Abdominal compartment syndrome: what radiologist needs to know

The intra-abdominal hypertension (IAH) and the abdominal compartment syndrome (ACS) are life-threatening conditions with a significant rate of mortality; therefore, early detection is paramount in their optimal management. IAH is diagnosed when the intra-abdominal pressure (IAP) is more than 12 mmHg. It can occur when the intra-abdominal volume increases (ileus, ascites, trauma, pancreatitis, etc.) and/or the abdominal wall compliance decreases. IAH can cause decreased venous flow, low cardiac output, renal impairment, and decreased respiratory compliance. Consequently, these complications can lead to multiple organ failure and induce the abdominal compartment syndrome (ACS) when IAP rises above 20 mmHg. The diagnosis is usually made with intravesical pressure measurement. However, this measurement was not always possible to obtain; therefore, alternative diagnostic techniques should be considered. In this setting, computed tomography (CT) may play a crucial role, allowing the detection and characterization of pathological conditions that may lead to IAH. This review is focused on the pathogenesis, clinical features, and radiological findings of ACS, because their presence allows radiologists to raise the suspicion of IAH/ACS in critically ill patients, guiding the most appropriate treatment.

Association between input/weight ratio and acute kidney injury in obese critical ill patients: a propensity analysis of multicenter clinical databases

Rehydration volume may be underestimated in obese critically ill patients, which can lead to acute kidney injury (AKI). This study aimed to investigate the association between input/weight ratio (IWR) and AKI risk in obese critical patients. This retrospective observational study analyzed data from three large open databases. Patients were divided into lean and obese groups and matched 1:1 based on age, sex, APACHE II score, SOFA score, sepsis status, mechanical ventilation status, renal replacement therapy status, and hospital type. The exposure of interest was the mean IWR during the first three ICU admission days. The primary outcome was the incidence of AKI within 28 days after ICU admission. Cox regression analysis was used to evaluate the association between IWR and AKI risk. A total of 82,031 eligible patients were included in the study, with 25,427 obese patients matched with 25,427 lean patients. The IWRs were significantly lower in the obese groups in both the unmatched cohort (35.85 ± 19.05 vs. 46.01 ± 30.43 ml/kg, p < 0.01) and the matched cohort (36.13 ± 19.16 vs. 47.34 ± 31.13 ml/kg, p < 0.01). An increase in IWR was significantly associated with decreased creatinine levels, increased urine output and a lower AKI risk. The interaction terms of IWR and obesity were significantly associated with decreased AKI incidence in both the unmatched cohort (hazard ratio [HR] = 0.97, 95% CI 0.96-0.97, p < 0.01) and the matched cohort (HR = 0.97, 95% CI 0.96-0.97, p < 0.01). Inadequate rehydration of patients with obesity may contribute to an increased risk of AKI in patients with obesity. These results highlight the need for better rehydration management in patients with obesity.

Sánchez-Margallo F, Eugenia Candanosa-Aranda I, Poelaert J, Castellanos G, L. N. G. Malbrain M. The pathophysiological impact of intra-abdominal hypertension in pigs

BACKGROUND

Intra-abdominal hypertension and abdominal compartment syndrome are common with clinically significant consequences. We investigated the pathophysiological effects of raised IAP as part of a more extensive exploratory animal study. The study design included both pneumoperitoneum and mechanical intestinal obstruction models.

METHODS

Forty-nine female swine were divided into six groups: a control group (Cr; n = 5), three pneumoperitoneum groups with IAPs of 20mmHg (Pn20; n = 10), 30mmHg (Pn30; n = 10), 40mmHg (Pn40; n = 10), and two mechanical intestinal occlusion groups with IAPs of 20mmHg (MIO20; n = 9) and 30mmHg (MIO30; n = 5).

RESULTS

There were significant changes (p<0.05) noted in all organ systems, most notably systolic blood pressure (SBP) (p<0.001), cardiac index (CI) (p = 0.003), stroke volume index (SVI) (p<0.001), mean pulmonary airway pressure (MPP) (p<0.001), compliance (p<0.001), pO2 (p = 0.003), bicarbonate (p = 0.041), hemoglobin (p = 0.012), lipase (p = 0.041), total bilirubin (p = 0.041), gastric pH (p<0.001), calculated glomerular filtration rate (GFR) (p<0.001), and urine output (p<0.001). SVV increased progressively as the IAP increased with no obvious changes in intravascular volume status. There were no significant differences between the models regarding their impact on cardiovascular, respiratory, renal and gastrointestinal systems. However, significant differences were noted between the two models at 30mmHg, with MIO30 showing worse metabolic and hematological parameters, and Pn30 and Pn40 showing a more rapid rise in creatinine.

CONCLUSIONS

This study identified and quantified the impact of intra-abdominal hypertension at different pressures on several organ systems and highlighted the significance of even short-lived elevations. Two models of intra-abdominal pressure were used, with a mechanical obstruction model showing more rapid changes in metabolic and haematological changes. These may represent different underlying cellular and vascular pathophysiological processes, but this remains unclear.

Abdominal perfusion pressure in critically ill cirrhotic patients: a prospective observational study

In critical patients, abdominal perfusion pressure (APP) has been shown to correlate with outcome. However, data from cirrhotic patients is scarce. We aimed to characterize APP in critically ill cirrhotic patients, analyze the prevalence and risk factors of abdominal hypoperfusion (AhP) and outcomes. A prospective cohort study in a general ICU specialized in liver disease at a tertiary hospital center recruited consecutive cirrhotic patients between October 2016 and December 2021. The study included 101 patients, with a mean age of 57.2 (± 10.4) years and a female gender proportion of 23.5%. The most frequent etiology of cirrhosis was alcohol (51.0%), and the precipitant event was infection (37.3%). ACLF grade (1-3) distribution was 8.9%, 26.7% and 52.5%, respectively. A total of 1274 measurements presented a mean APP of 63 (± 15) mmHg. Baseline AhP prevalence was 47%, independently associated with paracentesis (aOR 4.81, CI 95% 1.46-15.8, p = 0.01) and ACLF grade (aOR 2.41, CI 95% 1.20-4.85, p = 0.01). Similarly, AhP during the first week (64%) had baseline ACLF grade (aOR 2.09, CI 95% 1.29-3.39, p = 0.003) as a risk factor. Independent risk factors for 28-day mortality were bilirubin (aOR 1.10, CI 95% 1.04-1.16, p < 0.001) and SAPS II score (aOR 1.07, CI 95% 1.03-1.11, p = 0.001). There was a high prevalence of AhP in critical cirrhotic patients. Abdominal hypoperfusion was independently associated with higher ACLF grade and baseline paracentesis. Risk factors for 28-day mortality included clinical severity and total bilirubin. The prevention and treatment of AhP in the high-risk cirrhotic patient is prudential.

Feeding intolerance during prolonged prone position in overweight and obese patients with severe COVID-19

OBJECTIVE

the aim of this study was to compare the incidence rate of feeding intolerance (FI) during supine (SP) or prone positioning (PP) in critically ill COVID-19 patients.

METHODS

this was a retrospective cohort study of critically ill patients with overweight or obesity who received enteral nutrition (EN) in prone or supine positioning continuously during the first five days of mechanical ventilation. Nutritional risk, anthropometric measurements and body composition were assessed at the first 24 hours upon Intensive Care Unit (ICU) admission. Biochemical and clinical variables (Sequential Organ Failure Assessment [SOFA], Acute Physiology and Chronic Health Evaluation II [APACHE II], Acute Kidney Injury [AKI] or comorbidities diagnosis) were collected. Pharmacotherapy (prokinetics, sedatives or neuromuscular blocking agents) and FI incidence (gastric residual volume [GRV] ≥ 200 ml or ≥ 500 ml, vomiting or diarrhea) were daily recorded. Constipation was defined as the absence of evacuation for five consecutive days.

RESULTS

eighty-two patients were included. Higher rate of prophylactic prokinetic prescription was observed in PP (42.8 vs 12.5 %, p = 0.002). GRV ≥ 200 in supine position was not different when compared to PP (p = 0.47). Vomiting episodes in supine compared to PP showed no difference between groups (15 % vs 24 %, p = 0.31). No differences in diarrhea events were detected (10 % vs 4.7 %, p = 0.36). Constipation was common in both groups (95 % vs 82 %, p = 0.06).

CONCLUSION

FI during prone position was not different in comparison to supine position. Routinely use of prokinetics in continuous prone position may help to prevent FI incidence. Algorithm development is necessary for FI prevention and treatment so to avoid EN interruptions and adverse clinical outcomes.

Intra-abdominal hypertension in cardiac surgery patients: a multicenter observational sub-study of the Accuryn registry

Intra-abdominal hypertension (IAH) is frequently present in the critically ill and is associated with increased morbidity and mortality. Conventionally, intermittent 'spot-check' manual measurements of bladder pressure in those perceived as high risk are used as surrogates for intra-abdominal pressure (IAP). True patterns of IAH remain unknown. We explored the incidence of IAH in cardiac surgery patients and describe the intra-and postoperative course of IAP using a novel, high frequency, automated bladder pressure measurement system. Sub-analysis of a prospective, multicenter, observational study (NCT04669548) conducted in three large academic medical centers. Continuous urinary output (CUO) and IAP measurements were observed using the Accuryn Monitoring System (Potrero Medical, Hayward, CA). Data collected included demographics, hemodynamic support, and high-frequency IAP and CUO. One Hundred Thirty-Seven cardiac surgery patients were analyzed intraoperatively and followed 48 h postoperatively in the intensive care unit. Median age was 66.4 [58.3, 72.0] years, and 61% were men. Median Foley catheter dwell time was 56.0 [46.8, 77.5] hours, and median baseline IAP was 6.3 [4.0, 8.1] mmHg. 93% (128/137) of patients were in IAH grade I, 82% (113/137) in grade II, 39% (53/137) in grade III, and 5% (7/137) in grade IV for at least 12 cumulative hours. For maximum consecutive duration of IAH, 84% (115/137) of patients spent at least 12 h in grade I, 62% (85/137) in grade II, 18% (25/137) in grade III, and 2% (3/137) in grade IV IAH. During the first 48 h after cardiac surgery, IAH is common and persistent. Improved and automated monitoring of IAP will increase the detection of IAH-which normally would remain undetected using traditional intermittent monitoring methods.

Impact of Obesity on Clinical Outcomes of Patients with Intra-Abdominal Hypertension and Abdominal Compartment Syndrome

Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) are associated with high morbidity and mortality. Obesity may result in increased intra-abdominal pressure (IAP) and affect clinical outcomes of patients with IAH and/or ACS. This study aims to establish the impact of obesity on the clinical outcomes of IAH and ACS patients. A systematic search of Medline, Embase, and Scopus was performed in August 2022. Nine studies comprising 9938 patients were included. There were 65.1% males (n = 6250/9596). Patient demographics, comorbidities, and morbidities were analyzed in correlation with obesity and IAP. Obese patients had a higher risk of IAH (OR 8.5, p < 0.001). Obesity was associated with the need for renal replacement therapy, intensive care unit-acquired infections, systemic inflammatory response syndrome, acute respiratory distress syndrome, length of hospital stay, and mortality. This review highlights the lacunae in the existing literature to underpin the direct impact of obesity, independent of obesity-associated comorbidities, on the clinical outcomes of IAH and ACS.

Predicting the risk factors of diabetic ketoacidosis-associated acute kidney injury: A machine learning approach using XGBoost

Objective

The purpose of this study was to develop and validate a predictive model based on a machine learning (ML) approach to identify patients with DKA at increased risk of AKI within 1 week of hospitalization in the intensive care unit (ICU).

Methods

Patients diagnosed with DKA from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database according to the International Classification of Diseases (ICD)-9/10 code were included. The patient's medical history is extracted, along with data on their demographics, vital signs, clinical characteristics, laboratory results, and therapeutic measures. The best-performing model is chosen by contrasting the 8 Ml models. The area under the receiver operating characteristic curve (AUC), sensitivity, accuracy, and specificity were calculated to select the best-performing ML model.

Results

The final study enrolled 1,322 patients with DKA in total, randomly split into training (1,124, 85%) and validation sets (198, 15%). 497 (37.5%) of them experienced AKI within a week of being admitted to the ICU. The eXtreme Gradient Boosting (XGBoost) model performed best of the 8 Ml models, and the AUC of the training and validation sets were 0.835 and 0.800, respectively. According to the result of feature importance, the top 5 main features contributing to the XGBoost model were blood urea nitrogen (BUN), urine output, weight, age, and platelet count (PLT).

Conclusion

An ML-based individual prediction model for DKA-associated AKI (DKA-AKI) was developed and validated. The model performs robustly, identifies high-risk patients early, can assist in clinical decision-making, and can improve the prognosis of DKA patients to some extent.

Interrelationship between endotoxicosis and syndrome of intraabdominal hypertension in pathogenesis of abdominal sepsis

Objective. Studying of mutual role of the main pathogenetic factors of abdominal sepsis – the inflammation origin and intraabdominal hypertension, from the one side, endotoxicosis and the abdominal compression syndrome (ACS), from the other side. Materials and methods. Into the investigation 196 patients with abdominal sepsis were included, in whom after the certain preliminary preparation the operative procedure was done. The levels of neutrophils, macrophages, interleukin–6, interleukin–10 in peritoneal exudate were studied as indices of the inflammation source for abdominal cavity. These indices were characteristic for systemic answer on general reaction, the degree of which have determined the abdominal sepsis course and result. Determination of intraabdominal pressure was applied for estimation the intraabdominal hypertension role in abdominal sepsis. Results. The ratio of the endotoxicosis and the ACS indices in the complications structure, not dependent on some differences due to the complication type present, was practically similar. Conclusion. The results of the investigation conducted, witnesses the presence of interrelationship of roles of endotoxicosis and the abdominal compression syndrome in pathogenesis of abdominal sepsis, their indices changes are characterized by mutual activity strengthening, accompanied by clinical manifestations of the organs dysfunction, determining the severity of course and result of pathological process in the organism.

Physicians' Knowledge of Abdominal Compartment Syndrome and Intra-Abdominal Hypertension in Saudi Arabia: An Online Cross-Sectional Survey Study

Objective

To determine physicians' knowledge of abdominal compartment syndrome and intra-abdominal hypertension in Saudi Arabia.

Methods

A cross-sectional online survey study was conducted on physicians in Saudi Arabia between March and August 2022. A previously developed questionnaire was adapted and used in this study. The survey instrument investigated the knowledge and management of intra-abdominal hypertension and abdominal compartment syndrome among physicians. Logistic regression was used to identify predictors of being knowledgeable about abdominal compartment syndrome and intra-abdominal hypertension.

Results

A total of 266 physicians participated in this study. Around one-fifth (21.8%) the study participants were ICU physicians and 25.0% reported that they practice internal medicine. Intra-abdominal hypertension (IAH) and the impact of increased intra-abdominal pressure (IAP) on organ function were terms that the majority of research participants (70.3%) reported they were familiar with. A similar percentage (73.7%) reported that they are familiar with abdominal compartment syndrome (ACS). Around 43.0% of the study participants reported that they do not know how to measure IAP. The most frequently reported (13.5%) intervention in the treatment of IAH and ACS was the use of inotropes or vasopressors. The study participants showed a weak level of knowledge of ACS and IAH with a median score of 3.00 (IQR: 5.00-2.00), which represents 27.3% of the maximum attainable score. Physicians working at hospitals with 20-50 ICU beds were 41.0% (odds ratio: 0.59 (CI: 0.37-0.96)) less likely to be knowledgeable about intra-abdominal hypertension and abdominal compartment syndrome (p≤0.05).

Conclusion

Physicians demonstrated a low level of IAP and ACS knowledge. To increase the safety of medical practices and enhance clinical outcomes for patients, awareness should be raised about the proper diagnosis and management of IAP and ACS. Future research should focus on developing effective educational strategies to improve physicians' understanding of IAP and ACS.

Fluid Management, Intra-Abdominal Hypertension and the Abdominal Compartment Syndrome: A Narrative Review

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

Impact of intraabdominal hypertension on kidney failure in critically ill patients: A post-hoc database analysis

PURPOSE

To assess whether intraabdominal hypertension (IAH) may influence kidney failure as well as mortality.

METHODS

This post-hoc analysis of two databases (IROI and iSOFA study) tested the independent association between IAH and kidney failure. Mortality was assessed using four prespecified groups (IAH present, kidney failure present, IAH and kidney failure present and no IAH or kidney failure present).

RESULTS

Of 825 critically ill patients, 302 (36.6%) developed kidney failure and 192 (23.7%) died during the first 90 days. Only 'Cumulative days with IAH grade II or more' was significantly associated with kidney failure (OR 1.29 (1.08-1.55), p = 0.003) while 'cumulative days with IAH grade I or more' (p = 0.135) or highest daily IAP (p = 0.062) was not. IAH combined with kidney failure was independently associated with 90-day mortality (OR 2.20 (1.20-4.05), p = 0.011), which was confirmed for higher grades of IAH (grade II or more) alone (OR 2.14 (1.07-4.30), p = 0.032) and combined with kidney failure (OR 3.25 (1.72-6.12), p < 0.001).

CONCLUSIONS

This study suggest that duration as well as higher grades of IAH are associated with kidney failure and may increase mortality.

Low-Flow Acute Kidney Injury: The Pathophysiology of Prerenal Azotemia, Abdominal Compartment Syndrome, and Obstructive Uropathy

AKI is a syndrome, not a disease. It results from many different primary and/or secondary etiologies and is often multifactorial, especially in the hospitalized patient. This review discusses the pathophysiology of three etiologies that cause AKI, those being kidney hypoperfusion, abdominal compartment syndrome, and urinary tract obstruction. The pathophysiology of these three causes of AKI differs but is overlapping. They all lead to a low urine flow rate and low urine sodium initially. In all three cases, with early recognition and correction of the underlying process, the resulting functional AKI can be rapidly reversed. However, with continued duration and/or increased severity, cell injury occurs within the kidney, resulting in structural AKI and a longer and more severe disease state with increased morbidity and mortality. This is why early recognition and reversal are critical.

The effect of body mass index on the development of acute kidney injury and mortality in intensive care unit: is obesity paradox valid?

BACKGROUND

The conflicting results of studies on intensive care unit (ICU) mortality of obese patients and obese patients with acute kidney injury (AKI) reveal a paradox within a paradox. The aim of this study was to determine the effects of body mass index and obesity on AKI development and ICU mortality.

METHODS

The 4,459 patients treated between January 2015 and December 2019 in the ICU at a Tertiary Care Center in Turkey were analyzed retrospectively.

RESULTS

AKI developed more in obese patients with 69.8% (620). AKI development rates were similar in normal-weight (65.1%; 1172) and overweight patients (64.9%; 1149). The development of AKI in patients who presented with cerebrovascular diseases was higher in obese patients (81; 76.4%) than in normal-weight (158; 62.7%) and overweight (174; 60.8%) patients (p < 0.05). The risk of developing AKI was approximately 1.4 times (CI 95% = 1.177-1.662) higher in obese patients than in normal-weight patients. Dialysis was used more frequently in obese patients (24.3%, p < 0.001), who stayed longer in the ICU (p < 0.05). It was determined that the development of AKI in normal-weight and overweight patients increased mortality (p < 0.001) and that there was not a difference in mortality rates between obese patients with and without AKI.

CONCLUSION

The risk of AKI development was higher in obese patients but not in those who were in serious conditions. Another paradox was that the development of AKI was associated with a higher mortality rate in normal-weight and overweight patients, but not in obese patients. Cerebrovascular diseases as a cause of admission pose additional risks for AKI.

Manejo del abdomen abierto en el paciente crítico en un centro de nivel III de Popayán

Introducción. El abdomen abierto es un recurso útil para el tratamiento de pacientes con patología abdominal compleja, con potencial de complicaciones. El objetivo de este estudio fue adaptar la guía de World Society of Emergency Surgery (WSES) 2018, en un hospital de nivel III de atención de la ciudad de Popayán, Colombia, y comparar los resultados obtenidos con los previos a su implementación. Métodos. Estudio cuasi-experimental en dos mediciones de pacientes con abdomen abierto y estancia en cuidado crítico, durante los meses de abril a octubre de los años 2018 y 2019, antes y después de la adaptación con el personal asistencial de la guía de práctica clínica WSES 2018. Se utilizó estadística descriptiva, prueba de Chi cuadrado y se empleó el software SPSS V.25. Resultados. Se incluyeron 99 pacientes críticos, con una edad media de 53,2 años, con indicación de abdomen abierto por etiología traumática en el 28,3 %, infecciosa no traumática en el 32,3 % y no traumática ni infecciosa en el 37,4 %. La mortalidad global fue de 25,3 %, de los cuales, un 68 % se debieron a causas ajenas a la patología abdominal. Las complicaciones postoperatorias se presentaron en 10 pacientes con infección de sitio operatorio y 9 pacientes con fístula enterocutánea. El uso del doble Viaflex se implementó en un 63,6 %, logrando un cierre de la pared abdominal en el 79,8 % de los casos (p=0,038). Conclusión. El abdomen abierto requiere de un abordaje multidisciplinar. El uso de doble Viaflex es una herramienta simple y efectiva. La implementación de la guía disminuyó el porcentaje de mortalidad, los días de abdomen abierto y la estancia en cuidados intensivos.

Systematic Review of Diagnostic Sensors for Intra-Abdominal Pressure Monitoring

Intra-abdominal pressure (IAP) is defined as the steady-state pressure within the abdominal cavity. Elevated IAP has been implicated in many medical complications. This article reviews the current state-of-the-art in innovative sensors for the measurement of IAP. A systematic review was conducted on studies on the development and application of IAP sensors. Publications from 2010 to 2021 were identified by performing structured searches in databases, review articles, and major textbooks. Sixteen studies were eligible for the final systematic review. Of the 16 articles that describe the measurement of IAP, there were 5 in vitro studies (31.3%), 7 in vivo studies (43.7%), and 4 human trials (25.0%). In addition, with the advancement of wireless communication technology, an increasing number of wireless sensing systems have been developed. Among the studies in this review, five presented wireless sensing systems (31.3%) to monitor IAP. In this systematic review, we present recent developments in different types of intra-abdominal pressure sensors and discuss their inherent advantages due to their small size, remote monitoring, and multiplexing.

Deepening of sedation with propofol has limited effect on intra-abdominal pressure - An interventional study in mechanically ventilated adult patients with intra-abdominal hypertension

PURPOSE

To evaluate the effect of deepening of sedation on intra-abdominal pressure (IAP).

METHODS

37 adult mechanically ventilated ICU patients with intra-abdominal hypertension received a bolus dose and subsequent infusion of propofol (bolus: 1 mg/kg, infusion: 3 mg/kg/h). IAP, mean arterial pressure (MAP), abdominal perfusion pressure (APP), depth of sedation according to Richmond Agitation-Sedation Scale (RASS), respiratory parameters, and vasopressor dose were assessed after bolus and at 15, 30 and 60 min of infusion of propofol.

RESULTS

Median IAP at baseline was 15 (13-16) mm Hg. During the intervention, median IAP decreased by 1 mm Hg at all time points. In 24% of patients IAP decreased by ≥3 mm Hg. Compared to baseline, MAP and APP were reduced at all time points. Deepening of sedation per RASS was achieved in 70% of patients at all time points. No changes in respiratory tidal volumes nor plateau pressures were observed. Vasopressor therapy with noradrenaline was started or increased in 43% of patients, whereas the increase in patients already receiving noradrenaline prior to the intervention was not significant.

CONCLUSIONS

Deepening of sedation with propofol results in a small decrease in IAP and greater simultaneous decrease in MAP and APP, requiring increased vasopressor support in some cases.

The prevalence, incidence and mortality associated with intra-abdominal hypertension among patients in intensive care units of a low-income country: a cohort study

Background: Intra-abdominal hypertension (IAH) is sustained increase in intra-abdominal pressure (IAP) ≥12 mmHg in adults and ≥10 mmHg in children. IAH has been noted to be associated with increased morbidity and mortality among critically ill patients. Measurement of IAP is common among at risk patients in the developed world. However, it has not received due attention in the majority of intensive care units (ICUs) in low-income countries, Uganda being one of these. This is evidenced by paucity of data and lack of protocols from the Ugandan Ministry of Health. This multi-center study was thus conducted to assess the prevalence, incidence and mortality associated with IAH among patients admitted to Ugandan ICUs.Methods:A multi-center prospective cohort study was conducted from September 2017 to February 2018 at three ICUs in Uganda. We consecutively enrolled 126 patients into the study. IAP was measured using the Harrahil manometer technique. Categorical variables were analyzed using the Chi square test and continuous variables analyzed using the t-test and Man Whitney test. The prevalence and incidence were determined using proportions and mortality was determined using survival analysis.Results:The median age was 33 years (26-48.5) for the patients without IAH and 42 years (29-55) for those with IAH. The majority of the patients were male and 9.6% of the patients were below 18 years. The prevalence of IAH was 62.7 (CI 54.1-71.3), whereas the 24 hour and 72 hour incidence of IAH was 9.3% (CI 1.3-17.2) and 14.3 % (CI 4.1-24.4), respectively.  Mortality was higher in patients with IAH compared to those without (p-value 0.003 and 0.028, mean and maximum IAP, respectively). Conclusion:We found a high prevalence and incidence of IAH among critically ill patients, associated with a high mortality. Routine screening for IAH can preempt management strategies to mitigate this.

Effect of 2 Enteral Feeding Schedules on Intra-abdominal Pressure in Patients Receiving Mechanical Ventilation: A Randomized Controlled Trial

BACKGROUND

Elevated intra-abdominal pressure is associated with morbidity in critically ill patients. Enteral feeding is important for these patients but may cause complications.

OBJECTIVE

To compare the effects of 2 intermittent feeding schedules on intra-abdominal pressure in patients receiving mechanical ventilation.

METHODS

A single-blinded, prospective, parallel-group, randomized controlled trial was conducted in an intensive care unit in a teaching hospital in Egypt. Fifty adult patients requiring more than 48 hours of mechanical ventilation were enrolled. Patients were randomly sorted into 2 study groups. The intervention group received intermittent enteral feedings 5 times daily at 4-hour intervals. The control group received intermittent enteral feedings 10 times daily at 2-hour intervals. Both groups fasted for 8 hours overnight. Intra-abdominal pressure was measured 7 times: at admission and before and after the first 3 feedings on the third day of the intensive care unit stay.

RESULTS

One-way repeated-measures analysis of variance showed that mean intra-abdominal pressure was higher in the control group before the first feeding (t = 2.27, P = .03) but was higher in the intervention group after the second feeding (t = 2.51, P = .02) and after the third feeding (t = 2.41, P = .02). Vomiting and diarrhea were not significantly different between the groups. More constipation and abdominal distension occurred in the intervention group than in the control group.

CONCLUSION

Intra-abdominal pressure was not significantly affected by feeding interval. However, reducing the time interval between intermittent enteral feedings may minimize the risk for constipation and abdominal distension.

Abdominal compartment syndrome: Current concepts and management

Abdominal compartment syndrome occurs when 2 or more anatomic compartments have a sustained intra-abdominal pressure >20mmHg, associated with organ failure. Incidence is 2% and prevalence varies from 0% to 36.4%. A literature search was conducted utilizing different databases. Articles published from 1970 to 2018 were included, in English or Spanish, to provide the concepts, classifications, and comprehensive management in the approach to abdominal compartment syndrome, for its treatment and the prevention of severe complications associated with the entity. Intravesical pressure measurement is the standard diagnostic method. Treatment is based on evacuation of the intraluminal content, identification and treatment of intra-abdominal lesions, improvement of abdominal wall compliance, and optimum administration of fluids and tissue perfusion. Laparotomy is generally followed by temporary abdominal wall closure 5 to 7 days after surgery. Reconstruction is performed 6 to 12 months after the last operation. Abdominal compartment syndrome should be diagnosed and operated on before organic damage from the illness occurs. Kidney injury can frequently progress and is a parameter for considering abdominal decompression. Having a biomarker for early damage would be ideal. Surgical treatment is successful in the majority of cases. A multidisciplinary focus is necessary for the intensive care and reconstructive needs of the patient. Thus, efforts must be made to define and implement strategies for patient quality of life optimization.

Incidence, Risk Factors, and Outcomes of Intra-Abdominal Hypertension in Critically Ill Patients-A Prospective Multicenter Study (IROI Study)

Supplemental Digital Content is available in the text.

Objectives:

To identify the prevalence, risk factors, and outcomes of intra-abdominal hypertension in a mixed multicenter ICU population.

Design:

Prospective observational study.

Setting:

Fifteen ICUs worldwide.

Patients:

Consecutive adult ICU patients with a bladder catheter.

Interventions:

None.

Measurements and Main Results:

Four hundred ninety-one patients were included. Intra-abdominal pressure was measured a minimum of every 8 hours. Subjects with a mean intra-abdominal pressure equal to or greater than 12 mm Hg were defined as having intra-abdominal hypertension. Intra-abdominal hypertension was present in 34.0% of the patients on the day of ICU admission (159/467) and in 48.9% of the patients (240/491) during the observation period. The severity of intra-abdominal hypertension was as follows: grade I, 47.5%; grade II, 36.6%; grade III, 11.7%; and grade IV, 4.2%. The severity of intra-abdominal hypertension during the first 2 weeks of the ICU stay was identified as an independent predictor of 28- and 90-day mortality, whereas the presence of intra-abdominal hypertension on the day of ICU admission did not predict mortality. Body mass index, Acute Physiology and Chronic Health Evaluation II score greater than or equal to 18, presence of abdominal distension, absence of bowel sounds, and positive end-expiratory pressure greater than or equal to 7 cm H₂O were independently associated with the development of intra-abdominal hypertension at any time during the observation period. In subjects without intra-abdominal hypertension on day 1, body mass index combined with daily positive fluid balance and positive end-expiratory pressure greater than or equal to 7 cm H₂O (as documented on the day before intra-abdominal hypertension occurred) were associated with the development of intra-abdominal hypertension during the first week in the ICU.

Conclusions:

In our mixed ICU patient cohort, intra-abdominal hypertension occurred in almost half of all subjects and was twice as prevalent in mechanically ventilated patients as in spontaneously breathing patients. Presence and severity of intra-abdominal hypertension during the observation period significantly and independently increased 28- and 90-day mortality. Five admission day variables were independently associated with the presence or development of intra-abdominal hypertension. Positive fluid balance was associated with the development of intra-abdominal hypertension after day 1.

Preventing Perioperative Acute Kidney Injury

How to cite this article: Bhosale SJ, Kulkarni AP. Preventing Perioperative Acute Kidney Injury. Indian J Crit Care Med 2020;24(Suppl 3):S126–S128.

Intra-abdominal Pressure Has a Good Predictive Power for 28-Day Mortality: A Prospective Observational Study Conducted in Critically Ill Children

Objective: Elevated intra-abdominal pressure (IAP) is associated with organ dysfunction in critically ill children. Thus far, the predictive value of IAP for mortality remains unknown. Moreover, only few studies determined normal IAP values in pediatric intensive care unit (PICU) children. This study aimed to determine the predictive value of IAP for mortality and calculate normal IAP values in PICU patients. Methods: This prospective observational study was conducted in two PICUs of two tertiary care university teaching hospitals. Patients admitted to the PICU between December 2013 and November 2015 were included. IAP was determined by bladder pressure measurements performed every 8 h until 48 h or until PICU discharge. All patients (except neonatal patients) aged ≤ 14 years who were admitted to the PICUs and had no history of chemical neuromuscular blockade use, neurogenic bladder, or bladder surgery were enrolled. Binary logistic regression was used to analyze the predictive value of IAP for 28-day mortality. Receiver operating characteristic curves were generated to evaluate the prediction effect of IAP. Results: Overall, 229 patients were enrolled. IAP (hazard ratio 1.09, 95% confidence interval [CI] 1.029-1.161, P = 0.004) and lactic acid (hazard ratio 3.04, 95% CI 1.769-5.21, P < 0.001) were independent predictors of 28-day mortality. Additionally, IAP had good predictive power for 28-day mortality, with an area under the curve of 0.74. The optimal cutoff point was 12.13 mmHg (sensitivity 0.58, specificity 0.80). The Youden index was 0.38.Furthermore, 111 (48.47%) patients without high-risk factors or clinical manifestations of IAH were analyzed to determine normal IAP values, which were 7.57 ± 2.85 mmHg (range, 1.98-13.16 mmHg). There were no significant differences in normal IAP values according to different diseases, sex, age, weight, or body mass index (BMI). Conclusions: IAP has good predictive power for 28-day mortality. The optimal IAP cutoff point is 12.13 mmHg. The IAP reference range is 2.0-13.2 mmHg, which was not associated with factors such as sex, age, weight, and BMI in PICU children. We recommend that IAP be included in critical illness scoring systems in the future. IAP >12.13 mmHg may be more suitable for IAH definition in PICU patients.

The Association Between Obesity and Risk of Acute Kidney Injury After Cardiac Surgery

OBJECTIVE

To determine the relationship between obesity and the risk of AKI after cardiac surgery (CS-AKI) in a cohort study.

METHODS

A total of 1,601 patients undergoing cardiac surgery were collected and their incidence of CS-AKI was recorded. They were divided into underweight, normal weight, overweight, and obese groups. Logistic regression was used to estimate the association between BMI (body mass index) and CS-AKI risk. Then, a meta-analysis of published cohort studies was conducted to confirm this result using PubMed and Embase databases.

RESULTS

A significant association was observed in this independent cohort after adjusting age, gender, hypertension and New York Heart Association classification (NYHA) class. Compared with normal BMI group (18.5 ≤ BMI < 24.0), the individuals with aberrant BMI level had an increased AKI risk (OR: 1.68, 95% CI: 1.01-2.78) for BMI < 18.5 group and (OR: 1.43, 95% CI: 0.96-2.15) for BMI ≥ 28.0. Interestingly, the U-shape curve showed the CS-AKI risk reduced with the increasing of BMI when BMI ≤ 24.0. As BMI increases with BMI > 24.0, the risk of developing CS-AKI increased significantly. In the confirmed meta-analysis, compared with normal weight, overweight group with cardiac surgery had higher AKI risk (OR: 1.28, 95% CI: 1.16-1.41, P_{heterogeneity} = 0.49). The similar association was found in obesity subgroup (OR: 1.79, 95% CI: 1.57-2.03, P_{heterogeneity} = 0.42).

CONCLUSION

In conclusion, the results suggested that abnormal BMI was a risk factor for CS-AKI independently.

Incidence of Intra-Abdominal Hypertension and Abdominal Compartment Syndrome: A Systematic Review

OBJECTIVE

To determine the contemporary prevalence of intra-abdominal hypertension (IAH) and abdominal compartment syndrome in critically ill patients.

DATA SOURCES

Medline, Embase, and Central databases.

STUDY SELECTION

Studies reporting on the prevalence of IAH in consecutively admitted critically ill patients using the World Society of Abdominal Compartment Syndrome (WSACS) consensus guidelines for intra-abdominal pressure (IAP) measurement.

DATA EXTRACTION

Duplicate independent review and data abstraction.

DATA SYNTHESIS

The search identified 2428 titles with 6 eligible studies (n = 1965). Reported prevalence ranged from 30% to 49%. Despite abiding by the WSACS guidelines for IAP measurement, studies varied in their definition of IAH, frequency and duration of IAP measurement, and reporting of outcomes. Three of 6 studies reported that IAH, especially at higher grades, was an independent predictor of mortality.

CONCLUSIONS

Intra-abdominal hypertension is a common finding in critically ill patients and may be associated with increased mortality, especially at higher grades. Further prospective research is required to examine the effect of screening and treatment of IAH on patient outcomes.

Intra-Abdominal Hypertension Is More Common Than Previously Thought: A Prospective Study in a Mixed Medical-Surgical ICU

OBJECTIVES

To determine the prevalence of intra-abdominal hypertension in mixed medical-surgical critically ill patients using modern definitions and measurement techniques. Secondarily to determine variables associated with intra-abdominal hypertension and ICU mortality.

DESIGN

A prospective observational study.

SETTING

Single institution trauma, medical and surgical ICU in Canada.

PATIENTS

Consecutive adult patients admitted to the ICU (n = 285).

INTERVENTION

Intra-abdominal pressure measurements twice a day during admission to the ICU.

MEASUREMENTS AND MAIN RESULTS

In 285 patients who met inclusion criteria, 30% were diagnosed with intra-abdominal hypertension at admission and a further 15% developed intra-abdominal hypertension during admission. The prevalence of abdominal compartment syndrome was 3%. Obesity, sepsis, mechanical ventilation, and 24-hour fluid balance (> 3 L) were all independent predictors for intra-abdominal hypertension. Intra-abdominal hypertension occurred in 28% of nonventilated patients. Admission type (medical vs surgical vs trauma) was not a significant predictor of intra-abdominal hypertension. Overall ICU mortality was 20% and was significantly higher for patients with intra-abdominal hypertension (30%) compared with patients without intra-abdominal hypertension (11%). Intra-abdominal hypertension of any grade was an independent predictor of mortality (odds ratio, 3.33; 95% CI, 1.46-7.57).

CONCLUSIONS

Intra-abdominal hypertension is common in both surgical and nonsurgical patients in the intensive care setting and was found to be independently associated with mortality. Despite prior reports to the contrary, intra-abdominal hypertension develops in nonventilated patients and in patients who do not have intra-abdominal hypertension at admission. Intra-abdominal pressure monitoring is inexpensive, provides valuable clinical information, and there may be a role for its routine measurement in the ICU. Future work should evaluate the impact of early interventions for patients with intra-abdominal hypertension.

Development and validation of quick Acute Kidney Injury-score (q-AKI) to predict acute kidney injury at admission to a multidisciplinary intensive care unit

AKI is associated with increased risk of death, prolonged length of stay and development of de-novo chronic kidney disease. The aim of our study is the development and validation of prediction models to identify the risk of AKI in ICU patients up to 7 days. We retrospectively recruited 692 consecutive patients admitted to the ICU at San Bortolo Hospital (Vicenza, Italy) from 1 June 2016 to 31 March 2017: 455 patients were treated as the derivation group and 237 as the validation group. Candidate variables were selected based on a literature review and expert opinion. Admission eGFR< 90 ml/min /1.73 mq (OR 2.78; 95% CI 1.78–4.35; p<0.001); SOFAcv ≥ 2 (OR 2.23; 95% CI 1.48–3.37; p<0.001); lactate ≥ 2 mmol/L (OR 1.81; 95% CI 1.19–2.74; p = 0.005) and (TIMP-2)•(IGFBP7) ≥ 0.3 (OR 1.65; 95% CI 1.08–2.52; p = 0.019) were significantly associated with AKI. For the q-AKI score, we stratified patients into different AKI Risk score levels: 0–2; 3–4; 5–6; 7–8 and 9–10. In both cohorts, we observed that the proportion of AKI patients was higher in the higher score levels.

Obese trauma patients have increased need for dialysis

PURPOSE

Obesity is a risk factor for the development of acute kidney injury but its effect on the need for dialysis in trauma has not been elucidated. Additionally, the contribution that obesity has towards risk of mortality in trauma is unclear. We hypothesized that patients with a higher body mass index (BMI) will have a higher risk for need of dialysis and mortality after trauma.

METHODS

This is a retrospective analysis using the National Trauma Data Bank. All patients ≥ 8 years old were grouped based on BMI: normal (18.5-24.99 kg/m²), obese (30-34.99 kg/m²), severely obese (35-39.99 kg/m²) and morbidly obese (≥ 40 kg/m²). The primary outcome was hemodialysis initiation. The secondary outcome was mortality during the index hospitalization.

RESULTS

From 988,988 trauma patients, 571,507 (57.8%) had a normal BMI, 233,340 (23.6%) were obese, 94,708 (9.6%) were severely obese, and 89,433 (9.0%) were morbidly obese. The overall rate of hemodialysis was 0.3%. After adjusting for covariates, we found that obese (OR 1.36, CI 1.22-1.52, p < 0.001), severely obese (OR 1.89, CI 1.66-2.15, p < 0.001) and morbidly obese (OR 2.04, CI 1.82-2.29, p < 0.001) patients had a stepwise increased need for hemodialysis after trauma. Obese patients had decreased (OR 0.92, CI 0.88-0.95, p < 0.001), severely obese had similar (OR 1.02, CI 0.97-1.08, p = 0.50) and morbidly obese patients had increased (OR 1.06, CI 1.01-1.12, p = 0.011) risk of mortality after trauma.

CONCLUSIONS

Obesity was associated with an increased risk for dialysis after trauma. Mortality risk was reduced in obese, similar in severely obese, and increased in morbidly obese trauma patients suggesting an inflection threshold BMI for risk of mortality in trauma.

Ventilation in patients with intra-abdominal hypertension: what every critical care physician needs to know

The incidence of intra-abdominal hypertension (IAH) is high and still underappreciated by critical care physicians throughout the world. One in four to one in three patients will have IAH on admission, while one out of two will develop IAH within the first week of Intensive Care Unit stay. IAH is associated with high morbidity and mortality. Although considerable progress has been made over the past decades, some important questions remain regarding the optimal ventilation management in patients with IAH. An important first step is to measure intra-abdominal pressure (IAP). If IAH (IAP > 12 mmHg) is present, medical therapies should be initiated to reduce IAP as small reductions in intra-abdominal volume can significantly reduce IAP and airway pressures. Protective lung ventilation with low tidal volumes in patients with respiratory failure and IAH is important. Abdominal-thoracic pressure transmission is around 50%. In patients with IAH, higher positive end-expiratory pressure (PEEP) levels are often required to avoid alveolar collapse but the optimal PEEP in these patients is still unknown. During recruitment manoeuvres, higher opening pressures may be required while closely monitoring oxygenation and the haemodynamic response. During lung-protective ventilation, whilst keeping driving pressures within safe limits, higher plateau pressures than normally considered might be acceptable. Monitoring of the respiratory function and adapting the ventilatory settings during anaesthesia and critical care are of great importance. This review will focus on how to deal with the respiratory derangements in critically ill patients with IAH.

Mortality predictors of patients suffering of acute pancreatitis and development of intraabdominal hypertension

Background/aim

Intraabdominal hypertension (IAH) occurs frequently in patients with acute pancreatitis and adds to their morbidity and mortality. The main aim of the study was to identify the determination of the predictive factors connected to IAH that influence the evolution of acute pancreatitis.

Materials and methods

The prospective cohort study was conducted on 100 patients who had acute pancreatitis. According to obtained intraabdominal pressure (IAP) values, the patients were divided into two groups: one group (n = 40) with normal IAP values and the other (IAH group, n = 60) with increased IAP values. Deceased patients were specially analyzed within the IAH group in order to determine mortality predictors.

Results

Statistical significance of IAP (P = 0.048), lactates (P = 0.048), peak pressure (P = 0.043), abdominal perfusion pressure (P = 0.05), and mean arterial pressure (P = 0.041) was greater for deceased than for surviving patients in the IAH group. High mortality appears for patients younger than 65 years old, with lactate level higher than 3.22 mmol/L and filtration gradient (GF) lower than 67 mmHg.

Conclusion

Age, lactates, GF, and APACHE II score are determined as mortality predictors for patients suffering from acute pancreatitis who developed IAH. The mortality rate is higher when the level of GF is decreasing and the level of lactate increasing.

Abdominal compartment syndrome and intra-abdominal hypertension in critically ill patients: diagnostic value of computed tomography

AIMS

The aims of the present work were to reevaluate, prospectively, the diagnostic value of already-described computed tomography (CT) landmarks of intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) and to study the diagnostic value of some undescribed CT signs for the diagnosis of IAH and ACS.

MATERIALS AND METHODS

Consecutive patients admitted to the intensive care unit (ICU) in shock for whom an abdominal CT was clinically indicated were included. CT examinations were reviewed and scored by two reviewers for the 12 proposed CT features of IAH and ACS. Intravesical pressure (IVP) was measured for each patient. Imaging features and clinical data of patients with IAH (IVP ≥ 12 mmHg) were compared to those of patients with normal intra-abdominal pressure (IVP < 12 mmHg).

RESULTS

Forty-one patients were included. Twenty-one patients (51%) presented IAH with an IVP value ≥ 12 mmHg. Four patients (10%) were considered to have ACS (10%). Only an increased peritoneal-to-abdominal height ratio (PAR) was associated with the presence of IAH (PAR = 0.45 [0.40-0.49] in patients with IVP < 12 mmHg and PAR = 0.52 [0.48-0.53] in patients with IVP ≥ 12 mmHg; p < 0.001). Increased PAR ≥ 0.52 had a specificity of 85% for IAH diagnosis.

CONCLUSION

The present study suggests that a PAR ≥ 0.52 could help radiologists to identify IAH on abdominal CT scan and could lead to adequate identification and/or treatment, even at early stages of IAH.

KEY POINTS

• CT is an efficient first-intention procedure to evaluate and follow up underlying conditions in critically ill patients at risk of IAH and ACS overcome. • Raising the possibility of an IAH on a CT examination is relevant information for the clinician. • The only factors associated with intra-abdominal hypertension were the peritoneal-to-abdominal height ratio (PAR) and the ratio of maximal anteroposterior to transverse abdominal diameter (which define the round belly sign when > 0.8).

Open Abdomen in Trauma and Critical Care

The open abdomen technique and temporary abdominal closure after damage control surgery is fast becoming the standard of care for managing intra-abdominal bleeding and infectious or ischemic processes in critically ill patients. Expansion of this technique has evolved from damage control surgery in severely injured trauma patients to use in patients with abdominal compartment syndrome due to acute pancreatitis and other disorders. Subsequent therapies after use of the open abdomen technique and temporary abdominal closure are resuscitation in the intensive care unit and planned reoperation to manage the underlying cause of bleeding, infection, or ischemia. Determining the need for this potentially lifesaving intervention and managing the wound after the open abdomen has been created are all within the realm of critical care nurses. Case studies illustrate the implementation of the open abdomen technique and patient management strategies.

Obesity, acute kidney injury and mortality in patients with sepsis: a cohort analysis

Although the prognostic effect of obesity has been studied in critically ill patients its impact on outcomes of septic patients and its role as a risk factor for acute kidney injury (AKI) is not consensual. We aimed to analyze the impact of obesity on the occurrence of AKI and on in-hospital mortality in a cohort of critically ill septic patients. This study is retrospective including 456 adult patients with sepsis admitted to the Division of Intensive Medicine of the Centro Hospitalar Lisboa Norte (Lisbon, Portugal) between January 2008 and December 2014. Obesity was defined as a body mass index of 30 kg/m² or higher. The Kidney Disease Improving Global Outcomes classification was used to diagnose and classify patients developing AKI. AKI occurred in 87.5% of patients (19.5% with stage 1, 22.6% with stage 2 and 45.4% with stage 3). Obese patients developed AKI more frequently than non-obese patients (92.8% versus 85.5%, p = .035; unadjusted OR 2.2 (95% CI: 1.04–4.6), p = .039; adjusted OR 2.31 (95% CI: 1.07–5.02), p = .034). The percentage of obese patients, however, did not differ between AKI stages (stage 1, 25.1%; stage 2, 28.6%; stage 3, 15.4%; p = .145). There was no association between obesity and mortality (p = .739). Of note, when comparing AKI patients with or without obesity in terms of in-hospital mortality there were also no significant differences between those groups (38.4% versus 38.4%, p = .998). Obesity was associated with the occurrence of AKI in critically ill patients with sepsis; however, it was not associated with in-hospital mortality.

The gastro-renal effects of intra-abdominal hypertension: Implications for critical care nurses

Intra-abdominal hypertension is classified as either primary or secondary - primary occurs due to intra-abdominal or retro-peritoneal pathophysiology, whereas secondary results in alterations in capillary fluid dynamics due to factors, such as massive fluid resuscitation and generalised inflammation. The renal and gastro-intestinal effects occur early in the progression of intra-abdominal hypertension, and may lead to poor patient outcomes if not identified. As a direct response to intra-abdominal hypertension, renal function is reduced with remarkable impairment from pressures of around 10 mmHg, oliguria developing at 15 mmHg and anuria developing at 30 mmHg. Intestinal micro-circulation is significantly reduced by up to 50% with intra-abdominal pressures as low as 15 mmHg. Mucosal and submucosal tissue hypo-perfusion causes considerable damage to the intestinal cells, potentially resulting in bacterial translocation, endotoxin release, sepsis and multiple organ failure. The critical care nurse plays an important role in the early identification of intra-abdominal hypertension however, without this essential knowledge base and comprehension of intra-abdominal hypertension, clinical signs and symptoms may go unnoticed or be misinterpreted as signs of other critical illnesses.

Intra-abdominal infection combined with intra-abdominal hypertension aggravates the intestinal mucosal barrier dysfunction

Some patients with intra-abdominal infection (IAI) may develop intra-abdominal hypertension (IAH) during treatment. The present study investigated the impact of IAI combined with IAH on the intestinal mucosal barrier in a rabbit model. Forty-eight New Zealand white rabbits were randomly divided into four groups: (i) IAI and IAH; (ii) IAI alone; (iii) IAH alone; and (iv) Control group. IAI model: cecal ligation and puncture for 48 h; IAH model: raised intra-abdominal pressure (IAP) of 20 mmHg for 4 h. Pathological changes in intestinal mucosa were confirmed by light and scanning electron microscopy. FITC-conjugated dextran (FITC-dextran) by gavage was used to measure intestinal mucosal permeability in plasma. Endotoxin, d-Lactate, and diamine oxidase (DAO) in plasma were measured to determine intestinal mucosal damage. Malonaldehyde (MDA), superoxide dismutase (SOD), and GSH in ileum tissues were measured to evaluate intestinal mucosal oxidation and reducing state. Histopathologic scores were significantly higher in the IAI and IAH group, followed by IAI alone, IAH alone, and the control group. FITC-dextran, d-Lactate, DAO, and endotoxin in plasma and MDA in ileum tissues had similar trends. GSH and SOD were significantly lowest the in IAI and IAH group. Occludin levels were lowest in the ileums of the IAI and IAH group. All differences were statistically significant (P-values <0.001). IAI combined with IAH aggravates damage of the intestinal mucosal barrier in a rabbit model. The combined effects were significantly more severe compared with a single factor. IAI combined with IAH should be prevented and treated effectively.

Positive end-expiratory pressure adjusted for intra-abdominal pressure - A pilot study

PURPOSE

Intra-abdominal hypertension (IAH) is associated with impaired respiratory function. Animal data suggest that positive end-expiratory pressure (PEEP) levels adjusted to intra-abdominal pressure (IAP) levels may counteract IAH-induced respiratory dysfunction. In this pilot study, our aim was to assess whether PEEP adjusted for IAP can be applied safely in patients with IAH.

MATERIALS AND METHODS

We included patients on mechanical ventilation and with IAH. Patients were excluded with severe cardiovascular dysfunction or severe hypoxemia or if the patient was in imminent danger of dying. Following a recruitment manoeuvre, the following PEEP levels were randomly applied: PEEP of 5cmH₂O (baseline), PEEP=50% of IAP, and PEEP=100% of IAP. After a 30min equilibration period we measured arterial blood gases and cardio-respiratory parameters.

RESULTS

Fifteen patients were enrolled. Six (41%) patients did not tolerate PEEP=100% IAP due to hypoxemia, hypotension or endotracheal cuff leak. PaO₂/FiO₂ ratios were 234 (68), 271 (99), and 329 (107) respectively. The differences were significant (p=0.009) only between baseline and PEEP=100% IAP.

CONCLUSIONS

PEEP=100% of IAP was not well-tolerated and only marginally improved oxygenation in ventilated patients with IAH.

The influence of intraabdominal pressure on the mortality rate of patients with acute pancreatitis

BACKGROUND/AIM

Intraabdominal hypertension (IAH) is a common clinical finding in patients with acute pancreatitis and is associated with poor prognosis. This study aimed to determine the impact of intraabdominal pressure (IAP) on the mortality rate in patients with acute pancreatitis in an intensive care unit.

MATERIALS AND METHODS

A total of 50 patients with acute pancreatitis were included in this prospective cohort study. Based on the obtained values of IAP, the patients were divided into two groups: those with normal IAP (n = 14) and increased IAP (n = 36). Mean values of IAP were compared with examined variables.

RESULTS

The mortality rate of the study group was 40%. Comparing the IAP and treatment outcomes, it was proved that there were statistically highly significant differences (P = 0.012). Increasing the value of IAP increased the mortality rate. Deceased patients in the IAH group had greater statistical significance of APACHE II score (P = 0.016), abdominal perfusion pressure (P = 0.048), lactate (P = 0.049), hematocrit (P = 0.039), Ranson's criteria on admission (P = 0.017), Ranson's criteria after 48 h (P = 0.010), Sequential Organ Failure Assessment score (P = 0.014), and body mass index (P = 0.012) compared to the surviving patients.

CONCLUSION

IAP has an impact on the increase of mortality rates in patients with acute pancreatitis.

Intra-abdominal pressure and intra-abdominal hypertension in critically ill obstetric patients: a prospective cohort study

BACKGROUND

Critically ill obstetric patients may have risk factors for intra-abdominal hypertension. This study evaluated the intra-abdominal pressure and its effect on organ function and the epidemiology of intra-abdominal hypertension.

METHODS

Obstetric patients admitted to an Intensive Care Unit, with an anticipated stay greater than 24hours, were included. Intra-abdominal pressure was measured daily via a Foley catheter, based on intravesical pressure.

RESULTS

One-hundred-and-one patients were enrolled. The intra-abdominal pressure was 5-7mmHg in 34%; 7-12mmHg in 60%; and ≥12mmHg (intra-abdominal hypertension) in 6%. All six patients with intra-abdominal hypertension were pregnant at the time of admission. The intra-abdominal pressure in four patients normalized to <12mmHg following delivery, but in the remaining two it persisted ≥12mmHg and both these patients died. Correlation between intra-abdominal pressure and organ dysfunction was weak (r=0.211). Statistical comparison between patients with and without intra-abdominal hypertension for risk factors, daily intra-abdominal pressures, and Sequential Organ Failure Assessment score could not be done due to the disproportionately small number of patients with intra-abdominal hypertension as opposed to those without (6 versus 95). Intra-abdominal pressure did not significantly differ between survivors and non-survivors (8.5±1.1 vs 7.9±1.7mmHg, P=0.079).

CONCLUSIONS

The incidence of intra-abdominal hypertension in critically ill obstetric patients was lower than previously defined for mixed Intensive Care Unit populations, with an association with the pregnant state. Normalization of intra-abdominal pressure after delivery was associated with better survival. There was no correlation between intra-abdominal pressure and organ function or mortality.

Gastrointestinal failure in the ICU

PURPOSE OF REVIEW

The current review summarizes different aspects of assessment of gastrointestinal function and provides a practical approach to management of adult patients with gastrointestinal dysfunction in the ICU.

RECENT FINDINGS

Different ways to define gastrointestinal failure have been used in the past. Recently, the term 'acute gastrointestinal injury (AGI)' has been proposed to specifically describe gastrointestinal dysfunction as a part of multiple organ dysfunction syndrome. Possible pathophysiological mechanisms and different aspects in assessment of gastrointestinal function in adult ICU patients are presented. Currently, there is no single marker that could reliably describe gastrointestinal dysfunction. Therefore, monitoring and management is still based on complex assessment of different gastrointestinal symptoms and feeding intolerance, even though this approach includes a large amount of subjectivity. The possible role of biomarkers (citrulline, enterohormones, etc.) and additional parameters like intra-abdominal pressure remains to be clarified.

SUMMARY

Defining gastrointestinal failure remains challenging but broad consensus needs to be reached and disseminated soon to allow conduct of interventional studies. A systematic approach to management of gastrointestinal problems is recommended.

Increased pressure within the abdominal compartment: intra-abdominal hypertension and the abdominal compartment syndrome

PURPOSE OF REVIEW

This article reviews recent developments related to intra-abdominal hypertension (IAH)/abdominal compartment syndrome (ACS) and clinical practice guidelines published in 2013.

RECENT FINDINGS

IAH/ACS often develops because of the acute intestinal distress syndrome. Although the incidence of postinjury ACS is decreasing, IAH remains common and associated with significant morbidity and mortality among critically ill/injured patients. Many risk factors for IAH include those findings suggested to be indications for use of damage control surgery in trauma patients. Medical management strategies for IAH/ACS include sedation/analgesia, neuromuscular blocking and prokinetic agents, enteral decompression tubes, interventions that decrease fluid balance, and percutaneous catheter drainage. IAH/ACS may be prevented in patients undergoing laparotomy by leaving the abdomen open where appropriate. If ACS cannot be prevented with medical or surgical management strategies or treated with percutaneous catheter drainage, guidelines recommend urgent decompressive laparotomy. Use of negative pressure peritoneal therapy for temporary closure of the open abdomen may improve the systemic inflammatory response and patient-important outcomes.

SUMMARY

In the last 15 years, investigators have better clarified the pathogenesis, epidemiology, diagnosis, and appropriate prevention of IAH/ACS. Subsequent study should be aimed at understanding which treatments effectively lower intra-abdominal pressure and whether these treatments ultimately affect patient-important outcomes.

How central obesity influences intra-abdominal pressure: a prospective, observational study in cardiothoracic surgical patients

Background

Intra-abdominal hypertension (IAH) is frequently present in critically ill patients and is an independent predictor for mortality. Better recognition of clinically important thresholds is necessary. Increased intra-abdominal pressure (IAP) is associated with renal dysfunction, and renal failure is one of the most consistently described organ dysfunctions associated with IAH. Obesity is also associated with kidney injury. The underlying mechanisms are not yet fully understood. Increased IAP may be a link in this association. The aim of this study was firstly to find the range in values of intra-abdominal pressure (IAP) in cardiothoracic surgery patients a secondly to investigate the relationship between central obesity, body mass index (BMI) and IAP and thirdly to investigate the relationship between IAP, inflammation and renal function in this population.

Methods

Consecutive adult patients admitted to the cardiothoracic unit of the intensive care unit (ICU) after undergoing elective cardiothoracic surgery were included in this prospective, observational study. C-reactive protein (CRP) as a marker of inflammation and serum creatinine as a marker of renal function were measured pre- and postoperatively. Estimated glomerular filtration rates were calculated pre- and postoperatively. BMI was calculated. Waist circumference (WC), hip circumference (HC) and transvesical IAP were measured once directly after admission to the ICU postoperatively. Waist/hip ratio (WHR) was calculated (WC divided by HC). Three definitions of central obesity were used. Central obesity was defined according to WC, WHR or median WHR.

Results

In total, 186 patients undergoing cardiothoracic surgery were included. Mean IAP was 9.1 mmHg (SD 4.4). IAP ≥ 12 mmHg was observed in 50 patients (26.9 %). IAP > 20 mmHg was measured in 4 patients (2.2 %). There was a positive correlation between IAP and BMI (r² = 0.05, p = 0.003). Correlations between IAP and WC (r² = 0.02, p = 0.054) and between IAP and WHR (r² = 0.01, p = 0.173) were not significant. There were no correlations between pre- or postoperative CRP and IAP (r² = 2.3 × 10⁻⁴, p = 0.839 and r² = 0.013, p = 0.117, respectively). In obese patients postoperative CRP was significantly higher than in non-obese patients (p = 0.034). There were no correlations between pre-operative serum creatinine and IAP (r² = 3.3 × 10⁻⁵, p = 0.938) or postoperative serum creatinine and IAP (r² = 0.003, p = 0.491).

Conclusions

The range in IAP in patients undergoing cardiothoracic surgery was wide. There was a positive correlation between IAP and BMI. Correlations between IAP and indices for central obesity were not significant. In a multiple regression model BMI was a better predictor of IAP than WHR in this population. There were no correlations between pre- or postoperative CRP and IAP. Furthermore, this study did not find evidence for a relation between IAP and pre- and postoperative serum creatinine.

Electronic supplementary material

The online version of this article (doi:10.1186/s13613-016-0195-8) contains supplementary material, which is available to authorized users.

A survey of critical care nurses' knowledge of intra-abdominal hypertension and abdominal compartment syndrome

BACKGROUND

Intra-abdominal hypertension and abdominal compartment syndrome are potentially life threatening conditions. Critical care nurses need to understand the factors that predispose patients to intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS). Predicting and managing IAH and ACS are important to improve health outcomes.

AIM

The aim of this paper was to (1) assess the knowledge of Australian critical care nurses about current IAH and ACS practice guidelines, measurement techniques, predictors for the development of IAH and ACS and (2) identify barriers in recognizing IAH, ACS and measuring IAP.

METHODS

Between October 2014 and April 2015 86 registered nurses employed in the area of critical care were recruited via the form to participate in an on-line, 19-item questionnaire. The survey was distributed to critical care nurses via the Australian College of Critical Care Nurses (ACCCN) mailing list and directly to intensive care units via The majority of participants were women (n=62) all participants were registered nurses employed in critical care the response rate was 3.2%. The study design was used to establish demographic data, employment data, and individuals' knowledge related to IAH and ACS. Participants had the option to write hand written responses in addition to selecting a closed question response.

RESULTS

The results showed that most survey participants were able to identify some obvious causes of IAH. However, less than 20% were able to recognize less apparent indices of risk. A lack of education related to IAP monitoring was identified by nearly half (44.2%) of respondents as the primary barrier to monitoring IAP.

CONCLUSION

Critical care clinicians' knowledge of IAH and ACS is generally low in the areas of presentation and outcomes of IAH and ACS requiring tailored and targeted educational interventions.

Study of the occurrence of intra-abdominal hypertension and abdominal compartment syndrome in patients of blunt abdominal trauma and its correlation with the clinical outcome in the above patients

Background

Intra-abdominal pressure (IAP) measurements have been identified as essential for diagnosis and management of both intra-abdominal hypertension (IAH) and Abdominal compartment syndrome (ACS). It has gained prominent status in ICUs worldwide. We aimed to evaluate the utility of measurement of rise in bladder pressure to assess IAP levels in blunt abdominal trauma (BAT) patients.

Patients and methods

Thirty patients of BAT with solid organ injuries were included in this study. Intra-abdominal pressure was measured through a Foleys bladder catheter throughout their stay. Bladder pressure was compared with clinical parameters like mean arterial pressures(MAP), respiratory rate(RR), serum creatinine(SC) and abdominal girth(AG) and also with outcome in terms of intervention whether operative(OI) or non-operative(NOI).

Results

Bladder pressure showed significant correlation with MAP (R = −0.418; P = 0.022), AG (R = 0.755; P = 0.000), SC (R = 0.689; P = 0.000) and RR (R = 0.537; P = 0.002). Bladder pressure (R = 0.851; P = 0.000), SC (R = 0.625; P = 0.000), MAP (R = −0.350; P = 0.058) and maximum AG difference (R = 0.634; P = 0.000) showed significant correlation with intervention. In total, 17 patients (56 %) required intervention, 9 patients (30 %) underwent NOI (pigtailing or aspiration) while 8 (27 %) needed OI. More than 3 derailed parameters were associated with 100 % intervention (Mean 3.47, SD-1.23). High APACHE III score on admission (>40) was associated with increased intervention (p = 0.001). Intervention correlates well with Grade of injury (p = 0.000) and not with number of organs injured (p = 0.061). Blood transfusion of 2 or more units of blood was associated with increased intervention (p = 0.000).

Conclusion

Increased bladder pressure and other clinical parameters (MAP, SC, RR and change in AG) correlates well with intervention. Elevated bladder pressure correlates well with other clinical parameters in patients with BAT. Bladder pressure, SC, MAP, RR and AG difference can be used to determine the group of patients that can be managed conservatively and those that would benefit with minimal intervention or exploration. During Non-operative management (NOM) of patients with BAT and multiple solid organ injuries, IAP monitoring may be a simple and objective guideline to suggest further intervention whether NOI or OI. Although routine bladder pressure measurements will result in unnecessary monitoring of large number of patients it is hoped that patients with IAH can be detected early and subsequent ACS with morbid abdominal exploration can be prevented. However the criterion for non-operative failure and the point of decompression needs further refinement to prevent an increase of nontherapeutic operations.