Current insights in intra-abdominal hypertension and abdominal compartment syndrome

Incidence and risk factors of abdominal compartment syndrome in pediatric oncology patients: a prospective cohort study

Abdominal compartment syndrome (ACS) has been the subject of increasing research over the past decade owing to its effects on morbidity and mortality in critically ill patients. This study aimed to determine the incidence and risk factors of ACS in patients in an onco-hematological pediatric intensive care unit in a middle-income country and to analyze patient outcomes. This prospective cohort study was conducted between May 2015 and October 2017. Altogether, 253 patients were admitted to the PICU, and 54 fulfilled the inclusion criteria for intra-abdominal pressure (IAP) measurements. IAP was measured using the intra-bladder indirect technique with a closed system (AbViser AutoValve®, Wolfle Tory Medical Inc., USA) in patients with clinical indications for indwelling bladder catheterization. Definitions from the World Society for ACS were used. The data were entered into a database and analyzed. The median age was 5.79 years, and the median pediatric risk of mortality score was 7.1. The incidence of ACS was 27.7%. Fluid resuscitation was a significant risk factor for ACS in the univariate analysis. The mortality rates in the ACS and non-ACS groups were 46.6% and 17.9%, respectively (P < 0.05). This is the first study of ACS in critically ill children with cancer.   Conclusion: The incidence and mortality rates were high, justifying IAP measurement in children with ACS risk factors.

Estimation of Physiologic Pressures: Invasive and Non-Invasive Techniques, AI Models, and Future Perspectives

The measurement of physiologic pressure helps diagnose and prevent associated health complications. From typical conventional methods to more complicated modalities, such as the estimation of intracranial pressures, numerous invasive and noninvasive tools that provide us with insight into daily physiology and aid in understanding pathology are within our grasp. Currently, our standards for estimating vital pressures, including continuous BP measurements, pulmonary capillary wedge pressures, and hepatic portal gradients, involve the use of invasive modalities. As an emerging field in medical technology, artificial intelligence (AI) has been incorporated into analyzing and predicting patterns of physiologic pressures. AI has been used to construct models that have clinical applicability both in hospital settings and at-home settings for ease of use for patients. Studies applying AI to each of these compartmental pressures were searched and shortlisted for thorough assessment and review. There are several AI-based innovations in noninvasive blood pressure estimation based on imaging, auscultation, oscillometry and wearable technology employing biosignals. The purpose of this review is to provide an in-depth assessment of the involved physiologies, prevailing methodologies and emerging technologies incorporating AI in clinical practice for each type of compartmental pressure measurement. We also bring to the forefront AI-based noninvasive estimation techniques for physiologic pressure based on microwave systems that have promising potential for clinical practice.

COVID-19 and hepatorenal syndrome

Coronavirus disease 2019 (COVID-19) is a highly infectious disease which emerged into a global pandemic. Although it primarily causes respiratory symptoms for affected patients, COVID-19 was shown to have multi-organ manifestations. Elevated liver enzymes appear to be commonly observed during the course of COVID-19, and there have been numerous reports of liver injury secondary to COVID-19 infection. It has been established that patients with pre-existing chronic liver disease (CLD) are more likely to have poorer outcomes following COVID-19 infection compared to those without CLD. Co-morbidities such as diabetes, hypertension, obesity, cardiovascular and chronic kidney disease frequently co-exist in individuals living with CLD, and a substantial population may also live with some degree of frailty. The mechanisms of how COVID-19 induces liver injury have been postulated. Hepatorenal syndrome (HRS) is the occurrence of kidney dysfunction in patients with severe CLD/fulminant liver failure in the absence of another identifiable cause, and is usually a marker of severe decompensated liver disease. Select reports of HRS following acute COVID-19 infection have been presented, although the risk factors and pathophysiological mechanisms leading to HRS in COVID-19 infection or following COVID-19 treatment remain largely unestablished due to the relative lack and novelty of published data. Evidence discussing the management of HRS in high-dependency care and intensive care contexts is only emerging. In this article, we provide an overview on the speculative pathophysiological mechanisms of COVID-19 induced HRS and propose strategies for clinical diagnosis and management to optimize outcomes in this scenario.

Stretchable Capacitive Pressure Sensing Sleeve Deployable onto Catheter Balloons towards Continuous Intra-Abdominal Pressure Monitoring

Intra-abdominal pressure (IAP) is closely correlated with intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) diagnoses, indicating the need for continuous monitoring. Early intervention for IAH and ACS has been proven to reduce the rate of morbidity. However, the current IAP monitoring method is a tedious process with a long calibration time for a single time point measurement. Thus, there is the need for an efficient and continuous way of measuring IAP. Herein, a stretchable capacitive pressure sensor with controlled microstructures embedded into a cylindrical elastomeric mold, fabricated as a pressure sensing sleeve, is presented. The sensing sleeve can be readily deployed onto intrabody catheter balloons for pressure measurement at the site. The thin and highly conformable nature of the pressure sensing sleeve captures the pressure change without hindering the functionality of the foley catheter balloon.

Evaluation of the effects of intraabdominal hypertension on equine central venous pressure

OBJECTIVE

To evaluate the effect of changes in intraabdominal pressure (IAP) on central venous pressure (CVP) in normal horses.

DESIGN

Experimental, in vivo study.

SETTING

University Teaching Hospital.

ANIMALS

Convenience sample of 7 mixed breed horses-5 geldings and 2 mares.

INTERVENTIONS

Pneumoperitoneum was induced in horses under standing sedation with carbon dioxide gas using a laparoscopic insufflator for a total of 60 minutes to simulate clinical elevation in IAP. Pressure was increased stepwise to 20 mm Hg over 30 minutes, and maintained at that pressure for 30 minutes to evaluate the effect of sustained intraabdominal hypertension. CVP was obtained from the cranial vena cava, concurrent with pressure obtained from the peritoneal cavity.

MEASUREMENTS AND MAIN RESULTS

CVP increased as IAP increased up to 12 mm Hg, and declined as IAP increased further. The changes in CVP over time were significantly different (P < 0.03). Repeated measures correlation was positive, and highest, for mean CVP as IAP increased from 0 to 12 mm Hg (r = .70; 95% CI, .43-.85; P < 0.0001). Correlation of mean CVP with insufflation pressure became negative as IAP increased further from 15 to 20 mm Hg (r = -.47; 95% CI, -.66 to -.21; P = 0.0006).

CONCLUSIONS

This report provides preliminary data demonstrating a biphasic trend in equine CVP caused by changes in IAP, similar to that observed in other species. Further investigations are needed to evaluate this trend and to confirm these results in clinical patients.

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.

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

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

Current Approach to the Evaluation and Management of Abdominal Compartment Syndrome in Pediatric Patients

Abdominal compartment syndrome is an emergent condition caused by increased pressure within the abdominal compartment. It can be caused by a number of etiologies, which are associated with decreased abdominal wall compliance, increased intraluminal or intraperitoneal contents, or edema from capillary leak or fluid resuscitation. The history and physical examination are of limited utility, and the criterion standard for diagnosis is intra-abdominal pressure measurement, which is typically performed via an intravesical catheter. Management includes increasing abdominal wall compliance, evacuating gastrointestinal or intraperitoneal contents, avoiding excessive fluid resuscitation, and decompressive laparotomy in select cases.

Systematic Review of Laparostomy/Open Abdomen to Prevent Acute Compartimental Syndrome (ACS)

Laparostomy is defined as a surgical technique in which the peritoneal cavity is opened and left open, called "open abdomen" (OA). An open abdomen presents numerous challenges for the clinician. Specific pathologies like severe intraabdominal sepsis, trauma requiring damage control, abdominal compartment syndrome, staged abdominal repair and other complex abdominal pathologies can be managed with laparostomy. Laparostomy allows abdominal re-exploration, clearing and control of abdominal fluid of the fascia, avoiding intra-abdominal hypertension (IAH), abdominal wall closure.

Intestinal histopathological changes in a porcine model of pneumoperitoneum-induced intra-abdominal hypertension

BACKGROUND

Low splanchnic perfusion is an immediate effect of pneumoperitoneum-induced intra-abdominal hypertension (IAH). Anatomical structure results in the intestinal mucosa being the area most sensitive to hypoperfusion. The relationship between intestinal injury and clinical parameters of tissue perfusion [abdominal perfusion pressure (APP), gastric intramucosal pH (pH_i) and lactic acid (Lc)] has not been previously studied. This study aimed to monitorize intestinal pathogenesis through sequential ileal biopsies and to measure APP, pH_i, and Lc levels at different pneumoperitoneum-induced intra-abdominal pressures (20, 30, and 40 mmHg) to evaluate the potential relationships between them.

MATERIALS AND METHODS

Fifty pigs were divided into four groups; a control group (C) and three experimental groups with different pneumoperitoneum-induced levels [20 mmHg (G20), 30 mmHg (G30), and 40 mmHg (G40)], that were maintained for 3 and 5 h. APP, pH_i, and Lc were measured and ileal biopsies taken laparoscopically every 30 min. The mucosal damage was graded using the standardized Park's Score and animals were classified as injured (I+) or uninjured (I-).

RESULTS

Different histopathological lesions were observed in groups G20, G30, and G40 but no damage observed in group C. A 33.3% of animals in G20 and G30 were I+ after 3 h, while 93.3% were injured in G40. After 5 h, histopathological lesions were no longer seen in some animals in G20 and only 10% were I+. Conversely, in G30 I+ pigs increased to 80% while those in G40 remained at 93.3% I+. The I+ animals had significantly lower APP and pH_i than those I-. Lc was the clinical parameter that showed the earliest differences, with significantly higher figures in I+ animals.

CONCLUSIONS

The evolution of intestinal injuries from pneumoperitoneum-induced IAH depends on the degree of IAP. These damages may be associated with decreases in APP and pH_i, and increases in Lc.

Correlation of Procalcitonin and C-Reactive Protein with Intra-Abdominal Hypertension in Intra-Abdominal Infections: Their Predictive Role in the Progress of the Disease

AIM

To analyse the correlation of procalcitonin (PCT) and C-reactive protein (CRP) values with increased intra-abdominal pressure and to evaluate their predictive role in the progression of Intra-abdominal infections.

MATERIALS AND METHODS

A non-randomized prospective study conducted in the group of 80 patients. We have measured the PCT, CRP and intra-abdominal pressure (IAP).

RESULTS

According to IAH grades (G), there was a significant difference of PCT values: G I 3.6 ± 5.1 ng/ml, G II 10.9 ± 22.6 ng/ml, G III 15.2 ± 30.2 ng/ml (p = 0.045) until: CRP values were increased in all IAH groups but without distinction between the groups: GI 183 ± 64.5, GII 196 ± 90.2, GIII 224 ± 96.3 (p = 0.17). According to the severity of the infection, we yielded increased values of PCT, IAP and CRP in septic shock, severe sepsis and SIRS/sepsis resulting in significant differences of PCT and IAP.

CONCLUSION

Based on the results of our research, we conclude that the correlation of PCT values with IAH grades is quite significant while the CRP results remain high in IAH but without significant difference between the different grades of IAH.

Time-course evaluation of intestinal structural disorders in a porcine model of intra-abdominal hypertension by mechanical intestinal obstruction

BACKGROUND

A mechanical intestinal obstruction (MIO) can generate intraabdominal hypertension (IAH) that is life threatening. The intestines are very sensitive to IAH since the low splanchnic perfusion causes intestinal hypoxia, local acidosis and bacterial translocations. This may lead to acute intestinal distress syndrome (AIDS). The identification of intestinal injuries during IAH and its correlation with clinical parameters as the abdominal perfusion pressure (APP), the gastric intramucosal pH (pHi) and lactic acid (Lc) are still unknown. This study aimed to evaluate the sequence of intestinal histopathological findings in an MIO model and to analyze potential relationships with parameters currently used in clinical practice (APP, pHi and Lc).

MATERIAL AND METHODS

Twenty pigs were divided into three groups: a control group (n = 5) and two experimental groups with 20 mmHg (G1, n = 10) and 30 mmHg (G2, n = 5) of IAH by MIO. The pressures were maintained for 3 hours, except in 5 animals in G1 where it was maintained for 5 hours. The APP, pHi and LA were recorded and biopsies of the terminal ileum were taken every 30 minutes in all groups. The intestinal damage was graded according to the Park Score.

RESULTS

Intestinal injuries were found in 42.9% of pigs in the experimental groups. The lesions were independent of the level and duration of IAH. Although APP and pHi were slightly lower in injured animals (I +) of G1 and G2, there were no significant differences among those uninjured (I-). Lc was significantly increased in all I+ pigs from the onset of IAH.

CONCLUSION

The IAH by MIO causes intestinal lesions from the first 30 minutes with concurrent decreases in APP and pHi and increases in Lc. Lc could be the best clinical parameter related to intestinal damages with a clear difference between I + and I- animals.

Neutrophil Gelatinase-Associated Lipocalin as a Marker for Renal Dysfunction Detection in Critically Ill Patients with Increased Intraabdominal Pressure

Introduction

Elevated intraabdominal pressure (IAP) it is known to have an impact on renal function trough the pressure transmitted from the abdominal cavity to the vasculature responsible for the renal blood flow. Intraabdominal pressure is found to be frequent in intensive care patients and also to be a predictor of mortality. Intra-abdominal high pressure is an entity that can have serious impact on intensive care admitted patients, studies concluding that if this condition progresses to abdominal compartment syndrome mortality is as high as 80%.

Aim

The aim of this study was to observe if a link between increased intraabdominal pressure and modification in renal function exists (NGAL, creatinine clearance).

Material and Method

The study enrolled 30 critically ill patients admitted in the Intensive Care Unit of SCJU TîrguMures between November 2015 and August 2016. The study enrolled adult, hemodynamically stable patients admitted in intensive critical care - defined by a normal blood pressure maintained without any vasopressor or inotropic support, invasive monitoring using PICCO device and abdominal pressure monitoring.

Results

The patients were divided into two groups based on the intraabdominal pressure values: normal intraabdominal pressure group= 52 values and increased intraabdominal group= 35 values. We compared the groups in the light of NGAL values, 24 hours diuresis, GFR and creatinine clearance. The groups are significantly different when compared in the light of NGAL values and GFR values. We obtained a statistically significant correlation between NGAL value and 24 hour diuresis. No other significant correlations were encountered between the studied items.

Conclusions

NGAL values are increased in patients with high intraabdominal pressure which may suggest its utility as a cut off marker for patients with increased intraabdominal pressure. There is a significant decreased GFR in patient with elevated intraabdominal pressure, observation which can help in early detection of renal injury in patients due to high intraabdominal pressure. No correlation was found between creatinine clearance and increased intraabdominal pressure.

Intra-abdominal pressure: an integrative review

There is a growing request for measuring intra-abdominal pressure in critically ill patients with acute abdominal pain to be clarified. Summarizing the research results on measurement of vesical intra-abdominal pressure and analyzing the level of evidence were the purposes of this integrative literature review, carried out based on the databases LILACS, MEDLINE and PubMed, from 2005 to July 2012. Twenty articles were identified, in that, 12 literature reviews, 4 descriptive and exploratory studies, 2 expert opinions, one prospective cohort study and one was an experience report. The vesical intra-abdominal pressure measurement was considered gold standard. There are variations in the technique however, but some common points were identified: complete supine position, in absence of abdominal contracture, in the end of expiration and expressed in mmHg. Most research results indicate keeping the transducer zeroed at the level of the mid-axillary line at the iliac crest level, and instill 25mL of sterile saline. Strong evidence must be developed.

Mechanical Intestinal Obstruction in a Porcine Model: Effects of Intra-Abdominal Hypertension. A Preliminary Study

INTRODUCTION

Mechanical intestinal obstruction is a disorder associated with intra-abdominal hypertension and abdominal compartment syndrome. As the large intestine intraluminal and intra-abdominal pressures are increased, so the patient's risk for intestinal ischaemia. Previous studies have focused on hypoperfusion and bacterial translocation without considering the concomitant effect of intra-abdominal hypertension. The objective of this study was to design and evaluate a mechanical intestinal obstruction model in pigs similar to the human pathophysiology.

MATERIALS AND METHODS

Fifteen pigs were divided into three groups: a control group (n = 5) and two groups of 5 pigs with intra-abdominal hypertension induced by mechanical intestinal obstruction. The intra-abdominal pressures of 20 mmHg were maintained for 2 and 5 hours respectively. Hemodynamic, respiratory and gastric intramucosal pH values, as well as blood tests were recorded every 30 min.

RESULTS

Significant differences between the control and mechanical intestinal obstruction groups were noted. The mean arterial pressure, cardiac index, dynamic pulmonary compliance and abdominal perfusion pressure decreased. The systemic vascular resistance index, central venous pressure, pulse pressure variation, airway resistance and lactate increased within 2 hours from starting intra-abdominal hypertension (p<0.05). In addition, we observed increased values for the peak and plateau airway pressures, and low values of gastric intramucosal pH in the mechanical intestinal obstruction groups that were significant after 3 hours.

CONCLUSION

The mechanical intestinal obstruction model appears to adequately simulate the pathophysiology of intestinal obstruction that occurs in humans. Monitoring abdominal perfusion pressure, dynamic pulmonary compliance, gastric intramucosal pH and lactate values may provide insight in predicting the effects on endorgan function in patients with mechanical intestinal obstruction.

Simultaneous sampling of tissue oxygenation and oxygen consumption in skeletal muscle

Under physiologic conditions, microvascular oxygen delivery appears to be well matched to oxygen consumption in respiring tissues. We present a technique to measure interstitial oxygen tension (PISFO2) and oxygen consumption (VO2) under steady-state conditions, as well as during the transitions from rest to activity and back. Phosphorescence Quenching Microscopy (PQM) was employed with pneumatic compression cycling to achieve 1 to 10 Hz sampling rates of interstitial PO2 and simultaneous recurrent sampling of VO2 (3/min) in the exteriorized rat spinotrapezius muscle. The compression pressure was optimized to 120-130 mmHg without adverse effect on the tissue preparation. A cycle of 5s compression followed by 15s recovery yielded a resting VO2 of 0.98 ± 0.03 ml O2/100 cm(3)min while preserving microvascular oxygen delivery. The measurement system was then used to assess VO2 dependence on PISFO2 at rest and further tested under conditions of isometric muscle contraction to demonstrate a robust ability to monitor the on-kinetics of tissue respiration and the compensatory changes in PISFO2 during contraction and recovery. The temporal and spatial resolution of this approach is well suited to studies seeking to characterize microvascular oxygen supply and demand in thin tissues.

Bladder Pressure Measurements in Patients Admitted to a Medical Intensive Care Unit

BACKGROUND

Intra-abdominal hypertension is identified as an independent risk factor for death. However, this pathophysiological state is not always considered in patients in medical intensive care units and is frequently underdiagnosed.

METHODS

Serial bladder pressure measurements were recorded in patients admitted to the medical intensive care units to determine the frequency of intra-abdominal hypertension.

RESULTS

This study included 53 patients with a mean age of 59.0 ± 17.7 years. The average admission intra-abdominal pressure was 10.0 ± 5.4 mm Hg with a range of 0 to 28 mm Hg. Eleven patients (21%) had an initial pressure reading above normal (>12 mm Hg). Peak airway pressures were higher, and PaO2/FiO2 ratios were lower in patients with an initial pressure >12 mm Hg.

CONCLUSIONS

Bladder pressure measurements provide an easy method to estimate intra-abdominal pressures and provide an additional tool for the physiologic assessment of critically ill patients.

Intra-abdominal hypertension does not predict renal recovery or in-hospital mortality in critically ill patients with acute kidney injury

BACKGROUND

Although emerging evidence suggests that intra-abdominal hypertension (IAH) is a predictor of the development of acute kidney injury (AKI), it remains unclear whether the presence of IAH is a predictor of prognosis in patients with AKI. The purpose of this study was to assess whether the presence of IAH could predict prognosis in critically ill patients with AKI. The prognostic value of urinary biomarkers was also determined.

METHODS

In this prospective observational study, we enrolled 57 patients with established AKI, who were admitted to the intensive care unit between February 2012 and June 2014. IAH was defined as a sustained elevation in intra-abdominal pressure of ≥12 mmHg, in three consecutive measurements performed daily on the first 3 days. Urinary neutrophil gelatinase-associated lipocalin (NGAL), liver-type fatty acid-binding protein, and simplified acute physiology score II score at the time of admission were also examined.

RESULTS

IAH was observed in 78.9% of patients. The in-hospital mortality was 21.1%, and renal recovery during hospitalization was achieved in 40.4% of patients. Although high urinary NGAL [odds ratio (OR), 1.015] and liver-type fatty acid-binding protein (OR, 1.003) were found to be independent predictors of renal recovery, IAH was not. High urinary NGAL (OR, 1.003) and a high simplified acute physiology score II score (OR, 1.102) were independent predictors of in-hospital mortality, while IAH or urinary liver-type fatty acid-binding protein was not.

CONCLUSION

Although IAH is prevalent in critically ill patients with AKI, it did not predict AKI prognosis. However, urinary NGAL was found to be a useful predictor of both renal recovery and in-hospital mortality.

Measurement of Intra-abdominal Pressure in Critically-ill Children

INTRODUCTION

It is being increasingly recognized that intra-abdominal hypertension is an important cause of organ dysfunction. This pilot study was done to determine the feasibility of measuring intra-abdominal pressures (IAP) in critically-ill children using simple inexpensive equipment available in the PICU.

MATERIALS AND METHODS

This was a prospective study done in the paediatric intensive care unit (PICU) of a tertiary care general hospital. Thirty-two consecutive patients admitted to the PICU, staying for more than 24 h and requiring a urinary catheter were studied. IAP was measured by the intravesical method, using a disposable manometer, twice a day for seven days or till discharge/death, Risk factors associated with IAH were recorded.

RESULTS

The majority of the patients had an IAP less than 5 mm Hg. Three patients had grade 1 intra-abdominal hypertension (IAP>12 mm Hg).

CONCLUSION

It is feasible to measure IAP in paediatric patients without the use of sophisticated equipment.

Effect of intra-abdominal pressure on hepatic microcirculation: implications of the endothelin-1 receptor

OBJECTIVE

To investigate the effect of endothelin receptor A (ET(A)) and endothelin receptor B (ET(B)) blockade on liver microcirculation and oxygenation during intra-abdominal pressure (IAP) increase.

METHODS

Fifteen anesthetized pigs were randomized to receive either nonselective endothelin-1 (ET-1) blocker tezosentan (TG, n = 7) or saline (CG, n = 8). Helium was insufflated to increase IAP from 0 to 25 mmHg. Stroke volume variability was maintained ≤ 12% with colloid infusion. Total liver blood flow (TLBF), hepatic microcirculatory blood flow (MBF), hepatic tissue oxygenation (HpO(2)), hyaluronic acid and plasma disappearance rate (PDR) of indocyanine green (ICG) were recorded.

RESULTS

TLBF remained mostly unaltered in both groups at low IAP and decreased only in CG at the IAP of 25 mmHg. As IAP increased, a significant decline in MBF was observed without correlation with cardiac output or TLBF. In CG, HpO(2) decreased as early as IAP of 10 mmHg to high levels of pressure. However, in TG the decrease was significant only at the IAP of 25 mmHg. PDR of ICG decreased in both groups at IAP of 25 mmHg (P = 0.046 and P = 0.009 in TG and CG, respectively). These changes correlated with MBF (r = 0.793).

CONCLUSION

Blocking ET(A) and ET(B) receptors partially protects sinusoidal circulation and tissue oxygenation against stress induced by high IAP.

The effect of intra-abdominal hypertension incorporating severe acute pancreatitis in a porcine model

Introduction

Abdominal compartment syndrome (ACS) and intra abdominal hypertension(IAH) are common clinical findings in patients with severe acute pancreatitis(SAP). It is thought that an increased intra abdominal pressure(IAP) is associated with poor prognosis in SAP patients. But the detailed effect of IAH/ACS on different organ system is not clear. The aim of this study was to assess the effect of SAP combined with IAH on hemodynamics, systemic oxygenation, and organ damage in a 12 h lasting porcine model.

Measurements and Methods

Following baseline registrations, a total of 30 animals were divided into 5 groups (6 animals in each group): SAP+IAP30 group, SAP+IAP20 group, SAP group, IAP30 group(sham-operated but without SAP) and sham-operated group. We used a N₂ pneumoperitoneum to induce different levels of IAH and retrograde intra-ductal infusion of sodium taurocholate to induce SAP. The investigation period was 12 h. Hemodynamic parameters (CO, HR, MAP, CVP), urine output, oxygenation parameters(e.g., S_vO₂, PO₂, PaCO₂), peak inspiratory pressure, as well as serum parameters (e.g., ALT, amylase, lactate, creatinine) were recorded. Histological examination of liver, intestine, pancreas, and lung was performed.

Main Results

Cardiac output significantly decreased in the SAP+IAH animals compared with other groups. Furthermore, AST, creatinine, SUN and lactate showed similar increasing tendency paralleled with profoundly decrease in S_vO₂. The histopathological analyses also revealed higher grade injury of liver, intestine, pancreas and lung in the SAP+IAH groups. However, few differences were found between the two SAP+IAH groups with different levels of IAP.

Conclusions

Our newly developed porcine SAP+IAH model demonstrated that there were remarkable effects on global hemodynamics, oxygenation and organ function in response to sustained IAH of 12 h combined with SAP. Moreover, our model should be helpful to study the mechanisms of IAH/ACS-induced exacerbation and to optimize the treatment strategies for counteracting the development of organ dysfunction.

[Abdominal compartment syndrome and acute intestinal distress syndrome]

Seriously ill patients frequently present intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) as complications, and the associated mortality is very high. This review offers an update on the most controversial aspects of these entities: factors favoring their appearance, the most common causes, prognosis, and methods of measuring intra-abdominal pressure (IAP), physiopathological consequences in relation to the different organs and systems, and the currently accepted treatment measures (medical and/or surgical). Simultaneously to the strictly physical mechanisms of injury, such as direct compression of intra-abdominal organs and vessels, the transmission of IAP to other compartments, and the drop in cardiac output, a series of immune-inflammatory mediators generated in the intestine itself may also intervene. Hypoperfusion, sustained ischemia and the ischemia-reperfusion phenomenon, would act upon the microbiota, intestinal epithelium and intestinal immune system, triggering a systemic inflammatory response and multiorgan dysfunction that appears in the final stages of ACS.

Abdominal compartment syndrome - Intra-abdominal hypertension: Defining, diagnosing, and managing

Abdominal compartment syndrome (ACS) and intra-abdominal hypertension (IAH) are increasingly recognized as potential complications in intensive care unit (ICU) patients. ACS and IAH affect all body systems, most notably the cardiac, respiratory, renal, and neurologic systems. ACS/IAH affects blood flow to various organs and plays a significant role in the prognosis of the patients. Recognition of ACS/IAH, its risk factors and clinical signs can reduce the morbidity and mortality associated. Moreover, knowledge of the pathophysiology may help rationalize the therapeutic approach. We start this article with a brief historic review on ACS/IAH. Then, we present the definitions concerning parameters necessary in understanding ACS/IAH. Finally, pathophysiology aspects of both phenomena are presented, prior to exploring the various facets of ACS/IAH management.

A novel approach to severe acute pancreatitis in sequential liver-kidney transplantation: the first report on the application of VAC therapy

This work is the first report of vacuum-assisted closure (VAC) therapy applied as a life-saving surgical treatment for severe acute pancreatitis occurring in a sequential liver- and kidney-transplanted patient who had percutaneous biliary drainage for obstructive "late-onset" jaundice. Surgical exploration with necrosectomy and sequential laparotomies was performed because of increasing intra-abdominal pressure with hemodynamic instability and intra-abdominal multidrug-resistant sepsis, with increasingly difficult abdominal closure. Repeated laparotomies with VAC therapy (applying a continuous negative abdominal pressure) enabled a progressive, successful abdominal decompression, with the clearance of infection and definitive abdominal wound closure. The application of a negative pressure is a novel approach to severe abdominal sepsis and laparostomy management with a view to preventing compartment syndrome and fatal sepsis, and it can lead to complete abdominal wound closure.

Cardiopulmonary effects of matching positive end-expiratory pressure to abdominal pressure in concomitant abdominal hypertension and acute lung injury

BACKGROUND

To evaluate the cardiopulmonary effects of positive end-expiratory pressure (PEEP) equalization to intra-abdominal pressure (IAP) in an experimental model of intra-abdominal hypertension (IAH) and acute lung injury (ALI).

METHODS

Eight anesthetized pigs were submitted to IAH of 20 mm Hg with a carbon dioxide insufflator for 30 minutes and then submitted to lung lavage with saline and Tween (2.5%). Pressure x volume curves of the respiratory system were performed by a low flow method during IAH and ALI, and PEEP was subsequently adjusted to 27 cm . H2O for 30 minutes.

RESULTS

IAH decreases pulmonary and respiratory system static compliances and increases airway resistance, alveolar-arterial oxygen gradient, and respiratory dead space. The presence of concomitant ALI exacerbates these findings. PEEP identical to AP moderately improved oxygenation and respiratory mechanics; however, an important decline in stroke index and right ventricle ejection fraction was observed.

CONCLUSIONS

Simultaneous IAH and ALI produce important impairments in the respiratory physiology. PEEP equalization to AP may improve the respiratory performance, nevertheless with a secondary hemodynamic derangement.

Understanding of Abdominal Compartment Syndrome among Pediatric Healthcare Providers

Background. The sparse reporting of abdominal compartment syndrome (ACS) in the pediatric literature may reflect inadequate awareness and recognition among pediatric healthcare providers (HCP). Purpose. To assess awareness of ACS, knowledge of the definition and intraabdominal pressure (IAP) measurement techniques used among pediatric HCP. Method. A written survey distributed at two pediatric critical care conferences. Results. Forty-seven percent of 1107 questionnaires were completed. Participants included pediatric intensivists, pediatric nurses, and others. Seventy-seven percent (n = 513) of participants had heard of ACS. Only 46.8% defined ACS correctly. The threshold IAP value used to define ACS was variable among participants. About one-quarter of participants (83/343), had never measured IAP. Conclusion. Twenty-three percent of HCP surveyed were unaware of ACS. Criteria used to define ACS were variable. Focused education on recognition of ACS and measuring IAP should be promoted among pediatric HCP.

[Management of hemorrhage in patients with abdominal trauma: application of the European Guidelines for the management of bleeding following major trauma]

In patients with traumatic intraabdominal hemorrhage, urgent decisions must be made. Resuscitation measures must often be simultaneously combined with diagnostic actions and measures to control the source of the bleeding. Hemorrhages are usually complicated by coagulation disorders and the presence of acidosis and hypothermia. In these conditions, emergency measures are required that usually involve various specialists. However, given the paucity of the scientific evidence in this field, the intervention protocols differ from one center to another. The European Guidelines for the management of bleeding following major trauma has recently been published. These guidelines review aspects such as evaluation and initial management of bleeding, localization and control of the source of bleeding and replacement of blood products. In addition, recommendations based on the best available evidence to 2008 are made. This review describes the basic aspects of traumatic intraabdominal hemorrhage.

Initial experience of laparostomy with immediate vacuum therapy in patients with severe peritonitis

INTRODUCTION

To report our initial experience of laparostomy and immediate intra-abdominal vacuum therapy in patients with severe peritonitis due to intra-abdominal catastrophes.

PATIENTS AND METHODS

Twenty-seven patients underwent emergency laparotomy and laparostomy formation with the application of immediate intra-abdominal TRAC-VAC therapy (male:female ratio, 1:1.2; median age, 73 years; range, 34-84 years). Predicted mortality was assessed using the P-POSSUM score and compared with clinically observed outcomes.

RESULTS

Ten patients (37%) with a mean predicted P-POSSUM mortality of 72%, died of sepsis and multi-organ failure. Seventeen patients (mean P-POSSUM 48% expected mortality) survived to discharge. One patient with pancreatitis died from small bowel obstruction 1-year post discharge, two patients developed a small bowel fistula. One patient had an allergic reaction to the VAC dressing. Our patients, treated with laparostomy and TRAC VAC therapy, had a significantly improved observed survival when compared to P-POSSUM expected survival (P = 0.004).

CONCLUSIONS

Laparostomy with immediate intraperitoneal VAC therapy is a robust and effective system to manage patients with intra-abdominal catastrophes. There were significantly improved outcomes compared to the mortality predicted by P-POSSUM scores. Damage control surgery with laparostomy formation and intra-abdominal VAC therapy should be considered in patients with severe peritonitis.

Abdominal compartment syndrome: pathophysiology and definitions

"Intra-abdominal hypertension", the presence of elevated intra-abdominal pressure, and "abdominal compartment syndrome", the development of pressure-induced organ-dysfunction and failure, have been increasingly recognized over the past decade as causes of significant morbidity and mortality among critically ill surgical and medical patients. Elevated intra-abdominal pressure can cause significant impairment of cardiac, pulmonary, renal, gastrointestinal, hepatic, and central nervous system function. The significant prognostic value of elevated intra-abdominal pressure has prompted many intensive care units to adopt measurement of this physiologic parameter as a routine vital sign in patients at risk. A thorough understanding of the pathophysiologic implications of elevated intra-abdominal pressure is fundamental to 1) recognizing the presence of intra-abdominal hypertension and abdominal compartment syndrome, 2) effectively resuscitating patients afflicted by these potentially life-threatening diseases, and 3) preventing the development of intra-abdominal pressure-induced end-organ dysfunction and failure. The currently accepted consensus definitions surrounding the diagnosis and treatment of intra-abdominal hypertension and abdominal compartment syndrome are presented.

Review article: the abdominal compartment syndrome

BACKGROUND

The term abdominal compartment syndrome refers to hypoperfusion and ischaemia of intra-abdominal viscera and structures caused by raised intra-abdominal pressure. It occurs most commonly following major trauma and complex surgical procedures, but can also occur in their absence. Definitive treatment is decompression at laparotomy. Prevention and recognition of abdominal compartment syndrome are crucial to avoid additional morbidity and mortality. Postinjury abdominal compartment syndrome continues to complicate current resuscitation methods and new strategies for resuscitating critically ill patients need to be explored in addition to more accurate monitoring of intra-abdominal pressure.

AIM

To examine the published literature regarding the pathogenesis, diagnosis and management of the abdominal compartment syndrome.

METHODS

A comprehensive review of the literature was undertaken.

RESULTS

This syndrome is an important complication of major trauma and surgery as well as being recognized in critically-ill medical patients. It requires prompt recognition with a view to decompression at laparotomy.

CONCLUSIONS

The abdominal compartment syndrome is an important complication of trauma, surgery and resuscitation. Key to its management are its prompt recognition and abdominal decompression.

Abdominal compartment syndrome: a concise clinical review

OBJECTIVE

There has been an increased awareness of the presence and clinical importance of abdominal compartment syndrome. It is now appreciated that elevations of abdominal pressure occur in a wide variety of critically ill patients. Full-blown abdominal compartment syndrome is a clinical syndrome characterized by progressive intra-abdominal organ dysfunction resulting from elevated intra-abdominal pressure. This review provides a current, clinically focused approach to the diagnosis and management of abdominal compartment syndrome, with a particular emphasis on intensive care.

METHODS

Source data were obtained from a PubMed search of the medical literature, with an emphasis on the time period after 2000. PubMed "related articles" search strategies were likewise employed frequently. Additional information was derived from the Web site of the World Society of the Abdominal Compartment Syndrome (http://www.wsacs.org).

SUMMARY AND CONCLUSIONS

The detrimental impact of elevated intra-abdominal pressure, progressing to abdominal compartment syndrome, is recognized in both surgical and medical intensive care units. The recent international abdominal compartment syndrome consensus conference has helped to define, characterize, and raise awareness of abdominal compartment syndrome. Because of the frequency of this condition, routine measurement of intra-abdominal pressure should be performed in high-risk patients in the intensive care unit. Evidence-based interventions can be used to minimize the risk of developing elevated intra-abdominal pressure and to aggressively treat intra-abdominal hypertension when identified. Surgical decompression remains the gold standard for rapid, definitive treatment of fully developed abdominal compartment syndrome, but nonsurgical measures can often effectively affect lesser degrees of intra-abdominal hypertension and abdominal compartment syndrome.