Elderly persons with ICU-acquired weakness: the potential role for ß-hydroxy-ß-methylbutyrate (HMB) supplementation?

Intensive care unit (ICU)-acquired weakness is common and characterized by muscle loss, weakness, and paralysis. It is associated with poor short-term outcomes, including increased mortality, but the consequences of reduced long-term outcomes, including decreased physical function and quality of life, can be just as devastating. ICU-acquired weakness is particularly relevant to elderly patients who are increasingly consuming ICU resources and are at increased risk for ICU-acquired weakness and complications, including mortality. Elderly patients often enter critical illness with reduced muscle mass and function and are also at increased risk for accelerated disuse atrophy with acute illness. Increasingly, intensivists and researchers are focusing on strategies and therapies aimed at improving long-term neuromuscular function. ß-Hydroxy-ß-methylbutyrate (HMB), an ergogenic supplement, has shown efficacy in elderly patients and certain clinical populations in counteracting muscle loss. The present review discusses ICU-acquired weakness, as well as the unique physiology of muscle loss and skeletal muscle function in elderly patients, and then summarizes the evidence for HMB in elderly patients and in clinical populations. We subsequently postulate on the potential role and strategies in studying HMB in elderly ICU patients to improve muscle mass and function.

Monitoring nutrition therapy in the critically ill patient with obesity.

Obesity compounds the metabolic response to critical illness and augments the consequences of overfeeding. Effective monitoring is essential for the prevention of, or to avoid, worsening of preexistent morbidities associated with obesity during the implementation of specialized nutrition support. This monitoring should guide the clinician toward the selection of appropriate therapeutic options to reduce complications from significant hyperglycemia, dyslipidemia, hypercapnia, fluid overload, and worsening of hepatic steatosis. Conventional nutrition outcome markers should be employed, with their limitations understood, when used for the critically ill obese patient.

Nutrition therapy for the critically ill surgical patient: we need to do better!

BACKGROUND: To identify opportunities for quality improvement, the nutrition adequacy of critically ill surgical patients, in contrast to medical patients, is described. METHODS: International, prospective, and observational studies conducted in 2007 and 2008 in 269 intensive care units (ICUs) were combined for purposes of this analysis. Sites provided institutional and patient characteristics and nutrition data from ICU admission to ICU discharge for maximum of 12 days. Medical and surgical patients staying in ICU at least 3 days were compared. RESULTS: A total of 5497 mechanically ventilated adult patients were enrolled; 37.7% had surgical ICU admission diagnosis. Surgical patients were less likely to receive enteral nutrition (EN) (54.6% vs 77.8%) and more likely to receive parenteral nutrition (PN) (13.9% vs 4.4%) (P < .0001). Among patients initiating EN in ICU, surgical patients started EN 21.0 hours later on average (57.8 vs 36.8 hours, P < .0001). Consequently, surgical patients received less of their prescribed calories from EN (33.4% vs 49.6%, P < .0001) or from all nutrition sources (45.8% vs 56.1%, P < .0001). These differences remained after adjustment for patient and site characteristics. Patients undergoing cardiovascular and gastrointestinal surgery were more likely to use PN, were less likely to use EN, started EN later, and had lower total nutrition and EN adequacy rates compared with other surgical patients. Use of feeding and/or glycemic control protocols was associated with increased nutrition adequacy. CONCLUSIONS: Surgical patients receive less nutrition than medical patients. Cardiovascular and gastrointestinal surgery patients are at highest risk of iatrogenic malnutrition. Strategies to improve nutrition performance, including use of protocols, are needed.

Canadian clinical practice guidelines for nutrition support in mechanically ventilated, critically ill adult patients.

OBJECTIVE: This study was conducted to develop evidence-based clinical practice guidelines for nutrition support (ie, enteral and parenteral nutrition) in mechanically ventilated critically ill adults. OPTIONS: The following interventions were systematically reviewed for inclusion in the guidelines: enteral nutrition (EN) versus parenteral nutrition (PN), early versus late EN, dose of EN, composition of EN (protein, carbohydrates, lipids, immune-enhancing additives), strategies to optimize delivery of EN and minimize risks (ie, rate of advancement, checking residuals, use of bedside algorithms, motility agents, small bowel versus gastric feedings, elevation of the head of the bed, closed delivery systems, probiotics, bolus administration), enteral nutrition in combination with supplemental PN, use of PN versus standard care in patients with an intact gastrointestinal tract, dose of PN and composition of PN (protein, carbohydrates, IV lipids, additives, vitamins, trace elements, immune enhancing substances), and the use of intensive insulin therapy. OUTCOMES: The outcomes considered were mortality (intensive care unit [ICU], hospital, and long-term), length of stay (ICU and hospital), quality of life, and specific complications. EVIDENCE: We systematically searched MEDLINE and CINAHL (cumulative index to nursing and allied health), EMBASE, and the Cochrane Library for randomized controlled trials and meta-analyses of randomized controlled trials that evaluated any form of nutrition support in critically ill adults. We also searched reference lists and personal files, considering all articles published or unpublished available by August 2002. Each included study was critically appraised in duplicate using a standard scoring system. VALUES: For each intervention, we considered the validity of the randomized trials or meta-analyses, the effect size and its associated confidence intervals, the homogeneity of trial results, safety, feasibility, and the economic consequences. The context for discussion was mechanically ventilated patients in Canadian ICUs. BENEFITS, HARMS, AND COSTS: The major potential benefit from implementing these guidelines is improved clinical outcomes of critically ill patients (reduced mortality and ICU stay). Potential harms of implementing these guidelines include increased complications and costs related to the suggested interventions. SUMMARIES OF EVIDENCE AND RECOMMENDATIONS: When considering nutrition support in critically ill patients, we strongly recommend that EN be used in preference to PN. We recommend the use of a standard, polymeric enteral formula that is initiated within 24 to 48 hours after admission to ICU, that patients be cared for in the semirecumbent position, and that arginine-containing enteral products not be used. Strategies to optimize delivery of EN (starting at the target rate, use of a feeding protocol using a higher threshold of gastric residuals volumes, use of motility agents, and use of small bowel feeding) and minimize the risks of EN (elevation of the head of the bed) should be considered. Use of products with fish oils, borage oils, and antioxidants should be considered for patients with acute respiratory distress syndrome. A glutamine-enriched formula should be considered for patients with severe burns and trauma. When initiating EN, we strongly recommend that PN not be used in combination with EN. When PN is used, we recommend that it be supplemented with glutamine, where available. Strategies that maximize the benefit and minimize the risks of PN (hypocaloric dose, withholding lipids, and the use of intensive insulin therapy to achieve tight glycemic control) should be considered. There are insufficient data to generate recommendations in the following areas: use of indirect calorimetry; optimal pH of EN; supplementation with trace elements, antioxidants, or fiber; optimal mix of fats and carbohydrates; use of closed feeding systems; continuous versus bolus feedings; use of probiotics; type of lipids; and mode of lipid delivery. VALIDATION: This guideline was peer-reviewed and endorsed by official representatives of the Canadian Critical Care Society, Canadian Critical Care Trials Group, Dietitians of Canada, Canadian Association of Critical Care Nurses, and the Canadian Society for Clinical Nutrition. SPONSORS: This guideline is a joint venture of the Canadian Critical Care Society, the Canadian Critical Trials Group, the Canadian Society for Clinical Nutrition, and Dietitians of Canada. The Canadian Critical Care Society and the Institute of Nutrition, Metabolism, and Diabetes of the Canadian Institutes of Health Research provided funding for development of this guideline.

Glutamine supplementation in serious illness: a systematic review of the evidence.

OBJECTIVE: To examine the relationship between glutamine supplementation and hospital length of stay, complication rates, and mortality in patients undergoing surgery and experiencing critical illness. DATA SOURCES: Computerized search of electronic databases and search of personal files, abstract proceedings, relevant journals, and review of reference lists. STUDY SELECTION: We reviewed 550 titles, abstracts, and articles. Primary studies were included if they were randomized trials of critically ill or surgical patients that evaluated the effect of glutamine vs. standard care on clinical outcomes. DATA EXTRACTION We abstracted relevant data on the methodology and outcomes of primary studies in duplicate, independently. DATA SYNTHESIS There were 14 randomized trials comparing the use of glutamine supplementation in surgical and critically ill patients. When the results of these trials were aggregated, with respect to mortality, glutamine supplementation was associated with a risk ratio (RR) of 0.78 (95% confidence interval [CI], 0.58-1.04). Glutamine supplementation was also associated with a lower rate of infectious complications (RR, 0.81; 95% CI, 0.64-1.00) and a shorter hospital stay (-2.6 days; 95% CI, -4.5 to -0.7). We examined several -specified subgroups. Although there were no statistically significant subgroup differences detected, there were some important trends. With respect to mortality, the treatment benefit was observed in studies of parenteral glutamine (RR, 0.71; 95% CI, 0.51-0.99) and high-dose glutamine (RR, 0.73; 95% CI, 0.53-1.00) compared with studies of enteral glutamine (RR, 1.08; 95% CI, 0.57-2.01) and low-dose glutamine (RR, 1.02; 95% CI, 0.52-2.00). With respect to hospital length of stay, all of the treatment benefit was observed in surgical patients (-3.5 days; 95% CI, -5.3 to -1.7) compared with critically ill patients (0.9 days; 95% CI, -4.9 to 6.8). CONCLUSION: In surgical patients, glutamine supplementation may be associated with a reduction in infectious complication rates and shorter hospital stay without any adverse effect on mortality. In critically ill patients, glutamine supplementation may be associated with a reduction in complication and mortality rates. The greatest benefit was observed in patients receiving high-dose, parenteral glutamine.