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

Optimising the measurement of intra-bladder pressure in patients with predicted severe acute pancreatitis

BACKGROUND

Measuring intra-abdominal pressure (IAP) is important for management of patients with severe acute pancreatitis (SAP). Intra-bladder pressure (IBP) is an indirect index that reflects IAP, but measuring techniques vary. We sought to optimise IBP measuring techniques in predicted SAP patients.

METHODS

Predicted SAP patients consecutively admitted between June 2018 and January 2020 were scrutinised. Eligible patients had their IBP monitored for the first 72 h at 6-h intervals, and were then sequentially allocated into three research scenarios: (1) in the supine position along with head of bed elevation(HoBE)of 0, 15 and 30° at various points including the iliac crest the midaxillary line, pubic symphysis, and right atrium level, instilled with 25 mL normal saline (NS) at room temperature (RT); (2) NS instillation volume from 0, 10, 25, 40-50 mL at the iliac crest with HoBE15 at RT; and (3) NS instillation (25 mL) at either RT or 37 °C with HoBE15.

RESULTS

The dynamic IBP values measured at the pubic symphysis and iliac crest were fairly similar between HoBE0 and HoBE15 (all P > 0.05), but greatly increased at HoBE30 (all P < 0.01). IBP was significantly increased with escalating instillation volumes of NS (all P < 0.01 versus 0 mL NS), while there was no significant difference between 25 mL and 10 mL (P = 0.055). IBP was similar between NS at RT and under 37 °C (P = 0.643).

CONCLUSION

In predicted SAP patients, measuring IBP at the iliac crest with HoBE15 after instilling 10 mL of NS seems to be appropriate for monitoring IAP.

Intra-Abdominal Hypertension: A Systemic Complication of Severe Acute Pancreatitis

Patients with severe acute pancreatitis (SAP) present complications and organ failure, which require treatment in critical care units. These extrapancreatic complications determine the clinical outcome of the disease. Intra-abdominal hypertension (IAH) deteriorates the prognosis of SAP. In this paper, relevant recent literature was reviewed, as well as the authors’ own experiences, concerning the clinical importance of IAH and its treatment in SAP. The principal observations confirmed that IAH is a frequent consequence of SAP but is practically absent in mild disease. Common manifestations of AP such as pain, abdominal distension, and paralytic ileus contribute to increased abdominal pressure, as well as fluid loss in third space and aggressive fluid replacement therapy. A severe increase in IAP can evolve to abdominal compartment syndrome and new onset organ failure. Conservative measures are useful, but invasive interventions are necessary in several cases. Percutaneous drainage of major collections is preferred when possible, but open decompressive laparotomy is the final possibility in some cases in order to definitively reduce abdominal pressure. Intra-abdominal pressure should be measured in all SAP cases that worsen despite adequate treatment in critical care units. Conservative measures must be introduced to treat IAH, including negative fluid balance, digestive decompression by gastric–rectal tube, and prokinetics, including neostigmine. In the case of insufficient responses to these measures, minimally invasive interventions should be preferred.

Compound Probiotics Improve Body Growth Performance by Enhancing Intestinal Development of Broilers with Subclinical Necrotic Enteritis

The aim of this study is to explore whether or not the combined application of BS15 and H2 is capable to have a more effective control effect on SNE in broilers. A total of 240 1-day-old female chickens were randomly divided into 5 groups: (a) basal diet in negative control group (NC group); (b) basal diet + SNE infection (coccidiosis vaccine + CP) (PC group); (c) basal diet + SNE infection + H2 pre-treatment (BT group); (d) basal diet + SNE infection + BS15 pre-treatment (LT group); and (e) basal diet + SNE infection + H2 pre-treatment + BS15 pre-treatment (MT group). The results showed the MT group had the most positive effect on inhibiting the negative effect of growth performance at 42 days of age. In the detection of the NC, PC, and MT group indicators at 28 days of age, we found that MT group significantly promoted ileum tissue development of broilers, and the ileum of broilers in the MT group formed a flora structure different from NC and PC, although it was found that the MT group had no effect on the butyrate level in the cecum, but it could affect the serum immune level, such as significantly reducing the level of pro-inflammatory cytokine IL-8 and increasing the content of immunoglobulin IgM and IgG. In conclusion, the composite preparation of Lactobacillus johnsonii BS15 and Bacillus licheniformis H2 could effectively improve the growth performance against SNE broilers, which is possibly caused by the improvement of the immune levels, the reduction of inflammation levels, and the promotion of the intestinal development.

Macrophages Maintain Epithelium Integrity by Limiting Fungal Product Absorption

The colon is primarily responsible for absorbing fluids. It contains a large number of microorganisms including fungi, which are enriched in its distal segment. The colonic mucosa must therefore tightly regulate fluid influx to control absorption of fungal metabolites, which can be toxic to epithelial cells and lead to barrier dysfunction. How this is achieved remains unknown. Here, we describe a mechanism by which the innate immune system allows rapid quality check of absorbed fluids to avoid intoxication of colonocytes. This mechanism relies on a population of distal colon macrophages that are equipped with "balloon-like" protrusions (BLPs) inserted in the epithelium, which sample absorbed fluids. In the absence of macrophages or BLPs, epithelial cells keep absorbing fluids containing fungal products, leading to their death and subsequent loss of epithelial barrier integrity. These results reveal an unexpected and essential role of macrophages in the maintenance of colon-microbiota interactions in homeostasis. VIDEO ABSTRACT.

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.

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

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

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

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

Recent developments in the surgical management of complex intra-abdominal infection

BACKGROUND

Current guidance on the management of sepsis often applies to infection originating from abdominal or pelvic sources, which presents specific challenges and opportunities for efficient and rapid source control. Advances made in the past decade are presented in this article.

METHODS

A qualitative systematic review was undertaken by searching standard literature databases for English-language studies presenting original data on the clinical management of abdominal and pelvic complex infection in adults over the past 10 years. High-quality studies relevant to five topical themes that emerged during review were included.

RESULTS

Important developments and promising preliminary work are presented, relating to: imaging and other diagnostic modalities; antimicrobial therapy and the importance of antimicrobial stewardship; the particular challenges posed by fungal sepsis; novel techniques in percutaneous and endoscopic source control; and current issues relating to surgical source control and managing the abdominal wound. Logistical challenges relating to rapid access to cross-sectional imaging, interventional radiology and operating theatres need to be addressed so that international benchmarks can be met.

CONCLUSION

Important advances have been made in the diagnosis, non-operative and surgical control of abdominal or pelvic sources, which may improve outcomes in the future. Important areas for continued research include the diagnosis and therapy of fungal infection and the challenges of managing the open abdomen.

Abdominal Compartment Syndrome and Intra-abdominal Ischemia in Patients with Severe Acute Pancreatitis

Introduction

Severe acute pancreatitis may be complicated by intra-abdominal hypertension (IAH), abdominal compartment syndrome (ACS), and intestinal ischemia. The aim of this retrospective study is to describe the incidence, treatment, and outcome of patients with severe acute pancreatitis and ACS, in particular the occurrence of intestinal ischemia.

Methods

The medical records of all patients admitted with severe acute pancreatitis admitted to the ICU of a tertiary referral center were reviewed. The criteria proposed by the World Society of the Abdominal Compartment Syndrome (WSACS) were used to determine whether patients had IAH or ACS.

Results

Fifty-nine patients with severe acute pancreatitis were identified. Intra-abdominal pressure (IAP) measurements were performed in 29 patients (49.2 %). IAH was present in all patients (29/29). ACS developed in 13/29 (44.8 %) patients. Ten patients with ACS underwent decompressive laparotomy. A large proportion of patients with ACS had intra-abdominal ischemia upon laparotomy: 8/13 (61.5 %). Mortality was high in both the ACS group and the IAH group.

Conclusion

This study confirms that ACS is common in severe acute pancreatitis. Intra-abdominal ischemia occurs in a large proportion of patients with ACS. Swift surgical intervention may be indicated when conservative measures fail in patients with ACS. National and international guidelines need to be updated so that routine IAP measurements become standard of care for patients with severe acute pancreatitis in the ICU.

Endotoxemia-menace, marker, or mistake?

Endotoxemia is in its scientific ascendancy. Never has blood-borne, Gram-negative bacterial endotoxin (LPS) been invoked in the pathogenesis of so many diseases-not only as a trigger for septic shock, once its most cited role, but also as a contributor to atherosclerosis, obesity, chronic fatigue, metabolic syndrome, and many other conditions. Finding elevated plasma endotoxin levels has been essential supporting evidence for each of these links, yet the assays used to detect and quantitate endotoxin have important limitations. This article describes several assays for endotoxin in plasma, reviews what they do and do not measure, and discusses why LPS heterogeneity, LPS trafficking pathways, and host LPS inactivation mechanisms should be considered when interpreting endotoxin assay results.

Intra-Abdominal Pressure Reduction After Percutaneous Catheter Drainage Is a Protective Factor for Severe Pancreatitis Patients With Sterile Fluid Collections

OBJECTIVES

Severe acute pancreatitis (SAP) is a fatal disease with natural course of early SAP (ESAP) and late SAP (LSAP) phases. Peripancreatic percutaneous catheter drainage (PCD) is effective in management of LSAP. Although our previous study indicates that intra-abdominal PCD ahead of peripancreatic PCD benefits ESAP patients with sterile fluid collections, the mechanism is still uncovered.

METHODS

According to therapeutic results, 452 SAP patients who underwent PCD were divided into sterile group (248 cases), secondary infection group (145 cases), and primary infection group (59 cases).

RESULTS

The mortality was 4.1%, 10.9%, and 18.6%, respectively. Logistic-regression analysis indicated that multiorgan dysfunction syndrome (odds ratio [OR], 1.717; 95% confidence interval [95% CI], 1.098-2.685; P = 0.018), catheters located intra-abdominally (OR, 0.511; 95% CI, 0.296-0.884; P = 0.016), and intra-abdominal hypertension (OR, 1.534; 95% CI, 1.016-2.316; P = 0.042) were predictors for infection after PCD. Receiver operating characteristics curve delineated that decrease of intra-abdominal pressure (IAP) of more than 6.5 mm Hg after PCD had the ability to predict infection with sensitivity of 84.0% and specificity of 79.5%.

CONCLUSIONS

Intra-abdominal PCD for acute sterile fluid collections seems to be an effective option rather than peripancreatic PCD. Patients with a significant decrease of IAP had a lower incidence of infection and better alleviation of organ failure.

Effects of norepinephrine on tissue perfusion in a sheep model of intra-abdominal hypertension

BACKGROUND

The aim of the study was to describe the effects of intra-abdominal hypertension (IAH) on regional and microcirculatory intestinal blood flow, renal blood flow, and urine output, as well as their response to increases in blood pressure induced by norepinephrine.

METHODS

This was a pilot, controlled study, performed in an animal research laboratory. Twenty-four anesthetized and mechanically ventilated sheep were studied. We measured systemic hemodynamics, superior mesenteric and renal blood flow, villi microcirculation, intramucosal-arterial PCO2, urine output, and intra-abdominal pressure. IAH (20 mm Hg) was generated by intraperitoneal instillation of warmed saline. After 1 h of IAH, sheep were randomized to IAH control (n = 8) or IAH norepinephrine (n = 8) groups, for 1 h. In this last group, mean arterial pressure was increased about 20 mm Hg with norepinephrine. A sham group (n = 8) was also studied. Fluids were administered to prevent decreases in cardiac output. Differences between groups were analyzed with two-way repeated measures of analysis of variance (ANOVA).

RESULTS

After 2 h of IAH, abdominal perfusion pressure decreased in IAH control group compared to IAH norepinephrine and sham groups (49 ± 11, 73 ± 11, and 86 ± 15 mm Hg, P < 0.0001). There were no differences in superior mesenteric artery blood flow, intramucosal-arterial PCO2, and villi microcirculation among groups. Renal blood flow (49 ± 30, 32 ± 24, and 102 ± 45 mL.min(-1).kg(-1), P < 0.0001) and urinary output (0.3 ± 0.1, 0.2 ± 0.2, and 1.0 ± 0.6 mL.h(-1).kg(-1), P < 0.0001) were decreased in IAH control and IAH norepinephrine groups, compared to the sham group.

CONCLUSIONS

In this experimental model of IAH, the gut and the kidney had contrasting responses: While intestinal blood flow and villi microcirculation remained unchanged, renal perfusion and urine output were severely compromised.

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.

Intestinal Permeability in Inflammatory Bowel Disease: Pathogenesis, Clinical Evaluation, and Therapy of Leaky Gut

The pathogenesis of inflammatory bowel disease (IBD) is multifactorial with data suggesting the role of a disturbed interaction between the gut and the intestinal microbiota. A defective mucosal barrier may result in increased intestinal permeability which promotes the exposition to luminal content and triggers an immunological response that promotes intestinal inflammation. IBD patients display several defects in the many specialized components of mucosal barrier, from the mucus layer composition to the adhesion molecules that regulate paracellular permeability. These alterations may represent a primary dysfunction in Crohn's disease, but they may also perpetuate chronic mucosal inflammation in ulcerative colitis. In clinical practice, several studies have documented that changes in intestinal permeability can predict IBD course. Functional tests, such as the sugar absorption tests or the novel imaging technique using confocal laser endomicroscopy, allow an in vivo assessment of gut barrier integrity. Antitumor necrosis factor-α (TNF-α) therapy reduces mucosal inflammation and restores intestinal permeability in IBD patients. Butyrate, zinc, and some probiotics also ameliorate mucosal barrier dysfunction but their use is still limited and further studies are needed before considering permeability manipulation as a therapeutic target in IBD.

Searching for predictors of surgical complications in critically ill surgery patients in the intensive care unit: a review

We reviewed the use of the levels of C-reactive protein, lactate and procalcitonin and/or the Sequential Organ Failure Assessment score to determine their diagnostic accuracy for predicting surgical complications in critically ill general post-surgery patients. Included were all studies published in PubMed from inception to July 2013 that met the following inclusion criteria: evaluation of the above parameters, describing their diagnostic accuracy and the risk stratification for surgical complications in surgical patients admitted to an intensive care unit. No difference in the Sequential Organ Failure Assessment scores was seen between patients with or without complications. The D-lactate levels were significantly higher in those who developed colonic ischemic complications after a ruptured abdominal aortic aneurysm. After gastro-intestinal surgery, contradictory data were reported, with both positive and negative use of C-reactive protein and procalcitonin in the diagnosis of septic complications. However, in trauma patients, the C-reactive protein levels may help to discriminate between those with and without infectious causes. We conclude that the Sequential Organ Failure Assessment score, lactate concentration and C-reactive protein level have no significant predictive value for early postoperative complications in critically ill post-surgery patients. However, procalcitonin seems to be a useful parameter for diagnosing complications in specific patient populations after surgery and/or after trauma.

Meta-analysis of gut barrier dysfunction in patients with acute pancreatitis

BACKGROUND

The gut is implicated in the pathogenesis of acute pancreatitis but there is discrepancy between individual studies regarding the prevalence of gut barrier dysfunction in patients with acute pancreatitis. The aim of this study was to determine the prevalence of gut barrier dysfunction in acute pancreatitis, the effect of different co-variables, and changes in gut barrier function associated with the use of various therapeutic modalities.

METHODS

A literature search was performed using PRISMA and MOOSE guidelines. Summary estimates were presented as pooled prevalence of gut barrier dysfunction and the associated 95 per cent c.i.

RESULTS

A total of 44 prospective clinical studies were included in the systematic review, of which 18 studies were subjected to meta-analysis. The pooled prevalence of gut barrier dysfunction was 59 (95 per cent c.i. 48 to 70) per cent; the prevalence was not significantly affected by disease severity, timing of assessment after hospital admission or type of test used, but showed a statistically significant association with age. Overall, nine of 13 randomized clinical trials reported a significant improvement in gut barrier function following intervention compared with the control group, but only three of six studies that used standard enteral nutrition reported a statistically significant improvement in gut barrier function after intervention.

CONCLUSION

Gut barrier dysfunction is present in three of five patients with acute pancreatitis, and the prevalence is affected by patient age but not by disease severity. Clinical studies are needed to evaluate the effect of enteral nutrition on gut function in acute pancreatitis.

Effect of acute, slightly increased intra-abdominal pressure on intestinal permeability and oxidative stress in a rat model

INTRODUCTION

Intra-abdominal hypertension (IAH) is known as a common, serious complication in critically ill patients. Bacterial translocation and permeability changes are considered the pathophysiological bases for IAH-induced enterogenic endotoxemia and subsequent multiorgan failure. Nevertheless, the effects of slightly elevated intra-abdominal pressures (IAPs) on the intestinal mucosa and the associated mechanisms remain unclear.

METHODS

To investigate the acute effects of different nitrogen pneumoperitoneum grades on colonic mucosa, male Sprague-Dawley rats were assigned to six groups with different IAPs (0 [control], 4, 8, 12, 16, and 20 mmHg, n = 6/group). During 90 min of exposure, we dynamically monitored the heart rate and noninvasive hemodynamic parameters. After gradual decompression, arterial blood gas analyses were conducted. Thereafter, structural injuries to the colonic mucosa were identified using light microscopy. Colon permeability was determined using the expression of tight junction proteins, combined with fluorescein isothiocyanate dextran (FD-4) absorption. The pro-oxidant-antioxidant balance was determined based on the levels of malondialdehyde (MDA) and antioxidant enzymes.

RESULTS

IAH significantly affected the histological scores of the colonic mucosa, tight junction protein expression, mucosal permeability, and pro-oxidant-antioxidant balance. Interestingly, elevations of IAP that were lower than the threshold for IAH also showed a similar, undesirable effect. In the 8 mmHg group, mild hyponatremia, hypocalcemia, and hypoxemia occurred, accompanied by reduced blood and abdominal perfusion pressures. Mild microscopic inflammatory infiltration and increased MDA levels were also detected. Moreover, an 8-mm Hg IAP markedly inhibited the expression of tight junction proteins, although no significant differences in FD-4 permeability were observed between the 0- and 8-mmHg groups.

CONCLUSIONS

Acute exposure to slightly elevated IAP may result in adverse effects on intestinal permeability and the pro-oxidant-antioxidant balance. Therefore, in patients with critical illnesses, IAP should be dynamically monitored and corrected, as soon as possible, to prevent intestinal mucosal injury and subsequent gut-derived sepsis.

The role of intestinal mucosa injury induced by intra-abdominal hypertension in the development of abdominal compartment syndrome and multiple organ dysfunction syndrome

Introduction

Abdominal distension is common in critical illness. There is a growing recognition that intra-abdominal hypertension (IAH) may complicate nonsurgical critical illness as well as after abdominal surgery. However, the pathophysiological basis of the injury to the intestinal mucosal barrier and its influence on the onset of abdominal compartment syndrome (ACS) and multiorgan dysfunction syndrome (MODS) remain unclear. We measured intestinal microcirculatory blood flow (MBF) during periods of raised intra-abdominal pressure (IAP) and examined how this influenced intestinal permeability, systemic endotoxin release, and histopathological changes.

Methods

To test different grades of IAH to the injury of intestinal mucosa, 96 New Zealand white rabbits aged 5 to 6 months were exposed to increased IAP under nitrogen pneumoperitoneum of 15 mmHg or 25 mmHg for 2, 4 or 6 hours. MBF was measured using a laser Doppler probe placed against the jejunal mucosa through a small laparotomy. Fluorescein isothiocyanate (FITC)-conjugated dextran was administered by gavage. Intestinal injury and permeability were measured using assays for serum FITC-dextran and endotoxin, respectively, after each increase in IAP. Structural injury to the intestinal mucosa at different levels of IAH was confirmed by light and transmission electron microscopy.

Results

MBF reduced from baseline by 40% when IAP was 15 mmHg for 2 hours. This doubled to 81% when IAP was 25 mmHg for 6 hours. Each indicator of intestinal injury increased significantly, proportionately with IAP elevation and exposure time. Baseline serum FITC-dextran was 9.30 (± SD 6.00) μg/ml, rising to 46.89 (±13.43) μg/ml after 15 mmHg IAP for 4 hours (P <0.01), and 284.59 (± 45.18) μg/ml after 25 mmHg IAP for 6 hours (P <0.01). Endotoxin levels showed the same pattern. After prolonged exposure to increased IAP, microscopy showed erosion and necrosis of jejunal villi, mitochondria swelling and discontinuous intracellular tight junctions.

Conclusions

Intra-abdominal hypertension can significantly reduce MBF in the intestinal mucosa, increase intestinal permeability, result in endotoxemia, and lead to irreversible damage to the mitochondria and necrosis of the gut mucosa. The dysfunction of the intestinal mucosal barrier may be one of the important initial factors responsible for the onset of ACS and MODS.

Surveillance of intra-abdominal pressure and intestinal barrier function in a rat model of acute necrotizing pancreatitis and its potential early therapeutic window

OBJECTIVES

To monitor intra-abdominal pressure (IAP) and intestinal barrier function in a rat model of acute necrotizing pancreatitis (ANP) to elucidate a potential relevant therapeutic window.

METHODS

Sprague-Dawley rats were randomly divided into experimental or control groups. The ANP group (n = 40) was injected with 4.5% sodium taurocholate into the pancreatic duct to induce ANP. The controls received only abdominal opening surgery (sham-operated, SO; n = 40) or no treatment or surgery (baseline; 0 h, n = 20). The SO and ANP groups were then randomly subdivided into 3, 6, 12 and 24 h groups (n = 10 each). IAP was measured at each time point and the rats were sacrificed to measure the weight of accumulated ascites fluid and the amylase, endogenous creatinine (Cr), total bilirubin (TB), tumor necrosis factor- alpha (TNF-alpha), diamine oxidase (DAO), and D-lactate. Mortality and the development of pathological changes in the pancreas and intestines were also monitored.

RESULTS

IAP showed a continuous upward trend in the ANP group, with values 2 to 3 times higher than those in the SO group at the corresponding time points and the rising rate was peaking at 6 h. The levels of plasma amylase, TNF-alpha, Cr, TB, DAO, and D-lactate also gradually increased in the ANP group over time and were significantly higher than in the SO group at 3, 6, 12 and 24 h (all P<0.05). Moreover, the rising rate of TNF-alpha, DAO, and D-lactate also peaked at 6 h.

CONCLUSIONS

The ANP-induced changes in IAP, inflammatory factors and intestinal barrier that we observed in the rat model were especially obvious at 6 h post-induction, suggesting an early therapeutic window for the treatment of ANP in humans.

Early management of acute pancreatitis

Acute pancreatitis is the most common gastro-intestinal indication for acute hospitalization and its incidence continues to rise. In severe pancreatitis, morbidity and mortality remains high and is mainly driven by organ failure and infectious complications. Early management strategies should aim to prevent or treat organ failure and to reduce infectious complications. This review addresses the management of acute pancreatitis in the first hours to days after onset of symptoms, including fluid therapy, nutrition and endoscopic retrograde cholangiography. This review also discusses the recently revised Atlanta classification which provides new uniform terminology, thereby facilitating communication regarding severity and complications of pancreatitis.

IAP/APA evidence-based guidelines for the management of acute pancreatitis

BACKGROUND

There have been substantial improvements in the management of acute pancreatitis since the publication of the International Association of Pancreatology (IAP) treatment guidelines in 2002. A collaboration of the IAP and the American Pancreatic Association (APA) was undertaken to revise these guidelines using an evidence-based approach.

METHODS

Twelve multidisciplinary review groups performed systematic literature reviews to answer 38 predefined clinical questions. Recommendations were graded using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. The review groups presented their recommendations during the 2012 joint IAP/APA meeting. At this one-day, interactive conference, relevant remarks were voiced and overall agreement on each recommendation was quantified using plenary voting.

RESULTS

The 38 recommendations covered 12 topics related to the clinical management of acute pancreatitis: A) diagnosis of acute pancreatitis and etiology, B) prognostication/predicting severity, C) imaging, D) fluid therapy, E) intensive care management, F) preventing infectious complications, G) nutritional support, H) biliary tract management, I) indications for intervention in necrotizing pancreatitis, J) timing of intervention in necrotizing pancreatitis, K) intervention strategies in necrotizing pancreatitis, and L) timing of cholecystectomy. Using the GRADE system, 21 of the 38 (55%) recommendations, were rated as 'strong' and plenary voting revealed 'strong agreement' for 34 (89%) recommendations.

CONCLUSIONS

The 2012 IAP/APA guidelines provide recommendations concerning key aspects of medical and surgical management of acute pancreatitis based on the currently available evidence. These recommendations should serve as a reference standard for current management and guide future clinical research on acute pancreatitis.

Corticotropin-releasing factor: a possible key to gut dysfunction in the critically ill

Critically ill patients frequently display unexplained or incompletely explained features of gastrointestinal (GI) dysfunction, including gastric stasis, ileus, and diarrhea. This makes nutrition delivery challenging, and may contribute to poor outcomes. The typical bowel dysfunction seen in severely ill patients includes retarded gastric emptying, unsynchronized intestinal motility, and intestinal hyperpermeability. These functional changes appear similar to the corticotropin-releasing factor (CRF)-mediated bowel dysfunctions associated with stress of various types and some GI disorders and diseases. CRF has been shown to be present within the GI tract and its action on CRF receptors within the gut have been shown to reduce gastric emptying, alter intestinal motility, and increase intestinal permeability. However, the precise role of CRF in the GI dysfunction in critical illness remains unclear. In this short review, we provide an update on GI dysfunction during stress and review the possible role of CRF in the aetiology of gut dysfunction. We suggest that activation of CRF signaling pathways in critical illness might be key to understanding the mechanisms underlying the gut dysfunction that impairs enteral feeding in the intensive care unit.

Risk factors and outcome of intra-abdominal hypertension in patients with severe acute pancreatitis

BACKGROUND

Intra-abdominal hypertension (IAH) is common in patients with severe acute pancreatitis (SAP). The aim of the present study was to investigate the risk factors of IAH in SAP patients and assess the prognosis of SAP combined with IAH.

METHODS

To analyze the data from patients with SAP, both univariate and multivariate logistic regression analyses were applied, using 16 indices, including age, gender, Acute Physiology and Chronic Health Evaluation II scores (APACHE II), 24 h fluid balance, hematocrit, serum calcium level, and so on. Clinical prognosis such as mortality, hospital duration, of SAP patients with or without IAH was also compared.

RESULTS

First 24 h fluid balance (Odds Ratio [OR], 1.003; 95% Confidence Interval [CI], 1.001-1.006), number of fluid collections (OR, 1.652; 95% CI, 1.023-2.956), and serum calcium level (OR, 0.132; 95% CI, 0.012-0.775) were found to be independent risk factors for IAH in patients with SAP. Moreover, patients with SAP and IAH had significantly longer average length of stay, both in the hospital and in the intensive care unit, higher rates of systemic and local complications, and more invasive treatments.

CONCLUSIONS

The significant risk factors for IAH in patients with SAP include 24 h fluid balance (first day), number of fluid collections, and serum calcium level. Additionally, IAH is associated with extremely poor prognosis, evidenced by high rates of mortality, morbidity, and the need for invasive interventions.

Nourishing the dysfunctional gut and whey protein

PURPOSE OF REVIEW

This review discusses the mechanisms of the dysfunctional gut during the critical illness and the possibility that an immunonutrient such as whey protein can play a role in better tolerance of enteral nutrition, also decreasing inflammation and increasing anti-inflammatory defenses.

RECENT FINDINGS

Impaired gastric motor function and associated feed intolerance are common issues in critically ill patients. Some studies have been published with enteral nutrition enriched with whey protein as a dietary protein supplement that provides antimicrobial activity, immune modulation, improving muscle strength and body composition, and preventing cardiovascular disease and osteoporosis.

SUMMARY

Early enteral feeding will enhance patient recovery and the use of enteral diets enriched with whey protein may play a role in these patients.

Correlation between procalcitonin and intra-abdominal pressure and their role in prediction of the severity of acute pancreatitis

BACKGROUND/AIMS

Early assessment of disease severity and vigilant patient monitoring are key factors for adequate treatment of acute pancreatitis (AP). The aim of this study was to determine the correlation of procalcitonin (PCT) serum concentrations and intra-abdominal pressure (IAP) as prognostic markers in early stages of AP.

METHODS

This prospective observational study included 51 patients, of which 29 had severe AP (SAP). Patients were evaluated with the Acute Physiology And Chronic Health Evaluation (APACHE II) score, C-reactive protein (CRP) and PCT serum concentrations and IAP at 24 h from admission. PCT was measured three times in the 1st week of disease and three times afterward, while IAP was measured daily. PCT and IAP values correlated with each other, and also compared with APACHE II score and CRP values.

RESULTS

PCT, IAP, CRP values and APACHE II score at 24 h after hospital admission were significantly elevated in patients with SAP. There was significant correlation between PCT and IAP values measured at 24 h of admission, and between maximal PCT and IAP values. Sensitivity/specificity for predicting AP severity at 24 h after admission was 89%/69% for APACHE II score, 75%/86% for CRP, 86%/63% for PCT and 75%/77% for IAP.

CONCLUSIONS

Increased IAP was accompanied by increased PCT serum concentration in patients with AP. PCT and IAP can both be used as early markers of AP severity.

Influence of abdominal pressure on respiratory and abdominal organ function

PURPOSE OF REVIEW

Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) have been realized as severe complications in the intensive care patient. Laparoscopic surgery in older and more obese patients increases the risk of IAH and ACS.

RECENT FINDINGS

The incidence of IAH may be larger than thought of being approximately one-third of mechanically ventilated intensive care patients. In shock/trauma, three-fourths of all patients may suffer from IAH. Kidney and liver may dysfunction and the gut barrier may be impeded, permitting spread of inflammation to other organs. IAH and ACS have an impact on respiratory mechanics and may impede ventilation and require higher ventilation pressures than under normal conditions. Prone position and alternating (asynchronous) ventilation may moderate the IAH. In addition, surgical decompression should be considered.

SUMMARY

In view of the frequent occurrence of IAH in intensive care, the need of better understanding of the mechanisms behind IAH is a prerequisite for better treatment. Respiratory mechanics are affected but may also indicate routes of ventilatory treatment to lower IAH.