Comparison of Bioelectrical Impedance Analysis (BIA)-Derived Parameters in Healthy Volunteers and Critically Ill Patients.

OBJECTIVE: To compare bioelectrical impedance analysis (BIA)-derived parameters in healthy volunteers and critically ill patients and to assess its prognostic value in an ICU patient cohort. DESIGN: Retrospective, observational data analysis. SETTING: Single centre, tertiary-level ICU (Ziekenhuis Netwerk Antwerpen, ZNA Stuivenberg Hospital). PATIENTS: 101 patients and 101 healthy subjects, participants of International Fluid Academy Days. MEASUREMENTS AND MAIN RESULTS: Compared to healthy volunteers, both male and female ICU patients had significantly higher values for total body water (TBW), extracellular water (ECW), extracellular fluid (ECF), plasma, and interstitial fluid volumes. The phase angle was significantly lower and the malnutrition index was significantly higher in ICU patients, regardless of gender. Non-survivors in the ICU had significantly higher extracellular water content (ECW, 50.7 ± 5.1 vs. 48.9 ± 4.3%, p = 0.047) and accordingly significantly lower intracellular water (ICW, 49.2 ± 5.1 vs. 51.1 ± 4.3%, p = 0.047). The malnutrition index was also significantly higher in non-survivors compared to survivors (0.94 ± 0.17 vs. 0.87 ± 0.16, p = 0.048), as was the capillary leak index (ECW/ICW). CONCLUSIONS: Compared to healthy volunteers, this study observed a higher malnutrition index and TBW in ICU patients with an accumulation of fluids in the extracellular compartment. ICU non-survivors showed similar results, indicating that ICU patients and a fortiori non-survivors are generally overhydrated, with increased TBW and ECW, and more undernourished, as indicated by a higher malnutrition index.

A retrospective evaluation of three ethical triage tools for the allocation of ICU resources during the first wave of the COVID-19 pandemic.

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.

SARS-CoV-2 seroprevalence survey among health care providers in a Belgian public multiple-site hospital.

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.

Prognostic value of bioelectrical impedance analysis for assessment of fluid overload in ICU patients: a pilot study.

INTRODUCTION: The non-invasive analysis of body fluid composition with bio-electrical impedance analysis (BIA) provides additional information allowing for more persona-lised therapy to improve outcomes. The aim of this study is to assess the prognostic value of fluid overload (FO) in the first week of intensive care unit (ICU) stay. MATERIAL AND METHODS: A retrospective, observational analysis of 101 ICU patients. Whole-body BIA measurements were performed, and FO was defined as a 5% increase in volume excess from baseline body weight. RESULTS: Baseline demographic data, including severity scores, were similar in both the fluid overload-positive (FO+, n = 49) patients and in patients without fluid overload (FO-, n = 52). Patients with FO+ had significantly higher cumulative fluid balance during their ICU stay compared to those without FO (8.8 ± 7.0 vs. 5.5 ± 5.4 litres; P = 0.009), VE (9.9 ± 6.5 vs. 1.5 ± 1.5 litres; P < 0.001), total body water (63.0 ± 9.5 vs. 52.8 ± 8.1%; P < 0.001), and extracellular water (27.0 ± 7.3 vs. 19.6 ± 3.7 litres; P < 0.001). The presence of 5%, 7.5%, and 10% fluid overload was directly associated with increased ICU mortality rates. The percentage fluid overload (P = 0.039) was an independent predictor for hospital mortality. CONCLUSIONS: A higher mortality rate in ICU-patients with FO was observed. FO is an independent prognostic factor because neither APACHE-II, SOFA, nor SAPS-II significantly differed on admission between survivors and non-survivors. Further research is needed to confirm these data prospectively and to evaluate whether BIA-guided deresuscitation in the subacute phase will improve mortality rates.

Intravenous fluid therapy in the perioperative and critical care setting: Executive summary of the International Fluid Academy (IFA).

Intravenous fluid administration should be considered as any other pharmacological prescription. There are three main indications: resuscitation, replacement, and maintenance. Moreover, the impact of fluid administration as drug diluent or to preserve catheter patency, i.e., fluid creep, should also be considered. As for antibiotics, intravenous fluid administration should follow the four Ds: drug, dosing, duration, de-escalation. Among crystalloids, balanced solutions limit acid-base alterations and chloride load and should be preferred, as this likely prevents renal dysfunction. Among colloids, albumin, the only available natural colloid, may have beneficial effects. The last decade has seen growing interest in the potential harms related to fluid overloading. In the perioperative setting, appropriate fluid management that maintains adequate organ perfusion while limiting fluid administration should represent the standard of care. Protocols including a restrictive continuous fluid administration alongside bolus administration to achieve hemodynamic targets have been proposed. A similar approach should be considered also for critically ill patients, in whom increased endothelial permeability makes this strategy more relevant. Active de-escalation protocols may be necessary in a later phase. The R.O.S.E. conceptual model (Resuscitation, Optimization, Stabilization, Evacuation) summarizes accurately a dynamic approach to fluid therapy, maximizing benefits and minimizing harms. Even in specific categories of critically ill patients, i.e., with trauma or burns, fluid therapy should be carefully applied, considering the importance of their specific aims; maintaining peripheral oxygen delivery, while avoiding the consequences of fluid overload.

A Clinician's Guide to Management of Intra-abdominal Hypertension and Abdominal Compartment Syndrome in Critically Ill Patients.

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2020. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2020. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

Incidence and prognosis of intra-abdominal hypertension and abdominal compartment syndrome in severely burned patients: Pilot study and review of the literature.

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.

Methodological background and strategy for the 2012-2013 updated consensus definitions and clinical practice guidelines from the abdominal compartment society.

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 writingcommittee 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 and abdominal compartment syndrome in burns, obesity, pregnancy, and general medicine.

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.

Intra-abdominal hypertension and abdominal compartment syndrome in pancreatitis, paediatrics, and trauma.

Intra-abdominal hypertension (IAH) is an important contributor to early organ dysfunction among patients with trauma and sepsis. However, the impact of increased intra-abdominal pressure (IAP) among pediatric, pregnant, non-septic medical patients, and those with severe acute pancreatitis (SAP), obesity, and burns has been studied less extensively. The aim of this review is to outline the pathophysiologic implications and treatment options for IAH and abdominal compartment syndrome (ACS) for the above patient populations. We searched MEDLINE and PubMed to identify relevant studies. There is an increasing awareness of IAH in general medicine. The incidence of IAH and, to a lesser extent, ACS is high among patients with SAP. IAH should always be suspected and IAP measured routinely. In children, normal IAP in mechanically ventilated patients is approximately 7 ± 3 mm Hg. As an IAP of 10-15 mm Hg has been associated with organ damage in children, an IAP greater than 10 mm Hg should be considered IAH in these patients. Moreover, as ACS may occur in children at an IAP lower than 20 mm Hg, any elevation in IAP higher than 10 mm Hg associated with new organ dysfunction should be considered ACS in children until proven otherwise. Monitor IAP trends and be aware that specific interventions may need to be instituted at lower IAP than the current ACS definitions accommodate. Finally, IAH and ACS can occur both in abdominal trauma and extra-abdominal trauma patients. Early mechanical hemorrhage control and the avoidance of excessive fluid resuscitation are key elements in preventing IAH in trauma patients. IAH and ACS have been associated with many conditions beyond the general ICU patient. In adults and in children, the focus should be on the early recognition of IAH and the prevention of ACS. Patients at risk for IAH should be identified early during their treatment (with a low threshold to initiate IAP monitoring). Appropriate actions should be taken when IAP increases above 20 mm Hg, especially in patients developing difficulty with ventilation. Although on-operative measures should be instituted first, one should not hesitate to resort to surgical decompression if they fail.

Management of abdominal sepsis--a paradigm shift?

The abdomen is the second most common source of sepsis and secondary peritonitis. The most common causes of abdominal sepsis are perforation, ischemic necrosis or penetrating injury to the abdominal viscera. Management consists of control of the infection source, restoration of gastrointestinal tract (GI) function, systemic antimicrobial therapy and support of organ function. Mortality after secondary peritonitis is still high. Excluding patient-related factors such as age or co-morbidities that can not be influenced at the time of intervention, delay to surgical intervention and inability to obtain source control are the main determinants of outcome. In patients with severe physiological derangement or difficult intraperitoneal conditions, where a prolonged operation and complete anatomical repair may not be possible or appropriate, it is becoming increasingly popular to utilize a damage control strategy with abbreviated laparotomy and planned reoperations. The main components of damage control laparotomy for secondary peritonitis are postponing the reconstruction of intestinal anastomoses to a second operation (deferred anastomosis) and leaving the abdomen open with some form of temporary abdominal closure (TAC). Advances in the management techniques of the open abdomen and new negative pressure-based TAC-devices have significantly reduced the previously observed prohibitive morbidity associated with open abdomens. These advancements have led to current fascial closure rates after TAC approaching 90%. The cornerstones of appropriate antimicrobial therapy are the timing, spectrum and dosing of antibiotics. Enteral nutrition should be started as soon as possible in hemodynamically stable patients but withheld when the patient is on a significant dose of vasopressors or whenever GI hypoperfusion is suspected. Timely source control with appropriate use of antimicrobial agents and early intensive care offers the best chance of survival for patients with abdominal sepsis. The introduction of the concept of damage control to the management of secondary peritonitis represents a paradigm shift in the same way as in management of major trauma. Although limited and repeated surgical interventions have been shown to be safe, the actual benefits need to be demonstrated in controlled studies.

Common pitfalls and tips and tricks to get the most out of your transpulmonary thermodilution device: results of a survey and state-of-the-art review.

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.

Fluid therapy and perfusional considerations during resuscitation in critically ill patients with intra-abdominal hypertension.

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.

What's new in medical management strategies for raised intra-abdominal pressure: evacuating intra-abdominal contents, improving abdominal wall compliance, pharmacotherapy, and continuous negative extra-abdominal pressure.

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.

Awareness and knowledge of intra-abdominal hypertension and abdominal compartment syndrome: results of an international survey.

BACKGROUND: Surveys have demonstrated a lack of physician awareness of intra-abdominal hypertension and abdominal compartment syndrome (IAH/ACS) and wide variations in 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 2244 of the approximately 10,000 clinicians sent the survey responded (response rate, 22.4%). Most of the 2244 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 that 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 are inadequate.

The role of abdominal compliance, the neglected parameter in critically ill patients - a consensus review of 16. Part 1: definitions and pathophysiology.

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.

The role of abdominal compliance, the neglected parameter in critically ill patients - a consensus review of 16. Part 2: measurement techniques and management recommendations.

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.

Validation of a novel method for measuring intra-abdominal pressure and gastric residual volume in critically ill patients.

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 (GRVprototype) and via the classic method (GRVclassic). 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 (R2 = 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 GRVprototype was 80 mL (0-1050) and equal to the median GRVclassic of 80 mL (0-1250). Correlation between the 2 methods was excellent (R2 = 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 GRVclassic correlated well with changes in GRVprototype. 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.