(Mal)nutrition in critical illness and beyond: a narrative review.

Close liaison with ICU-trained dietitians and early initiation of nutrition is a fundamental principle of care of critically ill patients- this should be done while monitoring closely for refeeding syndrome. Enteral nutrition delivered by volumetric pumps should be used where possible, though parenteral nutrition should be started early in patients with high nutritional risk factors. Malnutrition and loss of muscle mass are common in patients who are admitted to ICUs and are prognostic for patient-centred outcomes including complications and mortality. Obesity is part of that story, and isocaloric and high-protein provision of nutrition is important in this group of patients who comprise a growing proportion of people treated. Assessing protein stores and appropriate dosing is, however, challenging in all groups of patients. It would be beneficial to develop strategies to reduce muscle wasting as well; various strategies including amino acid supplementation, ketogenic nutrition and exercise have been trialled, but the quality of data has been inadequate to address this phenomenon. Nutritional targets are rarely achieved in practice, and all ICUs should incorporate clear guidelines to help address this. These should include local nutritional and fasting guidelines and for the management of feed intolerance, early access to post-pyloric feeding and a multidisciplinary framework to support the importance of nutritional education.

Leucine-enriched essential amino acid supplementation in mechanically ventilated trauma patients: a feasibility study.

BACKGROUND: Critically ill patients lose up to 2% of muscle mass per day. We assessed the feasibility of administering a leucine-enriched essential amino acid (L-EAA) supplement to mechanically ventilated trauma patients with the aim of assessing the effect on skeletal muscle mass and function. METHODS: A randomised feasibility study was performed over six months in intensive care (ICU). Patients received 5 g L-EAA five times per day in addition to standard feed (L-EAA group) or standard feed only (control group) for up to 14 days. C-reactive protein, albumin, IL-6, IL-10, urinary 3-MH, nitrogen balance, protein turnover ([1-13C] leucine infusion), muscle depth change (ultrasound), functional change (Katz and Barthel indices) and muscle strength Medical Research Council (MRC) sum score to assess ICU Acquired Weakness were measured sequentially. RESULTS: Eight patients (9.5% of screened patients) were recruited over six months. L-EAA doses were provided on 91/124 (73%) occasions. Inflammatory and urinary marker data were collected; serial muscle depth measurements were lacking due to short length of stay. Protein turnover studies were performed on five occasions. MRC sum score could not be performed as patients were not able to respond to the screening questions. The Katz and Barthel indices did not change. L-EAA delivery was achievable, but meaningful functional and muscle mass outcome measures require careful consideration in the design of a future randomised controlled trial. CONCLUSION: L-EAA was practical to provide, but we found significant barriers to recruitment and measurement of the chosen outcomes which would need to be addressed in the design of a future, large randomised controlled trial. TRIAL REGISTRATION: ISRCTN Registry, ISRCTN79066838 . Registered on 25 July 2012.

Does body mass index impact on muscle wasting and recovery following critical illness? A pilot feasibility observational study.

BACKGROUND: Critical illness is associated with muscle loss, weakness and poor recovery. The impact that illness and the ensuing metabolic response has on obese patients is not known. Objectives were to test if obese patients lose less muscle depth compared to non-obese patients; if a reduction in muscle depth was associated with reduced strength and recovery; and to assess the feasibility of these methods with a range of body mass index's (BMI). METHODS: A prospective observational pilot study of muscle depth in critically ill patients categorised by BMI was performed. Muscle depth changes were assessed by ultrasound on study days 1, 3, 5, 7, 12 and 14. Strength was measured via handgrip dynamometry and Medical Research Council (MRC) sum score on waking and at discharge from the intensive care unit. Level of dependency was measured with the Barthel index. RESULTS: 44 critically ill patients; 17 had normal BMI, 10 were overweight and 17 were obese. The three groups did not differ in baseline characteristics, except obese patients had significantly greater initial muscle depth. Muscle depth loss was similar between the BMI groups at each of the time points. Handgrip and MRC sum score were only possible in a small number of patients because of reduced alertness and weakness. Majority were deemed fully dependent based on the Barthel index. CONCLUSIONS: Obese patients lost muscle depth in a comparable manner to non-obese patients, suggesting that BMI may not prevent muscle depth loss. It was not possible to determine the effect on strength because the clinical condition of patients precluded reliable measurements.

Impact of supplementation with amino acids or their metabolites on muscle wasting in patients with critical illness or other muscle wasting illness: a systematic review.

Muscle wasting during critical illness impairs recovery. Dietary strategies to minimise wasting include nutritional supplements, particularly essential amino acids. We reviewed the evidence on enteral supplementation with amino acids or their metabolites in the critically ill and in muscle wasting illness with similarities to critical illness, aiming to assess whether this intervention could limit muscle wasting in vulnerable patient groups. Citation databases, including MEDLINE, Web of Knowledge, EMBASE, the meta-register of controlled trials and the Cochrane Collaboration library, were searched for articles from 1950 to 2013. Search terms included 'critical illness', 'muscle wasting', 'amino acid supplementation', 'chronic obstructive pulmonary disease', 'chronic heart failure', 'sarcopenia' and 'disuse atrophy'. Reviews, observational studies, sport nutrition, intravenous supplementation and studies in children were excluded. One hundred and eighty studies were assessed for eligibility and 158 were excluded. Twenty-two studies were graded according to standardised criteria using the GRADE methodology: four in critical care populations, and 18 from other clinically relevant areas. Methodologies, interventions and outcome measures used were highly heterogeneous and meta-analysis was not appropriate. Methodology and quality of studies were too varied to draw any firm conclusion. Dietary manipulation with leucine enriched essential amino acids (EAA), ß-hydroxy-ß-methylbutyrate and creatine warrant further investigation in critical care; EAA has demonstrated improvements in body composition and nutritional status in other groups with muscle wasting illness. High-quality research is required in critical care before treatment recommendations can be made.

Identifying the factors that influence energy deficit in the adult intensive care unit: a mixed linear model analysis.

BACKGROUND: Critically ill patients frequently receive inadequate nutrition support as a result of under- or overfeeding. Malnutrition in intensive care unit (ICU) patients is associated with increased morbidity and mortality. The present study aimed to identify the significant factors that influence energy deficit in the ICU. METHODS: ICU patients with a length of stay of ≥3 days were studied for 30 days over two consecutive years at a large university teaching hospital. Fifty-six Patients were studied, with a total of 530 records of feeding days. Information was collected for: day when feed initiated, age, gender, length of stay, Acute Physiological and Chronic Health Evaluation score (APACHE II), fed within 24 h, speciality, type of ventilation, feeding route, outcome (survived/died), diarrhoea (yes/no), aspirate volume, dietitian observed nutritional status (malnourished/not), sedation, estimated energy requirements and energy received. Mixed linear models for longitudinal data were used with energy deficit (energy received - energy requirements) as the dependent variable. RESULTS: Factors that were found to have a significant association with energy deficit were: day feeding was initiated (P<0.001), whether fed within 24 h (P<0.001) and whether sedated (P<0.001). Furthermore, three combined effects were found: ventilation mode and aspirate volume (P<0.007), fed within 24 h and ventilation mode (P<0.001), fed within 24 h and sedation (P<0.017). CONCLUSIONS: The number of days after feeding was initiated, initiation of feeding within 24 h and sedation have been identified as factors that predict energy deficit during ICU stay. Efforts to initiate feeding as soon as possible and minimise interruptions to feeding may reduce energy deficits in these vulnerable patients.