Motility disorders in the ICU: recent therapeutic options and clinical practice

Should I Start With A Postpyloric Enteral Nutrition Modality?

Nutrition therapy is a key element in the management of malnourished and critically ill patients. Although many aspects of enteral nutrition (EN) have been well defined by research, with clear recommendations by 3 major society guidelines, EN delivery method remains a topic for debate. The goal of this manuscript is to concisely review gastric vs postpyloric enteral feeding in critically ill adult patients and provide a set of recommendations to individualize EN delivery method based on patient characteristics and specific needs.

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.

Is There a Role for Enterohormones in the Gastroparesis of Critically Ill Patients?

OBJECTIVES

Delayed gastric emptying occurs in critically ill patients and impairs the delivery, digestion, and absorption of enteral feeding. A pathophysiologic role of the enterohormones peptide YY and ghrelin is supported by preclinical data. To compare the circulating plasma levels of peptide YY and ghrelin in control subjects and in critically ill patients, during feeding and fasting, and to search for a correlation with gastric emptying.

DESIGN

A prospective observational trial.

SETTINGS

Mixed ICU of an academic hospital.

SUBJECTS

Healthy volunteers and patients expected to stay in ICU for at least 3 days in whom enteral nutrition was indicated.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Plasma peptide YY and ghrelin (enzyme-linked immunosorbent assay) were measured once in 10 fasting volunteers (controls) and daily from admission until day 5 of the ICU stay in 30 critically ill patients (median [interquartile range] age 63 [57-67] yr, median [interquartile range] Acute Physiology and Chronic Health Evaluation II score 21 [14-24]). Eight patients could not be fed (fasting group). In fed patients, 13 never had a gastric residual volume higher than 250 mL (low gastric residual volume group), in contrast to the high gastric residual volume group (n = 9). The plasma levels of peptide YY did not differ between patients (6.4 [0-18.1] pg/mL) and controls (4.8 [0.3-17.7] pg/mL). Ghrelin levels were lower in patients than in control (213 [54.4-522.7] vs 1,435 [1,321.9-1,869.3] pg/mL; p < 0.05). Plasma peptide YY or ghrelin did not differ between fasting and fed patients or between the high and low gastric residual volume groups.

CONCLUSIONS

In critically ill patients, plasma concentration of ghrelin significantly differs from that of controls, irrespective of the feeding status. No correlation was found between the temporal profile of ghrelin or peptide YY plasma concentration with bedside functional assessment of gastric emptying.

ACG Clinical Guideline: Nutrition Therapy in the Adult Hospitalized Patient

The value of nutrition therapy for the adult hospitalized patient is derived from the outcome benefits achieved by the delivery of early enteral feeding. Nutritional assessment should identify those patients at high nutritional risk, determined by both disease severity and nutritional status. For such patients if they are unable to maintain volitional intake, enteral access should be attained and enteral nutrition (EN) initiated within 24-48 h of admission. Orogastric or nasogastric feeding is most appropriate when starting EN, switching to post-pyloric or deep jejunal feeding only in those patients who are intolerant of gastric feeds or at high risk for aspiration. Percutaneous access should be used for those patients anticipated to require EN for >4 weeks. Patients receiving EN should be monitored for risk of aspiration, tolerance, and adequacy of feeding (determined by percent of goal calories and protein delivered). Intentional permissive underfeeding (and even trophic feeding) is appropriate temporarily for certain subsets of hospitalized patients. Although a standard polymeric formula should be used routinely in most patients, an immune-modulating formula (with arginine and fish oil) should be reserved for patients who have had major surgery in a surgical ICU setting. Adequacy of nutrition therapy is enhanced by establishing nurse-driven enteral feeding protocols, increasing delivery by volume-based or top-down feeding strategies, minimizing interruptions, and eliminating the practice of gastric residual volumes. Parenteral nutrition should be used in patients at high nutritional risk when EN is not feasible or after the first week of hospitalization if EN is not sufficient. Because of their knowledge base and skill set, the gastroenterologist endoscopist is an asset to the Nutrition Support Team and should participate in providing optimal nutrition therapy to the hospitalized adult patient.

Prophylaxis Versus Treatment Use of Laxative for Paralysis of Lower Gastrointestinal Tract in Critically Ill Patients

GOALS

To evaluate the prevalence of lower gastrointestinal tract paralysis and to compare the success to achieve defecation between treatment and prophylaxis strategies.

BACKGROUND

Laxatives use is commonly the first-level measure to achieve defecation in critically ill patients with lower gastrointestinal tract paralysis. Studies comparing prophylaxis versus treatment of lower gastrointestinal tract paralysis have not been performed yet.

STUDY

We designed 3 sequential phases of 4 months each: observational phase, treatment phase, and prophylaxis phase. First-level measure was intermittent polyethylene glycol (PEG) 4000 by nasogastric tube. Second-level measures were enema, neostigmine, and continuous PEG. Primary endpoints were the prevalence of constipation for the observational phase and the number of patients that failed to achieve defecation with first-level measures for the treatment and prophylaxis phases.

RESULTS

Paralysis of lower gastrointestinal tract in the observational phase was found in 57 of 63 patients (90.5%). Failure to achieve defecation with the first-level measure occurred in 16 of 64 patients (25%) in the treatment phase and in 6 of 70 patients (8.6%) in the prophylaxis phase (P=0.01). Eighteen measures of second level were applied in the treatment phase and 6 in the prophylaxis phase.

CONCLUSIONS

Paralysis of the lower gastrointestinal tract in mechanically ventilated ICU patients is common. PEG given as prophylaxis on the first day after mechanical ventilation is associated with faster resolution of paralysis of gastrointestinal tract than PEG given as a treatment on day 4.

Analysis of bowel sounds application status for gastrointestinal function monitoring in the intensive care unit

The auscultation of bowel sounds (BS) has been neglected as a reliable tool for determining gastrointestinal (GI) functioning in the critically ill patient. This article considers the validity of BS auscultation in the assessment and management of critically ill patients and outlines how the information may be utilized for monitoring GI function. A descriptive, cross-sectional design with self-administered questionnaires was used to survey 132 nurses and 38 doctors in the 6 general intensive care units in Beijing hospitals. Descriptive statistics and chi-square test analyses were used to assess the level of knowledge about BS among Chinese doctors and nurses and to determine how they applied their BS auscultation findings in the care of critically ill patients. Bowel sounds were found to be the primary indicator for determining GI functioning in the unconscious, critically ill patient. However, only 11.4% of nurses and 47.6% of doctors could make correct clinical judgments on the basis of their auscultatory findings. The attitudes of nurses and doctors differed significantly on whether BS auscultation was needed to monitor GI function for unconscious patients. Bowel sounds auscultation remains an important indicator of GI function. Distinct and feasible standards regarding BS auscultation and results interpretation need to be established.

Gastric feeding intolerance is not caused by mucosal ischemia measured by intragastric air tonometry in the critically ill

BACKGROUND

Gastric mucosal ischemia may be a risk factor for gastrointestinal intolerance to early feeding in the critically ill.

AIMS

To study intragastric PCO2 air tonometry and gastric residual volumes (GRV) before and after the start of gastric feeding.

METHODS

This is a two-center study in intensive care units of a university and teaching hospital. Twenty-nine critically ill, consecutive and consenting patients scheduled to start gastric feeding were studied after insertion of a gastric tonometry catheter and prior to and after start of gastric feeding (500 ml over 1 h), when clinically indicated.

RESULTS

Blood gasometry and intragastric tonometry were performed prior to and 2 h after gastric feeding. The intragastric to arterial PCO2 gap (normal <8 mm Hg) was elevated in 41% of patients prior to feeding and measured (mean ± standard deviation) 13 ± 20 and 16 ± 23 mm Hg in patients with normal (<100 ml, 42 ± 34 ml, n = 19) and elevated GRV (250 ± 141 ml, n = 10, P = 0.75), respectively. After feeding, the gradient did not increase and measured 27 ± 25 and 23 ± 34 mm Hg, respectively (P = 0.80).

CONCLUSION

Gastric mucosal ischemia is not a major risk factor for intolerance to early gastric feeding in the critically ill.

Impaired gastrointestinal transit and its associated morbidity in the intensive care unit

PURPOSE

To determine the proportion of critically ill adults developing impaired gastrointestinal transit (IGT) using a clinically pragmatic definition, its associated morbidity and risk factors.

MATERIALS AND METHODS

Critically ill adult patients receiving enteral nutrition for ≥ 72 hours and mechanically ventilated for ≥ 48 hours were prospectively identified. IGT was defined as absence of a bowel movement for ≥ 3 days, treatment for constipation, and one of the following: (1) radiologic confirmed ileus, (2) feed intolerance, (3) abdominal distention, or (4) gastric decompression.

RESULTS

One thousand patients were screened, and 248 were included for analysis. Fifty patients (20.1%; 95% confidence interval, 15.1-25.6%) developed IGT persisting for 6.5 ± 2.5 days. Patients with IGT had longer lengths of intensive care unit stay and were less likely to reach nutrition targets compared to patients without IGT or traditional definitions of constipation. Daily opioid use and pharmacological constipation prophylaxis were identified risk factors for IGT.

CONCLUSION

Traditional definitions of constipation or ileus in intensive care unit patients are simplistic and lack clinical relevance. Pragmatically defined IGT is a common complication of critical illness and is associated with significant morbidity. Future interventional studies for IGT in critically ill adults should use a more clinically relevant definition and evaluate energy deficits and lengths of stay as clinically relevant outcomes.

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.

Practicalities of nutrition support in the intensive care unit: the usefulness of gastric residual volume and prokinetic agents with enteral nutrition

The provision of early nutrition therapy to critically ill patients is established as the standard of care in most intensive care units around the world. Despite the known benefits, tolerance of enteral nutrition in the critically ill varies and delivery is often interrupted. Observational research has demonstrated that clinicians deliver little more than half of the enteral nutrition they plan to provide. The main clinical tool for assessing gastric tolerance is gastric residual volume; however, its usefulness in this setting is debated. There are several strategies employed to improve the tolerance and hence adequacy of enteral nutrition delivery in the critically ill. One of the most widely used strategies is that of prokinetic drug administration, most commonly metoclopramide and erythromycin. Although there are new agents being investigated, none are ready for routine application in the critically ill and the benefits are still being established. This review investigates current practice and considers the literature on assessment of enteral tolerance and optimization of enteral nutrition in the critically ill.

Drug-induced acute liver failure and gastrointestinal complications

The objective of this article is to describe adverse drug events related to the liver and gastrointestinal tract in critically ill patients. PubMed and other resources were used to identify information related to drug-induced acute liver failure, gastrointestinal hypomotility, constipation, diarrhea, gastrointestinal bleeding, and pancreatitis in critically ill patients. This information was reviewed, and data regarding pathophysiology, common drug causes, and guidelines for prevention and management were collected and summarized. In cases in which data in critically ill patients were unavailable, data were extrapolated from other patient populations. Drug-induced acute liver failure can be caused by many drugs routinely used in the intensive care unit and may be associated with significant morbidity and mortality. Drug-related hypomotility and constipation and drug-related diarrhea are reported with many drugs, and these are common adverse drug events in critically ill patients that can substantially complicate the care of these patients. Drug-induced gastrointestinal bleeding and drug-induced pancreatitis occur less frequently, can range in disease severity, and can be associated with morbidity and mortality. Many drugs used in critically ill patients are associated with adverse drug events related to the liver and gastrointestinal tract. Critical care clinicians should be aware of common drug causes of drug-induced acute liver failure, gastrointestinal hypomotility, constipation, diarrhea, gastrointestinal bleeding, and pancreatitis, and should be familiar with the prevention and management of these diverse conditions.

Critical illness, gastrointestinal complications, and medication therapy during enteral feeding in critically ill adult patients

Critically ill patients who are subjected to high stress or with severe injury can rapidly break down their body protein and energy stores. Unless adequate nutrition is provided, malnutrition and protein wasting may occur, which can negatively affect patient outcome. Enteral nutrition (EN) is the mainstay of nutrition support therapy in patients with a functional gastrointestinal (GI) tract who cannot take adequate oral nutrition. EN in critically ill patients provides the benefits of maintaining gut functionality, integrity, and immunity as well as decreasing infectious complications. However, the ability to provide timely and adequate EN to critically ill patients is often hindered by GI motility disorders and complications associated with EN. This paper reviews the GI complications and intolerances associated with EN in critically ill patients and provides recommendations for their prevention and treatment. It also addresses the role of commonly used medications in the intensive care unit and their impact on GI motility and EN delivery.

Tight glycaemic control: clinical implementation of protocols

Implementation of tight glycaemic control in hospitalised patients presents a huge challenge. It concerns many patients, there are many interfering factors and many health-care professionals are involved. The current literature provides little practical guidance. This article offers the clinical anesthesiologist direction for the organisation of inpatient blood glucose control in acute situations, in the perioperative setting and in the intensive care unit. An effective, safe and user-friendly algorithm for intravenous insulin administration is presented that can be executed by regular nurses and used in many situations. Practical advice is offered for the use of subcutaneous basal-bolus insulin, for fasting orders and for transition to discharge care. The main safety considerations are discussed.

Effectiveness of an aspiration risk-reduction protocol

BACKGROUND

Aspiration of gastric contents is a serious problem in critically ill, mechanically ventilated patients receiving tube feedings.

OBJECTIVES

The purpose of this study was to evaluate the effectiveness of a three-pronged intervention to reduce aspiration risk in a group of critically ill, mechanically ventilated patients receiving tube feedings.

METHODS

A two-group quasi-experimental design was used to compare outcomes of a usual care group (December 2002-September 2004) with those of an Aspiration Risk-Reduction Protocol (ARRP) group (January 2007-April 2008). The incidence of aspiration and pneumonia was compared between the usual care group (n = 329) and the ARRP group (n = 145). The ARRP had three components: maintaining head-of-bed elevation at 30 degrees or higher, unless contraindicated; inserting feeding tubes into distal small bowel, when indicated; and using an algorithmic approach for high gastric residual volumes.

RESULTS

Two of the three ARRP components were implemented successfully. Almost 90% of the ARRP group had mean head-of-bed elevations of 30 degrees or higher as compared to 38% in the usual care group. Almost three fourths of the ARRP group had feeding tubes placed in the small bowel as compared with less than 50% in the usual care group. Only three patients met the criteria for the high gastric residual volume algorithm. Aspiration was much lower in the ARRP group than that in the usual care group (39% vs. 88%, respectively). Similarly, pneumonia was much lower in the ARRP group than that in the usual care group (19% vs. 48%, respectively).

DISCUSSION

Findings from this study suggest that a combination of a head-of-bed position elevated to at least 30 degrees and use of a small-bowel feeding site can reduce the incidence of aspiration and aspiration-related pneumonia dramatically in critically ill, tube-fed patients.