Energy balance in elderly patients after surgery for a femoral neck fracture

To study energy and protein balances in elderly patients after surgery, spontaneous energy and protein intake and resting energy expenditure (REE) were measured in 20 elderly female patients with a femoral neck fracture (mean age 81 +/- 4, SD, range 74-87 years; weight 53 +/- 8, range 42-68 kg) during a 5-6 day period following surgery. REE, measured over 20-40 min by indirect calorimetry using a ventilated canopy, averaged 0.98 +/- 0.15 kcal/min on day 3 and decreased to 0.93 +/- 0.15 kcal/min on day 8-9 postsurgery (p less than 0.02). REE was positively correlated with body weight (r = 0.69, p less than 0.005). Mean REE extrapolated to 24 hr (24-REE) was 1283 +/- 194 kcal/day. Mean daily food energy intake measured over the 5-day follow-up period was 1097 +/- 333 kcal/day and was positively correlated with 24-REE (r = 0.50, p less than 0.05). Daily energy balance was -235 +/- 351 kcal/day on day 3 (p less than 0.01 vs zero) and -13 +/- 392 kcal/day on day 8-9 postsurgery (NS vs zero) with a mean over the study period of -185 +/- 289 kcal/day (p less than 0.01 vs zero). When an extra 100 kcal/day was allowed for the energy cost of physical activity, mean daily energy balance over the 5-day study period was calculated to be -285 +/- 289 kcal/day (p less than 0.01 vs zero). Measurements of total 24-hr urinary nitrogen (N) excretion were obtained in a subgroup of 14 patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Resting energy expenditure in asymptomatic HIV-infected females

The purpose of this study was to investigate whether resting energy expenditure (REE) is elevated in early, asymptomatic human immunodeficiency virus (HIV)-infected females and to study the contribution of a cytokine, tumor necrosis factor-alpha (TNF-alpha), to hypermetabolism. Cross-sectional comparison of REE in asymptomatic HIV+ females and a control group matched for age, body mass index (BMI), and fat-free mass (FFM). Twenty-six females aged 35 +/- 7 years (10 HIV+ [mean CD4+ T cell count 636/mm3] and 16 healthy controls) participated in this study. REE was measured by indirect calorimeter using a Deltatrac ventilated hood with a continuous rate of 40 L/min for 30 minutes after a 40-minute equilibrium period. All tests were performed after a 12-hour overnight fast. Twenty-four-hour urinary nitrogen was calculated to correct for respiratory quotient. Body composition was measured by bioelectrical impedance (BioAnalogics, Beaverton, OR). TNF-alpha was measured by ELISA (R & D Systems, Minneapolis, MN). Absolute REE was 17% higher (1755 kcal/kg +/- 410 versus 1497 kcal/kg +/- 197) in the HIV+ group compared with the control group (p < 0.05). REE remained significantly higher in the HIV+ group when REE was adjusted for body composition differences (p = 0.04). Results revealed a 23% higher level of TNF-alpha in the HIV+ subjects (p < 0.01); however, only a weak correlation existed between TNF-alpha and REE (r = .352). This study documented that hypermetabolism and elevated TNF-alpha exist in HIV+ females in the early stages of disease.     

Resting energy expenditure in patients with end-stage liver disease and in normal population

Resting energy expenditure (REE) was measured in 10 patients with end-stage liver disease (ELD) and in 31 normal controls. Basal energy expenditure (BEE) was also predicted by the Harris-Benedict equation. In order to correlate REE to lean body mass, the 24-hr urinary creatinine was measured in patients with ELD and in normal controls and expressed as kcal/g urinary creatinine. Linear regression analysis showed a statistically significant (p less than 0.0001) correlation (r = 0.72) between the REE and the 24-hr urinary creatinine in normal controls, irrespective of age and sex. Mean BEE (1580 +/- 160 vs 1575 +/- 210) and REE (1755 +/- 215 vs 1800 +/- 330) were not significantly different between patients with ELD and controls. However, the mean REE was 1900 +/- 610 kcal/g creatinine in patients with ELD and 1180 +/- 260 (p less than 0.0001) in controls. When related to lean tissue, patients with ELD had increased energy expenditure, confirming the hypermetabolic state suggested on clinical grounds. The use of urine creatinine to estimate energy expenditure may be a simple clinical technique to predict dietary energy needs in malnourished, unstressed patients. When this estimated energy expenditure/g creatinine (EEE) is compared to measured energy expenditure/g creatinine in malnourished, stressed patients, the EEE provides an index of the extent of hypermetabolism.     

Prospective study of resting energy expenditure changes in head and neck cancer patients treated with chemoradiotherapy measured by indirect calorimetry

OBJECTIVE: The prevalence of malnutrition is high in patients with head and neck cancer due to tumor location and coadjuvant treatment. We studied changes in resting energy expenditure (REE) during treatment with chemoradiotherapy and compared the measured REE by indirect calorimetry (IC) with the value estimated by the Harris-Benedict (HB) formula. METHODS: Eighteen patients with head and neck cancer (15 men and 3 women, mean age 57 +/- 10.7 y, age range 30-71 y) entered the study. All patients were treated with radiotherapy (70.8 +/- 1 Gy, range 70-72) and received 37.4 +/- 3.5 fractions (range 32-42) and concurrent chemotherapy with cisplatinum (absolute doses of 400 to 1000 mg). Nutrition assessment included anthropometry (body mass index, triceps skinfold thickness, subscapular skinfold thickness, midarm circumference, and midarm muscle circumference) and tetrapolar bioimpedance (Holtain BC). The IC (kcal/24 h; Deltatrac II MBM-200) was performed after an overnight fast. Measurements were done before treatment, at weeks 2, 4, and 6 of treatment, at the end of treatment, and 2 wk after treatment. RESULTS: Body mass index decreased during treatment from 24.7 +/- 4.4 kg/m(2) (range 16.9-31.4) to 22.3 +/- 4.2 kg/m(2) (range 15.1-29.6). REE (kcal/24 h) changed significantly during treatment (IC P < 0.05, HB formula P < 0.001). REE measured by IC appeared as a U-shaped curve, but REE estimated by the HB formula decreased during treatment. The HB underestimated REE measurements compared with IC. These differences were statistically significant before treatment, at the end of treatment, and 2 wk after treatment (P < 0.05) and showed a limited clinical agreement with the Bland-Altman method. CONCLUSIONS: REE measured by IC significantly changed during chemoradiotherapy. It was higher before treatment, at the end of treatment, and 2 wk after treatment. The HB formula underestimated REE in these patients. IC is a suitable method for measuring REE in this cohort of patients.     

Accurate determination of energy needs in hospitalized patients

OBJECTIVE: To evaluate the accuracy of seven predictive equations, including the Harris-Benedict and the Mifflin equations, against measured resting energy expenditure (REE) in hospitalized patients, including patients with obesity and critical illness. DESIGN: A retrospective evaluation using the nutrition support service database of a patient cohort from a similar timeframe as those used to develop the Mifflin equations. SUBJECTS/SETTING: All patients with an ordered nutrition assessment who underwent indirect calorimetry at our institution over a 1-year period were included. INTERVENTION: Available data was applied to REE predictive equations, and results were compared to REE measurements. MAIN OUTCOME MEASURES: Accuracy was defined as predictions within 90% to 110% of the measured REE. Differences >10% or 250 kcal from REE were considered clinically unacceptable. STATISTICAL ANALYSES PERFORMED: Regression analysis was performed to identify variables that may predict accuracy. Limits-of-agreement analysis was carried out to describe the level of bias for each equation. RESULTS: A total of 395 patients, mostly white (61%) and African American (36%), were included in this analysis. Mean age+/-standard deviation was 56+/-18 years (range 16 to 92 years) in this group, and mean body mass index was 24+/-5.6 (range 13 to 53). Measured REE was 1,617+/-355 kcal/day for the entire group, 1,790+/-397 kcal/day in the obese group (n=51), and 1,730+/-402 kcal/day in the critically ill group (n=141). The most accurate prediction was the Harris-Benedict equation when a factor of 1.1 was multiplied to the equation (Harris-Benedict 1.1), but only in 61% of all the patients, with significant under- and over-predictions. In the patients with obesity, the Harris-Benedict equation using actual weight was most accurate, but only in 62% of patients; and in the critically ill patients the Harris-Benedict 1.1 was most accurate, but only in 55% of patients. The bias was also lowest with Harris-Benedict 1.1 (mean error -9 kcal/day, range +403 to -421 kcal/day); but errors across all equations were clinically unacceptable. CONCLUSIONS: No equation accurately predicted REE in most hospitalized patients. Without a reliable predictive equation, only indirect calorimetry will provide accurate assessment of energy needs. Although indirect calorimetry is considered the standard for assessing REE in hospitalized patients, several predictive equations are commonly used in practice. Their accuracy in hospitalized patients has been questioned. This study evaluated several of these equations, and found that even the most accurate equation (the Harris-Benedict 1.1) was inaccurate in 39% of patients and had an unacceptably high error. Without knowing which patient's REE is being accurately predicted, indirect calorimetry may still be necessary in difficult to manage hospitalized patients.     

The effect of a high protein-low calorie diet on the energy expenditure of obese adolescents.

Resting energy expenditure (REE), and body composition, as fat-free mass (FFM) and fat mass, were determined in seven obese adolescents before and after weight loss of a mean 13.5 kg on an approximately 800 kcal/d (3349 kJ), high protein reducing diet regimen. Ideal body weight decreased from 166% to 142% in 8 weeks. There were no significant changes in total body potassium (TBK), extracellular water (ECW), intracellular water (ICW) or total body water (TBW) with weight loss. The REE (kcal/d) fell from 2034 +/- 392 (8514 +/- 1641 kJ) to 1762 +/- 453 (7376 +/- 1896 kJ) with weight loss (P < 0.05). However, when the REE was expressed as kcal/body weight there was no difference between before and after weight loss, 21.4 +/- 2.8 (90 +/- 21 kJ) and 21.6 +/- 4.5 (90 +/- 19 kJ). Similarly, when REE was examined in relation to FFM (kcal/kg) before and after weight loss, there were also no significant differences: 34.6 +/- 5.1 (145 +/- 21 kJ) and 32.1 +/- 7.9 (134 +/- 33 kJ).     

Resting energy expenditure and plasma leptin levels in anorexia nervosa during acute refeeding

OBJECTIVE: To examine changes in plasma leptin levels and resting energy expenditure (REE) during short-term refeeding of patients with anorexia nervosa (AN). METHOD: This was a longitudinal study of 21 women meeting the DSM-IV criteria for AN who were admitted to the hospital for renutrition. Height, weight, percent body fat (assessed by skin fold thickness), REE (measured by indirect calorimetry), and circulating plasma leptin concentration were assessed at the time of admission and 7 days later. RESULTS: Over the course of 1 week of refeeding, body mass index (BMI) increased 0.75 +/- 0.15 kg/m(2) (p <.0001), body fat increased 0.9 +/- 0.2% (p <.0001), and REE increased 107 +/- 33 kcal/24 hr (p =.0037). The change in mean leptin levels was not statistically significant (0.45 +/- 0.44 ng/ml; p =.32). DISCUSSION: Leptin is unlikely responsible for the increase in REE observed with short-term refeeding.     

Resting energy expenditure in children with cyanotic and noncyanotic congenital heart disease before and after open heart surgery

BACKGROUND: Failure to thrive is a common problem in children with congenital heart disease (CHD). Resting energy expenditure (REE) in cyanotic and noncyanotic children with CHD before and after open heart surgery has hardly been investigated. METHODS: Twenty-nine children younger than 3 years of age with CHD (14 cyanotic and 15 noncyanotic CHD) who were referred for open heart surgery were enrolled. Data on dietary intake, anthropometric measurements, and indirect calorimetry parameters were measured 24 hours before the surgery, (day -1), and on day 5 after surgery. The measured REE was compared with the Schofield and World Health Organization (WHO) REE prediction equations. RESULTS: The mean +/- SD measured REE was similar in the cyanotic and noncyanotic children before and after surgery (before surgery: 57 +/- 13 and 58 +/- 9 kcal/kg per day, respectively; 5 days after surgery: 59 +/- 10 and 62 +/- 10 kcal/kg per day, respectively). Oxygen consumption (VO2) and carbon dioxide production (VCO2) did not change significantly before and after surgery and were similar in both groups. The measured REE for all children on day -1 and day 5 was similar to the calculated REE using the Schofield equation but was significantly different from the calculated REE using the WHO equation (p < .01). CONCLUSIONS: Significant changes in REE, VCO2, and VO2 were not observed before and 5 days after open heart surgery in children with CHD. These parameters (REE, VCO2, and VO2) were also similar in children with cyanotic versus noncyanotic CHD. The Schofield equation is more accurate than the WHO equation in predicting energy needs of children with CHD, but measurement of REE is preferred over calculation of REE.     

Hypermetabolism in clinically stable patients with liver cirrhosis.

BACKGROUND: Hypermetabolism has a negative effect on prognosis in patients with liver cirrhosis. Its exact prevalence and associations with clinical data, the nutritional state, and beta-adrenergic activity are unclear. OBJECTIVE: We investigated resting energy expenditure (REE) in 473 patients with biopsy-proven liver cirrhosis. DESIGN: This was a cross-sectional study with a controlled intervention (beta-blockade) in a subgroup of patients. RESULTS: Mean REE was 7.12 +/- 1.34 MJ/d and correlated closely with predicted values (r = 0.70, P < 0.0001). Hypermetabolism was seen in 160 patients with cirrhosis (33.8% of the study population). REE was > 30% above the predicted value in 41% of the hypermetabolic patients with cirrhosis. Hypermetabolism had no association with clinical or biochemical data on liver function. REE correlated with total body potassium content (TBP; r = 0.49, P < 0.0001). Hypermetabolic patients had lower than normal body weight and TBP (P < 0.05). About 47% of the variance in REE could be explained by body composition whereas clinical state could maximally explain 3%. Plasma epinephrine and norepinephrine concentrations were elevated in hypermetabolic cirrhotic patients (by 56% and 41%, respectively; P < 0.001 and 0.01). Differences in REE from predicted values were positively correlated with epinephrine concentration (r = 0.462, P < 0.001). Propranolol infusion resulted in a decrease in energy expenditure (by 5 +/- 3%; P < 0.05), heart rate (by 13 +/- 4%; P < 0.01), and plasma lactate concentrations (by 32 +/- 12%; P < 0.01); these effects were more pronounced in hypermetabolic patients (by 50%, 33%, and 68%, respectively; each P < 0.05). CONCLUSIONS: Hypermetabolism has no association with clinical data and thus is an extrahepatic manifestation of liver disease. Increased beta-adrenergic activity may explain approximately 25% of hypermetabolism.     

Comparison of energy-restricted very low-carbohydrate and low-fat diets on weight loss and body composition in overweight men and women

OBJECTIVE: To compare the effects of isocaloric, energy-restricted very low-carbohydrate ketogenic (VLCK) and low-fat (LF) diets on weight loss, body composition, trunk fat mass, and resting energy expenditure (REE) in overweight/obese men and women. DESIGN: Randomized, balanced, two diet period clinical intervention study. Subjects were prescribed two energy-restricted (-500 kcal/day) diets: a VLCK diet with a goal to decrease carbohydrate levels below 10% of energy and induce ketosis and a LF diet with a goal similar to national recommendations (%carbohydrate:fat:protein = ~60:25:15%). SUBJECTS: 15 healthy, overweight/obese men (mean +/- s.e.m.: age 33.2 +/- 2.9 y, body mass 109.1 +/- 4.6 kg, body mass index 34.1 +/- 1.1 kg/m2) and 13 premenopausal women (age 34.0 +/- 2.4 y, body mass 76.3 +/- 3.6 kg, body mass index 29.6 +/- 1.1 kg/m2). MEASUREMENTS: Weight loss, body composition, trunk fat (by dual-energy X-ray absorptiometry), and resting energy expenditure (REE) were determined at baseline and after each diet intervention. Data were analyzed for between group differences considering the first diet phase only and within group differences considering the response to both diets within each person. RESULTS: Actual nutrient intakes from food records during the VLCK (%carbohydrate:fat:protein = ~9:63:28%) and the LF (~58:22:20%) were significantly different. Dietary energy was restricted, but was slightly higher during the VLCK (1855 kcal/day) compared to the LF (1562 kcal/day) diet for men. Both between and within group comparisons revealed a distinct advantage of a VLCK over a LF diet for weight loss, total fat loss, and trunk fat loss for men (despite significantly greater energy intake). The majority of women also responded more favorably to the VLCK diet, especially in terms of trunk fat loss. The greater reduction in trunk fat was not merely due to the greater total fat loss, because the ratio of trunk fat/total fat was also significantly reduced during the VLCK diet in men and women. Absolute REE (kcal/day) was decreased with both diets as expected, but REE expressed relative to body mass (kcal/kg), was better maintained on the VLCK diet for men only. Individual responses clearly show the majority of men and women experience greater weight and fat loss on a VLCK than a LF diet. CONCLUSION: This study shows a clear benefit of a VLCK over LF diet for short-term body weight and fat loss, especially in men. A preferential loss of fat in the trunk region with a VLCK diet is novel and potentially clinically significant but requires further validation. These data provide additional support for the concept of metabolic advantage with diets representing extremes in macronutrient distribution.     

Resting energy expenditure in cancer patients before and after gastrointestinal surgery.

The aim of this study was to assess the impact of surgical trauma on energy metabolism in cancer patients. Therefore, resting energy expenditure (REE) was determined before and after surgery in patients with newly detection gastric and colorectal cancer. Preoperative REE was measured in 104 patients. In 65 of these 104 patients REE was also measured on the seventh or eighth postoperative day. Postoperative REE was significantly higher than preoperative REE (mean +/- SD: 1471 +/- 238 vs 1376 +/- 231 kcal; p less than 0.001). After surgery 22 patients were hypermetabolic (REE greater than or equal to 115% predicted energy expenditure) compared with seven hypermetabolic patients before surgery. This hypermetabolism in the postoperative state can be explained by the administration of total parenteral nutrition (TPN), by an increased body temperature mainly as a consequence of postoperative complications and by the surgical trauma itself. Patients who received preoperative TPN (n = 12) showed a 10% increase in REE. Thirteen patients suffered from minor and major postoperative complications; postoperative REE in this group was increased by 10%. Forty patients who had undergone uncomplicated surgery showed a slight but significant increase of 3% in REE after operation. We conclude from this study that the increase in REE resulting from surgical trauma itself is modest at the seventh to eighth postoperative day. Therefore, energy requirements for patients undergoing major elective surgical stress are lower than generally presumed.     

Prediction of daily energy expenditure during a feeding trial using measurements of resting energy expenditure, fat-free mass, or Harris-Benedict equations

BACKGROUND: During feeding trials, it is useful to predict daily energy expenditure (DEE) to estimate energy requirements and to assess subject compliance. OBJECTIVE: We examined predictors of DEE during a feeding trial conducted in a clinical research center. DESIGN: During a 28-d period, all food consumed by 26 healthy, nonobese, young adults was provided by the investigators. Energy intake was adjusted to maintain constant body weight. Before and after this period, fat-free mass (FFM) and fat mass were assessed by using dual-energy X-ray absorptiometry, and DEE was estimated from the change (after - before) in body energy (DeltaBE) and in observed energy intake (EI): DEE = EI - DeltaBE. We examined the relation of DEE to pretrial resting energy expenditure (REE), FFM, REE derived from the average of REE and calculated from FFM [REE = (21.2 x FFM) + 415], and an estimate of DEE based on the Harris-Benedict equation (HB estimate) (DEE = 1.6 REE). RESULTS: DEE correlated (P < 0.001) with FFM (r = 0.78), REE (r = 0.73), average REE (r = 0.82), and the HB estimate (r = 0.81). In a multiple regression model containing all these variables, R(2) was 0.70. The mean (+/-SEM) ratios of DEE to REE, to average REE, and to the HB estimate were 1.86 +/- 0.06, 1.79 +/- 0.04, and 1.02 +/- 0.02, respectively. CONCLUSIONS: Although a slightly improved prediction of DEE is possible with multiple measurements, each of these measurements suggests that DEE equals 1.60-1.86 x REE. The findings are similar to those of previous studies that describe the relation of REE to DEE measured directly.     

DXA: potential for creating a metabolic map of organ-tissue resting energy expenditure components

OBJECTIVE: This study tested the hypothesis that tissue-organ components can be derived from DXA measurements, and in turn, resting energy expenditure (REE) can be calculated from the summed heat productions of DXA-estimated brain, skeletal muscle mass (SM), adipose tissue, bone, and residual mass (RM). RESEARCH METHODS AND PROCEDURES: Subjects were divided into five groups of adults <50 years of age. The specific metabolic rate of RM was developed in 13 Group I healthy subjects and a DXA-brain mass prediction formula in 52 Group II subjects. SM, adipose tissue, and bone models were developed based on earlier reports. The composite REE prediction model (REEp) was tested in 154 Group III subjects in whom REEp was compared with measured REE (REEm). Features of the developed model were determined in 94 normal-weight men and women (Group IV) and seven spinal cord injury patients and healthy matched controls (Group V). RESULTS: REEp and REEm in Group III were highly correlated (y = 0.85x + 233; r = 0.82, p < 0.001), and no bias was detected. Both REEm (mean +/- SD, 1,579 +/- 324 kcal/d) and REEp (1,585 +/- 316 kcal/d) were also highly correlated (r values = 0.85 to 0.98; p values < 0.001) and provided similar group values to REE estimated by the Harris-Benedict equations (1,597 +/- 279 kcal/d) and Wang's composite fat-free mass-based REE equation (1,547 +/- 248 kcal/d). New insights into the sources and distribution of REE were provided by analysis of the demonstration groups. DISCUSSION: This approach offers a new practical and educational opportunity to examine REE in subject groups using modeling strategies that reveal the magnitude and distribution of fundamental somatic heat-producing units.     

Glucose metabolism in advanced lung cancer patients.

Although it is generally accepted that altered nutrient intake and metabolism are responsible for the progressive loss of body weight observed in most advanced cancer patients, there is still considerable controversy regarding the contributory role of changes in both resting energy expenditure (REE) and glucose metabolism. Several studies suggest increases in both REE and glucose appearance in advanced cancer patients compared with healthy control subjects, whereas others revealed no changes in either metabolic parameter. We measured REE with indirect calorimetry and glucose kinetics with a primed constant infusion of D-[U-14C]glucose and D-[6-3H]glucose over the last 4 h of a 24-h fast in 32 advanced lung cancer patients immediately after diagnosis and before any chemotherapy or radiotherapy and in 19 healthy volunteer subjects. REE for the lung cancer group was not significantly different from that in the control group (1535.8 +/- 78.0 vs. 1670.2 +/- 53.9 kcal/day, respectively, p = 0.151). When REE was expressed as a function of body weight, or lean body mass, no differences between the two groups were observed. The rate of glucose appearance was 9.88 +/- 0.36 mumol.kg-1.min-1 in the cancer patients and 10.15 +/- 0.53 mumol.kg-1.min-1 in control subjects (p = 0.667), of which 50.4 versus 58.2%, respectively, was oxidized. The amount of glucose recycled was 13.54 +/- 1.22% in cancer patients and 15.08 +/- 0.99% in control subjects (p = 0.394). The amount of VCO2 from direct oxidation of glucose was 23.39 +/- 0.74% in cancer patients and 27.45 +/- 1.36% in control subjects (p = 0.006).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of exercise training on resting energy expenditure during caloric restriction

Resting energy expenditure (REE), maximum oxygen uptake (VO2max), and body composition were measured in seven moderately obese women during 9 wk of dietary restriction (800 kcal/d). During weeks 4-6, subjects underwent exercise training (30 min cycling/d, 5 d/wk, at 70% VO2max). The first 3 wk of caloric restriction decreased REE by 13% (from 1437 +/- 76 to 1254 +/- 66 kcal/24 h, means +/- SEM, p less than 0.05). Exercise training increased VO2max (from 1717 +/- 108 to 1960 +/- 120 mL/min, means +/- SEM, p less than 0.05) but did not elevate the dietary-depressed REE (from 1254 +/- 66 to 1262 +/- 62 kcal/24 h). The greatest decrease in body fat (3.7 +/- 0.4 kg) occurred during exercise training, resulting in a small apparent increase in REE when expressed per kilogram total body weight. However, expressed per unit lean body mass, REE remained suppressed throughout the period of caloric restriction. We conclude that exercise training of sufficient intensity to substantially increase VO2max does not reverse the dietary-induced depression of REE.     

Resting and sleeping energy expenditure in the elderly

An estimate of a patient's energy needs is usually derived from equations, which predict energy expenditure (EE) by considering sex, age and body weight. Due to the increasing number of elderly people in a hospital population, more data on energy requirements in this age-group are needed. In this study resting energy expenditure (REE) of 40 healthy men and women, aged 51-82 years, was measured using a ventilated hood system. The results showed that some commonly used prediction equations underestimated REE by approximately 6 per cent. REE was highly correlated with fat free mass (FFM) (r = 0.88; P less than 0.001) and body weight (r = 0.85; P less than 0.001). A stepwise multiple regression analysis showed that the combination of body weight, sex and age resulted in the best prediction for REE; REE (kcal) = 1641 + 10.7 weight (kg)--9.0 age (years)--203 sex (1 = male, 2 = female) (r = 0.92). However, REE of an individual may be over- or underestimated by +/- 225 kcal (10-20 per cent) due to large between-subject variations. We suggest therefore that the energy requirements of elderly people should be measured rather than predicted. Due to small within-subject variations (including measurement error) a single REE measurement would suffice. Sleeping energy expenditure (SEE) was 7 per cent lower than REE.     

Assessment of resting energy expenditure in mechanically ventilated patients

BACKGROUND: Usual equations for predicting resting energy expenditure (REE) are not appropriate for critically ill patients, and indirect calorimetry criteria render its routine use difficult. OBJECTIVE: Variables that might influence the REE of mechanically ventilated patients were evaluated to establish a predictive relation between these variables and REE. DESIGN: The REE of 70 metabolically stable, mechanically ventilated patients was prospectively measured by indirect calorimetry and calculated with the use of standard predictive models (Harris and Benedict's equations corrected for hypermetabolism factors). Patient data that might influence REE were assessed, and multivariate analysis was conducted to determine the relations between measured REE and these data. Measured and calculated REE were compared by using the Bland-Altman method. RESULTS: Multivariate analysis retained 4 independent variables defining REE: body weight (r(2) = 0.14, P < 0.0001), height (r(2) = 0.11, P = 0.0002), minute ventilation (r(2) = 0.04, P = 0.01), and body temperature (r(2) = 0.07, P = 0.002): REE (kcal/d) = 8 x body weight + 14 x height + 32 x minute ventilation + 94 x body temperature - 4834. REE calculated with this equation was well correlated with measured REE (r(2) = 0.61, P < 0.0001). Bland-Altman plots showed a mean bias approaching zero, and the limits of agreement between measured and predicted REE were clinically acceptable. CONCLUSION: Our results suggest that REE estimated on the basis of body weight, height, minute ventilation, and body temperature is clinically more relevant than are the usual predictive equations for metabolically stable, mechanically ventilated patients.     

Short-term overfeeding increases resting energy expenditure in patients with HIV lipodystrophy

BACKGROUND: HIV lipodystrophy and other lipodystrophy syndromes are characterized by extensive loss of subcutaneous adipose tissue. Lipodystrophy syndromes are also associated with increased resting energy expenditure (REE). This hypermetabolism may be an adaptive response to an inability to store triacylglycerol fuel in a normal manner. OBJECTIVE: This study was done to determine whether REE increases significantly after short-term overfeeding in patients with HIV lipodystrophy. DESIGN: REE was measured in HIV-infected patients with lipodystrophy (n = 9) and in HIV-infected (n = 10) and healthy (n = 9) controls after 3 d on a eucaloric diet and again after 3 d on a diet of similar composition but increased in calories by 50%. RESULTS: After 3 d of eucaloric feeding, REE was significantly higher in patients with HIV lipodystrophy [33.2 +/- 0.27 kcal/kg lean body mass (LBM)] than for both HIV-infected and healthy controls (29.9 +/- 0.26 and 29.6 +/- 0.27 kcal/kg LBM, respectively; P < 0.01). Furthermore, after 3 d of overfeeding, REE increased significantly in patients with HIV lipodystrophy but not in the control groups (33.2 +/- 0.27 vs 34.7 +/- 0.27 kcal/kg LBM; P < 0.01). Finally, postprandial thermogenesis did not differ among the groups after a "normal" test meal but tended to be higher in patients with HIV lipodystrophy than in healthy controls after a large test meal. CONCLUSIONS: Adaptive thermogenesis in the resting component of total daily energy expenditure and in the postprandial period may be a feature of the HIV lipodystrophy syndrome and may be due to an inability to store triacylglycerol fuel in a normal manner.     

Prevalence,outcome and associated factors of deranged liver function tests in patients on home parenteral nutrition

INTRODUCTION: The prevalence of deranged liver function tests (LFT) in patients on long-term home parenteral nutrition (HPN) is poorly documented. The aim of our study was to document the prevalence of this complication and possible associated factors. METHOD: Retrospective analysis of case notes of 107 patients on HPN was performed. Deranged LFT was defined as any biochemical parameter of LFT that is 1.5 times above the reference range. RESULTS:There were 39 males and the median age was 51 (range 20-73) years old. Median duration of HPN was 40 (range 6-252) months. Underlying diagnoses were Crohn's disease (40%), ischaemic bowel disease in 28.1% (arterial or venous), post-surgical intestinal adhesion and fistula (16.9%) and others (21.7%). The mean energy intake from HPN was 1003+/-544(SD) kcal/day with 845+/-474 kcal/day from glucose, 157+/-127 kcal/day from fat and mean nitrogen intake was 6.2+/-3.6 g/day. Raised alkaline phosphatase (mean 197+/-143(SD)U/L) was the most common abnormality (40 patients). Two patients had hyperbilirubinaemia; one patient had hereditary spherocytosis and in the other patient, the cause could be attributed to HPN with bilirubin of 54 micromol/l. Fifty-one patients (47.7%) had deranged LFT as judged from raised parameters on LFT. Abnormality in LFT was transient in nine patients. For the other 42 patients (39%), abnormalities in LFT remained stable for median duration of follow-up of 18.5 (range 3-180) months. No patients developed decompensated liver disease. On univariate analysis, length of small bowel of less than 100 cm, a higher total caloric intake from HPN (mean 1117+/-486 kcal against 907+/-576 kcal, P<0.05), and higher daily caloric intake from HPN in relation to calculated daily energy requirement (70+/-32% against 57+/-36%) were noted to be significantly associated with deranged LFT. However, on multivariate analysis, length of small bowel of less than 100 cm was the only significant variable for deranged LFT. CONCLUSION: Our finding showed the prevalence of deranged LFT to be 39% and raised alkaline phosphatase was the most common abnormality. Length of small bowel of less than 100 cm was found to be a significant independent variable for deranged LFT and the reason for this observation could be due to higher parenteral caloric intake. In our experience, LFT abnormalities are associated with a good prognosis as none of the patients developed decompensated liver disease.