Manu L.N.G. Malbrain

Intra-abdominal hypertension and the abdominal compartment syndrome: updated consensus definitions and clinical practice guidelines from the World Society of the Abdominal Compartment Syndrome

PurposeTo update the World Society of the Abdominal Compartment Syndrome (WSACS) consensus definitions and management statements relating to intra-abdominal hypertension (IAH) and the abdominal compartment syndrome (ACS).MethodsWe conducted systematic or structured reviews to identify relevant studies relating to IAH or ACS. Updated consensus definitions and management statements were then derived using a modified Delphi method and the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) guidelines, respectively. Quality of evidence was graded from high (A) to very low (D) and management statements from strong RECOMMENDATIONS (desirable effects clearly outweigh potential undesirable ones) to weaker SUGGESTIONS (potential risks and benefits of the intervention are less clear).ResultsIn addition to reviewing the consensus definitions proposed in 2006, the WSACS defined the open abdomen, lateralization of the abdominal musculature, polycompartment syndrome, and abdominal compliance, and proposed an open abdomen classification system. RECOMMENDATIONS included intra-abdominal pressure (IAP) measurement, avoidance of sustained IAH, protocolized IAP monitoring and management, decompressive laparotomy for overt ACS, and negative pressure wound therapy and efforts to achieve same-hospital-stay fascial closure among patients with an open abdomen. SUGGESTIONS included use of medical therapies and percutaneous catheter drainage for treatment of IAH/ACS, considering the association between body position and IAP, attempts to avoid a positive fluid balance after initial patient resuscitation, use of enhanced ratios of plasma to red blood cells and prophylactic open abdominal strategies, and avoidance of routine early biologic mesh use among patients with open abdominal wounds. NO RECOMMENDATIONS were possible regarding monitoring of abdominal perfusion pressure or the use of diuretics, renal replacement therapies, albumin, or acute component-parts separation.ConclusionAlthough IAH and ACS are common and frequently associated with poor outcomes, the overall quality of evidence available to guide development of RECOMMENDATIONS was generally low. Appropriately designed intervention trials are urgently needed for patients with IAH and ACS.

Different techniques to measure intra-abdominal pressure (IAP): time for a critical re-appraisal

The diagnosis of intra-abdominal hypertension (IAH) or abdominal compartment syndrome (ACS) is heavily dependant on the reproducibility of the intra-abdominal pressure (IAP) measurement technique. Recent studies have shown that a clinical estimation of IAP by abdominal girth or by examiner’s feel of the tenseness of the abdomen is far from accurate, with a sensitivity of around 40%. Consequently, the IAP needs to be measured with a more accurate, reproducible and reliable tool. The role of the intra-vesical pressure (IVP) as the gold standard for IAP has become a matter of debate. This review will focus on the previously described indirect IAP measurement techniques and will suggest new revised methods of IVP measurement less prone to error. Cost-effective manometry screening techniques will be discussed, as well as some options for the future with microchip transducers.

Thrombocytopenia and prognosis in intensive care

Objective To study the incidence and prognosis of thrombocytopenia in adult intensive care unit (ICU) patients. Design Prospective observational cohort study. Setting The medical ICU of a university hospital and the combined medical-surgical ICU of a regional hospital. Patients All patients consecutively admitted during a 5-month period. Interventions Patient surveillance and data collection. Measurements and Main Results The primary outcome measure was ICU mortality. Data of 329 patients were analyzed. Overall ICU mortality rate was 19.5%. A total of 136 patients (41.3%) had at least one platelet count <150 × 109/L. These patients had higher Multiple Organ Dysfunction Score (MODS), Simplified Acute Physiology Score (SAPS) II, and Acute Physiology and Chronic Health Evaluation (APACHE) II scores at admission, longer ICU stay (8 [4–16] days vs. 5 [2–9] days) (median [interquartile range]), and higher ICU mortality (crude odds ratio [OR], 5.0; 95% confidence interval [CI], 2.7–9.1) and hospital mortality than patients with daily platelet counts >150 × 109/L (p < .0005 for all comparisons). Bleeding incidence rose from 4.1% in nonthrombocytopenic patients to 21.4% in patients with minimal platelet counts between 101 × 109/L and 149 × 109/L (p = .0002) and to 52.6% in patients with minimal platelet counts <100 × 109/L (p < .0001). In all quartiles of admission APACHE II and SAPS II scores, a nadir platelet count <150 × 109/L was related with a substantially poorer vital prognosis. Similarly, a drop in platelet count to ≤50% of admission was associated with higher death rates (OR, 6.0; 95% CI, 3.0–12.0;p < .0001). In a logistic regression analysis with ICU mortality as the dependent variable, the occurrence of thrombocytopenia had more explanatory power than admission variables, including APACHE II, SAPS II, and MODS scores (adjusted OR, 4.2; 95% CI, 1.8–10.2). Conclusions Thrombocytopenia is common in ICUs and constitutes a simple and readily available risk marker for mortality, independent of and complementary to established severity of disease indices. Both a low nadir platelet count and a large fall of platelet count predict a poor vital outcome in adult ICU patients.

Decreased duration of mechanical ventilation when comparing analgesia-based sedation using remifentanil with standard hypnotic-based sedation for up to 10 days in intensive care unit patients: a randomised trial [ISRCTN47583497]

IntroductionThis randomised, open-label, multicentre study compared the safety and efficacy of an analgesia-based sedation regime using remifentanil with a conventional hypnotic-based sedation regime in critically ill patients requiring prolonged mechanical ventilation for up to 10 days.MethodsOne hundred and five randomised patients received either a remifentanil-based sedation regime (initial dose 6 to 9 μg kg-1 h-1 (0.1 to 0.15 μg kg-1 min-1) titrated to response before the addition of midazolam for further sedation (n = 57), or a midazolam-based sedation regime with fentanyl or morphine added for analgesia (n = 48). Patients were sedated to an optimal Sedation–Agitation Scale (SAS) score of 3 or 4 and a pain intensity (PI) score of 1 or 2.ResultsThe remifentanil-based sedation regime significantly reduced the duration of mechanical ventilation by more than 2 days (53.5 hours, P = 0.033), and significantly reduced the time from the start of the weaning process to extubation by more than 1 day (26.6 hours, P < 0.001). There was a trend towards shortening the stay in the intensive care unit (ICU) by 1 day. The median time of optimal SAS and PI was the same in both groups. There was a significant difference in the median time to offset of pharmacodynamic effects when discontinuing study medication in patients not extubated at 10 days (remifentanil 0.250 hour, comparator 1.167 hours; P < 0.001). Of the patients treated with remifentanil, 26% did not receive any midazolam during the study. In those patients that did receive midazolam, the use of remifentanil considerably reduced the total dose of midazolam required. Between days 3 and 10 the weighted mean infusion rate of remifentanil remained constant with no evidence of accumulation or of a development of tolerance to remifentanil. There was no difference between the groups in SAS or PI score in the 24 hours after stopping the study medication. Remifentanil was well tolerated.ConclusionAnalgesia-based sedation with remifentanil was well tolerated; it reduces the duration of mechanical ventilation and improves the weaning process compared with standard hypnotic-based sedation regimes in ICU patients requiring long-term ventilation for up to 10 days.

Decompressive laparotomy for abdominal compartment syndrome – a critical analysis

IntroductionAbdominal compartment syndrome (ACS) is increasingly recognized in critically ill patients, and the deleterious effects of increased intraabdominal pressure (IAP) are well documented. Surgical decompression through a midline laparotomy or decompressive laparotomy remains the sole definite therapy for ACS, but the effect of decompressive laparotomy has not been studied in large patient series.MethodsWe reviewed English literature from 1972 to 2004 for studies reporting the effects of decompressive laparotomy in patients with ACS. The effect of decompressive laparotomy on IAP, patient outcome and physiology were analysed.ResultsEighteen studies including 250 patients who underwent decompressive laparotomy could be included in the analysis. IAP was significantly lower after decompression (15.5 mmHg versus 34.6 mmHg before, p < 0.001), but intraabdominal hypertension persisted in the majority of the patients. Mortality in the whole group was 49.2% (123/250). The effect of decompressive laparotomy on organ function was not uniform, and in some studies no effect on organ function was found. Increased PaO2/FIO2 ratio (PaO2 = partial pressure of oxygen in arterial blood, FiO2 = fraction of inspired oxygen) and urinary output were the most pronounced effects of decompressive laparotomy.ConclusionThe effects of decompressive laparotomy have been poorly investigated, and only a small number of studies report its effect on parameters of organ function. Although IAP is consistently lower after decompression, mortality remains considerable. Recuperation of organ dysfunction after decompressive laparotomy for ACS is variable.

Intermittent versus continuous renal replacement therapy for acute kidney injury patients admitted to the intensive care unit: results of a randomized clinical trial

BACKGROUND There is uncertainty on the effect of different dialysis modalities for the treatment of patients with acute kidney injury (AKI), admitted to the intensive care unit (ICU). This controlled clinical trial performed in the framework of the multicentre SHARF 4 study (Stuivenberg Hospital Acute Renal Failure) aimed to investigate the outcome in patients with AKI, stratified according to severity of disease and randomized to different treatment options. METHODS This was a multicentre prospective randomized controlled trial with stratification according to severity of disease expressed by the SHARF score. ICU patients were eligible for inclusion when serum creatinine was >2 mg/dL, and RRT was initiated. The selected patients were randomized to intermittent (IRRT) or continuous renal replacement therapy (CRRT). RESULTS A total of 316 AKI patients were randomly assigned to IRRT (n = 144) or CRRT (n = 172). The mean age was 66 (range 18-96); 59% were male. Intention-to-treat analysis revealed a mortality of 62.5% in IRRT compared to 58.1% in CRRT (P = 0.430). No difference between IRRT and CRRT could be observed in the duration of ICU stay or hospital stay. In survivors, renal recovery at hospital discharge was comparable between both groups. Multivariate analysis, including the SHARF score, APACHE II and SOFA scores for correction of disease severity, showed no difference in mortality between both treatment modalities. This result was confirmed in pre-specified subgroup analysis (elderly, patients with sepsis, heart failure, ventilation) and after exclusion of possible confounders (early mortality, delayed ICU admission). CONCLUSIONS Modality of RRT, either CRRT or IRRT, had no impact on the outcome in ICU patients with AKI. Both modalities need to be considered as complementary in the treatment of AKI (Clinical Trial: SHARF 4, NCT00322933, http://ClinicalTrials.gov).

Is it wise not to think about intraabdominal hypertension in the ICU

Purpose of review This review focuses on the available literature published in the past 2 years. MEDLINE and PubMed searches were performed using intraabdominal pressure, intraabdominal hypertension, and abdominal compartment as search items. The aim was to find an answer to the question: “Is it wise not to measure or even not to think about intraabdominal hypertension in ICU?” Recent findings It is difficult to find a good gold standard for intraabdominal pressure measurement. Bladder pressure can be used as an intraabdominal pressure estimate provided it is measured in a reproducible way. Automated continuous intraabdominal pressure monitoring has recently become available. Key messages are (1) body mass index and fluid resuscitation are independent predictors of intraabdominal hypertension; (2) intraabdominal hypertension increases intrathoracic, intracranial, and intracardiac filling pressures; (3) transmural or transabdominal filling pressures combined with volumetric parameters better reflect preload; (4) volumetric target values need to be corrected for baseline ejection fractions; (5) intraabdominal hypertension decreases left ventricular, chest wall and total respiratory system compliance; (6) best positive end-expiratory pressure can be set to counteract intraabdominal pressure; (7) acute respiratory distress syndrome definitions should take into account best positive end-expiratory pressure and intraabdominal pressure but not wedge pressure; (8) lung protective strategies should aim at ΔPplat (plateau pressure − intraabdominal pressure); (9) intraabdominal hypertension causes atelectasis and increases extravascular lung water; (10) intraabdominal hypertension is an independent predictor of acute renal failure; (11) monitoring of abdominal perfusion pressure can be useful; and (12) intraabdominal hypertension triggers bacterial translocation and multiple organ system failure. Summary The answer is that it is unwise not to measure intraabdominal pressure in the ICU or even not to think about it.

Fluid overload, de-resuscitation, and outcomes in critically ill or injured patients: a systematic review with suggestions for clinical practice

BACKGROUND Sepsis is associated with generalised endothelial injury and capillary leak and has traditionally been treated with large volume fluid resuscitation. Some patients with sepsis will accumulate bodily fluids. The aim of this study was to systematically review the association between a positive fluid balance/fluid overload and outcomes in critically ill adults, and to determine whether interventions aimed at reducing fluid balance may be linked with improved outcomes. METHODS We searched MEDLINE, PubMed, EMBASE, Web of Science, The Cochrane Database, clinical trials registries, and bibliographies of included articles. Two authors independently reviewed citations and selected studies examining the association between fluid balance and outcomes or where the intervention was any strategy or protocol that attempted to obtain a negative or neutral cumulative fluid balance after the third day of intensive care compared to usual care. The primary outcomes of interest were the incidence of IAH and mortality. RESULTS Among all identified citations, one individual patient meta-analysis, 11 randomised controlled clinical trials, seven interventional studies, 24 observational studies, and four case series met the inclusion criteria. Altogether, 19,902 critically ill patients were studied. The cumulative fluid balance after one week of ICU stay was 4.4 L more positive in non-survivors compared to survivors. A restrictive fluid management strategy resulted in a less positive cumulative fluid balance of 5.6 L compared to controls after one week of ICU stay. A restrictive fluid management was associated with a lower mortality compared to patients treated with a more liberal fluid management strategy (24.7% vs 33.2%; OR, 0.42; 95% CI 0.32-0.55; P < 0.0001). Patients with intra-abdominal hypertension (IAH) had a more positive cumulative fluid balance of 3.4 L after one week of ICU stay. Interventions to decrease fluid balance resulted in a decrease in intra-abdominal pressure (IAP): an average total body fluid removal of 4.9 L resulted in a drop in IAP from 19.3 ± 9.1 mm Hg to 11.5 ± 3.9 mm Hg. CONCLUSIONS A positive cumulative fluid balance is associated with IAH and worse outcomes. Interventions to limit the development of a positive cumulative fluid balance are associated with improved outcomes. In patients not transgressing spontaneously from the Ebb to Flow phases of shock, late conservative fluid management and late goal directed fluid removal (de-resuscitation) should be considered.

Abdominal Contributions to Cardiorenal Dysfunction in Congestive Heart Failure

Current pathophysiological models of congestive heart failure unsatisfactorily explain the detrimental link between congestion and cardiorenal function. Abdominal congestion (i.e., splanchnic venous and interstitial congestion) manifests in a substantial number of patients with advanced congestive heart failure, yet is poorly defined. Compromised capacitance function of the splanchnic vasculature and deficient abdominal lymph flow resulting in interstitial edema might both be implied in the occurrence of increased cardiac filling pressures and renal dysfunction. Indeed, increased intra-abdominal pressure, as an extreme marker of abdominal congestion, is correlated with renal dysfunction in advanced congestive heart failure. Intriguing findings provide preliminary evidence that alterations in the liver and spleen contribute to systemic congestion in heart failure. Finally, gut-derived hormones might influence sodium homeostasis, whereas entrance of bowel toxins into the circulatory system, as a result of impaired intestinal barrier function secondary to congestion, might further depress cardiac as well as renal function. Those toxins are mainly produced by micro-organisms in the gut lumen, with presumably important alterations in advanced heart failure, especially when renal function is depressed. Therefore, in this state-of-the-art review, we explore the crosstalk between the abdomen, heart, and kidneys in congestive heart failure. This might offer new diagnostic opportunities as well as treatment strategies to achieve decongestion in heart failure, especially when abdominal congestion is present. Among those currently under investigation are paracentesis, ultrafiltration, peritoneal dialysis, oral sodium binders, vasodilator therapy, renal sympathetic denervation and agents targeting the gut microbiota.

Effect of bladder volume on measured intravesical pressure: a prospective cohort study

IntroductionCorrect bedside measurement of intra-abdominal pressure (IAP) is important. The bladder method is considered as the gold standard for indirect IAP measurement, but the instillation volumes reported in the literature vary substantially. The aim of this study was to evaluate the effect of instillation volume on intra-bladder pressure (IBP) as an estimation for IAP in critically ill patients.MethodsIn this prospective cohort study in 13 sedated and mechanically ventilated patients, we used a revised closed system repeated measurement technique for measurement of IBP. After the system was flushed, IBP was measured with 25 ml increments up to 300 ml. The absolute bias for each volume was calculated as IBP at a given volume minus IBP at zero volume.ResultsIn total, 30 measurement sets were performed (mean 2.3 per patient). The median IBP at 25 ml was already significantly higher than IBP at zero volume (7.5 versus 6 mmHg). There was no correlation between IBP at zero volume and absolute IBP bias at any bladder volume. Median absolute IBP bias was 1.5 mmHg at 50 ml; 2.5 mmHg at 100 ml; 5.5 mmHg at 150 ml; and up to 11 mmHg at 300 ml.ConclusionLarger instillation volumes than the usually recommended 50 ml to estimate IAP by bladder pressure may cause clinically relevant overestimation of IAP. Small volumes to a maximum of 25 ml, enough to create a fluid column and to remove air, may be sufficient.