[Abdominal compartment syndrome and acute intestinal distress syndrome]

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.

Intra-Abdominal Pressure as a Marker of Enteral Nutrition Intolerance in Critically Ill Patients. The PIANE Study

To determine whether elevated intra-abdominal pressure (IAP) is associated with a higher rate of enteral nutrition-related gastrointestinal (GI) complications; to assess the value of IAP as a predictor of enteral nutrition (EN) intolerance. Intensive Care Unit (ICU) patients on mechanical ventilation requiring at least 5 days of EN were recruited for a prospective, observational, non-interventional, multicenter study. EN was performed and GI complications were managed with an established protocol. IAP was determined via a urinary catheter. Patients who developed any GI complications were considered as presenting EN intolerance. Variables related to EN, IAP and GI complications were monitored daily. Statistical analysis compared patients without GI complications (group A) vs. GI complications (group B). 247 patients were recruited from 28 participating ICUs (group A: 119, group B: 128). No differences between groups were recorded. Patients in group B (p < 0.001) spent more days on EN (8.1 ± 8.4 vs. 18.1 ± 13.7), on mechanical ventilation (8.0 ± 7.7 vs. 19.3 ± 14.9) and in the ICU (12.3 ± 11.4 vs. 24.8 ± 17.5). IAP prior to the GI complication was (14.3 ± 3.1 vs. 15.8 ± 4.8) (p < 0.003). The best IAP value identified for EN intolerance was 14 mmHg but it had low sensitivity and specificity. Although a higher IAP was associated with EN intolerance, IAP alone did not emerge as a good predictor of EN intolerance in critically ill patients.

Lipoabdominoplasty: repercussions for diaphragmatic mobility and lung function in healthy women

Objective:

To evaluate the impact of lipoabdominoplasty on diaphragmatic mobility (DM) and lung function in healthy women.

Methods:

This was a prospective cohort study using high-resolution ultrasound and forced spirometry to assess DM and lung function, respectively, prior to lipoabdominoplasty, as well as on postoperative day (POD) 10 and POD 30. DM was measured under two conditions: during tidal volume breathing and during a VC maneuver.

Results:

The sample consisted of 20 women, with a mean age of 39.85 ± 7.52 years and a mean body mass index of 26.21 ± 2.0 kg/m². Comparing the preoperative and postoperative periods, we found that DM and lung function values were significantly lower after lipoabdominoplasty, the mean DM on POD 10 being 17% and 15% lower during tidal volume breathing and during the VC maneuver, respectively, in comparison with the preoperative mean (p = 0.009 and p < 0.001, respectively). In addition, FEV₁, FVC, and PEF were significantly lower on POD 10 than in the preoperative period (p = 0.046, p = 0.002, and p < 0.001, respectively), returning to preoperative values by POD 30.

Conclusions:

Lipoabdominoplasty appears to have negative short-term repercussions for DM and lung function in healthy women. However, lung function and DM are both apparently restored to preoperative conditions by POD 30. (ClinicalTrials.gov identifier: NCT02762526 [http://www.clinicaltrials.gov/])

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

BACKGROUND

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSION

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

MICU1 may be a promising intervention target for gut-derived sepsis induced by intra-abdominal hypertension

Intra-abdominal hypertension (IAH) is a common and serious complication in critically ill patients, for which there is no targeted therapy. IAH-induced dysfunction of intestinal barriers is closely associated with oxidative imbalances, which are considered to provide a pathophysiological basis for subsequent gut-derived sepsis. However, the upstream mechanism that produces oxidative damage during IAH remains unknown. It is not clear whether ‘mitochondrial Ca²⁺ uptake 1’ (MICU1, the key protein regulating the oxidative process) is involved in preventing Ca²⁺_m (mitochondrial Ca²⁺) overload. Here, we detected changes in the expression of MICU1 during the development of increased intestinal permeability in rats with IAH, and we explored the related mechanism regulating epithelial-barrier functions by knocking-down micu1 in Caco-2 cells. Our results demonstrated that, to combat IAH-induced dysfunction of intestinal barriers, MICU1 undergoes a compensatory increase in expression, whereas ‘mitochondrial calcium uniporter’ (MCU) – a conserved Ca²⁺ transporter – becomes transcriptionally suppressed. Silencing the expression of MICU1 destroyed Caco-2 cell barrier integrity, promoted paracellular permeability, and impaired the expression of tight junction proteins (occludin, ZO-1, and claudin 1). Meanwhile, oxidative imbalances were induced; malondialdehyde (MDA), a product of oxidation, was increased and antioxidant products (GSH-Px, CAT, and SOD) were decreased. In MICU1-deficient Caco-2 cells, proliferation was inhibited and apoptosis was promoted. Collectively, our results indicate that MICU1-related oxidation/antioxidation disequilibrium is strongly involved in IAH-induced damage to intestinal barriers. MICU1-targeted treatment may hold promise for preventing the progression of IAH to gut-derived sepsis.

Effects of acute intra-abdominal hypertension on multiple intestinal barrier functions in rats

Intra-abdominal hypertension (IAH) is a common and serious complication in critically ill patients for which there is no well-defined treatment strategy. Here, we explored the effect of IAH on multiple intestinal barriers and discussed whether the alteration in microflora provides clues to guide the rational therapeutic treatment of intestinal barriers during IAH. Using a rat model, we analysed the expression of tight junction proteins (TJs), mucins, chemotactic factors, and Toll-like receptor 4 (TLR4) by immunohistochemistry. We also analysed the microflora populations using 16S rRNA sequencing. We found that, in addition to enhanced permeability, acute IAH (20 mmHg for 90 min) resulted in significant disturbances to mucosal barriers. Dysbiosis of the intestinal microbiota was also induced, as represented by decreased Firmicutes (relative abundance), increased Proteobacteria and migration of Bacteroidetes from the colon to the jejunum. At the genus level, Lactobacillus species and Peptostreptococcaceae incertae sedis were decreased, whereas levels of lactococci remained unchanged. Our findings outline the characteristics of IAH-induced barrier changes, indicating that intestinal barriers might be treated to alleviate IAH, and the microflora may be an especially relevant target.

Intra-abdominal pressure: an integrative review

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

Amended Classification of the Open Abdomen

BACKGROUND

In 2009, a classification system for the open abdomen was introduced. The aim of such a classification is to aid the (1) description of the patient's clinical course; (2) standardization of clinical guidelines for guiding open abdomen management; and (3) facilitation of comparisons between studies and heterogeneous patient populations, thus serving as an aid in clinical research.

METHODS

As part of the revision of the definitions and clinical guidelines performed by the World Society of the Abdominal Compartment Syndrome, this 2009 classification system was amended following a review of experiences in teaching and research and published as part of updated consensus statements and clinical practice guidelines in 2013. Among 29 articles citing the 2009 classification system, nine were cohort studies. They were reviewed as part of the classification revision process. A total of 542 patients (mean: 60, range: 9-160) had been classified. Two problems with the previous classification system were identified: the definition of enteroatmospheric fistulae, and that an enteroatmospheric fistula was graded less severe than a frozen abdomen.

RESULTS

The following amended classification was proposed: Grade 1, without adherence between bowel and abdominal wall or fixity of the abdominal wall (lateralization), subdivided as follows: 1A, clean; 1B, contaminated; and 1C, with enteric leak. An enteric leak controlled by closure, exteriorization into a stoma, or a permanent enterocutaneous fistula is considered clean. Grade 2, developing fixation, subdivided as follows: 2A, clean; 2B, contaminated; and 2C, with enteric leak. Grade 3, frozen abdomen, subdivided as follows: 3A clean and 3B contaminated. Grade 4, an established enteroatmospheric fistula, is defined as a permanent enteric leak into the open abdomen, associated with granulation tissue.

CONCLUSIONS

The authors believe that, with these changes, the requirements on a functional and dynamic classification system, useful in both research and training, will be fulfilled. We encourage future investigators to apply the system and report on its merits and constraints.

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

Introduction

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

Materials and Methods

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

Results

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

Conclusion

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

Effect of taurine on intestinal recovery following intestinal ischemia-reperfusion injury in a rat

PURPOSE

Taurine (TAU) is a sulfur-containing amino acid that is involved in a diverse array of biological and physiological functions, including bile salt conjugation, osmoregulation, membrane stabilization, calcium modulation, anti-oxidation, and immunomodulation. Several studies have established that treatment with TAU significantly protects cerebral, cardiac and testicular injury from ischemia-reperfusion (IR). The purpose of the present study was to examine the effect of TAU on intestinal recovery and enterocyte turnover after intestinal IR injury in rats.

METHODS

Male Sprague-Dawley rats were divided into four experimental groups: (1) Sham rats that underwent laparotomy, (2) Sham-TAU rats that underwent laparotomy and were treated with intraperitoneal (IP) TAU (250 mg/kg); (3) IR-rats that underwent occlusion of both superior mesenteric artery and portal vein for 30 min followed by 48 h of reperfusion, and (4) IR-TAU rats that underwent IR and were treated with IP TAU (250 mg/kg) immediately before abdominal closure. Intestinal structural changes, Park's injury score, enterocyte proliferation and enterocyte apoptosis were determined 24 h following IR. The expression of Bax, Bcl-2, p-ERK and caspase-3 in the intestinal mucosa was determined using Western blot and immunohistochemistry.

RESULTS

Treatment with TAU resulted in a significant decrease in Park's injury score compared to IR animals. IR-TAU rats also demonstrated a significant increase in mucosal weight in jejunum and ileum, villus height in jejunum and ileum and crypt depth in ileum compared to IR animals. IR-TAU rats also experienced significantly lower apoptotic indices in jejunum and ileum which was accompanied by a higher Bcl-2/Bax ratio compared to IR animals.

CONCLUSIONS

Treatment with taurine prevents gut mucosal damage and inhibits intestinal epithelial cell apoptosis following intestinal IR in a rat.

TLR4-HMGB1-, MyD88- and TRIF-dependent signaling in mouse intestinal ischemia/reperfusion injury

AIM: To characterize high-mobility group protein 1-toll-like receptor 4 (HMGB1-TLR4) and downstream signaling pathways in intestinal ischemia/reperfusion (I/R) injury.

METHODS: Forty specific-pathogen-free male C57BL/6 mice were randomly divided into five groups (n = 8 per group): sham, control, anti-HMGB1, anti-myeloid differentiation gene 88 (MyD88), and anti-translocating-chain-associating membrane protein (TRIF) antibody groups. Vehicle with the control IgG antibody, anti-HMGB1, anti-MyD88, or anti-TRIF antibodies (all 1 mg/kg, 0.025%) were injected via the caudal vein 30 min prior to ischemia. After anesthetization, the abdominal wall was opened and the superior mesenteric artery was exposed, followed by 60 min mesenteric ischemia and then 60 min reperfusion. For the sham group, the abdominal wall was opened for 120 min without I/R. Levels of serum nuclear factor (NF)-κB p65, interleukin (IL)-6, and tumor necrosis factor (TNF)-α were measured, along with myeloperoxidase activity in the lung and liver. In addition,morphologic changes that occurred in the lung and intestinal tissues were evaluated. Levels of mRNA transcripts encoding HMGB1 and NF-κB were measured by real-time quantitative PCR, and levels of HMGB1 and NF-κB protein were measured by Western blot. Results were analyzed using one-way analysis of variance.

RESULTS: Blocking HMGB1, MyD88, and TRIF expression by injecting anti-HMGB1, anti-MyD88, or anti-TRIF antibodies prior to ischemia reduced the levels of inflammatory cytokines in serum; NF-κB p65: 104.64 ± 11.89, 228.53 ± 24.85, 145.00 ± 33.63, 191.12 ± 13.22, and 183.73 ± 10.81 (P < 0.05); IL-6: 50.02 ± 6.33, 104.91 ± 31.18, 62.28 ± 6.73, 85.90 ± 17.37, and 78.14 ± 7.38 (P < 0.05); TNF-α, 43.79 ± 4.18, 70.81 ± 6.97, 52.76 ± 5.71, 63.19 ± 5.47, and 59.70 ± 4.63 (P < 0.05) for the sham, control, anti-HMGB1, anti-MyD88, and anti-TRIF groups, respectively (all in pg/mL).Antibodies also alleviated tissue injury in the lung and small intestine compared with the control group in the mouse intestinal I/R model. The administration of anti-HMGB1, anti-MyD88, and anti-TRIF antibodies markedly reduced damage caused by I/R, for which anti-HMGB1 antibody had the most obvious effect.

CONCLUSION: HMGB1 and its downstream signaling pathway play important roles in the mouse intestinal I/R injury, and the effect of the TRIF-dependent pathway is slightly greater.

Omega-3 polyunsaturated fatty acids inhibit the increase in cytokines and chemotactic factors induced in vitro by lymph fluid from an intestinal ischemia-reperfusion injury model

OBJECTIVE

To investigate the active factors and the intervention effect of ω-3 polyunsaturated fatty acids (PUFAs) during intestinal ischemia-reperfusion (I/R) injury, which causes the inflammation of monocytes-macrophages cultured in lymph fluid and stimulated with ω-3 PUFAs.

METHODS

Forty-eight Sprague-Dawley male rats were randomly divided into the following two groups: A. (N + D) group and B. (I/R + D) group. The rats in the (N + D) group were drained of lymph for 180 min; the rats in the (I/R + D) group were subjected to 60 min ischemia by clamping the superior mesenteric artery followed by 120 min reperfusion and 180 min of lymph draining. Lymph fluid from each group was further divided into 4 subgroups, respectively: lymph group (A1, B1); eicosopentaenoic acid (EPA)-treated group (A2, B2); EPA + docosahexaeonic acid (DHA)-treated group (A3, B3); and DHA-treated group (A4, B4), then cultured monocyte-macrophage cell line.

RESULTS

The levels of tumor necrosis factor-α, interleukin (IL)-1 β, IL-6, soluble cell adhesion molecule-1, chemotactic factors macrophage chemoattractant protein-1, macrophage inflammatory protein-2, and high mobility group box protein 1 in the B1 group were significantly higher than in the A1 group. Importantly, addition of EPA, EPA + DHA, and DHA to the culture media significantly reduced the levels of the above-mentioned factors. Cell stimulation with EPA, EPA + DHA, and DHA also significantly decreased the expression of Toll-like receptor 4, nuclear factor-κB p65, macrophage chemoattractant protein-1, and macrophage inflammatory protein-2 with the combined treatment of EPA and DHA showing the strongest effect.

CONCLUSIONS

The factors induced in lymph during intestinal I/R injury can cause inflammation in vitro. These data provide in vitro evidence that ω-3 PUFAs provide a protective effect by reducing the inflammatory response caused by intestinal I/R lymph. Moreover, the synergism of EPA and DHA had the greatest effect, which is possibly mediated through Toll-like receptor 4 and nuclear factor-κB p65.

[«Surgical» analysis of the new clinical practice guide on compartmental syndrome]

The new published guidelines of compartment syndrome are supposed to be a helpful tool in order to make decisions in patients with abdominal hypertension. From a surgical perspective of view, an important effort has been made in order to reach consensus in different phases in which there is no clear answer in evidence-based medicine. It is mandatory the use of a universal classification of open abdomen and there are three main concepts that must be observed: make a decompressive laparotomy when conservative measures have failed, attempt to closure the abdomen as soon as possible and the use of negative-pressure treatments that facilitates the management of an open abdomen. Although most of recommendations that have been delivered are not high grades, the present guide is an important assistant for the management of intra-abdominal hypertension and several lines of investigation are opened in order to answer the doubts that have been addressed.

The Use of Laparostomy in Patients With Gynecologic Cancer: First Report From a UK Cancer Center

Objective

To report on the use of laparostomy after major gynecologic cancer surgery.

Methods

Operative records and surgical databases of patients who underwent major open abdominal surgery over a 6.5-year period at a tertiary referral center were searched. Patients who had diagnostic procedures, operative laparoscopy, and surgery for vulval cancer were excluded. All patients who had laparostomy were identified; and the diagnosis, indication for laparostomy, method of temporary cover, and complications were recorded.

Results

A total of 1592 laparotomies, including 37 emergencies, were performed. Of these, 14 patients (0.88%) had a laparostomy. Seven patients had primary cancer and 7 had recurrent cancer. As more patients had surgery for primary disease, laparostomy was more common in patients who underwent surgery for recurrent cancer. Seven patients had ovarian/fallopian tube/primary peritoneal cancer, 4 patients had uterine cancer, 2 patients had cervical cancer, and one patient had vaginal cancer. Ten laparostomies (71.4%) were performed after an emergency procedure; thus, laparostomy was approximately 100 times more common after emergency than elective major surgery. Massive bowel distension and bowel wall edema were the major indications for laparostomy. The method of temporary closure was variable, and a sterile saline bag was the most commonly used. The laparostomy was closed in all but 2 patients, most often on postoperative day 2 or 3. Two patients (14.3%) died within 30 days of the laparostomy, and 2 others died at postoperative days 40 and 62. Three of these 4 patients had recurrent cancer, and 2 patients had emergency procedures.

Conclusions

The overall incidence of laparostomy associated with laparotomy for gynecological cancer surgery was less than 1:100 cases, was more common after surgery for recurrent cancer, and in particular, was approximately 100 times more common after emergency procedures. The 30-day operative mortality rate was 14.3%.