal Pressure Monitoring.

[5] WSACS Consensus Recommendations 2007. https://www.wsacs.org/wp-content/uploads/2021/04/ICM_2007_consensus_part_II.pdf

[6] Desie N, Willems A, De laet I, Dits H, et al. Intra-abdominal pressure measurement using the FoleyManometer does not increase the risk for urinary tract infection in critically ill patients. Ann. Intensive Care 2, S10 (2012). https://doi.org/10.1186/2110-5820-2-S1-S10

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