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Purpose: To retrospectively evaluate the effect of ethical triage tools (ETT), designed to streamline the admission of patients during the first wave of the COVID-19 pandemic. We aimed to determine the characteristics and outcomes of the patients who would have been denied admission to the ICU according to these protocols, including the cumulative number of saved ICU days. Methods: We retrospectively identified the ethical triage status in every patient who was admitted to our 31-bed mixed ICU in Antwerp, Belgium during the first wave of the COVID-19 pandemic, regardless of the reason for admission. This study was possible since the capacity of our ICU had not been threatened, still enabling our usual case-per-case decision. We evaluated three different ETTs that were designed in our and two other hospitals during the COVID-19 pandemic. Results: During the 81-day study period, 182 patients were admitted to the ICU. Of the patients, 9-23% would have been denied ICU admission according to the three assessed ETTs (WBD cohort), responsible for 8-18% (n = 116-257) of the total number of ICU days. Of the WBD patients, 44-55% eventually survived their hospital stay, compared to 71-74% of the patients that would have been allowed admission. Of the WBD patients admitted for respiratory failure due to COVID-19, 18-25% survived, a number that decreased to 0-20% when these patients required mechanical ventilation. Conclusion: An ETT effectively reduces ICU bed occupancy but it does not accurately discriminate between survivors and non-survivors, as a substantial percentage of patients who are being denied admission to the ICU would eventually survive their hospital stay. (c) 2021 Elsevier Inc. All rights reserved.

Intra-abdominal hypertension (IAH) is common and associated with morbidity and mortality in critically ill patients. IAH exists along a continuum that begins with a mild asymptomatic elevation of intra-abdominal pressure (IAP) and extends to life-threatening abdominal compartment syndrome (ACS). In 2013, evidence-based guidelines were published on the definitions, diagnosis, and treatment of IAH and ACS. Even using these guidelines, making bedside decisions regarding management of individual patients with IAH/ACS remains challenging due to the wide variety of conditions associated with IAH/ACS, the varying degrees of associated organ dysfunction, and the large number of available treatment options. Using a simplified treatment paradigm, we advocate that the optimal treatment strategy should not be based purely on the degree of IAP alone, but on three critical elements: the magnitude of IAP, the degree and dynamics of organ dysfunction (or thus the impact of increased IAP), and the etiology of increased IAP. In this chapter, we propose a conceptual framework of how to diagnose and manage patients with IAH/ACS, taking into account patient physiology, current scientific evidence, and experience. In this practical and clinical approach, both the necessity and urgency of intervention are discussed.

Although the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is lasting for more than 1 year, the exposition risks of health-care providers are still unclear. Available evidence is conflicting. We investigated the prevalence of antibodies against SARS-CoV-2 in the staff of a large public hospital with multiple sites in the Antwerp region of Belgium. Risk factors for infection were identified by means of a questionnaire and human resource data. We performed hospital-wide serology tests in the weeks following the first epidemic wave (16 March to the end of May 2020) and combined the results with the answers from an individual questionnaire. Overall seroprevalence was 7.6%. We found higher seroprevalences in nurses [10.0%; 95% confidence interval (CI) 8.9-11.2] than in physicians 6.4% (95% CI 4.6-8.7), paramedical 6.0% (95% CI 4.3-8.0) and administrative staff (2.9%; 95% CI 1.8-4.5). Staff who indicated contact with a confirmed coronavirus disease 2019 (COVID-19) colleague had a higher seroprevalence (12.0%; 95% CI 10.7-13.4) than staff who did not (4.2%; 95% CI 3.5-5.0). The same findings were present for contacts in the private setting. Working in general COVID-19 wards, but not in emergency departments or intensive care units, was also a significant risk factor. Since our analysis points in the direction of active SARS-CoV-2 transmission within hospitals, we argue for implementing a stringent hospital-wide testing and contact-tracing policy with special attention to the health care workers employed in general COVID-19 departments. Additional studies are needed to establish the transmission dynamics. European Research Council (ERC) under the European UnionEuropean Research Council (ERC) [682540 TransMID]

WSACS--The Abdominal Compartment Society. A Society dedicated to the study of the physiology and pathophysiology of the abdominal compartment and its interactions with all organ systems.

Over the last few decades, increasing attention has been paid to understanding the pathophysiology, aetiology, prognosis, and treatment of elevated intra-abdominal pressure (IAP) in trauma, surgical, and medical patients. However, there is presently a relatively poor understanding of intra-abdominal volume (IAV) and the relationship between IAV and IAP (i.e. abdominal compliance). Consensus definitions on Cab were discussed during the 5th World Congress on Abdominal Compartment Syndrome and a writing committee was formed to develop this article. During the writing process, a systematic and structured Medline and PubMed search was conducted to identify relevant studies relating to the topic. According to the recently updated consensus definitions of the World Society on Abdominal Compartment Syndrome (WSACS), abdominal compliance (Cab) is defined as a measure of the ease of abdominal expansion, which is determined by the elasticity of the abdominal wall and diaphragm. It should be expressed as the change in IAV per change in IAP (mL [mm Hg]⁻¹). Importantly, Cab is measured differently than IAP and the abdominal wall (and its compliance) is only a part of the total abdominal pressure-volume (PV) relationship. During an increase in IAV, different phases are encountered: the reshaping, stretching, and pressurisation phases. The first part of this review article starts with a comprehensive list of the different definitions related to IAP (at baseline, during respiratory variations, at maximal IAV), IAV (at baseline, additional volume, abdominal workspace, maximal and unadapted volume), and abdominal compliance and elastance (i.e. the relationship between IAV and IAP). An historical background on the pathophysiology related to IAP, IAV and Cab follows this. Measurement of Cab is difficult at the bedside and can only be done in a case of change (removal or addition) in IAV. The Cab is one of the most neglected parameters in critically ill patients, although it plays a key role in understanding the deleterious effects of unadapted IAV on IAP and end-organ perfusion. The definitions presented herein will help to understand the key mechanisms in relation to Cab and clinical conditions and should be used for future clinical and basic science research. Specific measurement methods, guidelines and recommendations for clinical management of patients with low Cab are published in a separate review.

Background: Gastric residual volume (GRV) can be measured in a variety of ways in critically ill patients, most often, the nasogastric tube is disconnected and the GRV is aspirated via a 60 mL syringe. Bladder pressure (IBP) measurement is the gold standard for intra-abdominal pressure (IAP) estimation. This study will look at the validation of a novel method combining measurement of GRV and estimation of IAP via intra-gastric pressure (IGP). Methods: In total 135 paired IAP and 146 paired GRV measurements were performed in 37 mechanically ventilated ICU patients. The IAP was estimated via the bladder (i.e. IBP) using the FoleyManometer and via the stomach (i.e. IGP) with the new device. The GRV was measured with the new device (GRV prototype ) and via the classic method (GRV classic ). The devices were provided by Holtech Medical (Charlottenlund, Denmark) and data were retrospectively analysed. Results: The number of paired measurements in each patient was 4 ± 1. The mean IBP was 10.7 ± 4.1 and mean IGP was 11.6 ± 4.1 mm Hg. Correlation between the IBP and IGP was significant, however moderate (R 2 = 0.51). Analysis according to Bland and Altman showed a bias and precision of 0.8 and 2.7 mm Hg respectively, however the limits of agreement (LA) were large and ranged from −4.5 to 6.1 mm Hg. Changes in IGP correlated well with changes in IBP. The median GRV prototype was 80 mL (0–1050) and equal to the median GRV classic of 80 mL (0−1250). Correlation between the 2 methods was excellent (R 2 = 0.89). Analysis according to Bland and Altman showed a bias and precision of -0.8 and 52.3 mL respectively and the LA ranged from –103 to 102 mL. Changes in GRV classic correlated well with changes in GRV prototype . Conclusions: The results of this multicentre pilot study show that GRV can be measured with the new device. Furthermore this allows simultaneous screening for intra-abdominal hypertension with IAP estimation via IGP.

Background: Little is known about serum galactomannan (GM) testing in (mostly non-neutropenic) mixed intensive care unit (ICU) patients. The aim of this study was to look for the incidence of invasive aspergillosis (IA) in critically ill patients, to validate previously reported GM thresholds, and to evaluate the prognostic value of GM. Methods: This was a retrospective study of 474 GM samples in 160 patients from the start of January 2003 until the start of February 2004. GM tests were ordered because of a clinical suspicion of IA or on a regular basis in immune compromised patients. The number of samples per patient was 3 ± 2.6. We used the criteria of the European Organisation for Research and Treatment of Cancer (EORTC) to define proven IA, probable IA, and possible IA. The number of positive samples, with GM optical density (OD) > 0.5 was 230 (48.5%). Results: In our study population, five (3%) patients had proven IA, 11 (7%) had probable, 27 (17.5%) had possible, and 116 (72.5%) had no IA. We could not identify a GM threshold for IA with analysis of receiver operating characteristics (ROC) curves: with a sensitivity of (56.3%, 50%, 50%, 37.5%), specificity (38.2%, 67.5%, 68.8%, 72.9%), NPV (88.7%, 91.8%, 92.5%, 91.3%) and PPV (9.2%, 12.9%, 15.1%, 13.3%) for a cut-off of OD > 0.5, > 0.8, > 1.1 and > 1.5 respectively. IA was associated with high mortality of 87.5% and 100% in patients with probable and proven IA respectively. Patients with IA had a significant increase of GM during their stay (GM delta 0.7 ± 1.5 vs –0.2 ± 1.5, P = 0.027). The overall ICU mortality was 41.9% and the hospital mortality was 58.1%. Patients who died in the ICU and in the hospital had higher APACHE-II, SAPS-II and SOFA scores (P < 0.0001) and also a significant increase in GM during their stay with 0.27 ± 1.26 (ICU non-survivors) and 0.11 ± 1.55 (hospital non-survivors) compared to a decrease in GM –0.43 ± 1.7 (P = 0.004) and –0.48 ± 1.51 (P = 0.017) in ICU and hospital survivors respectively. Non-survivors also had higher mean GM values but this was not statistically significant. There was a trend towards higher GM values in patients treated with piperacillin/ta zobactam (n = 34), but this did not reach statistical significance. Neutropenic patients (n = 31) showed an increase in GM during their stay 0.32 ± 1.3 vs a decrease with –0.43 ± 1.7 in non-neutropenic patients (P = 0.07). Patients on total parenteral nutrition (n = 125) had higher maximal GM levels (1.55 ± 1.94 vs 0.88 ± 1.25, P = 0.058). Patients who were mechanically ventilated had significantly higher mean ( P = 0.038) and maximal (P = 0.007) GM levels. Conclusions: We found a high incidence of proven and probable IA in a group of mixed ICU patients (10%) and the presence of IA was associated with a high mortality. The serum GM antigen detection test may not be useful in the diagnosis of IA in mixed ICU patients, according to the results of the ROC analysis. We could not define a useful threshold.

A compartment syndrome (CS) exists when increased pressure in a closed anatomic space threatens the viability of enclosed tissue. Within the body there are four types of compartments, the head, the chest, the abdomen, and the extremities, but when a compartment syndrome occurs in the abdominal cavity the impact on end-organ function both within and outside of the cavity can be devastating (Table 1). Intra-abdominal hypertension (IAH) is a graded phenomenon and can evolve to the end-stage abdominal compartment syndrome (ACS), which is an all or nothing phenomenon. The ACS is not a disease and as such it can have many causes and it can develop within many disease processes. The development of IAH is of extreme importance in the care of critically ill patients, because of the impact of increased intraabdominal pressure (IAP) on end-organ function. Recent animal and human data suggest that the adverse effects of elevated IAP can occur at much lower levels than previously thought and even before the development of clinically overt ACS. This review gives a concise overview of the definitions, epidemiology, pathophysiology, and management of IAH and ACS.

OBJECTIVE: To investigate the effect of different reference transducer positions on intra-abdominal pressure (IAP) measurement. Three reference levels were studied: the symphysis pubis; the phlebostatic axis; and the midaxillary line at the level of the iliac crest. DESIGN: Prospective cohort study. SETTING: The intensive care units of participating hospitals PATIENTS AND PARTICIPANTS: One hundred thirty-two critically ill patients at risk for intra-abdominal hypertension (IAH). INTERVENTIONS: In each patient, three sets of IAP measurements were obtained in the supine position, using the different reference levels. The IAP measurements obtained at the different reference levels were compared using a paired t-test and Bland-Altman statistics were calculated. MEASUREMENTS AND RESULTS: IAP(phlebostatic) (9.9 +/- 4.67 mmHg) and IAP(pubis) (8.4 +/- 4.60 mmHg) were significantly lower that IAP(midax) (12.2 +/- 4.66 mmHg; p < 0.0001 for both comparisons). The bias between the IAP(midax) and IAP(pubis) was 3.8 mmHg (95% CI 3.5-4.1) and 2.3 mmHg (95% CI 1.9-2.6) between the IAP(midax) and the IAP(phlebostatic). The precision was 3.03 and 3.40, respectively. CONCLUSIONS: In the supine position, IAP(midax) is higher than both IAP(phlebostatic) and IAP(pubis), differences found to be clinically significant; therefore, the symphysis pubis or phlebostatic axis reference lines are not interchangeable with the midaxillary level.

OBJECTIVE: Intra-abdominal pressure (IAP) measurement is important in daily clinical practice. Most measurement techniques vary in automaticity and reproducibility. This study tested a new fully automated continuous technique for IAP measurement, the CiMON. METHODS: Three IAP measurement catheters (a Foley manometer and two balloon-tipped catheters) contained in a 50-ml infusion bag were placed on the bottom of a half open 3-l container. To simulate IAH the container was filled with water using 5 cmH2O increments (0-30 cmH2O). Pressure was estimated by observers using the Foley manometer (IAP(FM)) and simultaneously recorded using two IAP monitors: IAP(spie) with Spiegelberg and IAP(CiM) with CiMON. Observers were blinded to the reference levels. Fifteen observers (three intensivists, four residents, two medical students, and six nurses) conducted three pressure readings at each of the seven pressure levels with the FM technique, giving 315 readings. These were paired with the automated IAP(spie) and IAP(CiM) readings and the height of the H2O column. RESULTS: The intra- and interobserver coefficients of variation (COVA) were low for all methods. There was no difference in the results between specialists, physicians in training, andnurses. Spearman's correlation coefficient (R2) values for all paired measurements were greater than 0.9, and Bland-Altman analysis comparing the reference H2O column, IAP(FM), and IAP(spie) to IAP(CiM) showed a very good agreement at all pressure levels (bias -0.1+/-0.6 cmH2O, 95%CI -0.2 to 0). There was a consistent, low underestimation of the reference H2O pressure by the Spiegelberg technique and a low overestimation at pressures below 20 cmH2O by both other techniques. CONCLUSIONS: All three measurement techniques, IAP(FM), IAP(spie), and IAP(CiM) have good agreement with the applied hydrostatic pressure in this in vitro model of IAP measurement.

Background: Burn patients are at high risk for secondary intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) due to capillary leak and large volume fluid resuscitation. Our objective was to examine the incidence the incidence of IAH and ACS and their relation to outcome in mechanically ventilated (MV) burn patients. Methods: This observational study included all MV burn patients admitted between April 2007 and December 2009. Various physiological parameters, intra-abdominal pressure (IAP) measurements and severity scoring indices were recorded on admission and/or each day in ICU. Transpulmonary thermodilution parameters were also obtained in 23 patients. The mean and maximum IAP during admission was calculated. The primary endpoint was ICU (burn unit) mortality. Results: Fifty-six patients were included. The average Simplified Acute Physiology Score (SAPS II) and Sequential Organ Failure Assessment (SOFA) scores were 43.4 (± 15.1) and 6.4 (± 3.4), respectively. The average total body surface area (TBSA) affected by burns was 24.9% (± 24.9), with 33 patients suffering inhalational injuries. Forty-four (78.6%) patients developed IAH and 16 (28.6%) suffered ACS. Patients with ACS had higher TBSAs burned (35.8 ± 30 vs. 20.6 ± 21.4%, P = 0.04) and higher cumulative fluid balances after 48 hours (13.6 ± 16L vs. 7.6 ± 4.1 L, P = 0.03). The TBSA burned correlated well with the mean IAP (R = 0.34, P = 0.01). Mortality was notably high (26.8%) and significantly higher in patients with IAH (34.1%, P = 0.014) and ACS (62.5%, P < 0.0001). Most patients received more fluids than calculated by the Parkland Consensus Formula while, interestingly, non-survivors received less. However, when patients with pure inhalation injury were excluded there were no differences. Non-surgical interventions (n = 24) were successful in removing body fluids and were related to a significant decrease in IAP, central venous pressure (CVP) and an improvement in oxygenation and urine output. Non-resolution of IAH was associated with a significantly worse outcome ( P < 0.0001). Conclusion: Based on our preliminary results we conclude that IAH and ACS have a relatively high incidence in MV burn patients compared to other groups of critically ill patients. The percentage of TBSA burned correlates with the mean IAP. The combination of high CLI, positive (daily and cumulative) fluid balance, high IAP, high EVLWI and low APP suggest a poor outcome. Non-surgical interventions appear to improve end-organ function. Non-resolution of IAH is related to a worse outcome.

The Abdominal Compartment Society (www.wsacs.org) previously created highly cited Consensus Definitions/Management Guidelines related to intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS). Implicit in this previous work, was a commitment to regularly reassess and update in relation to evolving research. Two years preceding the Fifth World Congress on Abdominal Compartment Syndrome, an International Guidelines committee began preparation. An oversight/steering committee formulated key clinical questions regarding IAH//ACS based on polling of the Executive to redundancy, structured according to the Patient, Intervention, Comparator, and Outcome (PICO) format. Scientific consultations were obtained from Methodological GRADE experts and a series of educational teleconferences were conducted to educate scientific review teams from among the wscacs. org membership. Each team conducted systematic or structured reviews to identify relevant studies and prepared evidence summaries and draft Grades of Recommendation Assessment, Development and Evaluation (GRADE) recommendations. The evidence and draft recommendations were presented and debated in person over four days. Updated consensus definitions and management statements were derived using a modified Delphi method. A writing committee subsequently compiled the results utilizing frequent Internet discussion and Delphi voting methods to compile a robust online Master Report and a concise peer-reviewed summarizing publication. A dedicated Paediatric Guidelines Subcommittee reviewed all recommendations and either accepted or revised them for appropriateness in children. Of the original 12 IAH/ACS definitions proposed in 2006, three (25%) were accepted unanimously, with four (33%) accepted by >80%, and four (33%) accepted by >50%, but required discussion to produce revised definitions. One (8%) was rejected by >50%. In addition to previous 2006 definitions, the panel also defined the open abdomen, lateralization of the abdominal musculature, polycompartment syndrome, abdominal compliance, and suggested a refined open abdomen classification system. Recommendations were possible regarding intra-abdominal pressure (IAP) measurement, approach to sustained IAH, philosophy of protocolized IAP management and same-hospital-stay fascial closure, use of decompressive laparotomy, and negative pressure wound therapy. Consensus suggestions included use of non-invasive therapies for treating IAH/ACS, considering body position and IAP, damage control resuscitation, prophylactic open abdomen usage, and prudence in early biological mesh usage. No recommendations were made for the use of diuretics, albumin, renal replacement therapies, and utilizing abdominal perfusion pressure as a resuscitation-endpoint. Collaborating Methodological Guideline Development and Clinical Experts produced Consensus Definitions/Clinical Management statements encompassing the most contemporary evidence. Data summaries now exist for clinically relevant IAH/ACS questions, which will facilitate future scientific reanalysis.

Intra-abdominal hypertension (IAH) is an important contributor to early organ dysfunction in trauma and sepsis. However, relatively little is known about the impact of intra-abdominal pressure (IAP) in general internal medicine, pregnant patients, and those with obesity or burns. The aim of this paper is to review the pathophysiologic implications and treatment options for IAH in these specific situations. A MEDLINE and PubMed search was performed and the resulting body-of-evidence included in the current review on the basis of relevance and scientific merit. There is increasing awareness of the role of IAH in different clinical situations. Specifically, IAH will develop in most (if not all) severely burned patients, and may contribute to early mortality. One should avoid over-resuscitation of these patients with large volumes of fluids, especially crystalloids. Acute elevations in IAP have similar effects in obese patients compared to non-obese patients, but the threshold IAP associated with organ dysfunction may be higher. Chronic elevations in IAP may, in part, be responsible for the pathogenesis of obesity-related co-morbid conditions such as hypertension, pseudotumor cerebri, pulmonary dysfunction, gastroesophageal reflux disease, and abdominal wall hernias. At the bedside, measuring IAP and considering IAH in all critical maternal conditions is essential, especially in preeclampsia/eclampsia where some have hypothesized that IAH may have an additional role. IAH in pregnancy must take into account the precautions for aorto-caval compression and has been associated with ovarian hyperstimulation syndrome. Recently, IAP has been associated with the cardiorenal dilemma and hepatorenal syndrome, and this has led to the recognition of the polycompartment syndrome. In conclusion, IAH and ACS have been associated with several patient populations beyond the classical ICU, surgical, and trauma patients. In all at risk conditions the focus should be on the early recognition of IAH and prevention of ACS. Patients at risk for IAH should be identified early through measurements of IAP. Appropriate actions should be taken when IAP increases above 15 mm Hg, especially if pressures reach above 20 mm Hg with new onset organ failure. Although non-operative measures come first, surgical decompression must not be delayed if these fail. Percutaneous drainage of ascites is a simple and potentially effective tool to reduce IAP if organ dysfunction develops, especially in burn patients. Escharotomy may also dramatically reduce IAP in the case of abdominal burns.

In the future, medical management may play an increasingly important role in the prevention and management of intra-abdominal hypertension (IAH). A review of different databases was used (PubMed, MEDLINE and EMBASE) with the search terms 'Intra-abdominal Pressure' (IAP), 'IAH', ' Abdominal Compartment Syndrome' (ACS), 'medical management' and 'non-surgical management'. We also reviewed all papers with the search terms 'IAH', 'IAP' and 'ACS' over the last three years, only extracting those papers which showed a novel approach in the non-surgical management of IAH and ACS.IAH and ACS are associated with increased morbidity and mortality. Non-surgical management is an important treatment option in critically ill patients with raised IAP. There are five medical treatment options to be considered to reduce IAP: 1) improvement of abdominal wall compliance; 2) evacuation of intra-luminal contents; 3) evacuation of abdominal fluid collections; 4) optimisation of fluid administration; and 5) optimisation of systemic and regional perfusion. This paper will review the first three treatment arms of the WSACS algorithm: abdominal wall compliance; evacuation of intra-luminal contents and evacuation of abdominal fluid collections. Emerging medical treatments will be analysed and finally some alternative specific treatments will be assessed. Other treatment options with regard to optimising fluid administration and systemic and regional perfusion will be described elsewhere, and are beyond the scope of this review. Medical management of critically ill patients with raised IAP should be instigated early to prevent further organ dysfunction and to avoid progression to ACS. Many treatment options are available and are often part of routine daily management in the ICU (nasogastric, rectal tube, prokinetics, enema, sedation, body position). Some of the newer treatments are very promising options in specific patient populations with raised IAP. Future studies are warranted to confirm some of these findings.

Intra-abdominal hypertension (IAH) is an important contributor to early organ dysfunction in trauma and sepsis. However, relatively little is known about the impact of intra-abdominal pressure (IAP) in general internal medicine, pregnant patients, and those with obesity or burns. The aim of this paper is to review the pathophysiologic implications and treatment options for IAH in these specific situations. A MEDLINE and PubMed search was performed and the resulting body-of-evidence included in the current review on the basis of relevance and scientific merit. There is increasing awareness of the role of IAH in different clinical situations. Specifically, IAH will develop in most (if not all) severely burned patients, and may contribute to early mortality. One should avoid over-resuscitation of these patients with large volumes of fluids, especially crystalloids. Acute elevations in IAP have similar effects in obese patients compared to non-obese patients, but the threshold IAP associated with organ dysfunction may be higher. Chronic elevations in IAP may, in part, be responsible for the pathogenesis of obesity-related co-morbid conditions such as hypertension, pseudotumor cerebri, pulmonary dysfunction, gastroesophageal reflux disease, and abdominal wall hernias. At the bedside, measuring IAP and considering IAH in all critical maternal conditions is essential, especially in preeclampsia/eclampsia where some have hypothesized that IAH may have an additional role. IAH in pregnancy must take into account the precautions for aorto-caval compression and has been associated with ovarian hyperstimulation syndrome. Recently, IAP has been associated with the cardiorenal dilemma and hepatorenal syndrome, and this has led to the recognition of the polycompartment syndrome. In conclusion, IAH and ACS have been associated with several patient populations beyond the classical ICU, surgical, and trauma patients. In all at risk conditions the focus should be on the early recognition of IAH and prevention of ACS. Patients at risk for IAH should be identified early through measurements of IAP. Appropriate actions should be taken when IAP increases above 15 mm Hg, especially if pressures reach above 20 mm Hg with new onset organ failure. Although non-operative measures come first, surgical decompression must not be delayed if these fail. Percutaneous drainage of ascites is a simple and potentially effective tool to reduce IAP if organ dysfunction develops, especially in burn patients. Escharotomy may also dramatically reduce IAP in the case of abdominal burns.

Background: Haemodynamic monitoring with transpulmonary thermodilution (TPTD) is less invasive than a pulmonary artery catheter, and is increasingly used in the Intensive Care Unit and the Operating Room. Optimal treatment of the critically ill patient demands adequate, precise and continuous monitoring of clinical parameters. Little is known about staff knowledge of the basic principles and practical implementation of TPTD measurements at the bedside. The aims of this review are to: 1) present the results of a survey on the knowledge of TPTD measurement among 252 nurses and doctors; and 2) to focus on specific situations and common pitfalls in order to improve patient management in daily practice. Methods: Web-based survey on knowledge of PiCCO technology (Pulsion Medical Systems, Feldkirchen, Germany), followed by PubMed and Medline search with review of the relevant literature regarding the use of TPTD in specific situations. Results: In total, 252 persons participated in the survey: 196 nurses (78%) and 56 medical doctors (22%) of whom 17 were residents in training. Knowledge on the use of TPTD appears to be suboptimal, with an average score of 58.3%. Doctors performed better than nurses (62.7% vs 57.0%, P = 0.012). About 190 out of 252 (75.4%) scored at least 50% but only 45 respondents (17.9%) obtained a score of 70% or more. Having five years of PiCCO experience was present in 15.8% of the participants and this was correlated to passing the test, defined as obtaining a test result of ≥ 50% ( P = 0.07) or obtaining a test result of ≥ 70% ( P = 0.05). There were no other parameters significantly predictive for obtaining a result above 50% or above 70% such as gender or doctor versus nurse or Belgian versus Dutch residency, or years of ICU experience. High quality education of nursing and medical staff is necessary to perform the technique correctly and to analyse and interpret the information that can be obtained. Visual inspection of thermodilution curves is important as this can point towards specific pathology. Interpretation of the parameters that can be obtained with TPTD in specific conditions is discussed. Finally, a practical approach is given in ten easy steps for nurses and doctors. Conclusion: TPTD has gained its place in the haemodynamic monitoring field, but, as with any technique, its virtue is only fully appreciated with correct use and interpretation.

Background: Surveys have demonstrated a lack of physician awareness of intra-abdominal hypertension and abdominal compartment syndrome (IAH/ACS) and wide variations in the management of these conditions, with many intensive care units (ICUs) reporting that they do not measure intra-abdominal pressure (IAP). We sought to determine the association between publication of the 2006/2007 World Society of the Abdominal Compartment Syndrome (WSACS) Consensus Definitions and Guidelines and IAH/ACS clinical awareness and management. Methods: The WSACS Executive Committee created an interactive online survey with 53 questions, accessible from November 2006 until December 2008. The survey was endorsed by the WSACS, the European Society of Intensive Care Medicine (ESICM) and the Society of Critical Care Medicine (SCCM). A link to the survey was emailed to all members of the supporting societies. Participants of the 3rd World Congress on Abdominal Compartment Syndrome meeting (March 2007, Antwerp, Belgium) were also asked to complete the questionnaire. No reminders were sent. Based on 13 knowledge questions, an overall score was calculated (expressed as percentage). Results: A total of 2,244 of the approximately 10,000 clinicians who were sent the survey responded (response rate: 22.4%). Most of the 2,244 respondents (79.2%) completing the survey were physicians or physicians in training and the majority were residing in North America (53.0%). The majority of responders (85%) were familiar with IAP/IAH/ACS, but only 28% were aware of the WSACS consensus definitions for IAH/ACS. Three quarters of respondents considered the cut-off for IAH to be at least 15 mm Hg, and nearly two thirds believed the cut-off for ACS was higher than the currently suggested consensus definition (20 mm Hg). In 67.8% of respondents, organ dysfunction was only considered a problem with IAP of 20 mm Hg or higher. IAP was measured most frequently via the bladder (91.9%), but the majority reported that they instilled volumes well above the current guidelines. Surgical decompression was frequently used to treat IAH/ACS, whereas medical management was only attempted by about half of the respondents. Decisions to decompress the abdomen were predominantly based on the severity of IAP elevation and presence of organ dysfunction (74.4%). Overall knowledge scores were low (43 +/- 15%); respondents who were aware of the WSACS had a better score compared to those who were not (49.6% vs 38.6%, P < 0.001). Conclusions: This survey showed that although most responding clinicians claim to be familiar with IAH and ACS, knowledge of published consensus definitions, measurement techniques, and clinical management is inadequate.

Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) are consistently associated with morbidity and mortality among the critically ill or injured. Thus, avoiding or potentially treating these conditions may improve patient outcomes. With the aim of improving the outcomes for patients with IAH/ACS, the World Society of the Abdominal Compartment Syndrome recently updated its clinical practice guidelines. In this article, we review the association between a positive fluid balance and outcomes among patients with IAH/ACS and how optimisation of fluid administration and systemic/regional perfusion may potentially lead to improved outcomes among this patient population.Evidence consistently associates secondary IAH with a positive fluid balance. However, despite increased research in the area of non-surgical management of patients with IAH and ACS, evidence supporting this approach is limited. Some evidence exists to support implementing goal-directed resuscitation protocols and restrictive fluid therapy protocols in shocked and recovering critically ill patients with IAH. Data from animal experiments and clinical trials has shown that the early use of vasopressors and inotropic agents is likely to be safe and may help reduce excessive fluid administration, especially in patients with IAH. Studies using furosemide and/or renal replacement therapy to achieve a negative fluid balance in patients with IAH are encouraging. The type of fluid to be administered in patients with IAH remains far from resolved. There is currently insufficient evidence to recommend the use of abdominal perfusion pressure as a resuscitation endpoint in patients with IAH. However, it is important to recognise that IAH either abolishes or increases threshold values for pulse pressure variation and stroke volume variation to predict fluid responsiveness, while the presence of IAH may also result in a false negative passive leg raising test.Correct fluid therapy and perfusional support during resuscitation form the cornerstone of medical management in patients with abdominal hypertension. Controlled studies determining whether the above medical interventions may improve outcomes among those with IAH/ACS are urgently required.

The recent definitions on intra-abdominal pressure (IAP), intra-abdominal volume (IAV) and abdominal compliance (Cab) are a step forward in understanding these important concepts. They help our understanding of the pathophysiology, aetiology, prognosis, and treatment of patients with low Cab. However, there is still a relatively poor understanding of the different methods used to measure IAP, IAV and Cab and how certain conditions may affect the results. This review will give a concise overview of the different methods to assess and estimate Cab; it will list important conditions that may affect baseline values and suggest some therapeutic options. Abdominal compliance (Cab), defined as a measure of the ease of abdominal expansion, is measured differently than IAP. The compliance of the abdominal wall is only a part of the total abdominal pressure-volume (PV) relationship. Measurement or estimation of Cab is difficult at the bedside and can only be done in a case of change (removal or addition) in IAV. The different measurement techniques will be discussed in relation to decreases (ascites drainage, haematoma evacuation, gastric suctioning) or increases in IAV (gastric insufflation, laparoscopy with CO₂ pneumoperitoneum, peritoneal dialysis). More specific techniques using the interactions between the thoracic and abdominal compartment during positive pressure ventilation will also be discussed (low flow PV loop, respiratory IAP variations, respiratory abdominal variation test, mean IAP and abdominal pressure variation), together with the concept of the polycompartment model. The relation between IAV and IAP is linear at low IAV and becomes curvilinear and exponential at higher volumes. Specific conditions in relation to increased (previous pregnancy or laparoscopy, gynoid fat distribution, ellipse-shaped internal abdominal perimeter) or decreased Cab (obesity, fluid overload, android fat distribution, sphere-shaped internal abdominal perimeter) will be discussed as well as their impact on baseline IAV, IAP, reshaping capacity and abdominal workspace volume. Finally, we suggest possible treatment options in situations of unadapted IAV according to existing Cab, which results in high IAP. A large overlap exists between the treatment of patients with abdominal hypertension and those with low Cab. The Cab plays a key role in understanding the deleterious effects of unadapted IAV on IAP and end-organ perfusion and function. If we can identify patients with low Cab, we can anticipate and select the most appropriate surgical treatment to avoid complications such as IAH or ACS.

This review will describe the definitions on intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS). In order to understand these definitions the reader must be aware of the interactions between intra-abdominal pressure (IAP) and intra-abdominal volume (IAV), explaining why dramatic IAP increases can be observed in some patients related to anthropomorphic measurements, body positioning, use of positive pressure ventilation, or relatively small accumulations of fluid or blood. The adverse effects related to increased IAP have been named IAH for moderate cases and ACS for advanced cases. In order to improve clinical communication as well as evaluation of the scientific literature, the World Society for the Abdominal Compartment Syndrome (WSACS) has published its first guidelines and definitions in 2006. The definitions and guidelines have recently been revised according to evidence based medicine and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. This review will be based on the revised guidelines. The standard method to measure IAP is via the bladder and as experience with IAP measurement has evolved considerably, a number of tips and potential pitfalls are listed.

In this study we compared the accuracy of three continuous cardiac output (CCO) measurement methods, with intermittent transcardiopulmonary thermodilution (TPTD-CO) as the gold standard. The three studied CCO measurement methods were: uncalibrated peripheral pulse contour measurement (FCCO), calibrated central pulse contour measurement (PCCO), and CCO obtained by indirect Fick principle (NCCO).We performed an observational study in 23 critically ill patients. Statistical analysis was done using Pearson's correlation and Bland-Altman analysis. A review of the relevant medical literature was performed.Only PCCO showed good correlation (R = 0.9) and agreement with a bias of 0.0 ± 0.8 L min⁻¹ and percentage error of 24.5% when compared to TPTD-CO. In patients with normal systemic vascular resistance index (SVRI1,700 dyne sec cm⁻⁵ m⁻²), NCCO (R = 0.8 and bias 0.4 ± 1.3 L min⁻¹) and FCCO (R = 0.8 and bias 0.1 ± 1 L min⁻¹) also produced reliable results.These results indicate that in our patient population, CCO can be most reliably monitored by calibrated central pulse contour measurements. All other methods appeared less accurate, especially in situations of low SVRI.

BACKGROUND: Monitoring hepatic blood flow and function might be crucial in treating critically ill patients. Intra-abdominal hypertension is associated with decreased abdominal blood flow, organ dysfunction, and increased mortality. The plasma disappearance rate (PDR) of indocyanine green (ICG) is considered to be a compound marker for hepatosplanchnic perfusion and hepatocellular membrane transport and correlates well with survival in critically ill patients. However, correlation between PDRICG and intra-abdominal pressure (IAP) remains poorly understood. The aim of this retrospective study was to investigate the correlation between PDRICG and classic liver laboratory parameters, IAP and abdominal perfusion pressure (APP). The secondary goal was to evaluate IAP, APP, and PDRICG as prognostic factors for mortality. METHODS: A total of 182 paired IAP and PDRICG measurements were performed in 40 critically ill patients. The mean values per patient were used for comparison. The IAP was measured using either a balloon-tipped stomach catheter connected to an IAP monitor (Spiegelberg, Hamburg, Germany, or CiMON, Pulsion Medical Systems, Munich, Germany) or a bladder FoleyManometer (Holtech Medical, Charlottenlund, Denmark). PDRICG was measured at the bedside using the LiMON device (Pulsion Medical Systems, Munich, Germany). Primary endpoint was hospital mortality. RESULTS: There was no significant correlation between PDRICG and classic liver laboratory parameters, but PDRICG did correlate significantly with APP (R = 0.62) and was inversely correlated with IAP (R = -0.52). Changes in PDRICG were associated with significant concomitant changes in APP (R = 0.73) and opposite changes in IAP (R = 0.61). The IAP was significantly higher (14.6 ± 4.6 vs. 11.1 ± 5.3 mmHg, p = 0.03), and PDRICG (10 ± 8.3 vs. 15.9 ± 5.2%, p = 0.02) and APP (43.6 ± 9 vs. 57.9 ± 12.2 mmHg, p < 0.0001) were significantly lower in non-survivors. CONCLUSIONS: PDRICG is positively correlated to APP and inversely correlated to IAP. Changes in APP areassociated with significant concomitant changes in PDRICG, while changes in IAP are associated with opposite changes in PDRICG, suggesting that an increase in IAP may compromise hepatosplanchnic perfusion. Both PDRICG and IAP are correlated with outcome. Measurement of PDRICG may be a useful additional clinical tool to assess the negative effects of increased IAP on liver perfusion and function.

Background Little is known about the effects of renal replacement therapy (RRT) with fluid removal on intra-abdominal pressure (IAP). The global end-diastolic volume index (GEDVI) and extravascular lung water index (EVLWI) can easily be measured bedside by transpulmonary thermodilution (TPTD). The aim of this study is to evaluate the changes in IAP, GEDVI and EVLWI in critically ill patients receiving slow extended daily dialysis (SLEDD) or continuous venovenous haemofiltration (CVVH) with the intention of net fluid removal. Methods We performed a retrospective cohort study in ICU patients who were treated with SLEDD or CVVH and in whom IAP was also measured, and RRT sessions were excluded when the dose of vasoactive medication needed to be changed between the pre- and post-dialysis TPTD measurements and when net fluid loss did not exceed 500 ml. The TPTD measurements were performed within 2 h before and after SLEDD; in case of CVVH, before and after an interval of 12 h. Results We studied 25 consecutive dialysis sessions in nine patients with acute renal failure and cardiogenic or non-cardiogenic pulmonary oedema. The GEDVI and EVLWI values before dialysis were 877 ml/m² and 14 ml/kg, respectively. Average net ultrafiltration per session was 3.6 l, with a net fluid loss 1.9 l. The GEDVI decreased significantly during dialysis, but not more than 47.8 ml/m² (p = 0.008), as also did the EVLWI with 1 ml/kg (p = 0.03). The IAP decreased significantly from 12 to 10.5 mmHg (p < 0.0001). Conclusions Net fluid removal by SLEDD or CVVH in the range observed in this study decreased IAP, GEDVI and EVLWI in critically ill patients although EVLWI reduction was modest.

Introduction Achievement of a negative fluid balance in patients with capillary leak is associated with improved outcome. We investigated the effects of a multi-modal restrictive fluid strategy aiming for negative fluid balance in patients with acute lung injury (ALI). Methods In this retrospective matched case-control study, we included 114 mechanically ventilated (MV) patients with ALI. We compared outcomes between a group of 57 patients receiving PAL-treatment (PAL group) and a matched control group, abstracted from a historical cohort. PAL-treatment combines high levels of positive end-expiratory pressure, small volume resuscitation with hyperoncotic albumin, and fluid removal with furosemide (Lasix®) or ultrafiltration. Effects on extravascular lung water index (EVLWI), intra-abdominal pressure (IAP), organ function, and vasopressor therapy were recorded during 1 week. The primary outcome parameter was 28-day mortality. Results At baseline, no significant intergroup differences were found, except for lower PaO2/FIO2 and increased IAP in the PAL group (174.5 ± 84.5 vs 256.5 ± 152.7, p = 0.001; 10.0 ± 4.2 vs 8.0 ± 3.7 mmHg, p = 0.013, respectively). After 1 week, PAL-treated patients had a greater reduction of EVLWI, IAP, and cumulative fluid balance (-4.2 ± 5.6 vs -1.1 ± 3.7 mL/kg, p = 0.006; -0.4 ± 3.6 vs 1.8 ± 3.8 mmHg, p = 0.007; -1,451 ± 7,761 vs 8,027 ± 5,254 mL, p < 0.001). Repercussions on cardiovascular and renal function were limited. PAL-treated patients required fewer days of intensive care unit admission and days on MV (23.6 ± 15 vs 37.1 ± 19.9 days, p = 0.006; 14.6 ± 10.7 vs 25.5 ± 20.2 days, respectively) and had a lower 28-day mortality (28.1% vs 49.1%, p = 0.034). Conclusion PAL-treatment in patients with ALI is associated with a negative fluid balance, a reduction of EVLWI and IAP, and improved clinical outcomes without compromising organ function.

Objective The aim of this study was to determine whether intra-abdominal pressure (IAP) monitoring using the FoleyManometer (Holtech Medical, Charlottenlund, Denmark) increases the risk of urinary tract infection (UTI). Design A retrospective database review was conducted. Setting The study was conducted in the 12-bed medical intensive care unit of ZNA Stuivenberg Hospital (Antwerp, Belgium), a tertiary hospital. Patients There were 5,890 patients admitted to the medical intensive care unit of which 1,097 patients underwent intrabladder pressure (IBP) monitoring as estimate for IAP. Interventions Crude and adjusted UTI rates were compared among patients undergoing IAP measurements with three different intrabladder methods: a modified homemade technique, a FoleyManometer with 35 ml reservoir, and a FoleyManometer low volume (FoleyManometerLV) with less than 10 ml priming volume. Measurements and results Four consecutive time periods of 24 months were defined and compared with regard to IAP measurement: period 1 (2000-2001), during which IAP monitoring was not used routinely (which serves as a control group), was compared with period 2 (2002-2003), using a modified homemade technique; period 3 (2004-2005), introducing the FoleyManometer; and finally period 4 (2006-2007), in which the FoleyManometerLV was introduced. The incidence of IBP measurements increased from 1.4% in period 1 to 45.4% in period 4 (p < 0.001). At the same time, the Simplified Acute Physiology Score (version 2) (SAPS-II) increased significantly from 24.4 ± 21.5 to 34.9 ± 18.7 (p < 0.001) together with the percentage of ventilated patients from 18.6% to 40.7% (p < 0.001). In total, 1,097 patients had IAP measurements via the bladder. The UTI rates were adjusted for disease severity by multiplying each crude rate with the ratio of control versus study patient SAPS-II probability of mortality. Crude and adjusted UTI rates per 1,000 catheter days (CD) were on average 16.1 and 12.8/1,000 CD, respectively, and were not significantly different between the four time periods. Conclusions Intrabladder pressure monitoring as estimate for IAP either via a closed transducer technique or the closed FoleyManometer technique seems safe and does not alter the risk of UTI in critically ill patients.

Introduction Capillary leak in critically ill patients leads to interstitial edema. Fluid overload is independently associated with poor prognosis. Bedside measurement of intra-abdominal pressure (IAP), extravascular lung water index (EVLWI), fluid balance, and capillary leak index (CLI) may provide a valuable prognostic tool in mechanically ventilated patients. Methods We performed an observational study of 123 mechanically ventilated patients with extended hemodynamic monitoring, analyzing process-of-care variables for the first week of ICU admission. The primary outcome parameter was 28-day mortality. ΔmaxEVLWI indicated the maximum difference between EVLWI measurements during ICU stay. Patients with a ΔmaxEVLWI Results CLI had a biphasic course. ΔmaxEVLWI was lower if CLFM was achieved and in survivors (−2.4 ± 4.8 vs 1.0 ± 5.5 mL/kg, p = 0.001; −3.3 ± 3.8 vs 2.5 ± 5.3 mL/kg, p = 0.001, respectively). No CLFM achievement was associated with increased CLI and IAPmean on day 3 and higher risk to be nonresponder (odds ratio (OR) 2.76, p = 0.046; OR 1.28, p = 0.011; OR 5.52, p = 0.001, respectively). Responders had more ventilator-free days during the first week (2.5 ± 2.3 vs 1.5 ± 2.3, p = 0.023). Not achieving CLFM and being nonresponder were strong independent predictors of mortality (OR 9.34, p = 0.001 and OR 7.14, p = 0.001, respectively). Conclusion There seems to be an important correlation between CLI, EVLWI kinetics, IAP, and fluid balance in mechanically ventilated patients, associated with organ dysfunction and poor prognosis. In this context, we introduce the global increased permeability syndrome.

This article focuses primarily on the recent literature on abdominal compartment syndrome (ACS) and the definitions and recommendations published by the World Society for the Abdominal Compartment Syndrome. The definitions regarding increased intra-abdominal pressure (IAP) are listed and are followed by an overview of the different mechanisms of organ dysfunction associated with intra-abdominal hypertension (IAH). Measurement techniques for IAP are discussed, as are recommendations for organ function support and options for treatment in patients who have IAH. ACS was first described in surgical patients who had abdominal trauma, bleeding, or infection; but recently, ACS has been described in patients who have other pathologies. This article intends to provide critical care physicians with a clear insight into the current state of knowledge regarding IAH and ACS.

Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) have been rediscovered in the last decades, and appear to frequently complicate severe sepsis and septic shock. IAH affects all organ systems and contributes to the development of MODS. Intra-abdominal pressure measurement is therefore mandatory as IAP should be incorporated in the clinical management of hemodynamics and respiration, and used as a therapeutic target. Comprehensive management of IAH in the critically ill patient is based on recognition of the problem, prevention where possible, and medical and surgical treatment when indicated. In this review, we will give an overview of the current understanding of IAH and ACS in general, and explore how it is relevant for severe sepsis patients and their treatment.

Increased intra-abdominal pressure (IAP), also referred to as intra-abdominal hypertension (IAH), affects organ function in critically ill patients and may lead to abdominal compartment syndrome (ACS). Although initially described in surgical patients, IAH and ACS also occur in medical patients without abdominal conditions. IAP can be measured easily and reliably in patients through the bladder using simple tools. The effects of increased IAP are multiple, but the kidney is especially vulnerable to increased IAP because of its anatomic position. Although the means by which kidney function is impaired in patients with ACS is incompletely elucidated, available evidence suggests that the most important factor involves alterations in renal blood flow. IAH should be considered as a potential cause of acute kidney injury in critically ill patients; its role in other conditions, such as hepatorenal syndrome, remains to be elucidated. Because several treatment options (both medical and surgical) are available, IAH and ACS should no longer be considered irrelevant epiphenomena of severe illness or critical care. An integrated approach targeting IAH may improve outcomes and decrease hospital costs, and IAP monitoring is a first step toward dedicated IAH management. IAH prevention, most importantly during abdominal surgery but also during fluid resuscitation, may avoid ACS altogether. However, when ACS occurs and medical treatment fails, decompressive laparotomy is the only option.

We read with interest the article byBecker et al. [1] looking at the cor-relation between directintraabdominal pressure (IAP) andpressures in the stomach obtained viaa balloon-tipped catheter in tenpatients with cirrhosis. We agree thatthe CiMON system needs to be clin-ically validated. However, we feel theauthors misinterpret their data statingthat the CiMON device cannot beregarded as a reliable substitute forstandard IAP measurement tech-niques, for the simple reason that nogold standard IAP technique wasused. The sample size is small, andthere are issues about themethodology.First, the statistical linear regres-sion analysis used suffers from anessential misconception. On average,approximately nine repeated sets ofmeasurements were collected fromten patients, giving a total of 90paired measurements. This meansthat there were two sources of varia-tion that have to be distinguished: thebetween-patients variation and thewithin-patients variation. This paperdeals mainly with the second kind ofvariation in view of the small samplesize and the (high) number ofrepeated measurements. However,instead of analysing the within-patients variation, the data weretreated as if they came from onepatient. Although it is not sure thatthis was the case, this kind of analysismay produce erroneous results [2, 3].Second, the major drawback isthat no clinically acceptable goldstandard method for IAP measure-ment like bladder pressure was used.We don’t agree with the statementthat the gold standard in experimen-tal studies is direct monitoring ofintraperitoneal pressure. This mayhold true for animal research; how-ever, this is not in accordance withthe latest recommendations for clin-ical research [4–6].Third, the population under studyis not homogeneous since somepatients were mechanically venti-lated, while others were not, and thedemographics were only brieflydescribed. The patient sample wasprobably more convenient than a realcohort sample, which is not a fair wayto validate a new measurementmethod [7]. The evolution ofabdominal wall compliance (Cab)could have been calculated as shownin Table 1 and Fig. 1.Finally, although the authors cor-rectly state some limitations of theirstudy, they try to explain the observeddifferences by alluding to the relativeposition of the probes. This suggeststhey do not consider the abdomen tobe primarily fluid in character, hencenot following the laws of Pascal. Isthis the case? Decramer [8] reportedindeed that gastric pressure swings indogs were not simply hydrostatic.This study found the abdomen notbehaving as a hydraulic system orliquid-filled container. However, theIAP differences observed in the dogsdisappeared when the abdominalcavity was filled with 2 l of saline.9] measuredpressures in the abdomen next to theventral abdominal wall and within thestomach of anaesthetised dogs, andconcluded there were three factorsaffecting IAP: gravity, uniform com-pression and shear deformation. In1996, Tzelepis [10] re-established theconcept that the abdomen behaves asa hydraulic system. Based on theavailable data, we hypothesise theimpact of the above-mentioned threefactors on the measurement of IAP isprobably not significant in the fullysedated mechanically ventilatedpatient with sepsis, capillary leak anda positive fluid balance, with orwithout neuromuscular blockingagents [11]. Therefore, in situationsof large amounts of intraperitonealfluid (as was the case in the presentstudy), the abdomen does probablybehave as a hydraulic container, and

Surveillance for intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) should be implemented in every intensive care unit (ICU), because it has been demonstrated that surveillance is effective. Several criteria that have led to the conclusion that IAH/ACS monitoring is of value: First, IAH is a frequent problem in critically ill patients that directly affects function of all organ systems to some degree, and that is associated with considerable mortality. Furthermore, simple tools for intra-abdominal pressure (IAP) monitoring are available, and it can be safely applied without the need for advanced tools. Finally, both ACS and IAH can be treated with either medical or surgical interventions. Treatment for IAH/ACS should be selected on the basis of the severity of symptoms and the cause of IAH. IAP monitoring should also be incorporated in the daily ICU management of the patient.

BACKGROUND AND AIMS: The abdominal compartment syndrome (ACS) is associated with organ dysfunction and mortality in critically ill patients. Furthermore, the deleterious effects of increased IAP have been shown to occur at levels of intra-abdominal pressure (IAP) previously deemed to be safe. The aim of this article is to provide an overview of all aspects of this underrecognized pathological syndrome for surgeons. METHODS AND CONTENTS: This review article will focus primarily on the recent literature on ACS as well as the definitions and recommendations published by the World Society for the Abdominal Compartment Syndrome. The definitions regarding increased IAP will be listed, followed by a brief but comprehensive overview of the different mechanisms of organ dysfunction associated with intra-abdominal hypertension (IAH). Measurement techniques for IAP will be discussed, as well as recommendations for organ function support in patients with IAH. Finally, surgical treatment and management of the open abdomen are briefly discussed, as well as some minimally invasive techniques to decrease IAP. CONCLUSIONS: The ACS was first described in surgical patients with abdominal trauma, bleeding, or infection, but in recent years ACS has also been described in patients with other pathologies such as burn injury and sepsis. Some of these so-called nonsurgical patients will require surgery to treat their ACS. This review article is intended to provide surgeons with a clear insight into the current state of knowledge regarding IAH, ACS, and the impact of IAP on the critically ill patient.

The objective was to prospectively study the effect of neuromuscular blockers on intra-abdominal pressure (IAP) and a number of physiological variables in patients with increased IAP.Prospective cohort study.Intensive care unit of the Ghent University Hospital.Ten critically ill patients with intra-abdominal hypertension (IAH).An intravenous bolus of cisatracurium at a dose of 0.15 mg/kg was administered, and IAP was measured just before administration and then at 15, 30, 60 and 120 min. The effect of cisatracurium on central venous pressure (CVP), mean arterial pressure (MAP), abdominal perfusion pressure (APP) and heart rate (HR) was also evaluated. Urinary output was recorded prior to administration and after 60 and 120 min.The median age of the patients was 50 years (interquartile range 38-65); five of them were male. APACHE II score on admission was 29 (IQR 14-37). IAH was caused by massive fluid resuscitation without obvious abdominal problem in five patients, by abdominal trauma in three, and by burns and bowel distension in one patient each. Bolus administration of cisatracurium significantly decreased IAP from 18 mmHg (16-20) at baseline to 14 mmHg (12-16) at 15 min (p = 0.01) and to 14 mmHg (13-17) at 30 min (p = 0.02). MAP, APP, CVP and HR remained unchanged. No significant effect on urinary output was observed. In all patients, IAP returned to the baseline level after 2 h.Bolus administration of cisatracurium can be used to temporarily reduce IAP in patients with IAH.