It's all in the gut: introducing the concept of acute bowel injury and acute intestinal distress syndrome

Effect of opioids on constipation in critically ill patients: A meta-analysis

OBJECTIVES

This meta-analysis evaluated the effect of opioids on constipation in ICU patients.

REVIEW METHOD USED

Systematic review and meta-analysis.

DATA SOURCES

PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), and Wanfang DATA databases.

REVIEW METHODS

Random or fixed-effects meta-analyses were used. Subgroup analysis was performed according to the definition of constipation (three vs. six days), opioids (fentanyl vs. morphine), study design (prospective vs. retrospective), adjustment of confounders (No vs. Yes), and patient's age (adults vs. children). We used sensitivity analysis to test the robustness of results with significant statistical heterogeneity.

RESULTS

Seven studies (2264 patients) were included. Opioid use in ICU patients was associated with an increased risk of constipation (relative risk [RR]=1.14; 95% confidence interval [CI]=1.05 to 1.24; I2=49.8%). Subgroup analysis further showed that adjustment form, category of opioid, study design, and patient's age significantly influenced the relationship between opioid use and the risk of constipation. Sensitivity analysis confirmed the robustness of pooled results.

CONCLUSION

Opioids significantly increase the risk of constipation in critically ill patients, especially children. It is worth noting that the adjustment of the constipation definition used for ICU significantly influenced the relationship between opioid use and the risk of constipation. Therefore, It is necessary to clearly define ICU constipation and conduct time-based layered treatment. Additional prospective studies are needed to investigate the consistent definition of ICU constipation.

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

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

Intra-abdominal hypertension and abdominal compartment syndrome in pediatrics. A review

PURPOSE

To consolidate pediatric intensivists' understanding of the pathophysiology, definition, incidence, monitoring, and management of intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS); and to highlight the characteristics related to the pediatric population.

METHODS

This is a narrative review article that utilized a systematic search of the medical literature published in the English language between January 1990 and august 2016. Studies were identified by conducting a comprehensive search of Pub Med databases. Search terms included "intra-abdominal hypertension and child", "intra-abdominal hypertension and pediatrics", "abdominal compartment syndrome and child", and "abdominal compartment syndrome and pediatrics".

RESULTS

Intra-abdominal hypertension and ACS are associated with a number of pathophysiological disturbances and increased morbidity and mortality. These conditions have been well described in critically ill adults. In children, the IAH and the ACS have a reported incidence of 13% and 0.6 to 10% respectively; they carry similar prognostic impact but are still under-diagnosed and under-recognized by pediatric health care providers.

CONCLUSIONS

Intra-abdominal hypertension and ACS are conditions that are regularly encountered in critically ill children. They are associated with an increased morbidity and mortality. Early recognition, prevention and timely management of this critical condition are necessary to improve its outcome.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

The Michigan Appropriateness Guide for Intravenous Catheters (MAGIC): Results From a Multispecialty Panel Using the RAND/UCLA Appropriateness Method

Use of peripherally inserted central catheters (PICCs) has grown substantially in recent years. Increasing use has led to the realization that PICCs are associated with important complications, including thrombosis and infection. Moreover, some PICCs may not be placed for clinically valid reasons. Defining appropriate indications for insertion, maintenance, and care of PICCs is thus important for patient safety. An international panel was convened that applied the RAND/UCLA Appropriateness Method to develop criteria for use of PICCs. After systematic reviews of the literature, scenarios related to PICC use, care, and maintenance were developed according to patient population (for example, general hospitalized, critically ill, cancer, kidney disease), indication for insertion (infusion of peripherally compatible infusates vs. vesicants), and duration of use (≤5 days, 6 to 14 days, 15 to 30 days, or ≥31 days). Within each scenario, appropriateness of PICC use was compared with that of other venous access devices. After review of 665 scenarios, 253 (38%) were rated as appropriate, 124 (19%) as neutral/uncertain, and 288 (43%) as inappropriate. For peripherally compatible infusions, PICC use was rated as inappropriate when the proposed duration of use was 5 or fewer days. Midline catheters and ultrasonography-guided peripheral intravenous catheters were preferred to PICCs for use between 6 and 14 days. In critically ill patients, nontunneled central venous catheters were preferred over PICCs when 14 or fewer days of use were likely. In patients with cancer, PICCs were rated as appropriate for irritant or vesicant infusion, regardless of duration. The panel of experts used a validated method to develop appropriate indications for PICC use across patient populations. These criteria can be used to improve care, inform quality improvement efforts, and advance the safety of medical patients.

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.

Intestinal ischemia following laparoscopic surgery: a case series

Introduction

Intestinal ischemia is a rare complication of laparoscopic surgery. Its prognosis depends on a high index of suspicion and effective early treatment.

Case presentation

In the present report, we describe three cases where intestinal ischemia developed following laparoscopic surgery. Case 1 concerns a 52-year-old Caucasian man who developed large bowel ischemia following laparoscopic adjustable gastric band surgery. Case 2 concerns an 82-year-old Caucasian woman who developed fatal intestinal ischemia following laparoscopic cholecystectomy. Case 3 concerns a 58-year old Caucasian woman who developed right-sided lower intestinal ischemia following open cholecystectomy.

Conclusions

Intestinal ischemia is a rare complication of laparoscopic surgery. The identification of high-risk patients is an essential primary preventive measure. A high index of suspicion is required to make an early diagnosis, which may help improve outcomes.

Toward computational identification of multiscale "tipping points" in acute inflammation and multiple organ failure

Sepsis accounts annually for nearly 10% of total U.S. deaths, costing nearly $17 billion/year. Sepsis is a manifestation of disordered systemic inflammation. Properly regulated inflammation allows for timely recognition and effective reaction to injury or infection, but inadequate or overly robust inflammation can lead to Multiple Organ Dysfunction Syndrome (MODS). There is an incongruity between the systemic nature of disordered inflammation (as the target of inflammation-modulating therapies), and the regional manifestation of organ-specific failure (as the subject of organ support), that presents a therapeutic dilemma: systemic interventions can interfere with an individual organ system's appropriate response, yet organ-specific interventions may not help the overall system reorient itself. Based on a decade of systems and computational approaches to deciphering acute inflammation, along with translationally-motivated experimental studies in both small and large animals, we propose that MODS evolves due to the feed-forward cycle of inflammation → damage → inflammation. We hypothesize that inflammation proceeds at a given, "nested" level or scale until positive feedback exceeds a "tipping point." Below this tipping point, inflammation is contained and manageable; when this threshold is crossed, inflammation becomes disordered, and dysfunction propagates to a higher biological scale (e.g., progressing from cellular, to tissue/organ, to multiple organs, to the organism). Finally, we suggest that a combination of computational biology approaches involving data-driven and mechanistic mathematical modeling, in close association with studies in clinically relevant paradigms of sepsis/MODS, are necessary in order to define scale-specific "tipping points" and to suggest novel therapies for sepsis.

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.

Peritoneal negative pressure therapy prevents multiple organ injury in a chronic porcine sepsis and ischemia/reperfusion model

Sepsis and hemorrhage can result in injury to multiple organs and is associated with an extremely high rate of mortality. We hypothesized that peritoneal negative pressure therapy (NPT) would reduce systemic inflammation and organ damage. Pigs (n = 12) were anesthetized and surgically instrumented for hemodynamic monitoring. Through a laparotomy, the superior mesenteric artery was clamped for 30 min. Feces was mixed with blood to form a fecal clot that was placed into the peritoneum, and the abdomen was closed. All subjects were treated with standard isotonic fluid resuscitation, wide spectrum antibiotics, and mechanical ventilation, and were monitored for 48 h. Animals were separated into two groups 12 h (T12) after injury: for NPT (n = 6), an abdominal wound vacuum dressing was placed in the laparotomy, and negative pressure (-125 mmHg) was applied (T12 - T48), whereas passive drainage (n = 6) was identical to the NPT group except the abdomen was allowed to passively drain. Negative pressure therapy removed a significantly greater volume of ascites (860 ± 134 mL) than did passive drainage (88 ± 56 mL). Systemic inflammation (e.g. TNF-α, IL-1β, IL-6) was significantly reduced in the NPT group and was associated with significant improvement in intestine, lung, kidney, and liver histopathology. Our data suggest NPT efficacy is partially due to an attenuation of peritoneal inflammation by the removal of ascites. However, the exact mechanism needs further elucidation. The clinical implication of this study is that sepsis/trauma can result in an inflammatory ascites that may perpetuate organ injury; removal of the ascites can break the cycle and reduce organ damage.

A clinically applicable porcine model of septic and ischemia/reperfusion-induced shock and multiple organ injury

BACKGROUND

Although many sepsis treatments have shown efficacy in acute animal models, at present only activated protein C is effective in humans. The likely reason for this discrepancy is that most of the animal models used for preclinical testing do not accurately replicate the complex pathogenesis of human sepsis. Our objective in this study was to develop a clinically applicable model of severe sepsis and gut ischemia/reperfusion (I/R) that would cause multiple organ injury over a period of 48 h.

MATERIALS AND METHODS

Anesthetized, instrumented, and ventilated pigs were subjected to a "two-hit" injury by placement of a fecal clot through a laparotomy and by clamping the superior mesenteric artery (SMA) for 30 min. The animals were monitored for 48 h. Wide spectrum antibiotics and intravenous fluids were given to maintain hemodynamic status. FiO(2) was increased in response to oxygen desaturation. Twelve hours following injury, a drain was placed in the laparotomy wound. Extensive hemodynamic, lung, kidney, liver, and renal function measurements and serial measurements of arterial and mixed venous blood gases were made. Bladder pressure was measured as a surrogate for intra-peritoneal pressure to identify the development of the abdominal compartment syndrome (ACS). Plasma and peritoneal ascites cytokine concentration were measured at regular intervals. Tissues were harvested and fixed at necropsy for detailed morphometric analysis.

RESULTS

Polymicrobial sepsis developed in all animals. There was a progressive deterioration of organ function over the 48 h. The lung, kidney, liver, and intestine all demonstrated clinical and histopathologic injury. Acute lung injury (ALI) and ACS developed by consensus definitions. Increases in multiple cytokines in serum and peritoneal fluid paralleled the dysfunction found in major organs.

CONCLUSION

This animal model of Sepsis+I/R replicates the systemic inflammation and dysfunction of the major organ systems that is typically seen in human sepsis and trauma patients. The model should be useful in deciphering the complex pathophysiology of septic shock as it transitions to end-organ injury thus allowing sophisticated preclinical studies on potential treatments.

Constipation in long-term ventilated patients: associated factors and impact on intensive care unit outcomes

OBJECTIVES

To characterize the factors associated with delayed defecation in long-term ventilated patients and to examine the relationship between delayed defecation and logistic organ dysfunction scores, acquired bacterial infections, and mortality in the intensive care unit.

DESIGN

Prospective observational cohort study.

SETTING

A 21-bed polyvalent intensive care unit in a university hospital.

PATIENTS

A total of 609 adult patients admitted over a 41-month period who underwent mechanical ventilation for ≥ 6 days.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Three hundred fifty-three patients (58%) passed stools ≥ 6 days after they were admitted to the intensive care unit ("late" defecation). Patients with early and late defecation had similar general characteristics when admitted to the intensive care unit and had similar logistic organ dysfunction scores on the first day of mechanical ventilation. Several variables were independently associated with a delay in defecation: a Pao2/Fio2 ratio of less than 150 mm Hg (adjusted hazard ratio 1.40; 95% confidence interval: 1.06-1.60; p = .0073), a systolic blood pressure between 70 and 89 mm Hg (adjusted hazard ratio 1.48; 95% confidence interval: 1.17-1.79; p = .002), and systolic blood pressure < 68 mm Hg (adjusted hazard ratio 1.29; 95% confidence interval: 1.01-1.60; p = .03). Logistic organ dysfunction scores were significantly higher on the fourth and ninth days of mechanical ventilation in patients with late defecation than in those with early defecation. The crude intensive care unit mortality rate was 18% in patients with early defecation and 30% in patients with late defecation (p < .001). Acquired bacterial infections at any site occurred in 34% of patients with early defecation and 66% of patients with late defecation (p < .001).

CONCLUSION

A Pao2/Fio2 ratio of < 150 mm Hg and systolic blood pressure of < 90 mm Hg during the first 5 days of mechanical ventilation were independently associated with a delay in defecation. Our results suggest that constipation is associated with adverse outcomes in long-term ventilated patients.