Intra-abdominal hypertension and the abdominal compartment syndrome

The outcomes and biliary complications of a staged biliary reconstruction in living donor liver transplantation: a propensity score matched analysis

BACKGROUND

Uncontrolled massive bleeding and bowel edema are critical issues during liver transplantation. Temporal intra-abdominal packing with staged biliary reconstruction (SBR) yields acceptable outcomes in deceased donor liver transplantation; however, data on living donor liver transplantation (LDLT) are scarce.

METHODS

A retrospective analysis of 1269 patients who underwent LDLT was performed. After one-to-two propensity score matching, patients who underwent LDLT with SBR were compared with those who underwent LDLT with one-stage biliary reconstruction (OSBR). The primary outcomes were graft survival (GS) and overall survival (OS), and the secondary outcomes were postoperative biliary complications.

RESULTS

There were 55 and 110 patients in the SBR and OSBR groups, respectively. The median blood loss was 6500 mL in the SBR and 4875 mL in the OSBR group. Patients receiving SBR-LDLT had higher incidence of sepsis (69.0% vs. 43.6%; P < 0.01) and intra-abdominal infections (60.0% vs. 30.9%; P < 0.01). Biliary complication rates (14.5% vs. 19.1%; P = 0.47) and 1-and 5-year GS (87.27%, 74.60% vs. 83.64%, 72.71%; P = 0.98) and OS (89.09%, 78.44% vs. 84.55%, 73.70%; P = 0.752) rates were comparable between the two groups.

CONCLUSIONS

SBR could serve as a life-saving procedure for patients undergoing complex critical LDLT, with GS, OS, and biliary outcomes comparable to those of OSBR.

Avoiding High Pressure Abdominal Closure of Congenital Abdominal Wall Defects-One Step Further to Improve Outcomes

The main goal of surgical treatment for gastroschisis and omphalocele is the reduction of viscera in the abdominal cavity and closure of the abdomen, but the challenge is to succeed without the detrimental effects of increased intraabdominal pressure. In this regard, we performed a retrospective study for all patients admitted for gastroschisis and omphalocele to the Neonatal Intensive Care Unit of 'Marie Sklodowska Curie' Emergency Clinical Hospital for Children, from January 2011 until June 2021. Our aim was to highlight the presence of postoperative abdominal compartment syndrome. We observed that six out of forty-seven patients developed clinical signs of abdominal compartment syndrome, five associated with primary closure and one with staged closure with a polyvinyl chloride patch. Following the results, we decided to implement the trans-bladder measurement of intraabdominal pressure to avoid closing the abdomen at pressures higher than 10 mmHg in order to prevent the development of abdominal compartment syndrome. We consider that there is still place for the improvement of congenital abdominal wall defects management and that the measurement of intraabdominal pressure might help us reach our goal.

Intra-abdominal hypertension and abdominal compartment syndrome in acute pancreatitis

Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) are underrecognized entities in patients of acute pancreatitis (AP). IAH develops in 30% to 60% and ACS in 15% to 30% of all AP patients and they are markers of severe disease with high morbidity and mortality. The detrimental effect of increased IAP has been recognized in several organ systems, including the central nervous system, cardiovascular, respiratory, renal and gastrointestinal systems. The pathophysiology of IAH/ACS development in patients with AP is multifactorial. Pathogenetic mechanisms include over-zealous fluid management, visceral edema, ileus, peripancreatic fluid collections, ascites and retroperitoneal edema. Laboratory and imaging markers are neither sensitive nor specific enough to detect IAH/ACS and intra-abdominal pressure (IAP) monitoring is vital for early diagnosis and the management of patients of AP with IAH/ACS. The treatment of IAH/ACS requires a multi-modality approach with both medical and surgical attention. Medical management consists of nasogastric/rectal decompression, prokinetics, fluid management and diuretics or hemodialysis. If conservative management is not effective, percutaneous drainage of fluid collection or ascites is necessary. Despite medical management, if IAP worsens, surgical decompression is warranted. The review discusses the relevance of IAH/ACS in patients of AP and its management.

Abdominal Compartment Syndrome in Acute Pancreatitis: A Narrative Review

Abdominal compartment syndrome (ACS) represents a severe complication of acute pancreatitis (AP), resulting from an acute and sustained increase in abdominal pressure >20 mmHg, in association with new organ dysfunction. The harmful effect of high intra-abdominal pressure on regional and global perfusion results in significant multiple organ failure and is associated with increased morbidity and mortality. There are several deleterious consequences of elevated intra-abdominal pressure on end-organ function, including respiratory, cardiovascular, gastrointestinal, neurologic, and renal effects. It is estimated that about 15% of patients with severe AP develop intra-abdominal hypertension or ACS, with a mortality rate around 50%. The treatment of abdominal compartment syndrome in acute pancreatitis begins with medical intervention and percutaneous drainage, where possible. Abdominal compartment syndrome unresponsive to conservatory treatment requires immediate surgical decompression, along with vacuum-assisted closure therapy techniques, followed by early abdominal fascia closure.

Stable Gastric Pentadecapeptide BPC 157 Therapy for Primary Abdominal Compartment Syndrome in Rats

Recently, the stable gastric pentadecapeptide BPC 157 was shown to counteract major vessel occlusion syndromes, i.e., peripheral and/or central occlusion, while activating particular collateral pathways. We induced abdominal compartment syndrome (intra-abdominal pressure in thiopental-anesthetized rats at 25 mmHg (60 min), 30 mmHg (30 min), 40 mmHg (30 min), and 50 mmHg (15 min) and in esketamine-anesthetized rats (25 mmHg for 120 min)) as a model of multiple occlusion syndrome. By improving the function of the venous system with BPC 157, we reversed the chain of harmful events. Rats with intra-abdominal hypertension (grade III, grade IV) received BPC 157 (10 µg or 10 ng/kg sc) or saline (5 ml) after 10 min. BPC 157 administration recovered the azygos vein via the inferior–superior caval vein rescue pathway. Additionally, intracranial (superior sagittal sinus), portal, and caval hypertension and aortal hypotension were reduced, as were the grossly congested stomach and major hemorrhagic lesions, brain swelling, venous and arterial thrombosis, congested inferior caval and superior mesenteric veins, and collapsed azygos vein; thus, the failed collateral pathway was fully recovered. Severe ECG disturbances (i.e., severe bradycardia and ST-elevation until asystole) were also reversed. Microscopically, transmural hyperemia of the gastrointestinal tract, intestinal mucosa villi reduction, crypt reduction with focal denudation of superficial epithelia, and large bowel dilatation were all inhibited. In the liver, BPC 157 reduced congestion and severe sinusoid enlargement. In the lung, a normal presentation was observed, with no alveolar membrane focal thickening and no lung congestion or edema, and severe intra-alveolar hemorrhage was absent. Moreover, severe heart congestion, subendocardial infarction, renal hemorrhage, brain edema, hemorrhage, and neural damage were prevented. In conclusion, BPC 157 cured primary abdominal compartment syndrome.

Powering Implantable and Ingestible Electronics

Implantable and ingestible biomedical electronic devices can be useful tools for detecting physiological and pathophysiological signals, and providing treatments that cannot be done externally. However, one major challenge in the development of these devices is the limited lifetime of their power sources. The state-of-the-art of powering technologies for implantable and ingestible electronics is reviewed here. The structure and power requirements of implantable and ingestible biomedical electronics are described to guide the development of powering technologies. These powering technologies include novel batteries that can be used as both power sources and for energy storage, devices that can harvest energy from the human body, and devices that can receive and operate with energy transferred from exogenous sources. Furthermore, potential sources of mechanical, chemical, and electromagnetic energy present around common target locations of implantable and ingestible electronics are thoroughly analyzed; energy harvesting and transfer methods befitting each energy source are also discussed. Developing power sources that are safe, compact, and have high volumetric energy densities is essential for realizing long-term in-body biomedical electronics and for enabling a new era of personalized healthcare.

BPC 157 Therapy and the Permanent Occlusion of the Superior Sagittal Sinus in Rat: Vascular Recruitment

We show the complex syndrome of the occluded superior sagittal sinus, brain swelling and lesions and multiple peripheral organs lesions in rat. Recovery goes centrally and peripherally, with the stable gastric pentadecapeptide BPC 157, which alleviated peripheral vascular occlusion disturbances, rapidly activating alternative bypassing pathways. Assessments were gross recording, venography, ECG, pressure, microscopy, biochemistry. The increased pressure in the superior sagittal sinus, portal and caval hypertension, aortal hypotension, arterial and venous thrombosis, severe brain swelling and lesions (cortex (cerebral, cerebellar), hypothalamus/thalamus, hippocampus), particular veins (azygos, superior mesenteric, inferior caval) dysfunction, heart dysfunction, lung congestion as acute respiratory distress syndrome, kidney disturbances, liver failure, and hemorrhagic lesions in gastrointestinal tract were all assessed. Rats received BPC 157 medication (10 µg/kg, 10 ng/kg) intraperitoneally, intragastrically, or topically to the swollen brain at 1 min ligation-time, or at 15 min, 24 h and 48 h ligation-time. BPC 157 therapy rapidly attenuates the brain swelling, rapidly eliminates the increased pressure in the ligated superior sagittal sinus and the severe portal and caval hypertension and aortal hypotension, and rapidly recruits collateral vessels, centrally ((para)sagittal venous collateral circulation) and peripherally (left superior caval vein azygos vein-inferior caval vein). In conclusion, as shown by all assessments, BPC 157 acts against the permanent occlusion of the superior sagittal sinus and syndrome (i.e., brain, heart, lung, liver, kidney, gastrointestinal lesions, thrombosis), given at 1 min, 15 min, 24 h or 48 h ligation-time. BPC 157 therapy rapidly overwhelms the permanent occlusion of the superior sagittal sinus in rat.

Effect of intra-abdominal hypertension on the intraocular pressure of the conscious dogs

This study was performed to evaluate the effect of intra-abdominal pressure (IAP) on intraocular pressure (IOP) in conscious dog models using a balloon technique to generate intra-abdominal hypertension. Six healthy dogs without ocular abnormalities were evaluated in this study. A balloon device was placed in the intra-abdominal cavity. The abdomen was insufflated to IAP levels of 15 and 25 mmHg using the balloon device. Intraocular pressure was measured at baseline, at IAP levels of 15 and 25 mmHg, and after decompression. In comparison with the mean baseline IOP (15.1 ± 2.0 mmHg), there was a significant increase in IOP at IAP levels of 15 mmHg (20.0 ± 2.1 mmHg) and 25 mmHg (19.9 ± 2.2 mmHg), corresponding to a 32.4% and 31.7% increase from baseline IOP, respectively. The mean IOP after decompression (14.8 ± 1.7 mmHg) was significantly lower compared to those at IAP levels of 15 and 25 mmHg. The present findings demonstrate that increased IAP has a clinically significant effect on IOP in dogs under conscious conditions. Although more research is needed to determine of increased IAP on IOP, these findings suggest that increased IAP leads to mild and reversible increase in IOP.

Timing of surgical intervention for compartment syndrome in different body region: systematic review of the literature

Compartment syndrome can occur in many body regions and may range from homeostasis asymptomatic alterations to severe, life-threatening conditions. Surgical intervention to decompress affected organs or area of the body is often the only effective treatment, although evidences to assess the best timing of intervention are lacking. Present paper systematically reviewed the literature stratifying timings according to the compartmental syndromes which may beneficiate from immediate, early, delayed, or prophylactic surgical decompression. Timing of decompression have been stratified into four categories: (1) immediate decompression for those compartmental syndromes whose missed therapy would rapidly lead to patient death or extreme disability, (2) early decompression with the time burden of 3-12 h and in any case before clinical signs of irreversible deterioration, (3) delayed decompression identified with decompression performed after 12 h or after signs of clinical deterioration has occurred, and (4) prophylactic decompression in those situations where high incidence of compartment syndrome is expected after a specific causative event.

Prevalence of intra-abdominal hypertension in horses with colic

OBJECTIVE

To determine an abdominal pressure cutoff value for intra-abdominal hypertension (IAH) in the horse and characterize IAH in horses with acute colic.

DESIGN

Prospective clinical cohort.

SETTING

University teaching hospital.

ANIMALS

Nine healthy adult horses and 56 horses with acute colic.

INTERVENTIONS

Ventral intra-abdominal pressure (IAP) was measured in triplicate at end expiration and averaged. Each colic case was classified as medical or surgical and large intestine (LI) or small intestine (SI). Management and final outcome (alive, euthanized, or died) were recorded. IAH was defined as ≥32 mm Hg (mean + 2 SDs of ventral IAP in control horses). Proportions of horses with and without IAH for different lesions were expressed as fractions and percentages. Differences in IAP between groups were determined using ANOVA with post-testing or t-tests. Odds ratio for management strategy (ie, need for medical or surgical) in horses with IAH was performed using Fisher's exact test. P < 0.05 was considered significant.

MEASUREMENTS AND MAIN RESULTS

IAP was higher in horses with colic compared to controls (P = 0.025). Over 18 months, 30.4% of horses with colic had IAH (n = 10 LI lesions, n = 7 SI lesions). Horses with LI medical lesions had the highest IAP of all lesions (mean 36.5 mm Hg). IAH horses with medical lesions were 15 times more likely to survive than IAH horses requiring surgery (P = 0.03).

CONCLUSIONS

Acute colic in horses is associated with an increased ventral IAP compared with healthy controls. IAH does exist in horses with colic, notably LI medical lesions, and is associated with nonsurvival in horses that require surgery.

Monitoring intra-abdominal pressure after liver transplantation in children

IAH after LTX can impair perfusion and threaten graft viability. This study aimed to assess the feasibility of longitudinal IAP measurements as an IAH screening method in children after LTX. A cohort of 23 children with a mean age (range) 3.1 (3 months-14 years) who underwent LTX between May 2017 and February 2018 were evaluated retrospectively. Longitudinal IAP measurements were compared to bedside Doppler US monitoring data. In total, 425 IAP measurements and 257 US examinations were performed. The mean ± SD (range) time expenditure for IAP measurement was 1.9 ± 0.4 (0.5-3.2) minutes. The mean post-operative IAP was 7.9 ± 3.6 (1-25) mm Hg. IAH (IAP ≥ 10 mm Hg) was noted in 102 (24%) of 257 measurements. Agitation had a significant impact on IAP (estimate: 9.3 mm Hg, CI: 6.72-11.97, P < .01). In patients with TAC, IAP was increased (6.7 ± 2.1 vs 8.7 ± 3.1 mm Hg, P = .02) while peak portal venous velocities decreased (38 ± 27 vs 26 ± 22 cm/s, P = .03) after patch reduction. An abdominal compartment syndrome with severely impaired vascular flow was noted in one patient. Episodes of elevated IAP were noted in a large proportion of patients, underscoring the need for IAP monitoring in pediatric liver transplant recipients. The safety and low time expenditure associated with IAP measurement could be included easily into standard nursing procedures for these patients.

Effect of intra-abdominal hypertension on plasma exogenous creatinine clearance in conscious and anesthetized dogs

OBJECTIVE

To evaluate the effect of intra-abdominal pressure (IAP) on plasma exogenous creatinine clearance in both conscious and anesthetized dog models using a balloon technique to generate intra-abdominal hypertension.

DESIGN

Prospective, cross-over, experimental study.

SETTING

University-based small animal research facility.

ANIMALS

Six healthy male Beagle dogs.

INTERVENTIONS

A balloon device comprising a Foley urinary catheter and latex balloon was placed in the intra-abdominal cavity. Plasma exogenous creatinine clearance was compared after intravenous administration of exogenous creatinine solution at 80 mg/kg under 4 different treatment conditions as follows: control and IAP levels of 25 mm Hg in conscious dogs and control and IAP levels of 25 mm Hg in anesthetized dogs (CC, C25, AC, and A25, respectively). Samples were obtained before (T0) and 10, 20, 30, 60, 90, 120, 240, 360, 480, and 600 min after administration of creatinine in all treatment groups.

MEASUREMENTS AND MAIN RESULTS

There were no significant differences in plasma creatinine concentration for CC, AC, and C25 during the treatment period. However, in the A25 treatment condition, the plasma creatinine concentration increased significantly at 10, 20, 30, 60, 90, and 120 min after administration of creatinine (P < 0.05). Plasma creatinine clearances were 5.0 ± 0.5, 4.7 ± 1.2, 5.5 ± 0.9, and 2.5 ± 0.5 mL/kg/min for 600 min (CC, AC, C25, and A25, respectively). In the A25 treatment condition, the plasma exogenous creatinine clearance decreased significantly to 50%, 47%, and 55% of that under control conditions (CC, AC, and C25, respectively). After decompression of the abdomen, plasma creatinine concentrations declined rapidly and returned to basal concentrations.

CONCLUSIONS

Intra-abdominal hypertension under general anesthesia could cause renal hypoperfusion. Timely decompression may improve the outcome of acutely increased IAP when surgery and/or general anesthesia is required in canine patients.

Computed tomographic features of intra-abdominal hypertension in three dogs

OBJECTIVE

To describe computed tomographic (CT) features of intra-abdominal hypertension (IAH) in 3 dogs with abdominal distension.

CASE SUMMARY

Three dogs with anorexia, distended abdomen, or labored breathing were presented for CT imaging. All 3 dogs were premedicated with IV butorphanol (0.2 mg/kg). A Foley urinary catheter was aseptically placed and the transvesical technique was used to obtain intra-abdominal pressure (IAP). The IAP measurements were obtained with the dogs in a standing position after a stabilization period of 5 minutes. The mean IAP values for each of the 3 dogs were 26.0, 12.0, and 13.0 mm Hg. Anesthesia was induced with IV propofol (2.0-4.0 mg/kg, to effect) in all 3 dogs and maintained with sevoflurane in 2 dogs. Compression of the caudal vena cava and elevation of the diaphragm were observed in all 3 dogs, whereas renal compression and the extension of peritoneal fluid to the vaginal canal and cavity were seen in the dog with the highest IAP.

NEW OR UNIQUE INFORMATION PROVIDED

Compression of the caudal vena cava, direct renal compression, and the extension of peritoneal fluid into the vaginal canal and vaginal cavity are consistent with a diagnosis of IAH. Measurement of IAP and detection of these CT features should alert clinicians to the possible presence of IAH in veterinary patients.

A novel balloon technique to induce intra-abdominal hypertension and its effects on cardiovascular parameters in a conscious dog model

OBJECTIVE

To evaluate a new balloon technique to induce intra-abdominal hypertension (IAH) and abdominal compartment syndrome in a conscious dog model, and to evaluate the effect of intra-abdominal pressure (IAP) on cardiovascular, respiratory, and arterial blood gas values in conscious dogs with IAH.

DESIGN

Prospective, experimental study.

SETTING

University-based small animal research facility.

ANIMALS

Six healthy Beagle dogs, 4 males, and 2 females.

INTERVENTIONS

A new balloon device designed for this study using a Foley urethral catheter and latex balloon was placed in the abdominal cavity. Consecutive measurements of IAP were made by measuring the intravesicular pressure. The abdomen was inflated with air to IAPs of 10, 15, 20, and 25 mm Hg. Heart rate, respiratory rate, systolic arterial blood pressure, and arterial blood gases were evaluated at baseline and at 15, 30, 45, 60, 120, 240, and 300 minutes after IAP increase.

MEASUREMENTS AND MAIN RESULTS

The air insufflated into the intra-abdominal balloon device significantly increased the IAP and led to sustained IAH. The respiratory rate increased significantly (P < 0.05) when IAP was increased to 15, 20, and 25 mm Hg. Although heart rate, systolic arterial blood pressure, PaO₂ , and PaCO₂ did not show statistically significant differences between baseline and posttreatment values over time, the dogs with increased IAP showed a distended abdomen and apparent discomfort, and 4/6 (67%) vomited. After measurement of IAP, air was removed. There were no adverse effects noted after removal of the balloon device.

CONCLUSION

The balloon device was successfully insufflated and led to sustained IAH in conscious dogs. This balloon technique does not require general anesthesia for instillation or removal of gas after installment. An acute IAP increase in normal conscious dogs induced discomfort, vomiting, and increased respiratory effort.

Anesthetic management of intestinal obstruction: A postgraduate educational review

Intestinal obstruction is associated with significant morbidity and mortality. Scientific assessment of the cause, site of obstruction, appropriate correction of the fluid deficit and electrolyte imbalance with preoperative stabilization of blood gases is ideal as a preoperative workup. Placement of a preoperative epidural catheter especially in the thoracic interspace takes care of perioperative pain and stress reduction. Intraoperative management by controlled general anesthesia administering a relative high inspired fraction of oxygen with invasive monitoring in selected sick cases is mandatory. Preoperative monitoring and stabilizing raised intra-abdominal pressure reduces morbidity. Caution should be exercised during opening and closure of abdomen to avoid cardiorespiratory ill effects. There should be an emphasis on avoiding hypothermia. The use of nonsteroidal anti-inflammatory drugs may worsen sick, fragile patients. The use of sugammadex rather than neostigmine will obscure certain controversies in the healing of intestinal anastomotic site. Replacement of blood loss continued correction of fluids and electrolytes with possible postoperative mechanical ventilation in sick cases may improve outcomes in these patients.

Inverted U-Shaped Relationship between Central Venous Pressure and Intra-Abdominal Pressure in the Early Phase of Severe Acute Pancreatitis: A Retrospective Study

OBJECTIVE

Many studies have indicated that intra-abdominal pressure (IAP) is positively correlated with central venous pressure (CVP) in severe cases. However, although elevated IAP is common in patients with severe acute pancreatitis (SAP), its relationship with CVP remains unclear. Our study aimed to investigate the association of IAP with CVP in early-phase SAP patients.

METHODS

In total, 116 SAP patients were included in this retrospective study. On the first day of hospitalization, blood samples were collected for biochemical examination and cytokine concentration monitoring. Additionally, a urinary catheter and right subclavian vein catheter were inserted for IAP and CVP measurement, respectively. Other routine clinical data were also recorded.

RESULTS

Within 24 hours after hospitalization, CVP fluctuated and increased with increasing IAP up to 15.7 mmHg (P = 0.054) but decreased with increasing IAP when the IAP was > 15.7 mmHg (P < 0.001). After adjusting for abdominal perfusion pressure (APP) and mean arterial pressure (MAP), a similar distribution was observed. An inverted U-shaped trend between IAP and CVP was also present in the groups classified according to the patient's sex, local complications, ascites, and serum amylase levels.

CONCLUSIONS

CVP and IAP have an inverted U-shaped relationship, with a peak at an IAP of 15.7 mmHg in the early phase of SAP. After this peak, CVP decreases as IAP increases. These results have crucial implications for clinical fluid resuscitation in SAP patients. In particular, because one CVP value might be correlated with different IAP values in patients with the same CVP, the volume of fluid needed might be different.

Rational intraabdominal pressure monitoring: how to do it?

INTRODUCTION

Intraabdominal hypertension (IAH) is increasingly appreciated by intensivists as an important cause of organ dysfunction, even at pressure levels which were previously thought to be harmless. Therefore, the goal of this review is to describe the different methods commonly used in clinical practice for intraabdominal pressure (IAP) measurement, the advised methodology for each measurement method, and finally to give a rational approach for IAP monitoring in daily clinical practice.

METHODS

A Medline search of the English literature was performed using the term "intra abdominal pressure" and "measurement". This resulted in 194 studies, which were then analysed based on the title and abstract. Only clinical studies in human subjects with IAP measurement or related issues as the subject of the study, were considered for inclusion in the study. Reviews, animal experiments and case reports were excluded, while one specific review on IAP measurement and 3 large animal studies (domestic swine > 40 kg) were included in the analysis. This left us with 19 studies, published between 1984 and 2006: 1 specific review, 2 studies in children, 13 in adults and 3 in domestic swine. The references from these studies were searched for relevant articles that may have been missed in the primary search. These articles served as the basis for the recommendations below.

RESULTS

Clinical data regarding the validation of new IAP measurement methods or the reliability of established measurement techniques are scarce. The transvesical route, which has been studied most extensively, can be used as reliable route for intermittent IAP measurement, as long as instillation volumes below 25mL are used. Continuous IAP and APP monitoring can be done via a balloon-tipped catheter placed in the stomach or directly intraperitoneal.

CONCLUSIONS

Rational IAP monitoring should be based on a site specific protocol, based on known risk factors, the monitoring equipment available and nursing staff experience, and should be linked directly to a local treatment protocol.

Clinical awareness of intra-abdominal hypertension and abdominal compartment syndrome in 2007

INTRODUCTION

There has been an exponentially increasing interest in intra-abdominal hypertension (IAH). The aim of this review is to evaluate the evolution in clinical awareness of this syndrome.

METHODS

A PubMed (U.S. National Library of Medicine) search and a ScienceDirect (Elsevier B.V.) search of recent literature were performed in order to assess clinical awareness of IAH and abdominal compartment syndrome (ACS).

RESULTS

In total, 489 articles and 8 clinical surveys have been identified. The results of the landmark papers and the surveys will be briefly discussed in this review.

CONCLUSION

Clinical awareness of ACS is steadily increasing. It is time to pay attention to ACS, but further, it is time to move forward with therapeutic bundles in a multi-centered, outcome trial on IAH/ACS therapy in order to elevate IAH/ACS management to an international standard of care.

Intra-abdominal high pressure induces intestinal barrier dysfunction in rats

AIM: To study the effect of different degrees of intra-abdominal high pressure on intestinal mucosal barrier dysfunction and to explore the possible mechanisms involved.

METHODS: Forty-five adult male SD rats were randomly divided into a normal control group, a 10 mmHg and a 20 mmHg group (n = 15 for each). Nitrogen pneumoperitoneum was induced to generate intra-abdominal high pressure in animal models. The two pneumoperitoneum groups were further divided into three subgroups (five rats in each subgroup) for testing when pneumoperitoneum was maintained for 1, 2 and 4 h, respectively. Twenty-four hours after the relief of pneumoperitoneum, a spectrophotometer was used to measure the concentration of blue dextran 2000 in different segments of the small intestine. Malondialdehyde (MDA), reduced glutathione (GSH) and superoxide dismutase (SOD) in intestinal tissue homogenates, as well as plasma diamine oxidase (DAO) and D-lactic acid were measured. Morphological changes in the intestinal tissue were observed by light microscopy and electron microscopy.

RESULTS: Compared to the control group, intestinal transit was significantly delayed, but intestinal SOD, GSH and MDA levels and plasma D-lactate level showed no significant changes in the two high intra-abdominal pressure groups (all P > 0.05). Plasma DAO level did not differ significantly between the 10 mmHg group and control group, but was significantly different between the 20 mmHg and control groups (1412.93 ± 1397.19 vs 542.41 ± 314.93, P < 0.05). Under the light microscope, postoperative intestinal mucosa showed no damage in the control group; however, mild (increase in small intestinal subepithelial gaps and villus capillary congestion) and severe (varying degrees of intestinal mucosal changes, small intestinal mucosal congestion and edema, expansion of small intestinal subepithelial gaps, and intestinal villus degeneration, necrosis or loss) pathological changes were observed in the 10 and 20 mmHg groups, respectively. Electron microscopy demonstrated that intestinal villus cells in the 10 mmHg group showed mild swelling of tight junctions, and the 20 mmHg group showed significant changes in the microvillus and mitochondrial structures.

CONCLUSION: High intra-abdominal pressure can delay intestinal transit, alter plasma DAO activity, cause significant damage to intestinal epithelial cells, and increase intestinal permeability.

Biochemical and histopathological changes of intra-abdominal hypertension on the kidneys: Experimental study in rats

OBJECTIVE

This study aimed to evaluate the effects of experimentally induced intra-abdominal hypertension on renal functions, with the combination of biochemical and histopathological properties.

MATERIAL AND METHODS

Thirty male Wistar albino rats were used in this experimental study. Rats were divided into four groups. Group 1 (control group, n=6) only received anesthesia. After the induction of anesthesia, a 20 G catheter was introduced intraperitoneally to Group 2 (sham group, n=8), Group 3 (n=8) and Group 4 (n=8). The intra-abdominal pressure was not increased in Group 2. We applied 20 mmHg intra-peritoneal pressure to Group 3 and 30 mmHg to Group 4 for 3 hours. After withdrawing 3 mL intracardiac blood from all groups, the kidneys were removed for histopathological examination. Serum urea and creatinine levels were measured in all groups.

RESULTS

Biochemical examination showed that blood urea and creatinine levels were statistically different among all groups (p<0.05). Serum creatinine levels in Group 3 and serum urea and creatinine levels in Group 4 were significantly increased. In the histopathological examination, the kidneys in Group 1 and Group 2 were classified as normal. In Group 3, areas with congestion were detected in the glomeruli and interstitial regions. In addition to these findings seen in Group 3, dilatation of the pelvi-caliceal structures and proximal ureters were noticed in Group 4.

CONCLUSION

The levels of serum urea and creatinine are elevated when intra-abdominal pressure is increased due to kidney damage. Foci of hemorrhage in the interstitial area, dilatations in the proximal ureter, renal pelvis, and lymphatics were the pathologic findings seen in the kidneys under such circumstances.

Renal consequences of intraabdominal hypertension in a porcine model. Search for the choice indirect technique for intraabdominal pressure measurement

OBJECTIVE

To study the effects on the renal system in a porcine model of intraabdominal hypertension, and to determine the indirect technique of choice for determination of the intraabdominal pressure.

MATERIAL AND METHODS

30 pigs were used divided in two groups according with increased intraabdominal pressure values (20 mmHg and 30 mmHg). In both groups pressures were registered 8 times, summing up to 3 hours, with a CO₂ insufflator. Three different measures of the intraabdominal pressure were taken: a direct transperitoneal measure, using a catheter of Jackson-Pratt connected to a pressure transducer, and two indirect measures, a transvesical by means of a Foley to manometer system, and a transgastric by introducing in the stomach a catheter connected to a pressure monitor with electronic hardware. Mean arterial pressure was calculated, along with the cardiac index, production of urine and serum creatinine.

RESULTS

There was a greater correlation between the transvesical and the transperitoneal intraabdominal pressures (R(2)=0,95). Average transgastric intraabdominal pressure was inferior to the transperitoneal indicator in all taken measurements. The average arterial pressure descended in both groups, with earlier significant differences observed at 30 mmHg (p<0,020). Urine production was lower at 30 mmHg compared with the 20 mmHg group (9,63 ± 1,57 versus 3.26 ml ± 1,73). Serum creatinine increased in both groups being pathological at 30 mmHg after 1h 20 min, with existing differences between early pressures (p<0,027).

CONCLUSIONS

This study revealed marked renal affectation with higher severity at 30 mmHg pressures. The transvesical technique showed a greater correlation with the direct measurement technique used, defining this as the method of choice for determination of intraabdominal pressure.

Measurement of intra-abdominal pressure in dogs and cats

OBJECTIVE

To review and summarize the human and veterinary literature on intra-abdominal pressure measurement techniques.

DATA SOURCES

Human and veterinary clinical studies, research articles, reviews, and textbooks with no date restrictions with a focus on techniques for intra-abdominal pressure (IAP) measurement and their limitations.

HUMAN DATA SYNTHESIS

Human literature has established the intravesicular method as the gold standard for indirect measurement of IAP. However, current research has explored the intragastric method as a valid alternative. Recently, debate has focused on the shortcomings of the various measurement methods.

VETERINARY DATA SYNTHESIS

Early human literature using dogs as models contributed to the original data for IAP measurements in small animals. Since that time, a number of clinical studies and 1 case report have contributed to that original information. A reference interval for IAP measured by the intravesicular method has recently been determined in healthy cats.

CONCLUSIONS

Further studies investigating IAP in critically ill veterinary patients are required to establish the optimal technique for this measurement in veterinary medicine.

Effect of mechanical ventilation on intra-abdominal pressure in critically ill patients without other risk factors for abdominal hypertension: an observational multicenter epidemiological study

BACKGROUND

Mechanical ventilation (MV) is considered a predisposing factor for increased intra-abdominal pressure (IAP), especially when positive end-expiratory pressure (PEEP) is applied or in the presence of auto-PEEP. So far, no prospective data exists on the effect of MV on IAP. The study aims to look on the effects of MV on IAP in a group of critically ill patients with no other risk factors for intra-abdominal hypertension (IAH).

METHODS

An observational multicenter study was conducted on a total of 100 patients divided into two groups: 50 patients without MV and 50 patients with MV. All patients were admitted to the intensive care units of the Medical and Surgical Research Centre, the Carlos J. Finlay Hospital, the Julio Trigo University Hospital, and the Calixto García Hospital, in Havana, Cuba between July 2000 and December 2004. The IAP was measured twice daily on admission using a standard transurethral technique. IAH was considered if IAP was greater than 12 mmHg. Correlations were made between IAP and body mass index (BMI), diagnostic category, gender, age, and ventilatory parameters.

RESULTS

The mean IAP in patients on MV was 6.7 ± 4.1 mmHg and significantly higher than in patients without MV (3.6 ± 2.4 mmHg, p < 0.0001). This difference was maintained regardless of gender, age, BMI, and diagnosis. The use of MV and BMI were independent predictors for IAH for the whole population, while male gender, assisted ventilation mode, and the use of PEEP were independent factors associated with IAH in patients on MV.

CONCLUSIONS

In this study, MV was identified as an independent predisposing factor for the development of IAH. Critically ill patients, which are on MV, present with higher IAP values on admission and should be monitored very closely, especially if PEEP is applied, even when they have no other apparent risk factors for IAH.

Correct the Coagulopathy and Scoop It Out: Complete Reversal of Anuric Renal Failure through the Operative Decompression of Extraperitoneal Hematoma-Induced Abdominal Compartment Syndrome

We report two cases of extraperitoneal compression of the intra-abdominal space resulting in abdominal compartment syndrome (ACS) with overt renal failure, which responded to operative decompression of the extra-peritoneal spaces. This discussion includes patient presentation, clinical course, diagnosis, interventions, and outcomes. Data was collected from the patient's electronic medical record and a radiology database. ACS appears to be a rare but completely reversible complication of both retroperitoneal hematoma (RH) and rectus sheath hematoma (RSH). In patients with large RH or RSH consideration of intra-abdominal pressure (IAP) monitoring combined with aggressive operative drainage after correction of the coagulopathy should be considered. These two cases illustrate how a relatively benign pathology can result in increased IAP, organ failure, and ultimately ACS. Intervention with decompressive laparotomy and evacuation of clot resulted in return to normal physiologic function.

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.

Clinical review: use of renal replacement therapies in special groups of ICU patients

Acute kidney injury (AKI) in ICU patients is typically associated with other severe conditions that require special attention when renal replacement therapy (RRT) is performed. RRT includes a wide range of techniques, each with specific characteristics and implications for use in ICU patients. In the present review we discuss a wide range of conditions that can occur in ICU patients who have AKI, and the implications this has for RRT. Patients at increased risk for bleeding should be treated without anticoagulation or with regional citrate anticoagulation. In patients who are haemodynamically unstable, continuous therapies are most often employed. These therapies allow slow removal of volume and guarantee a stable blood pH. In patients with cerebral oedema, continuous therapy is recommended in order to prevent decreased cerebral blood flow, which will lead to cerebral ischemia. Continuous therapy will also prevent sudden change in serum osmolality with aggravation of cerebral oedema. Patients with hyponatraemia, as in liver failure or decompensated heart failure, require extra attention because a rapid increase of serum sodium concentration can lead to irreversible brain damage through osmotic myelinolysis. Finally, in patients with severe lactic acidosis, RRT can be used as a bridging therapy, awaiting correction of the underlying cause. Especially in ICU patients who have severe AKI, treatment with RRT requires balancing the pros and cons of different options and modalities. Exact and specific guidelines for RRT in these patients are not available for most clinical situations. In the present article we provide an update on the existing evidence.

Abdominal compartment syndrome caused by massive pyonephrosis in an infant with primary obstructive megaureter

The authors report a case of abdominal compartment syndrome caused by massive pyonephrosis in an infant with primary obstructive megaureter successfully treated with emergency surgical decompression.

Abdominal compartment syndrome due to spontaneous retroperitoneal hemorrhage in a patient undergoing anticoagulation

Spontaneous retroperitoneal hemorrhage is one of the most serious and often lethal complications of anticoagulation therapy. The clinical symptoms vary from femoral neuropathy to abdominal compartment syndrome or fatal hypovolemic shock. Of these symptoms, abdominal compartment syndrome is the most serious of all, because it leads to anuria, worsening of renal failure, a decrease in cardiac output, respiratory failure, and intestinal ischemia. We report a case of a spontaneous retroperitoneal hemorrhage in a 48-year-old female who had been receiving warfarin and aspirin for her artificial aortic valve. She presented with a sudden onset of lower abdominal pain, dizziness and a palpable abdominal mass after prolonged straining to defecate. Computed tomography demonstrated a huge retroperitoneal hematoma and active bleeding from the right internal iliac artery. After achieving successful bleeding control with transcatheter arterial embolization, surgical decompression of the hematoma was performed for management of the femoral neuropathy and the abdominal compartment syndrome. She recovered without any complications. We suggest that initial hemostasis by transcatheter arterial embolization followed by surgical decompression of hematoma is a safe, effective treatment method for a spontaneous retroperitoneal hemorrhage complicated with intractable pain, femoral neuropathy, or abdominal compartment syndrome.

Prospective study of intra-abdominal pressure following major elective abdominal surgery

BACKGROUND

Studies in emergency surgical patients have shown that raised intra-abdominal pressure may adversely affect organ function. The major aim of the present study was to establish the incidence of intra-abdominal hypertension (IAH) in patients undergoing major elective abdominal surgery. A secondary aim was to determine if the development of IAH was associated with poorer outcome.

METHODS

Patients undergoing major elective general surgical procedures were recruited to a prospective study in which intra-abdominal pressure was measured for 72 h postoperatively. Outcome data were collected on all patients.

RESULTS

A total of 42 patients with a median age of 63.5 years were studied. Five patients (12%) developed IAH, but this did not lead to a significant increase in the incidence of major organ dysfunction. There was no significant difference in the median length of hospital stay. However the development of IAH was associated with delayed return to oral diet (p < 0.05).

CONCLUSIONS

Intra-abdominal hypertension occurs in 12% of patients following major elective abdominal surgery and leads to a significantly delayed return to oral diet, but not to an increased length of hospital stay or increased incidence of major organ dysfunction.

Intra-abdominal hypertension due to heparin - induced retroperitoneal hematoma in patients with ventricle assist devices: report of four cases and review of the literature

INTRODUCTION

Elevated intra-abdominal pressure (IAP) has been identified as a cascade of pathophysiologic changes leading in end-organ failure due to decreasing compliance of the abdomen and the development of abdomen compartment syndrome (ACS). Spontaneous retroperitoneal hematoma (SRH) is a rare clinical entity seen almost exclusively in association with anticoagulation states, coagulopathies and hemodialysis; that may cause ACS among patients in the intensive care unit (ICU) and if treated inappropriately represents a high mortality rate.

CASE PRESENTATION

We report four patients (a 36-year-old Caucasian female, a 59-year-old White-Asian male, a 64-year-old Caucasian female and a 61-year-old Caucasian female) that developed an intra-abdominal hypertension due to heparin-induced retroperitoneal hematomas after implantation of ventricular assist devices because of heart failure. Three of the patients presented with dyspnea at rest, fatigue, pleura effusions in chest XR and increased heart rate although b-blocker therapy. A 36-year old female (the forth patient) presented with sudden, severe shortness of breath at rest, 10 days after an "acute bronchitis". At the time of the event in all cases international normalized ratio (INR) was <3.5 and partial thromboplastin time <65 sec. The patients were treated surgically, the large hematomas were evacuated and the systemic manifestations of the syndrome were reversed.

CONCLUSION

Identifying patients in the ICU at risk for developing ACS with constant surveillance can lead to prevention. ACS is the natural progression of pressure-induced end-organ changes and develops if IAP is not recognized and treated in a timely manner. Failure to recognize and appropriately treat ACS is fatal while timely intervention - if indicated - is associated with improvements in organ function and patient survival. Means for surgical decision making are based on clinical indicators of adverse physiology, rather than on a single measured parameter.

Gut barrier dysfunction in critically ill surgical patients with abdominal compartment syndrome

OBJECTIVES

This study investigated the effects of intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) on gut barrier function in critically ill surgical patients.

METHODS

A prospective observational cohort study on patients with severe acute pancreatitis or abdominal sepsis admitted to an intensive care or high-dependency unit. Intra-abdominal pressure (IAP) and plasma levels of immunoglobulin G (IgG) and IgM antiendotoxin core antibodies (EndoCAb) and procalcitonin (ProCT) were measured serially.

RESULTS

Among 32 recruited patients, 24 (75%) and 8 patients (25%) developed IAH and ACS, respectively. The state of ACS was associated with significant reductions in plasma IgG EndoCAb (P = 0.015) and IgM EndoCAb (P = 0.016) and higher concentrations of plasma ProCT (P = 0.056) compared with absence of ACS. Resolution of IAH and ACS was associated with significant recovery of plasma IgG EndoCAb (P = 0.003 and P = 0.009, respectively) and IgM EndoCAb (P = 0.002 and P = 0.003, respectively) and reduction in plasma ProCT concentration (P = 0.049 and P = 0.019, respectively). Negative correlations were observed between IAP and plasma IgG EndoCAb (P = 0.003) and IgM EndoCAb (P = 0.002).

CONCLUSIONS

Intra-abdominal hypertension and ACS are associated with significantly higher endotoxin exposure and ProCT concentrations, suggestive of gut barrier dysfunction. Resolution of IAH and ACS is associated with evidence for recovery of gut barrier function.

Massive gastric dilatation and anuria resolved with naso-gastric tube decompression

We report for the first time a case of acute kidney injury associated with severe gastric distention after a laparoscopic Nissen-Rossetti fundoplication of the stomach for hiatal hernia. An abdominal compartment syndrome secondary to intra-abdominal hypertension was suspected. Naso-gastric tube decompression resulted in immediate resaturation of the diuresis and progressive recovery of renal function.

Abdominal compartment syndrome: A review

OBJECTIVES

The aims of this review were to summarize a) the consensus definitions of normal and pathologic intra-abdominal pressure (IAP); b) the techniques to measure IAP; c) the risk factors for intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS); d) the pathophysiology of ACS; and e) the current recommendations for management and prevention of ACS.

DATA SOURCES

PubMed was searched using the following terms: ACS, IAH, IAP, and abdominal decompression.

DATA SYNTHESIS

ACS represents the natural progression of end-organ dysfunction caused by increased IAP and develops if IAH is not recognized and treated appropriately. Although the reported incidence of ACS is relatively low in critically ill children (0.6%-4.7%) it may be under-recognized and under-reported. The diagnosis of IAH/ACS depends on a high index of suspicion and the accurate and frequent measurement of IAP in patients at risk. Mortality from ACS remains high (50%-60%) even when decompression of the abdomen is performed early, which highlights the importance of detection and treatment of elevated IAP before end-organ damage occurs.

CONCLUSIONS

A widespread awareness of the recognition and current approach to management and prevention of IAH and ACS is needed among pediatric intensivists, so outcome of these life-threatening disease processes might be improved.

Management of abdominal compartment syndrome in a very low birth weight neonate using Penrose drains and subsequent management of abdominal-wall defects

Percutaneous drainage of the peritoneal cavity has been recently evaluated for the treatment of perforated viscous in the very low birth weight (VLBW) neonate and percutaneous decompression for abdominal compartment syndrome (ACS) has been studied in older patient populations. This is the first reported case of using this technique to treat ACS in a VLBW neonate.

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.

Severe acute pancreatitis: Pathogenetic aspects and prognostic factors

Approximately 20% of patients with acute pancreatitis develop a severe disease associated with complications and high risk of mortality. The purpose of this study is to review pathogenesis and prognostic factors of severe acute pancreatitis (SAP). An extensive medline search was undertaken with focusing on pathogenesis, complications and prognostic evaluation of SAP. Cytokines and other inflammatory markers play a major role in the pathogenesis and course of SAP and can be used as prognostic markers in its early phase. Other markers such as simple prognostic scores have been found to be as effective as multifactorial scoring systems (MFSS) at 48 h with the advantage of simplicity, efficacy, low cost, accuracy and early prediction of SAP. Recently, several laboratory markers including hematocrit, blood urea nitrogen (BUN), creatinine, matrix metalloproteinase-9 (MMP-9) and serum amyloid A (SAA) have been used as early predictors of severity within the first 24 h. The last few years have witnessed a tremendous progress in understanding the pathogenesis and predicting the outcome of SAP. In this review we classified the prognostic markers into predictors of severity, pancreatic necrosis (PN), infected PN (IPN) and mortality.

Clinical relevance of intra-abdominal hypertension in patients with severe acute pancreatitis

OBJECTIVES

Intra-abdominal hypertension (IAH) contributes to organ failure in patients with abdominal trauma and sepsis and leads to the development of abdominal compartment syndrome (ACS). This study aims to investigate the clinical significance of IAH in patients with severe acute pancreatitis (SAP).

METHODS

Patients admitted to intensive care with SAP underwent daily measurement of intra-abdominal pressure (IAP), recording of the clinical data, and calculation of 4 organ dysfunction scores.

RESULTS

Among 18 patients with SAP, 11 (61%) developed IAH (median, 20 mm Hg), whereas 10 (56%) developed ACS. The IAP correlated significantly with the 4 organ dysfunction scores; the scores were significantly higher when IAH existed than when it did not. The admission IAP correlated significantly with the duration of intensive care stay. Patients who developed IAH/ACS had significantly higher organ failure score and greater mortality compared with those who did not. Laparotomy and drainage reduced the IAP by a median of -11 mm Hg and relieved the IAH/ACS in all patients.

CONCLUSIONS

Intra-abdominal hypertension and ACS are frequent findings in patients with SAP and are associated with deterioration in organ function. Intra-abdominal pressure correlates with the severity of organ failure, and a high admission IAP is associated with prolonged intensive care stay.