Nutritional papers in ICU patients: what lies between the lines?

Nutritional support for critically ill children

BACKGROUND

Nutritional support in the critically ill child has not been well investigated and is a controversial topic within paediatric intensive care. There are no clear guidelines as to the best form or timing of nutrition in critically ill infants and children. This is an update of a review that was originally published in 2009. .

OBJECTIVES

The objective of this review was to assess the impact of enteral and parenteral nutrition given in the first week of illness on clinically important outcomes in critically ill children. There were two primary hypotheses:1. the mortality rate of critically ill children fed enterally or parenterally is different to that of children who are given no nutrition;2. the mortality rate of critically ill children fed enterally is different to that of children fed parenterally.We planned to conduct subgroup analyses, pending available data, to examine whether the treatment effect was altered by:a. age (infants less than one year versus children greater than or equal to one year old);b. type of patient (medical, where purpose of admission to intensive care unit (ICU) is for medical illness (without surgical intervention immediately prior to admission), versus surgical, where purpose of admission to ICU is for postoperative care or care after trauma).We also proposed the following secondary hypotheses (a priori), pending other clinical trials becoming available, to examine nutrition more distinctly:3. the mortality rate is different in children who are given enteral nutrition alone versus enteral and parenteral combined;4. the mortality rate is different in children who are given both enteral feeds and parenteral nutrition versus no nutrition.

SEARCH METHODS

In this updated review we searched: the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 2); Ovid MEDLINE (1966 to February 2016); Ovid EMBASE (1988 to February 2016); OVID Evidence-Based Medicine Reviews; ISI Web of Science - Science Citation Index Expanded (1965 to February 2016); WebSPIRS Biological Abstracts (1969 to February 2016); and WebSPIRS CAB Abstracts (1972 to February 2016). We also searched trial registries, reviewed reference lists of all potentially relevant studies, handsearched relevant conference proceedings, and contacted experts in the area and manufacturers of enteral and parenteral nutrition products. We did not limit the search by language or publication status.

SELECTION CRITERIA

We included studies if they were randomized controlled trials; involved paediatric patients, aged one day to 18 years of age, who were cared for in a paediatric intensive care unit setting (PICU) and had received nutrition within the first seven days of admission; and reported data for at least one of the pre-specified outcomes (30-day or PICU mortality; length of stay in PICU or hospital; number of ventilator days; and morbid complications, such as nosocomial infections). We excluded studies if they only reported nutritional outcomes, quality of life assessments, or economic implications. Furthermore, we did not address other areas of paediatric nutrition, such as immunonutrition and different routes of delivering enteral nutrition, in this review.

DATA COLLECTION AND ANALYSIS

Two authors independently screened the searches, applied the inclusion criteria, and performed 'Risk of bias' assessments. We resolved discrepancies through discussion and consensus. One author extracted data and a second checked data for accuracy and completeness. We graded the evidence based on the following domains: study limitations, consistency of effect, imprecision, indirectness, and publication bias.

MAIN RESULTS

We identified only one trial as relevant. Seventy-seven children in intensive care with burns involving more than 25% of the total body surface area were randomized to either enteral nutrition within 24 hours or after at least 48 hours. No statistically significant differences were observed for mortality, sepsis, ventilator days, length of stay, unexpected adverse events, resting energy expenditure, nitrogen balance, or albumin levels. We assessed the trial as having unclear risk of bias. We consider the quality of the evidence to be very low due to there being only one small trial. In the most recent search update we identified a protocol for a relevant randomized controlled trial examining the impact of withholding early parenteral nutrition completing enteral nutrition in pediatric critically ill patients; no results have been published.

AUTHORS' CONCLUSIONS

There was only one randomized trial relevant to the review question. Research is urgently needed to identify best practices regarding the timing and forms of nutrition for critically ill infants and children.

Guidelines, guidelines, guidelines: what are we to do with all of these North American guidelines?

Over the past decade, clinical guidelines for nutrition therapy in the critically ill have been developed by different North American societies. To avoid target audience confusion and uncertainty, there is a need to undergo a review of the content of these guidelines. In this review, the authors compared the grading systems, the levels of evidence used, and the content of North American nutrition clinical guidelines. The 3 clinical guidelines that met their search criteria and hence were included in the comparison are the Canadian Clinical Practice Guidelines, the American Dietetics Association's evidence-based guideline for critical illness, and the Society of Critical Care Medicine and American Society of Parenteral and Enteral Nutrition's joint guideline. Through their comparison, the authors have shown that although there are several topics where there is a similar direction of recommendation across the 3 societies/organizations, there are stark contrasts among many of the recommendations. These major differences can be attributed to the admission of different populations, lower levels of evidence or expert opinion into the guideline production process, lack of clarity in the link between the evidence and the recommendation, and lack of uniformity in the reporting of levels of evidence and grades of recommendation. The authors have identified the need for the North American nutrition organizations to harmonize the development of future nutrition guidelines in a timely way, so that they remain current and up-to-date. Furthermore, guideline users need to be aware of the dissimilarities in these guidelines before applying the recommendations to their daily practice.

Randomized trials in critical care nutrition: look how far we've come! (and where do we go from here?)

BACKGROUND

The purpose of this methodological review is to quantify and qualify critical care nutrition randomized controlled trials (RCTs) that inform our practice, to evaluate their strengths and limitations, and to recommend strategies for improving the design of future trials in this area.

METHODS

The literature was systematically reviewed to find all RCTs published between 1980 and December 2008 that evaluated nutrition interventions in critical care. Data were abstracted on the nature and quality of included RCTs.

RESULTS

A total of 207 RCTs met the inclusion criteria. Of these, 170 (82.1%) were single-center, and 37 (17.9%) were multicenter. The largest number of trials evaluated intensive insulin therapy (n = 25), arginine-supplemented diets (n = 22), and supplemental parenteral glutamine (n = 17). The first RCTs were published in 1983 (n = 2), and the mean sample size was 39.0. In 2008, there were 26 RCTs, each enrolling an average of 237.1 patients. Excluding 2 cluster RCTs, 62 of 205 (30.2%) trials had concealed randomization, 125 of 205 (61.0%) reported on intention-to-treat analyses, and 69 of 205 (33.7%) had a double-blinded intervention; 18 of 205 (8.8%) studies reported on all 3 design characteristics. Currently, 60 critical care nutrition RCTs (18 multicenter trials) are registered on clinical trials registries.

CONCLUSIONS

The future of clinical critical care nutrition research is promising, with more trials of increasing sample size being conducted. Robust trial methodology, transparent reporting, and the development of research networks will help to further advance this important field.

Fish oil in critical illness: mechanisms and clinical applications

Fish oil is rich in omega-3 fatty acids, which have been shown to be beneficial in multiple disease states that involve an inflammatory process. It is now hypothesized that omega-3 fatty acids may decrease the inflammatory response and be beneficial in critical illness. After a review of the mechanisms of omega-3 fatty acids in inflammation, research using enteral nutrition formulas and parenteral nutrition lipid emulsions fortified with fish oil were examined. The results of this research to date are inconclusive for both enteral and parenteral omega-3 fatty acid administration. More research is required before definitive recommendations can be made on fish oil supplementation in critical illness.

Omega-3 fatty acids in critical illness

Supplementation of enteral nutritional formulas and parenteral nutrition lipid emulsions with omega-3 fatty acids is a recent area of research in patients with critical illness. It is hypothesized that omega-3 fatty acids may help reduce inflammation in critically ill patients, particularly those with sepsis and acute lung injury. The objective of this article is to review the data on supplementing omega-3 fatty acids during critical illness; enteral and parenteral supplemental nutrition are reviewed separately. The results of the research available to date are contradictory for both enteral and parenteral omega-3 fatty acid administration. Supplementation with omega-3 fatty acids may influence the acute inflammatory response in critically ill patients, but more research is needed before definitive recommendations about the routine use of omega-3 fatty acids in caring for critically ill patients can be made.

Nutritional support for critically ill children

BACKGROUND

Nutritional support in the critically ill child has not been well investigated and is a controversial topic within paediatric intensive care. There are no clear guidelines as to the best form or timing of nutrition in critically ill infants and children.

OBJECTIVES

To assess the impact of enteral and total parenteral nutrition on clinically important outcomes for critically ill children.

SEARCH STRATEGY

We searched: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, Issue 1); Ovid MEDLINE (1966 to February 2007); Ovid EMBASE (1988 to February 2007); OVID Evidence-Based Medicine Reviews; ISI Web of Science - Science Citation Index Expanded (1965 to February 2007); WebSPIRS Biological Abstracts (1969 to February 2007); and WebSPIRS CAB Abstracts (1972 to February 2007). We also searched trial registries; reviewed reference lists of all potentially relevant studies; handsearched relevant conference proceedings; and contacted experts in the area and manufacturers of enteral and parenteral nutrition products. We did not limit the search by language or publication status.

SELECTION CRITERIA

We included studies if they were randomized controlled trials; involved paediatric patients, aged one day to 18 years of age, cared for in a paediatric intensive care unit setting (PICU) and received nutrition within the first seven days of admission; and reported data for at least one of the pre-specified outcomes (30-day or PICU mortality; length of stay in PICU or hospital; number of ventilator days; and morbid complications, such as nosocomial infections). We excluded studies if they only reported nutritional outcomes, quality of life assessments, or economic implications. Furthermore, other areas of paediatric nutrition, such as immunonutrition and different routes of delivering enteral nutrition, were not addressed in this review.

DATA COLLECTION AND ANALYSIS

Two authors independently screened searches, applied inclusion criteria, and performed quality assessments. We resolved discrepancies through discussion and consensus. One author extracted data and a second checked data for accuracy and completeness.

MAIN RESULTS

Only one trial was identified as relevant. Seventy-seven children in intensive care with burns involving > 25% of the total body surface area were randomized to either enteral nutrition within 24 hours or after at least 48 hours. No statistically significant differences were observed for mortality, sepsis, ventilator days, length of stay, unexpected adverse events, resting energy expenditure, nitrogen balance, or albumin levels. The trial was assessed as of low methodological quality (based on the Jadad scale) with an unclear risk of bias.

AUTHORS' CONCLUSIONS

There was only one randomized trial relevant to the review question. Research is urgently needed to identify best practices regarding the timing and forms of nutrition for critically ill infants and children.

Evidence-based nutrition support in the intensive care unit: an update on reported trial quality

PURPOSE OF REVIEW

Meta-epidemiological reviews report that trials of nutritional support in critical illness rarely fulfil basic quality requirements, with overall quality rated as 'worse than poor'. This update reviews recently published trials to determine whether current evidence meets or exceeds basic quality requirements.

RECENT FINDINGS

Although recent trials were significantly more likely to report blinding, there is a concerning trend towards a decrease in overall trial quality. Many recent trials fail to report the use of 'any' of three key validity criteria: use of blinding, presentation of intention-to-treat analysis and the maintenance allocation concealment.

SUMMARY

Future researchers must improve the quality with which trials are conducted and reported. Submitting a clinical trial to an approved registry prior to enrolling patients provides transparency of conduct. Investigators must ensure that an intention-to-treat analysis is reported, especially when a subset efficacy analysis is presented, even if the intention-to-treat analysis requires imputing missing data values. Investigators also need to improve reporting details concerning allocation concealment and blinding. Finally, until investigators, editors and reviewers embrace these measures, we strongly recommend that readers should become familiar with the appropriate evidence-based medicine users' guides so that they can base clinical decisions on valid studies.

Feeding the injured intestine: enteral nutrition in the critically ill patient

PURPOSE OF REVIEW

The utilization of enteral nutrition in critically ill patients is frequently suboptimal. This may be due, in part, to ongoing controversies regarding appropriate use of enteral support, but there are also perceived barriers to its use even when there is good evidence that it can be given. This review was undertaken to outline some of these controversies and barriers to use of enteral nutrition in the ICU.

RECENT FINDINGS

Although the advantages of enteral nutrition may have been overstated, it remains preferable to parenteral nutrition for support of critically ill patients. Early initiation of enteral support is a reasonable approach. Many patients with perceived contraindications to enteral therapy are actually good candidates for its use. Frequent interruptions in enteral nutrition lead to suboptimal nutrient delivery, but might be overcome by use of specific protocols emphasizing safe and effective utilization of enteral support.

SUMMARY

Use of enteral nutritional support is recommended for critically ill patients requiring specialized nutritional support. Barriers to its use could be overcome by better educating providers about indications for use and by developing methods to avoid undue interruption of therapy.

Effect of mode of hydrocortisone administration on glycemic control in patients with septic shock: a prospective randomized trial

Introduction

Low-dose hydrocortisone treatment is widely accepted therapy for the treatment of vasopressor-dependent septic shock. The question of whether corticosteroids should be given to septic shock patients by continuous or by bolus infusion is still unanswered. Hydrocortisone induces hyperglycemia and it is possible that continuous hydrocortisone infusion would reduce the fluctuations in blood glucose levels and that tight blood glucose control could be better achieved with this approach.

Methods

In this prospective randomized study, we compared the blood glucose profiles, insulin requirements, amount of nursing workload needed, and shock reversal in 48 septic shock patients who received hydrocortisone treatment either by bolus or by continuous infusion with equivalent dose (200 mg/day). Duration of hydrocortisone treatment was five days.

Results

The mean blood glucose levels were similar in the two groups, but the number of hyperglycemic episodes was significantly higher in those patients who received bolus therapy (15.7 ± 8.5 versus 10.5 ± 8.6 episodes per patient, p = 0.039). Also, more changes in insulin infusion rate were needed to maintain strict normoglycemia in the bolus group (4.7 ± 2.2 versus 3.4 ± 1.9 adjustments per patient per day, p = 0.038). Hypoglycemic episodes were rare in both groups. No difference was seen in shock reversal.

Conclusion

Strict normoglycemia is more easily achieved if the hydrocortisone therapy is given to septic shock patients by continuous infusion. This approach also reduces nursing workload needed to maintain tight blood glucose control.

Trial Registration Number

ISRCTN98820688

Immunonutrition in septic patients: A philosophical view of the current situation

BACKGROUND & AIMS

Two different ways of thinking pervaded the history of science: rationalism and empiricism. In theory, these two paradigms are not necessarily in conflict. In practice, there has always been tension between them. The coming of evidence-based medicine put empiricism in a privileged position, but empiricism without a rationalistic guide could even be usefulness. The aim of this work is to present the tension between the rational reasons to administer immunonutrients to patients with sepsis and the controversial empirical evidence stemming from clinical trials.

METHODS

We reviewed the literature on immunonutrition in sepsis from the rationalist and the empiricist perspectives.

RESULTS

The large body of evidence for positive effects of immunonutrients in experimental models and the contradictory results from clinical trials make the discussion on immunonutrition in sepsis a typical example where the conflict between rationalism and empiricism hampered the advancement of knowledge and the implementation of new effective therapies into clinical practice.

CONCLUSIONS

Future research projects involving immunonutrients should be based on robust knowledge of basic mechanisms of action to be properly addressed in clinical trials.

Risks and benefits of nutritional support during critical illness

Critically ill patients who depend on intensive care for more than a few days reveal profound erosion of lean body mass, which is thought to contribute to high morbidity and mortality. Despite a shortfall of evidence that supplemental feeding actually alters clinical outcome of these life-threatening disease states, this observation evoked an almost universal, albeit often inappropriate, use of nutritional support (NS) in the critically ill, administered via the parenteral or the enteral route. Lack of knowledge and overenthusiasm subsequently resulted in complications associated with both parenteral nutrition (PN) and enteral nutrition (EN), which led to the standing controversy over which should be preferred. With time, however, it became clear that EN and PN are not mutually exclusive and that critically ill patients requiring NS should be fed according to the functional status of the gastrointestinal tract. In addition, tight blood glucose control with insulin is advised in fed critically ill patients because overall metabolic control appears to surpass any outcome benefit attributed to the route of feeding. Recently, various special nutritional formulas have been suggested to prevent or treat multiorgan failure in the critically ill, among other pathways via modulation of immune function. Although special nutritional formulas may be promising in a variety of clinical settings, based on currently available data, these cannot be recommended for routine use in critically ill patients.

Age and caloric restriction diets are confounding factors that modify the response to lipopolysaccharide by peritoneal macrophages in C57BL/6 mice

Aging is the result of several detrimental changes that lead to a decrease in homeostasis, an increase in the incidence of degenerative diseases, and death. A caloric-restricted diet (CR), which consists of a significant reduction in calorie intake (40%) without malnutrition, has been shown to delay the onset of age-related diseases and pathologies and to extend life span. The aims of this study were to assess the effects of aging and CR on lipopolysaccharide (LPS)-dependant cytokine production by peritoneal macrophages (PMphis). Resident naïve PMphis were isolated from 2- to 24-month-old male C57BL/6 mice and were stimulated with Escherichia coli LPS (100 ng/mL) for 1 to 5 h in culture conditions. A linear decrease in the production of LPS-induced tumor necrosis factor alpha (TNF-alpha) and interleukin (IL) 10 was observed with age. LPS-induced IL-6 and IL-1beta levels were also reduced with age, but in a nonlinear fashion. Expression of CD14, the major receptor for LPS, on the PMphi surface was also observed to decline with age. Moreover, TNF-alpha production by PMphis was reduced in mice undergoing the two different CR diets of limited daily feeding and intermittent fasting, as compared with ad libitum-fed mice. The results of this study add the new variables age and diet to the paradigm proposing that the response to LPS is modulated by multiple components, including genetic background and sex.

A review of the true methodological quality of nutritional support trials conducted in the critically ill: time for improvement

In this review we sought to appraise the true methodological quality of nutritional support studies conducted in critically ill patients and to compare these findings to the methodological quality of sepsis trials. An extensive literature search revealed 111 randomized controlled trials conducted in critically ill patients evaluating the impact of nutritional support interventions on clinically meaningful outcomes. Compared with sepsis trials, nutritional support studies were significantly less likely to use blinding (32 of 40 versus 35 of 111, P < 0.001) or present an intention-to-treat analysis (37 of 40 versus 64 of 111, P < 0.001). There was a trend toward the less frequent use of randomization methods that are known to maintain allocation concealment (12 of 40 versus 19 of 111, P = 0.10). Although nutritional support studies demonstrated a significant increase in the use of blinding after the publication of the CONSORT statement in 1996 (9 of 47 versus 26 of 64 post-CONSORT, P = 0.023), there were no improvements in other key areas. Previous publications have described the overall methodological quality of sepsis trials as "poor." Nutritional support studies were significantly worse than sepsis trials in all aspects of methodological quality, and there were few improvements noted over time. To detect important differences in clinically meaningful outcomes in critical care, the methodological quality of future studies must be improved.

Parenteral vs. enteral nutrition in the critically ill patient: a meta-analysis of trials using the intention to treat principle

OBJECTIVE

Controversy surrounds the use of parenteral nutrition in critical illness. Previous overviews used composite scales to identify high-quality trials, which may mask important differences in true methodological quality. Using a component-based approach this meta-analysis investigated the effect of trial quality on overall conclusions reached when standard enteral nutrition is compared to standard parenteral nutrition in critically ill patients.

METHODS

An extensive literature search was undertaken to identify all eligible trials. We retrieved 465 publications, and 11 qualified for inclusion. Nine trials presented complete follow-up, allowing the conduct of an intention to treat analysis.

RESULTS

Aggregation revealed a mortality benefit in favour of parenteral nutrition, with no heterogeneity. A priori specified subgroup analysis demonstrated the presence of a potentially important treatment-subgroup interaction between studies of parenteral vs. early enteral nutrition compared to parenteral vs. late enteral. Six trials with complete follow-up reported infectious complications. Infectious complications were increased with parenteral use. The I(2) measure of heterogeneity was 37.7%.

CONCLUSIONS

Intention to treat trials demonstrated reduced mortality associated with parenteral nutrition use. A priori subgroup analysis attributed this reduction to trials comparing parenteral to delayed enteral nutrition. Despite an association with increased infectious complications, a grade B+ evidence-based recommendation (level II trials, no heterogeneity) can be generated for parenteral nutrition use in patients in whom enteral nutrition cannot be initiated within 24 h of ICU admission or injury.

Costs of patients under nutritional therapy: from prescription to discharge

PURPOSE OF REVIEW

This review will discuss the financial cost of the decisions taken regarding the nutritional therapy of hospitalized patients compared with those treated at home. To facilitate comprehension, the authors present a concise introduction to the general concepts of economic health studies, including a glossary of technical terms.

RECENT FINDINGS

From a revision of the literature, economic aspects are underscored involving the cost of malnutrition, the maintenance of work in a nutritional support team, the use of nutritional therapy in home-care programmes, and in the use of nutritional therapy as a prophylactic action against surgical complications.

SUMMARY

Hospital malnutrition burdens the system financially by provoking a higher rate of surgical complications, mortality and longer hospital stays. Investment in nutritional therapy provides economic returns. The cost of the creation and maintenance of the nutritional support team is easily offset by the resources generated by the team itself. Nutritional therapy in home-care is highly advantageous. In Brazilian trials, groups of surgical patients receiving nutritional therapy within the integrated hospital-home model demonstrated a cost 2.6 times less than the conventional group (exclusively intra-hospital treatment). The adoption of preoperative immunomodulatory nutritional therapy in patients undergoing elective surgery as a prophylactic against postoperative surgical complications presented a 2.24 times reduction in the total treatment cost. The search for the ideal model of nutritional therapy is based on the binomial of quality and cost. The prescription of nutritional therapy has a favourable impact on financial and resource-generating aspects of the institution, when practised by properly trained groups.