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

Is monitoring of gastric residual volume for critically ill patients with enteral nutrition necessary? A meta-analysis and systematic review

BACKGROUND

There are many controversies over the necessity of monitoring gastric residual volume in the nursing care of enteral nutrition. We aimed to conduct an updated meta-analysis to evaluate the effects of monitoring or not monitoring gastric residual volume on patients' outcomes and complications.

METHODS

We searched the Cochrane Library database to 15 April 2021 for randomized controlled trials (RCTs) on the effects of gastric residual volume and no gastric residual volume monitoring. Review Manager software was used for data analysis.

RESULTS

A total of seven RCTs involving 1240 enteral nutrition patients were included. Gastric residual volume monitoring was associated with reduced incidence of vomiting (OR2.33, 95% CI:1.68-3.24), whereas no gastric residual volume monitoring was associated with reduced incidence of unnecessary interruptions of enteral nutrition (OR0.38,95% CI:0.26-0.55). There were no significant differences on the incidence of abdominal distention (OR1.87, 95% CI:0.82-4.28), diarrhoea (OR1.03,95% CI:0.74-1.43), VAP (OR0.83, 95%CI:0.37-1.89), duration of mechanical ventilation (MD -0.06,95% CI:-1.22-1.10), length of ICU stay (MD -1.33, 95% CI:-3.58-0.91) and mortality (OR0.90,95% CI:0.61-1.34).

CONCLUSIONS

Not monitoring gastric residual volume is associated with reduced unnecessary interruptions of enteral nutrition related to inadequate feeding and increased risk of vomiting.

ESPEN practical and partially revised guideline: Clinical nutrition in the intensive care unit

Following the new ESPEN Standard Operating Procedures, the previous 2019 guideline to provide best medical nutritional therapy to critically ill patients has been shortened and partially revised. Following this update, we propose this publication as a practical guideline based on the published scientific guideline, but shortened and illustrated by flow charts. The main goal of this practical guideline is to increase understanding and allow the practitioner to implement the Nutrition in the ICU guidelines. All the items discussed in the previous guidelines are included as well as special conditions.

Estimating the time point for nutritional failure in patients suffering from acute brain attacks in the intensive care unit

BACKGROUND

Severe brain attack patients demonstrate hypermetabolic state and gastrointestinal dysfunction, leading to faster onset of nutritional failure.

AIM

To estimate the time point where the development of nutritional failure is more probable among patients with acute brain attacks in the intensive care unit (ICU).

METHODS

Direct bedside observation for selected nutritional parameters was performed. When enteral nutrition was initiated, observation was performed at five points over 9 days.

FINDINGS

84 patients with 55% mortality risk and on mechanical ventilation were included. Over the observation period, gastric residual volume increased (144 ml vs 196 ml), body weight decreased (79.4 kg vs 74.3 kg), and serum albumin reduced (3.6 g/dl to 3.1 g/dl). Caloric attainment and malnutrition score deteriorated, and feeding-related complications increased. Nutritional failure was evidently prevalent between the third and fifth day of observation.

CONCLUSION

An earlier period of enteral nutrition entails higher probability of nutritional failure among severe brain attack patients in the ICU.

Gut dysmotility in the ICU: diagnosis and therapeutic options

PURPOSE OF REVIEW

To provide a comprehensive update of diagnosis and treatment of gastrointestinal dysmotility in the critically ill, with a focus on work published in the last 5 years.

RECENT FINDINGS

Symptoms and clinical features consistent with upper and/or lower gastrointestinal dysmotility occur frequently. Although features of gastrointestinal dysmotility are strongly associated with adverse outcomes, these associations may be because of unmeasured confounders. The use of ultrasonography to identify upper gastrointestinal dysmotility appears promising. Both nonpharmacological and pharmacological approaches to treat gastrointestinal dysmotility have recently been evaluated. These approaches include modification of macronutrient content and administration of promotility drugs, stool softeners or laxatives. Although these approaches may reduce features of gastrointestinal dysmotility, none have translated to patient-centred benefit.

SUMMARY

'Off-label' metoclopramide and/or erythromycin administration are effective for upper gastrointestinal dysmotility but have adverse effects. Trials of alternative or novel promotility drugs have not demonstrated superiority over current pharmacotherapies. Prophylactic laxative regimens to prevent non-defecation have been infrequently studied and there is no recent evidence to further inform treatment of established pseudo-obstruction. Further trials of nonpharmacological and pharmacological therapies to treat upper and lower gastrointestinal dysmotility are required and challenges in designing such trials are explored.

Effects of not monitoring gastric residual volume in intensive care patients: A meta-analysis

BACKGROUND

Monitoring gastric residual volume has been a common practice in intensive care patients receiving enteral feeding worldwide. Recent studies though, have challenged the reliability and necessity of this routine monitoring process. Several studies even reported improvements in the delivery of enteral feeding without monitoring gastric residual volume, while incurring no additional adverse events. However, the benefit of monitoring gastric residual volume remains controversial in intensive care patients.

OBJECTIVE

The aim of this review is to identify the effects of not monitoring gastric residual volume in intensive care patients through a meta-analysis of the data pooled from published studies that meet our inclusion criteria.

DESIGN

A systematic review DATA SOURCES: An electronic search of Embase, Pubmed, and the Cochrane Library was completed up to April 2018. The data included basic population characteristics, related complications, mortality, duration of mechanical ventilation and intensive care unit length of stay.

REVIEW METHODS

Eligibility and methodological quality of the studies were assessed by two researchers independently according to the Joanna Briggs Institute guidelines. The Review Manager Software was used to calculate the pooled risk ratio (RR), weighted mean difference, and the corresponding 95% confidential interval (95% CI). Sensitivity analyses were done by excluding each study. Publication bias analyses were conducted to avoid the exaggerated effect of the overall estimates.

RESULTS

Five studies involving 998 patients were included in this meta-analysis. Compared with monitoring gastric residual volume, not monitoring gastric residual volume decreased the rate of feeding intolerance in critically ill patients (RR = 0.61, 95%CI 0.51-0.72), and did not result in an increment in the rate of mortality (RR = 0.97, 95%CI 0.73-1.29, P = 0.84) or the rate of ventilator-associated pneumonia (RR = 1.03, 95%CI 0.74-1.44, P = 0.85). There were also no differences in the duration of mechanical ventilation (MD = 0.09, 95%CI, -0.99 to 1.16, P = 0.88) or intensive care unit length of stay (MD=-0.18, 95%CI, -1.52 to 1.17, P = 0.79).

CONCLUSION

Except for an increased risk of vomiting, the absence of monitoring gastric residual volume was not inferior to routine gastric residual volume monitoring in terms of feeding intolerance development, mortality, and ventilator-associated pneumonia in intensive care patients. There is encouraging evidence that not measuring gastric residual volume does not induce additional harm to the patients. More multicenter, randomized clinical trials are required to verify these findings.

ESPEN guideline on clinical nutrition in the intensive care unit

Following the new ESPEN Standard Operating Procedures, the previous guidelines to provide best medical nutritional therapy to critically ill patients have been updated. These guidelines define who are the patients at risk, how to assess nutritional status of an ICU patient, how to define the amount of energy to provide, the route to choose and how to adapt according to various clinical conditions. When to start and how to progress in the administration of adequate provision of nutrients is also described. The best determination of amount and nature of carbohydrates, fat and protein are suggested. Special attention is given to glutamine and omega-3 fatty acids. Particular conditions frequently observed in intensive care such as patients with dysphagia, frail patients, multiple trauma patients, abdominal surgery, sepsis, and obesity are discussed to guide the practitioner toward the best evidence based therapy. Monitoring of this nutritional therapy is discussed in a separate document.

Gastric residual volume measurement in the intensive care unit: an international survey reporting nursing practice

BACKGROUND

Gastric residual volume measurement is routinely used to evaluate the feeding tolerance and gastro-oesophageal reflux in patients receiving enteral feeding therapy in the intensive care unit. However, little supportive evidence for this intervention is available as the usefulness of gastric residual volume measurements in patients receiving enteral feeding therapy in the intensive care is controversial.

AIM

The aim of this study was to assess the practice of intensive care unit nurses related to gastric residual volume measurement in patients receiving enteral nutrition.

METHODS

A survey was conducted among a sample of intensive care unit nurses (n = 832) from four hospitals in Turkey (n = 182) and attendees of the Annual Congress of the Flemish Society for Critical Care Nurses in Flanders, Belgium (n = 650). The survey instrument was developed by the researchers based on the related literature.

RESULTS

A total of 480 nurses completed the questionnaire (response rate = 73%). Gastric residual volume is measured by 98·0% of respondents, with wide variations in the frequency of measuring. A 50-200 mL gastric residual volume is considered problematic by 45·5% (n = 183) of the participants, and only 18·4% (n = 81) reported their practice to be based on a current guideline. Strikingly, more experienced intensive care unit nurses appear to perform gastric residual volume measurements more commonly than their less experienced colleagues (p = 0·004), while the practice is more often reported to be performed in Belgium than in Turkey (p < 0·001).

CONCLUSION

Gastric residual volume management could be improved by applying current evidence to daily nursing practice.

RELEVANCE TO CLINICAL PRACTICE

Our results show that increased awareness of these guidelines by nurses is needed to reduce inefficient use of working time and resources, streamline clinical practices and improve patient outcomes. Current gastric residual volume measurement guidelines and up-to-date, relevant training should be provided to nurses.

Measuring gastric residual volumes in critically ill burn patients - A systematic review

PURPOSE

Measuring gastric residual volumes (GRV) is common in intensive care units (ICU) in patients receiving enteral nutrition (EN) and are a common source of feeding interruptions. Interruptions in EN yield adverse outcomes and are an area of improvement in burn care. The objectives of this study are to summarize the literature's ICU GRV practices and offer practical suggestions to GRV management in the burn patient.

METHODS

PubMed, SCOPUS, and OvidSP Medline were systematically reviewed using the keywords: burns; thermal injury; gastric residual volume; enteral feeding; tube feeding; enteral nutrition; gastric intolerance; ICU; critical illness. Reviews, case reports, and consensus and opinion papers were excluded.

RESULTS

26 articles were identified. Six burn-specific studies were identified. GRV practices vary widely and are a common cause of EN interruption. Elevated GRVs do not equate to gastrointestinal intolerance and do not always reflect aspiration risk.

CONCLUSIONS

We advocate a GRV threshold of 500mL should be used to optimize the benefits of EN in burn ICUs. A single incident of elevated GRVs should not mandate immediate EN rate reduction or cessation but should prompt a thoughtful examination of secondary causes of gastrointestinal intolerance. Randomized controlled trials are needed to define the ideal GRV threshold and re-evaluate its role in burn care.

Routine gastric residual volume measurement and energy target achievement in the PICU: a comparison study

Critically ill children frequently fail to achieve adequate energy intake, and some care practices, such as the measurement of gastric residual volume (GRV), may contribute to this problem. We compared outcomes in two similar European Paediatric Intensive Care Units (PICUs): one which routinely measures GRV (PICU-GRV) to one unit that does not (PICU-noGRV). An observational pilot comparison study was undertaken. Eighty-seven children were included in the study, 42 (PICU-GRV) and 45 (PICU-noGRV). There were no significant differences in the percentage of energy targets achieved in the first 4 days of PICU admission although PICU-noGRV showed more consistent delivery of median (and IQR) energy targets and less under and over feeding for PICU-GRV and PICU-noGRV: day 1 37 (14-72) vs 44 (0-100), day 2 97 (53-126) vs 100 (100-100), day 3 84 (45-112) vs 100 (100-100) and day 4 101 (63-124) vs 100 (100-100). The incidence of vomiting was higher in PICU-GRV. No necrotising enterocolitis was confirmed in either unit, and ventilator-acquired pneumonia rates were not significantly different (7.01 vs 12 5.31 per 1000 ventilator days; p = 0.70) between PICU-GRV and PICU-noGRV units.

CONCLUSIONS

The practice of routine gastric residual measurement did not significantly impair energy targets in the first 4 days of PICU admission. However, not measuring GRV did not increase vomiting, ventilator-acquired pneumonia or necrotising enterocolitis, which is the main reason clinicians cite for measuring GRV. What is known: • The practice of routinely measuring gastric residual volume is widespread in critical care units • This practice is increasingly being questioned in critically ill patients, both as a practice that increases • The likelihood of delivering inadequate enteral nutrition amounts and as a tool to assess feeding tolerance What is new: • Not routinely measuring gastric residual volume did not increase adverse events of ventilator acquired pneumonia, necrotising enterocolitis or vomiting. • In the first 4 days of PICU stay, energy target achievement was not significantly different, but the rates of under and over feeding were higher in the routine GRV measurement unit.

Electroacupuncture Improves Gastric Emptying in Critically Ill Neurosurgical Patients: A Pilot Study

Objective

To compare the efficacy of combined electroacupuncture and metoclopramide treatment with that of metoclopramide only in improving gastric emptying in critically ill neurosurgical patients.

Methods

In this prospective case-control pilot study, a total of 16 adult critically ill mechanically ventilated patients who were treated in the surgical intensive care unit were enrolled. Electrical stimulation was applied to 4 pairs of points (maximum intensity < 9.8 mA at 2 Hz). Patients in the control group received standard treatment with intravenous metoclopramide only. Patients in the experimental group received intravenous metoclopramide plus electroacupuncture treatment once daily for 6 consecutive days.

Results

Gastric residual volume in the experimental group (n = 7) reduced gradually until the fourth day after treatment with electroacupuncture combined with routine metoclopramide administration. Beginning on the fourth day, residual volume was maintained at less than 200 ml per day for the following two days. In the control group (n = 9), there was a gradual reduction in residual volume during the first four days followed by a rebounding increase over the next two days.

Conclusions

Electroacupuncture combined with intravenous metoclopramide is a more effective treatment for gastric emptying than metoclopramide alone in adult critically ill patients with impaired brain function.

Enteral nutrition in the prevention and treatment of pressure ulcers in adult critical care patients

Prevention and healing of pressure ulcers in critically ill patients can be especially challenging because of the patients' burden of illness and degree of physiological compromise. Providing adequate nutrition may help halt the development or worsening of pressure ulcers. Optimization of nutrition can be considered an essential ingredient in prevention and healing of pressure ulcers. Understanding malnutrition in critical care patients, the effect of nutrition on wound healing, and the application of evidence-based nutritional guidelines are important aspects for patients at high risk for pressure ulcers. Appropriate screenings for nutritional status and risk for pressure ulcers, early collaboration with a registered dietician, and administration of appropriate feeding formulations and micronutrient and macronutrient supplementation to promote wound healing are practical solutions to improve the nutritional status of critical care patients. Use of nutritional management and enteral feeding protocols may provide vital elements to augment nutrition and ultimately result in improved clinical outcomes.

Gastroesophageal reflux in critically ill patients

Gastroesophageal reflux (GER) is a common occurrence in critically ill, mechanically ventilated patients. Reflux can lead to pulmonary aspiration of gastric contents and subsequent pneumonia. Several characteristics of patients, interventions provided in the intensive care unit setting, and factors associated with feeding increase a patient's risk for reflux. Critical care nurses and clinical nurse specialists can identify patients at highest risk for GER by utilizing the patient's history, reviewing the medications, and assessing the current status to provide interventions to reduce the risk of GER and its sequelae of aspiration pneumonia. This article reviews the physiology of GER, risk factors, and interventions to decrease GER in the critically ill patient.

A novel protein mixture containing vegetable proteins renders enteral nutrition products non-coagulating after in vitro gastric digestion

BACKGROUND & AIMS

Non-coagulation of protein from enteral nutrition (EN) in the stomach is considered to improve gastric emptying and may result in reduced upper gastrointestinal complications such as reflux and aspiration pneumonia. For the development of a new EN protein mixture with reduced gastric coagulation, the coagulating properties of individual proteins, a novel blend of four proteins (P4 protein blend) and commercial EN products were investigated.

METHODS

A semi-dynamic, computer controlled setup was developed to mimic gastric digestion. The coagulation behaviour of 150 ml protein solutions and EN products was investigated. These were heat-treated calcium caseinate, sodium caseinate, whey, soy and pea protein, and the P4 protein blend comprising of the latter four (all solutions 6% w/v protein), four new enteral nutrition product varieties (New Nutrison® .0 or 1.5 kcal/ml, with and without MultiFibre MF6™) based on the P4 protein blend and two other commercially available casein dominant EN products (T1 and T2).

RESULTS

Calcium caseinate and sodium caseinate yielded a total wet coagulate of 43.5 ± 0.7 g and 52.7 ± 6.2 g, respectively. Whey, soy, pea and the P4 protein blend did not produce any measurable coagulate. T1 and T2 resulted in a total wet coagulate of 37.5 ± 0.8 g and 57.3 ± 0.8 g, respectively, while all new EN product varieties based on the P4 protein blend did not produce any measurable coagulate.

CONCLUSIONS

The P4 protein blend renders EN product varieties non-coagulating after in vitro gastric digestion.

Role of disease and macronutrient dose in the randomized controlled EPaNIC trial: a post hoc analysis

RATIONALE

Early parenteral nutrition to supplement insufficient enteral feeding during intensive care (early PN) delays recovery as compared with withholding parenteral nutrition for 1 week (late PN).

OBJECTIVES

To assess whether deleterious effects of early PN relate to severity of illness or to the dose or type of macronutrients.

METHODS

Secondary analyses of a randomized controlled trial (EPaNIC; n = 4,640) performed in seven intensive care units from three departments in two Belgian hospitals. In part 1, all patients were included to assess the effect of the randomized allocation to early PN or late PN in subgroups of patients with increasing-on-admission severity of illness. In part 2, observationally, the association of the amount and type of macronutrients with recovery was documented in those patient cohorts still present in intensive care on Days 3, 5, 7, 10, and 14.

MEASUREMENTS AND MAIN RESULTS

The primary end point was time to live discharge from the intensive care unit. For part 1, a secondary end point, acquisition of new infections, was also analyzed. All statistical analyses were performed by univariable and adjusted multivariable methods. In none of the subgroups defined by type or severity of illness was a beneficial effect of early PN observed. The lowest dose of macronutrients was associated with the fastest recovery and any higher dose, administered parenterally or enterally, was associated with progressively more delayed recovery. The amount of proteins/amino acids rather than of glucose appeared to explain delayed recovery with early feeding.

CONCLUSIONS

Early combined parenteral/enteral nutrition delayed recovery irrespective of severity of critical illness. No dose or type of macronutrient was found to be associated with improved outcome. Clinical trial registered with www.clinicaltrials.gov (NCT 00512122).

Optimal timing for the initiation of enteral and parenteral nutrition in critical medical and surgical conditions

The early provision of nutrients as part of specialized therapy for critically ill patients admitted for critical medical and surgical conditions is recommended by various international guidelines. Enteral nutrition is the first option and should be initiated 24-48 h after admission to an intensive care unit. Even after gastrointestinal anastomosis, early oral or enteral feeding is not only safe but also associated with enhanced recovery and fewer complications. Recent studies showed that the use of an enteral diet or parenteral nutrition that contains immune nutrients enhances the recovery of critically ill patients. Although the precise caloric target remains controversial, the general consensus advocates the avoidance of prolonged hypocaloric or hypercaloric feeding. However, there is still debate about the timing of the initiation of parenteral nutrition when enteral nutrition either is impossible or does not meet the nutritional goals. Although controversy remains, two recent studies showed that when enteral feeding is not feasible the early initiation of parenteral nutrition was not associated with palpable benefit.

Monitoring for intolerance to gastric tube feedings: a national survey

BACKGROUND

Confusion about how to assess for intolerance to feedings often results in unnecessary feeding interruptions.

OBJECTIVES

To report findings from a national survey of methods used by critical care nurses to assess tolerance to gastric tube feedings and to discuss the findings in light of current enteral nutrition guidelines.

METHODS

A paper-and-pencil survey was mailed to 1909 members of the American Association of Critical-Care Nurses. In addition, the same survey was posted online in a newsletter circulated to association members. Results from both surveys were pooled for data analysis.

RESULTS

A total of 2298 responses were obtained; most respondents reported using a combination of methods to assess tolerance to gastric tube feedings (listening for bowel sounds, measuring gastric residual volumes, observing for abdominal distention/discomfort and for nausea and vomiting). More than 97% of the nurses reported measuring gastric residual volumes; the most frequently cited threshold levels for interrupting feedings were 200 mL and 250 mL. About 25% of the nurses reported interrupting feedings for gastric residual volumes of 150 mL or less; only 12.6% of the respondents reported allowing gastric residual volumes of up to 500 mL before interrupting feedings.

CONCLUSIONS

Practice among the 2298 critical care nurses varied widely. Many of the survey respondents are practicing in ways that can unnecessarily diminish the delivery of calories to patients. Protocols based on current enteral nutrition guidelines must be developed and implemented in practice settings.

Metabolic conditioning to attenuate the adverse effects of perioperative fasting and improve patient outcomes

PURPOSE OF REVIEW

To review recent articles, published between October 2009 and September 2011, that examined the adverse metabolic consequences of perioperative fasting and interventions that may be utilized to minimize these effects.

RECENT FINDINGS

Fasting induces metabolic stress and insulin resistance consequent upon effects on cellular mitochondria, gene and protein expression. Development of perioperative insulin resistance leads to increased postoperative morbidity and mortality. Preoperative carbohydrate loading attenuates insulin resistance via effects on cellular gene and protein expression, but its effects on clinical outcomes remain unclear. Perioperative arginine-supplemented diets were shown to be associated with significant reductions in infectious complications and length of hospital stay in patients undergoing elective surgery. Perioperative metabolic conditioning using glutamine and L-carnitine may be used to modulate insulin sensitivity but further studies need to determine whether these interventions result in clinical benefit. Finally, energy and protein provision to critically ill patients remains inadequate and is hampered by a number of factors including reliance on inaccurate means of estimating energy expenditure and enteral feed tolerance, conflicting data on the effects of energy deficit on clinical outcomes, and poor methodological quality of studies of perioperative nutritional interventions.

SUMMARY

Numerous perioperative interventions are available, which if utilized should help attenuate the adverse effects of perioperative fasting and lead to improved patient outcomes.

Enteral nutrition: better navigation, yet unknown destination?

The nutrition dose truly absorbed by a patient is crucial information in the management or the investigation of nutrition during critical illness. In the present issue of Critical Care, assessment of nutritional losses in stools was studied. These losses together with enteral nutrition lost in gastric fluids and enteral nutrition prescribed but never infused make up the difference between the dose supposedly given to a patient and the amount effectively taken up. Additionally, the optimal dosing and timing of nutrition during critical illness are still debated. When enteral nutrition is insufficient, the options are limited.