The ratio of energy expenditure to nitrogen loss in diverse patient groups--a systematic review.

BACKGROUND & AIMS: The ratio of energy expenditure to nitrogen loss respectively of energy to nitrogen provision (E/N) is considered a valuable tool in the creation of an enteral or parenteral formulation. Specific E/N ratios for parenteral nutrition (PN) have not yet been clearly defined. To determine the range of energy expenditure, nitrogen (protein) losses, and E/N ratios for various patient groups, we performed a systematic review of the literature. METHODS: Medline 1950-2011 was searched for all studies on patients or healthy controls reporting energy expenditure and nitrogen loss at the same time. RESULTS: We identified 53 studies with 91 cohorts which comprised 1107 subjects. Mean TEE ± standard deviation (SD) was 31.2 ± 7.2 kcal/kg BW/day in patients (n = 881) and 35.6 ± 4.3 kcal/kg BW/day in healthy controls (n = 266). Mean total protein loss (TPL) was 1.50 ± 0.57 g/kg BW/day in patients and 0.94 ± 0.24 g/kg BW/day in healthy controls. A non-linear significant correlation was found between TPL and the E/N ratio. CONCLUSION: The E/N ratio is not a constant value but decreases continuously with increasing protein loss. These variations should be considered in the nutritional support of patients.

Feeding practices of severely ill intensive care unit patients: an evaluation of energy sources and clinical outcomes.

OBJECTIVE: The quantity of nutrition that is provided to intensive care unit (ICU) patients has recently come under more scrutiny in relation to clinical outcomes. The primary objective of this study was to assess energy intake in severely ill ICU patients and to evaluate the relationship of energy intake with clinical outcomes. DESIGN: Prospective cohort study. SUBJECTS/SETTINGS: Seventy-seven adult surgery and medical ICU patients with length of ICU stay of at least 5 days. STATISTICAL ANALYSES PERFORMED: Student's t test and chi2 tests were used to examine ICU populations. To determine the relationship of patient variables to hospital length of stay and ICU, length of stay regression trees were calculated. RESULTS: Both groups were underfed with 50% of goal met in surgical ICU and 56% of goal met in medical ICU. Medical ICU patients received less propofol and significantly less dextrose-containing intravenous fluids when compared to surgical ICU patients (P=0.013). From regression analysis, approaching full nutrient requirements during ICU stay was associated with greater hospital length of stay and ICU length of stay. For combined groups, if % goal was > or =82%, the estimated average value for ICU length of stay was 24 days; whereas, if the % goal was <82%, the average ICU length of stay was 12 days. This relationship held true for hospital length of stay. CONCLUSIONS: Medical and surgical ICU patients were insufficiently fed during their ICU stay when compared with registered dietitian recommendations. Medical ICU patients received earlier nutrition support, on average more enteral nutrition, with fewer kilocalories supplied from lipid-based sedatives and intravenous fluid relative to surgical ICU patients. Based upon length of stay, the data suggest that the most severely ill patient may not benefit from delivery of full nutrient needs in the ICU.

Inflammatory mediators and immune function are altered in home parenteral nutrition patients.

OBJECTIVES: Patients who used home parenteral nutrition (HPN) and healthy, volunteer control subjects were examined to assess relative immune potential and inflammatory marker expression and to investigate the association between HPN and immune parameters. METHODS: Subjective Global Assessments were performed on all subjects. The peripheral blood concentration of C-reactive protein was determined by enzyme-linked immunosorbent assay. The peripheral blood concentration of systemic inflammatory mediators that included tumor necrosis factor-alpha (TNF-alpha), soluble TNF-alpha receptors p55 and p75, and interleukin-6 were similarly determined. Peripheral blood lymphocytes were isolated and the percentage of circulating CD4+ and CD8+ lymphocytes was determined by flow cytometry. In addition, peripheral blood lymphocytes were cultured in the presence of the T-cell mitogen, phytohemagglutinin, and the proliferative response of the CD3+ population was assessed by flow cytometry. Results of these experiments were obtained for 10 clinically stable patients who had used HPN longer than 2 y and these results were compared by Student's t test with data obtained for 12 normal, volunteer control subjects. RESULTS: Of the 10 patients who used HPN and were examined, seven had short bowel syndrome, two had dysmotility, and one required HPN due to radiation enteritis. Based on Subjective Global Assessments, all patients were well nourished. No difference was observed in TNF-alpha level between groups and C-reactive protein levels were within normal limits (1.2 mg/L in patients, 0.99 mg/L in controls). Soluble TNF-alpha receptors p55 and p75 were significantly increased (P < 0.001), but serum interleukin-6 was not (P = 0.07). The percentage of CD8+ cells and the CD4+/CD8+ ratio were not statistically different between groups. In contrast to this result, the percentage of CD4+ cells and the proliferative T-cell response to phytohemagglutinin were significantly depressed in patients who used HPN versus control subjects. CONCLUSIONS: These data suggest the presence of an underlying inflammatory process and subsequent abnormal T-lymphocyte function in patients who use HPN.

Evidence-based clinical practice: dispelling the myths.

Evidence-based practice merges the best and most relevant clinical research data with clinician experience, pathophysiology of disease state, and the specifics of individual patient care. Currently, there is a significant gap between the best research evidence in healthcare and application of this evidence to clinician practices. Consistent with this finding, nutrition support is not always applied effectively or consistently, despite available scientific evidence that could be used to enhance a given treatment protocol. Cited obstacles that prevent the incorporation of research evidence into daily practice include lack of time, inadequate research skills, and information overload. Identification and application of the most valid primary research and evidence summaries (clinical guides to practice and meta-analyses) should, however, be an integral part of appropriate nutrition care. Consequently, it is important that clinicians develop and improve upon the basic skills required to allow efficient and accurate searches and evaluations of the literature. This review describes the basic and practical components of evidence-based medicine and provides tools to determine whether current nutrition practices are based upon an analysis of valid clinical evidence or anecdotal nutrition traditions and myths.

Validation of energy intake measurements determined from observer-recorded food records and recall methods compared with the doubly labeled water method in overweight and obese individuals.

BACKGROUND: Measurements of dietary intake in obese and overweight populations are often inaccurate because food intakes are underestimated. OBJECTIVE: The purpose of this study was to evaluate the validity of the combined use of observer-recorded weighed-food records and 24-h snack recalls in estimating energy intakes in overweight and obese individuals. DESIGN: Subjects were 32 healthy women and 22 healthy men with mean body mass indexes (in kg/m(2)) of 29.5 and 30.3, respectively. Energy intake (EI) was measured over 2 wk in a university cafeteria. No restrictions were made on meal frequency or EI. To document food consumed outside the cafeteria, 24-h snack recalls were conducted before meals. Energy expenditure (EE) was measured with the doubly labeled water (DLW) method (EE(DLW)). Energy balance was determined by measuring body weight at the beginning and end of the 2-wk period. RESULTS: The mean EI in the women (10.40 +/- 1.94 MJ/d) and men (14.37 +/- 3.21 MJ/d) was not significantly lower than the EE(DLW) in the women (10.86 +/- 1.76 MJ/d) and men (14.14 +/- 2.83 MJ/d). The mean EI represented 96.9 +/- 17.0% and 103 +/- 18.9% of the measured EE for women and men, respectively. There were no significant changes in weight in the group as a whole or by sex at the end of the testing period; the men lost 0.23 +/- 1.58 kg and the women lost 0.25 +/- 1.09 kg. CONCLUSION: The combination of observer-recorded food records and 24-h snack recalls is a valid method for measuring EI in overweight and obese individuals.