Prescribed hypocaloric nutrition support for critically‐ill adults

This Cochrane Systematic Review by Perman and colleagues was published in June 2018.  The full text of the systematic review is available via this link.

Background:  There are controversies about the amount of calories and thecochrane-57-1 type of nutritional support that should be given to critically‐ill people. Several authors advocate the potential benefits of hypocaloric nutrition support, but the evidence is inconclusive.

Objectives:  To assess the effects of prescribed hypocaloric nutrition support in comparison with standard nutrition support for critically‐ill adults.

Search methods:  We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Cochrane Library), MEDLINE, Embase and LILACS (from inception to 20 June 2017) with a specific strategy for each database. We also assessed three websites, conference proceedings and reference lists, and contacted leaders in the field and the pharmaceutical industry for undetected/unpublished studies. There was no restriction by date, language or publication status.
Selection criteria:  We included randomized and quasi‐randomized controlled trials comparing hypocaloric nutrition support to normo‐ or hypercaloric nutrition support or no nutrition support (e.g. fasting) in adults hospitalized in intensive care units (ICUs).
Data collection and analysis:  We used standard methodological procedures expected by Cochrane. We meta‐analysed data for comparisons in which clinical heterogeneity was low. We conducted pre-specified subgroup and sensitivity analyses, and post hoc analyses, including meta‐regression. Our primary outcomes were: mortality (death occurred during the ICU and hospital stay, or 28‐ to 30‐day all‐cause mortality); length of stay (days stayed in the ICU and in the hospital); and Infectious complications. Secondary outcomes included: length of mechanical ventilation. We assessed the quality of evidence with GRADE.
Main results:  We identified 15 trials, with a total of 3129 ICU participants from university‐associated hospitals in the USA, Colombia, Saudi Arabia, Canada, Greece, Germany and Iran. There are two ongoing studies. Participants suffered from medical and surgical conditions, with a variety of inclusion criteria. Four studies used parenteral nutrition and nine studies used only enteral nutrition; it was unclear whether the remaining two used parenteral nutrition. Most of them could not achieve the proposed caloric targets, resulting in small differences in the administered calories between intervention and control groups. Most studies were funded by the US government or non‐governmental associations, but three studies received funding from industry. Five studies did not specify their funding sources.
The included studies suffered from important clinical and statistical heterogeneity. This heterogeneity did not allow us to report pooled estimates of the primary and secondary outcomes, so we have described them narratively.
When comparing hypocaloric nutrition support with a control nutrition support, for hospital mortality (9 studies, 1775 participants), the risk ratios ranged from 0.23 to 5.54; for ICU mortality (4 studies, 1291 participants) the risk ratios ranged from 0.81 to 5.54, and for mortality at 30 days (7 studies, 2611 participants) the risk ratios ranged from 0.79 to 3.00. Most of these estimates included the null value. The quality of the evidence was very low due to unclear or high risk of bias, inconsistency and imprecision.
Participants who received hypocaloric nutrition support compared to control nutrition support had a range of mean hospital lengths of stay of 15.70 days lower to 10.70 days higher (10 studies, 1677 participants), a range of mean ICU lengths of stay 11.00 days lower to 5.40 days higher (11 studies, 2942 participants) and a range of mean lengths of mechanical ventilation of 13.20 days lower to 8.36 days higher (12 studies, 3000 participants). The quality of the evidence for this outcome was very low due to unclear or high risk of bias in most studies, inconsistency and imprecision.

The risk ratios for infectious complications (10 studies, 2804 participants) of each individual study ranged from 0.54 to 2.54. The quality of the evidence for this outcome was very low due to unclear or high risk of bias, inconsistency and imprecision.
We were not able to explain the causes of the observed heterogeneity using subgroup and sensitivity analyses or meta‐regression.

Authors’ conclusions:  The included studies had substantial clinical heterogeneity. We found very low‐quality evidence about the effects of prescribed hypocaloric nutrition support on mortality in hospital, in the ICU and at 30 days, as well as in length of hospital and ICU stay, infectious complications and the length of mechanical ventilation. For these outcomes there is uncertainty about the effects of prescribed hypocaloric nutrition, since the range of estimates includes both appreciable benefits and harms.

Given these limitations, results must be interpreted with caution in the clinical field, considering the unclear balance of the risks and harms of this intervention. Future research addressing the clinical heterogeneity of participants and interventions, study limitations and sample size could clarify the effects of this intervention.

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Energy-Dense versus Routine Enteral Nutrition in the Critically Ill

The article was published by the Target Investigators for the ANZICS Clinical Trails Group in the New England Journal of Medicine in November 2018

Background:  The effect of delivering nutrition at different calorie levels during critical illness is uncertain, and patients typically receive less than the recommended amount.

Methods:  We conducted a multicenter, double-blind, randomized trial, involving adults undergoing mechanical ventilation in 46 Australian and New Zealand intensive care units (ICUs), to evaluate energy-dense (1.5 kcal per milliliter) as compared with routine (1.0 kcal per milliliter) enteral nutrition at a dose of 1 ml per kilogram of ideal body weight per hour, commencing at or within 12 hours of the initiation of nutrition support and continuing for up to 28 days while the patient was in the ICU. The primary outcome was all-cause mortality within 90 days.

Results:  There were 3957 patients included in the modified intention-to-treat analysis (1971 in the 1.5-kcal group and 1986 in the 1.0-kcal group). The volume of enteral nutrition delivered during the trial was similar in the two groups; however, patients in the 1.5-kcal group received a mean (±SD) of 1863±478 kcal per day as compared with 1262±313 kcal per day in the 1.0-kcal group (mean difference, 601 kcal per day; 95% confidence interval [CI], 576 to 626). By day 90, a total of 523 of 1948 patients (26.8%) in the 1.5-kcal group and 505 of 1966 patients (25.7%) in the 1.0-kcal group had died (relative risk, 1.05; 95% CI, 0.94 to 1.16; P=0.41). The results were similar in seven predefined subgroups. Higher calorie delivery did not affect survival time, receipt of organ support, number of days alive and out of the ICU and hospital or free of organ support, or the incidence of infective complications or adverse events.

Conclusions:  In patients undergoing mechanical ventilation, the rate of survival at 90 days associated with the use of an energy-dense formulation for enteral delivery of nutrition was not higher than that with routine enteral nutrition.

The printed copy of the New England Journal of Medicine is available in the Health Care Library on D Level of Rotherham Hospital.

Implementing an educational program to improve critical care nurses’ enteral nutritional support

This research by Kim and Chang was published in “Australian Critical Care: Official Journal of the Confederation of Australian Critical Care Nurses” in May 2018.
Background:  Although international nutrition societies recommend enteral nutrition guidelines for patients in intensive care units (ICUs), large gaps exist between these recommendations and actual clinical practice. Education programs designed to improve nurses’ knowledge about enteral nutrition are therefore required. In Korea, there are no educational intervention studies about evidence-based guidelines of enteral nutrition for critically ill patients.
Objectives:  We aimed to evaluate the effects of an education program to improve critical care nurses’ perceptions, knowledge, and practices towards providing enteral nutritional support for ICU patients.
Methods:  A quasi-experimental, one-group study with a pre- and post-test design was conducted from March to April 2015. Nurses (N = 205) were recruited from nine ICUs from four tertiary hospitals in South Korea. The education program comprised two sessions of didactic lectures. Data were collected before (pre-test) and 1 month after (post-test) the education program using questionnaires that addressed nurses’ perceptions, knowledge, and practices relating to providing enteral nutritional support for ICU patients.
Results:  After the program, nurses showed a significant improvement in their perceptions and knowledge of enteral nutrition for ICU patients. There was a significant improvement in inspecting nostrils daily, flushing the feeding tube before administration, providing medication that needs to be crushed correctly, changing feeding sets, and adjusting feeding schedules.
Conclusions:  The findings indicate that an enteral nutrition education program could be an effective strategy to increase critical care nurses’ support for the critically ill. This education program can be incorporated into hospital education or in-service training for critical care nurses to strengthen their perceptions and knowledge of nutritional support in the ICU. This may improve the clinical outcomes of ICU patients.
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Permissive or Trophic Enteral Nutrition and Full Enteral Nutrition Had Similar Effects on Clinical Outcomes in Intensive Care: A Systematic Review of Randomized Clinical Trials

This article by Silva et al was published in Nutrition in Clinical Practice in January 2018.
The aim of this study was to systematically review the effect of permissive underfeeding/trophic feeding on the clinical outcomes of critically ill patients. A systematic review of randomized clinical trials to evaluate the mortality, length of stay, and mechanical ventilation duration in patients randomized to either hypocaloric or full-energy enteral nutrition was performed. Data sources included PubMed and Scopus and the reference lists of the articles retrieved. Two independent reviewers participated in all phases of this systematic review as proposed by the Cochrane Handbook, and the review was reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A total of 7 randomized clinical trials that included a total of 1,717 patients were reviewed. Intensive care unit length of stay and mechanical ventilation duration were not statistically different between the intervention and control groups in all randomized clinical trials, and mortality rate was also not different between the groups. In conclusion, hypocaloric enteral nutrition had no significantly different effects on morbidity and mortality in critically ill patients when compared with full-energy nutrition. It is still necessary to determine the safety of this intervention in this group of patients, the optimal amount of energy provided, and the duration of this therapy.
Library members can order the full text of individual articles such as this one via the Rotherham NHS Foundation Trust Library and Knowledge Service using the article requests online via this link.

The role of nutritional support in the physical and functional recovery of critically ill patients

The lack of benefit from randomised controlled trials has resulted in significant controversy regarding the role of nutrition during critical illness in terms of long-term recovery and outcome | Critical Care

Although methodological caveats with a failure to adequately appreciate biological mechanisms may explain these disappointing results, it must be acknowledged that nutritional support during early critical illness, when considered alone, may have limited long-term functional impact.

This narrative review focuses specifically on recent clinical trials and evaluates the impact of nutrition during critical illness on long-term physical and functional recovery.

Specific focus on the trial design and methodological limitations has been considered in detail. Limitations include delivery of caloric and protein targets, patient heterogeneity, short duration of intervention, inappropriate clinical outcomes and a disregard for baseline nutritional status and nutritional intake in the post-ICU period.

With survivorship at the forefront of critical care research, it is imperative that nutrition studies carefully consider biological mechanisms and trial design because these factors can strongly influence outcomes, in particular long-term physical and functional outcome. Failure to do so may lead to inconclusive clinical trials and consequent rejection of the potentially beneficial effects of nutrition interventions during critical illness.

Full reference: Bear, D.E. et al. (2017) The role of nutritional support in the physical and functional recovery of critically ill patients: a narrative review. Critical Care. Vol. 21 (no. 226)

NutritionDay ICU: A 7 year worldwide prevalence study of nutrition practice in intensive care

Introduction:  To determine the nutrition practice in intensive care units and the associated outcome across the world, a yearly 1 day cross sectional audit was performed from 2007 to 2013. The data of this initiative called “nutrition Day ICU” were analyzed.

Material and methods:  A questionnaire translated in 17 languages was used to determine the unit’s characteristics, patient’s condition, nutrition condition and therapy as well as outcome. All the patients present in the morning of the 1 day prevalence study were included from 2007 to 2013.

Results:  9777 patients from 46 countries and 880 units were included. Their SAPS 2 was median 38 (IQR 27-51), predicted mortality was 30.7% ± 26.9, and their SOFA score 4.5 ± 3.4 with median 4 (IQR 2-7). Administration of calories did not appear to be related to actual or ideal body weight within all BMI groups. Patients with a BMI 40 received slightly less calories than all other BMI groups. Two third of the patients were either ventilated or were in the ICU for longer than 24 h at nutrition.  Day. Routes of feeding used were the oral, enteral and parenteral routes. More than 40% of the patients were not fed during the first day. The mean energy administered using enteral route was 1286 ± 663 kcal/day and using parenteral nutrition 1440 ± 652 kcal/day. 60 days mortality was 26.0%.

Discussion:  This very large collaborative cohort study shows that most of the patients are underfed during according to actual recommendations their ICU stay. Prescribed calories appear to be ordered regardless to the ideal weight of the patient. Nutritional support is slow to start and never reaches the recommended targets. Parenteral nutrition prescription is increasing during the ICU stay but reaching only 20% of the population studied if ICU stay is one week or longer. The nutritional support worldwide does not seem to be guided by weight or disease but more to be standardized and limited to a certain level of calories. These observations are showing the poor observance to guidelines.

This research by Bendavid and colleagues was published in the Clinical Nutrition August issue.  Library members can order the full text of this and other articles via the Rotherham NHS Foundation Trust Library and Knowledge Service website using the article requests online via this link

Disturbed Microbiome Clinically Detrimental in ICU

Patients in the intensive care unit with an imbalanced microbiome are at increased risk for complications and longer ICU stays, according to findings presented at Clinical Nutrition Week 2017 | Anesthesiology News

B0011080 Bacterial microbiome mapping, bioartistic experiment
Image source: François-Joseph Lapointe, Université de Montréal – Wellcome Images // CC BY 4.0

Image shows bacterial microbiome mapping – a bioartistic experiment.

Paul Wischmeyer, MD, professor of anesthesiology and surgery and director of perioperative research at Duke Clinical Research Institute, in Durham, N.C., who also is part of the ICU Microbiome Project, told meeting attendees that ICU patients experience significant microbiome perturbations and added complications, including acute respiratory distress syndrome (ARDS).

“ICU patients have massive loss of health-promoting bacteria and higher levels of pathogenic species, compared with healthy patients,” Dr. Wischmeyer said. “It is astonishing how rapidly pathogenic bacteria flourish and how this shift to dysbiosis appears to affect a variety of outcomes.”

Dr. Wischmeyer and his colleagues have been examining fecal and oral microbiome samples from 115 ICU patients treated at four hospitals and comparing them with samples from healthy people participating in the American Gut project. In previous research, they found decreases in populations of Bacteroides and Firmicutes, as well as the healthy bacterium, Faecalibacterium prausnitzii, which produces short-chain fatty acids that help preserve normal gut barrier function (mSphere 2016;1[4]. pii:e00199-16). Meanwhile, they discovered increases in the relative abundance of Proteobacteria, a phylum of gram-negative bacteria linked to infections in ICU and hospitalized patients.

ICU patients also tended to lose overall fecal microbiota diversity, with some patients having only one organism compose 95% of their fecal bacteria after a short time in the ICU, he explained.