Can the intestinal dysmotility of critical illness be differentiated from postoperative ileus?

Does Ileus Represent the Forgotten End Organ Failure in Critical Illness?

PURPOSE OF REVIEW

This review evaluates the current literature on ileus, impaired gastrointestinal transit (IGT), and acute gastrointestinal injury (AGI) and its impact on multiple organ dysfunction syndrome.

RECENT FINDINGS

Ileus is often under recognized in critically ill patients and is associated with significant morbidity and is potentially a marker of disease severity as seen in other organs like kidneys (ATN).

Radiographic and histopathological study of gastrointestinal dysmotility in lipopolysaccharide-induced sepsis in the rat

BACKGROUND

Sepsis is a highly incident condition in which a cascade of proinflammatory cytokines is involved. One of its most frequent consequences is ileus, which can increase mortality. Animal models such as that induced by systemic administration of lipopolysaccharide (LPS) are useful to deeply evaluate this condition. The effects of sepsis on the gastrointestinal (GI) tract have been explored but, to our knowledge, in vivo studies showing the motor and histopathological consequences of endotoxemia in an integrated way are lacking. Our aim was to study in rats the effects of sepsis on GI motility, using radiographic methods, and to assess histological damage in several organs.

METHODS

Male rats were intraperitoneally injected with saline or E. coli LPS at 0.1, 1, or 5 mg kg-1 . Barium sulfate was intragastrically administered, and X-rays were performed 0-24 h afterwards. Several organs were collected for organography, histopathology, and immunohistochemistry studies.

KEY RESULTS

All LPS doses caused gastroparesia, whereas changes in intestinal motility were dose-and time-dependent, with an initial phase of hypermotility followed by paralytic ileus. Lung, liver, stomach, ileum, and colon (but not spleen or kidneys) were damaged, and density of neutrophils and activated M2 macrophages and expression of cyclooxygenase 2 were increased in the colon 24 h after LPS 5 mg kg-1 .

CONCLUSIONS AND INFERENCES

Using radiographic, noninvasive methods for the first time, we show that systemic LPS causes dose-, time-, and organ-dependent GI motor effects. Sepsis-induced GI dysmotility is a complex condition whose management needs to take its time-dependent changes into account.

Mechanosensing in the Physiology and Pathology of the Gastrointestinal Tract

Normal gastrointestinal function relies on sensing and transducing mechanical signals into changes in intracellular signaling pathways. Both specialized mechanosensing cells, such as certain enterochromaffin cells and enteric neurons, and non-specialized cells, such as smooth muscle cells, interstitial cells of Cajal, and resident macrophages, participate in physiological and pathological responses to mechanical signals in the gastrointestinal tract. We review the role of mechanosensors in the different cell types of the gastrointestinal tract. Then, we provide several examples of the role of mechanotransduction in normal physiology. These examples highlight the fact that, although these responses to mechanical signals have been known for decades, the mechanosensors involved in these responses to mechanical signals are largely unknown. Finally, we discuss several diseases involving the overstimulation or dysregulation of mechanotransductive pathways. Understanding these pathways and identifying the mechanosensors involved in these diseases may facilitate the identification of new drug targets to effectively treat these diseases.

Gut Microbiota and Probiotics/Synbiotics for Modulation of Immunity in Critically Ill Patients

Patients suffering from critical illness have host inflammatory responses against injuries, such as infection and trauma, that can lead to tissue damage, organ failure, and death. Modulation of host immune response as well as infection and damage control are detrimental factors in the management of systemic inflammation. The gut is the motor of multiple organ failure following injury, and it is recognized that gut dysfunction is one of the causative factors of disease progression. The gut microbiota has a role in maintaining host immunity, and disruption of the gut microbiota might induce an immunosuppressive condition in critically ill patients. Treatment with probiotics and synbiotics has been reported to attenuate systemic inflammation by maintaining gut microbiota and to reduce postoperative infectious complications and ventilator-associated pneumonia. The administration of prophylactic probiotics/synbiotics could be an important treatment option for preventing infectious complications and modulating immunity. Further basic and clinical research is needed to promote intestinal therapies for critically ill patients.

Are Classic Bedside Exam Findings Required to Initiate Enteral Nutrition in Critically Ill Patients: Emphasis on Bowel Sounds and Abdominal Distension

The general physical examination of a patient is an axiom of critical care medicine, but evidence to support this practice remains sparse. Given the lack of evidence for a comprehensive physical examination of the entire patient on admission to the intensive care unit, which most clinicians consider an essential part of care, should clinicians continue the practice of a specialized gastrointestinal system physical examination when commencing enteral nutrition in critically ill patients? In this review of literature related to gastrointestinal system examination in critically ill patients, the focus is on gastrointestinal sounds and abdominal distension. There is a summary of what these physical features represent, an evaluation of the evidence regarding use of these physical features in patients after abdominal surgery, exploration of the rationale for and against using the physical findings in routine practice, and detail regarding what is known about each feature in critically ill patients. Based on the available evidence, it is recommended that an isolated symptom, sign, or bedside test does not provide meaningful information. However, it is submitted that a comprehensive physical assessment of the gastrointestinal system still has a role when initiating or administering enteral nutrition: specifically, when multiple features are present, clinicians should consider further investigation or intervention.

Promotility agents for the treatment of ileus in adult surgical patients: A practice management guideline from the Eastern Association for the Surgery of Trauma

BACKGROUND

Ileus is a common challenge in adult surgical patients with estimated incidence to be 17% to 80%. The main mechanisms of the postoperative ileus pathophysiology are fluid overload, exogenous opioids, neurohormonal dysfunction, gastrointestinal stretch, and inflammation. Management includes addressing the underlying cause and supportive care. Multiple medical interventions have been proposed, but effectiveness is uncertain. A working group of the Eastern Association for the Surgery of Trauma aimed to evaluate the effectiveness of metoclopramide, erythromycin, and early enteral nutrition (EEN) on ileus in adult surgical patients and to develop recommendations applicable in a daily clinical practice.

METHODS

Literature search identified 45 articles appropriate for inclusion. The Grading of Recommendations Assessment, Development and Evaluation methodology was applied to evaluate the effect of metoclopramide, erythromycin, and EEN on the resolution of ileus in adult surgical patients based on selected outcomes: return of normal bowel function, attainment of enteral feeding goal, and hospital length of stay. The recommendations were made based on the results of a systematic review, a meta-analysis, and evaluation of levels of evidence.

RESULTS

The level of evidence for all PICOs was assessed as low. Neither metoclopramide nor erythromycin were effective in expediting the resolution of ileus. Analyses of 32 randomized controlled trials showed that EEN facilitates return of normal bowel function, achieving enteral nutrition goals, and reducing hospital length of stay.

CONCLUSION

In patients who have undergone abdominal surgery, we strongly recommend EEN to expedite resolution of Ileus, but we cannot recommend for or against the use of either metoclopramide or erythromycin to hasten the resolution of ileus in these patients.

LEVEL OF EVIDENCE

Type of Study Therapeutic, level II.

Interstitial cells of Cajal are diminished in critically ill patients: Autopsy cases

OBJECTIVE

Gastrointestinal dysmotility in critically ill patients is important as enteral nutrition is crucial. However, normal gut motility is impaired under conditions of critical illness subsequent to severe insult. Interstitial cells of Cajal (ICC) form an extensive network associated with the myenteric plexus in the enteric nervous system. There are few reports about ICC distribution in critically ill patients. The aim of this study was to evaluate ICC in critically ill patients.

METHODS

Postmortem colon harvest was obtained from critically ill patients. Control specimens were obtained from patients without bowel movement problems who underwent hemicolectomy. The tissues were stained with c-Kit for ICC. The number of ICC was identified by counting from 10 high-power fields (HPFs).

RESULTS

Specimens from six patients were analyzed and compared with those from six control patients. All patients had abnormalities of crypt architecture and inflammatory cell infiltrations. Mucosal thickness tended to be lower in the critically ill patients than in the controls (147 ± 47 versus 231 ± 127 μm; P = 0.15). Muscle layer thickness tended to be higher in the critically ill patients than in the controls (494 ± 163 versus 394 ± 258 μm; P = 0.44). ICC in the critically ill patients were almost depleted in the colon compared with those in the controls. Significantly fewer ICC were present in the critically ill patients than in the controls (0.45 versus 7.25 cells/HPF; P < 0.05).

CONCLUSIONS

Critical illness is associated with diminished numbers of ICC in the colon. This finding could have implications for dysmotility in critically ill patients.

Targeting IL-17A Improves the Dysmotility of the Small Intestine and Alleviates the Injury of the Interstitial Cells of Cajal during Sepsis

Intestinal dysmotility is a frequent complication during sepsis and plays an important role in the development of secondary infections and multiple organ failure. However, the central mechanisms underlying this process have not been well elucidated. Currently, effective therapies are still lacking for the treatment of sepsis-induced intestinal dysmotility. In this study, we found that the activation of IL-17 signaling within the muscularis propria might be associated with dysmotility of the small intestine during polymicrobial sepsis. Furthermore, we demonstrated that targeting IL-17A partially rescued the motility of the small intestine and alleviated interstitial cells of Cajal (ICC) injury during sepsis. The blockade of IL-17A suppressed the dominant sepsis-induced infiltration of M1-polarized macrophages into the muscularis. Additionally, impaired ICC survival may be associated with the oxidative stress injury induced by dominant infiltration of M1-polarized macrophages. Our findings reveal the important role of the IL-17 signaling pathway in the small intestine during sepsis and provide clues for developing a novel therapeutic strategy for treating gastrointestinal dysmotility during sepsis.

Association of prophylactic synbiotics with reduction in diarrhea and pneumonia in mechanically ventilated critically ill patients: A propensity score analysis

INTRODUCTION

The preventive association of synbiotics therapy has not been thoroughly clarified in mechanically ventilated patients. The purpose of this study was to evaluate whether synbiotics therapy has preventive association against septic complications in ventilated critically ill patients.

METHODS

Critically ill patients who were mechanically ventilated were included in this retrospective observational study. Patients who received synbiotics (Bifidobacterium breve, Lactobacillus casei, and galactooligosaccharides) within 3 days after admission (denoted as synbiotics group) were compared with patients who did not receive synbiotics. The incidences of enteritis, pneumonia, and bacteremia were evaluated as clinical outcome. Enteritis was defined as an acute onset of diarrhea consisting of continuous liquid watery stools for more than 12 h. The confounding factors include APACHE II on admission, gender, the cause of admission and antibiotics.

RESULTS

We included 179 patients in this study: 57 patients received synbiotics and 122 patients did not receive synbiotics. The incidences of enteritis were significantly lower in the synbiotics group compared with the control group (3.5% vs. 15.6%; p < 0.05). The odds ratios for diarrhea-free days during the first 28 days for the synbiotics group as compared with the controls were 4.354 (95% confidence interval (CI), 2.407 to 7.877; p < 0.001) in an ordinal logistic regression model with propensity scores. The odds ratios for pneumonia-free days during the first 28 days for the synbiotics group were 2.529 (95% CI, 1.715 to 3.731; p < 0.001). The incidences of bacteremia did not have significant differences.

CONCLUSION

Prophylactic synbiotics appeared to have preventive association on enteritis and pneumonia in mechanically ventilated critically ill patients.

Effects of Rhubarb on Intestinal Dysmotility in Critically Ill Patients

Intestinal dysmotility is a major problem in critically ill patients. This report describes the successful treatment of intestinal dysmotility with rhubarb as a laxative in six critically ill patients on mechanical ventilation. Bowel movement and defecation occurred in all patients an average of 1.8 days after the administration of powdered rhubarb. In 4 patients who also had gastric reflux, the reflux volume via nasal tube was decreased an average of 3.5 days after the initiation of rhubarb treatment, and enteral nutrition was able to be started. Rhubarb may be useful for the treatment of incompetent gastric and intestinal motility in critically ill patients.

Barriers and Solutions to Delivery of Intensive Care Unit Nutrition Therapy

Despite recommendations for early enteral nutrition (EN) in critically ill patients, numerous factors contribute to incomplete delivery of EN, including insufficient nutrition risk screening in critically ill patients, underutilization of enteral feeding protocols, fixed rate-based enteral infusion targets with frequent EN interruption, and suboptimal provider practices regarding nutrition support therapy. The purpose of this narrative review is to identify common barriers to optimizing and delivering nutrition in critically ill patients, and suggest strategies and solutions to overcome barriers.

In Search of the Ideal Promotility Agent: Optimal Use of Currently Available Promotility Agents for Nutrition Therapy of the Critically Ill Patient

PURPOSE OF REVIEW

Enteral nutrition therapy is essential in the management of critically ill patients. Prokinetic agents have been used successfully to aid in the delivery of nutrition and improve feeding tolerance in patients in the intensive care unit (ICU). The aim of this report is to review the existing promotility agents available for use in the critically ill as well as outline the role of potential investigative drugs in order to provide a guide to the management of this difficult and important clinical dilemma.

RECENT FINDINGS

While no single currently available agent currently meets all of the desired goals in the critical care setting, there are an increasing number of available agents from which to choose including motilin receptor agonists, 5HT4 receptor agonists, D2 receptor antagonists, and Mu opioid receptor antagonists. We recommend a multifaceted approach to optimizing enteral nutrition in the critical care setting which should include the early, prophylactic use of promotility agents and should focus on the management of reversible causes of impaired gastrointestinal motility.

Critically ill patients and gut motility: Are we addressing it?

Gastrointestinal (GI) dysmotility is a common problem in the critically ill population. It can be a reflection and an early sign of patient deterioration or it can be an independent cause of morbidity and mortality. GI dysmotility can be divided for clinical purposes on upper GI dysmotility and lower GI dysmotility. Upper GI dysmotility manifests by nausea, feeding intolerance and vomiting; its implications include aspiration into the airway of abdominal contents and underfeeding. Several strategies to prevent and treat this condition can be tried and they include prokinetics and post-pyloric feeds. It is important to note that upper GI dysmotility should be treated only when there are clinical signs of intolerance (nausea, vomiting) and not based on measurement of gastric residual volumes. Lower GI dysmotility manifests throughout the spectrum of ileus and diarrhea. Ileus can present in the small bowel and the large bowel as well. In both scenarios the initial treatment is correction of electrolyte abnormalities, avoiding drugs that can decrease motility and patient mobilization. When this fails, in the case of small bowel ileus, lactulose and polyethylene glycol solutions can be useful. In the case of colonic pseudo obstruction, neostigmine, endoscopic decompression and cecostomy can be tried when the situation reaches the risk of rupture. Diarrhea is also a common manifestation of GI dysmotility and the most important step is to differentiate between infectious sources and non-infectious sources.

Inhaled hydrogen ameliorates endotoxin-induced bowel dysfunction

Aim

Gastrointestinal dysmotility frequently occurs during sepsis and multiple organ failure, remaining a major cause of morbidity and mortality in critically ill patients. Previous studies have shown that hydrogen, a new therapeutic gas, can improve various organ damage associated with sepsis. In this study, we investigated the protective efficacies of inhaled hydrogen against lipopolysaccharide (LPS)‐induced ileus.

Methods

Sepsis was induced in rats and mice by a single i.p. injection of LPS at 15 mg/kg for mice and 5 mg/kg for rats. Four groups of rats and mice including sham/air, sham/hydrogen, LPS/air, and LPS/hydrogen were analyzed. Hydrogen (1.3%) was inhaled for 25 h beginning at 1 h prior to LPS treatment. Gastrointestinal transit was quantified and cytokine levels, as well as neutrophil extravasation, in the intestinal muscularis propria were determined.

Results

Lipopolysaccharide challenge remarkably delayed gastrointestinal transit of non‐absorbable dextran, associated with increased leukocyte recruitment and upregulation of pro‐inflammatory cytokine mRNA expressions in the muscularis propria. Hydrogen significantly prevented LPS‐induced bowel dysmotility and reduced leukocyte extravasation, as well as inhibition of inflammatory cytokine expression. In vitro analysis of cytokine levels after LPS treatment of cultured macrophages showed an increase of interleukin‐10 by hydrogen regardless of the presence of nitric oxide.

Conclusions

This study showed the protective effects of hydrogen inhalation on LPS‐induced septic ileus through inhibition of inflammation in the muscularis propria. These inhibitory effects on the pro‐inflammatory response may be partially derived from anti‐inflammatory cytokine interleukin‐10 induction.

Enteral Nutrition for Adults in the Hospital Setting

In patients unable to tolerate oral intake, multiple options of nutrient delivery are available to the clinician. Administration of enteral nutrition (EN) has long been considered the standard of care for nutrition support among patients unable to meet energy and protein requirements orally. Healthcare practitioners must make careful decisions related to ordering, administering, and monitoring EN therapy. In the hospital setting, the registered dietitian is a key resource in enteral formula selection and method of administration, monitoring for and troubleshooting EN-related complications, and transitioning to oral feeding. The hospital setting also presents many unique challenges in providing optimal nutrition to the enterally fed patient.

Gradual sucrose gastric loading test: A method for the prediction of nonsuccess gastric enteral feeding in critically ill surgical patients

Background and Aims:

Intolerance of gastric enteral feeding (GEN) commonly occurs in surgical Intensive Care Unit (SICU). A liquid containing sugar could prolong gastric emptying time. This study was to propose a method for prediction of nonsuccess GEN using gastric volume after loading (GVAL) following gradual sucrose gastric loading.

Materials and Methods:

Mechanical ventilator supported and hemodynamically stable patients in SICU were enrolled. About 180-240 min before the GEN starting, a sucrose solution (12.5%; 450 mosmole/kg, 800 mL) was administered via gastric feeding tube over 30 min with 45° head upright position. GVAL was measured at 30, 60, 90, and 120 min after loading. GEN success status using clinical criteria was assessed at 72 h after the starting GEN protocol. The receiving operating characteristic (ROC) and c statistic were used for discrimination at each time point of GVAL.

Results:

A total of 32 patients were enrolled and completed the protocol. 14 patients (43.7%) were nonsuccessful GEN. The nonsuccess group was found to have significantly more GVAL than the other group at all-time points during the test (P < 0.05). The most discriminating point of GVAL for the prediction of nonsuccess was 150 mL at 120 min after loading with a sensitivity of 92.3%, specificity of 88.9%, positive predictive value of 85.7%, negative predictive value of 94.1%, and ROC area 0.97 (95% confidence interval 0.91–1.00).

Conclusion:

A high GVAL following sucrose gastric loading test might be a method to predict nonsuccess GEN in critically ill surgical patients.

Is enteral feeding tolerated during therapeutic hypothermia?

OBJECTIVE

To determine whether patients undergoing therapeutic hypothermia following cardiac arrest tolerate early enteral nutrition.

METHODS

We undertook a single-centre longitudinal cohort analysis of the tolerance of enteral feeding by 55 patients treated with therapeutic hypothermia following resuscitation from cardiac arrest. The observation period was divided into three phases: (1) 24h at target temperature (32-34 °C); (2) 24h rewarming to 36.5 °C; and (3) 24h maintained at a core temperature below 37.5 °C.

RESULTS

During period 1, patients tolerated a median of 72% (interquartile range (IQR) 68.7%; range 31.3-100%) of administered feed. During period 2 (rewarming phase), a median of 95% (IQR 66.2%; range 33.77-100%) of administered feed was tolerated. During period 3 (normothermia) a median of 100% (IQR 4.75%; range 95.25-100%) of administered feed was tolerated. The highest incidence of vomiting or regurgitation of feed (19% of patients) occurred between 24 and 48 h of therapy.

CONCLUSIONS

Patients undergoing therapeutic hypothermia following cardiac arrest may be able to tolerate a substantial proportion of their daily nutritional requirements. It is possible that routine use of prokinetic drugs during this period may increase the success of feed delivery enterally and this could usefully be explored.

Gastrointestinal motility problems in critical care: a clinical perspective

Advances in surgery, anesthesia and intensive care have led to a dramatic increase in the number of patients who spend time in our intensive care units (ICU). Gastrointestinal (GI) motility disorders are common complications in the intensive care setting and are predictors of increased mortality and length of the stay in the ICU. Several risk factors for developing GI motility problems in the ICU setting have been identified and include sepsis, being on mechanical ventilation and the use of vasopressors, opioids or anticholinergic medications. Our focus is on the most common clinical manifestations of GI motor dysfunction in the ICU patient: gastroesophageal reflux, gastroparesis, ileus and acute pseudo-obstruction of the colon.

Perioperative nutrition: what is the current landscape?

Poor nutrition status has long been linked to increases in postoperative complications and adverse outcomes for the patient undergoing elective surgery. While optimal planning for nutrition therapy should be comprehensive spanning throughout the perioperative period, recent advances have focused on the concept of "prehabilitation" to best prepare the patient prior to the insult of surgery. Adding immune/metabolic modulating formulas the week of surgery with carbohydrate drinks to optimize glycogen deposition immediately prior to surgery, enhances patient recovery and return to baseline function. Such nutrition strategies should now be combined with a host of other practices (such as smoking cessation, weight loss, glucose control, and specialized exercise program) as part of a structured protocol to maximize patients' chances for a full and rapid recovery from their elective surgical procedure.

Patients requiring perioperative nutritional support

One of the most important factors affecting outcome and recovery from surgical trauma is preoperative nutritional status. Research in perioperative nutritional support has suffered from a lack of consensus as to the definition of malnutrition, no recognition of which nutrients are important to surgical healing, and a paucity of well-designed studies. In the past decade, there has been some activity to address this situation, recognizing the importance of nutrition as a therapy before surgery, after surgery, and possibly even during surgery.