Effects of Pseudomonas colonization on body composition and resting energy expenditure in children with cystic fibrosis.

BACKGROUND: To determine the extent and effects of increased metabolic demand represented by Pseudomonas colonization on body composition and resting energy expenditure in children with cystic fibrosis (CF). METHODS: The study comprised 18 stable children with CF, of whom 10 (6 male/4 female) were colonized with Pseudomonas species and 8 (4 male/4 female) were not. The groups were of similar age range and genotype. Measured resting energy expenditure (REE) was performed by open circuit indirect calorimetry and compared with predicted REE calculated from standard equations. Body composition was determined by dual-energy x-ray absorptiometry, including lean body mass (LBM), fat mass (FM), bone mineral density (BMD), and anterior-posterior spine density (APS); these were compared using z-scores. Routine pulmonary function testing assessed forced vital capacity, forced expiratory volume in 1 second (FEV1), and forced expiratory flow over middle half of vital capacity (FEF25% to 75%); these were compared as percent predicted. RESULTS: As expected, results of pulmonary function testing showed significant deterioration among the children colonized with Pseudomonas species when compared with the children who were not, while standard anthropometry showed no differences in weight, height, or weight-for-height percentile and respective z-scores. Although a trend of lower LBM was noted among the children colonized with Pseudomonas species, no significant differences were found between these children and children who were not colonized with Pseudomonas species when z-scores for LBM, FM, BMD, or APS were compared during body composition analysis. In addition, neither REE as kilocalories per day (kcal/d) nor REE expressed as a percent predicted by standard equations discriminated between subgroups of children colonized with Pseudomonas species and children who were not. However, metabolic demand, expressed as resting energy expenditure in kilocalories per kilogram (kcal/kg) of LBM (REE/LBM), revealed significant differences between children colonized with Pseudomonas species and children who were not (75.4+/-4.4 vs 58.6+/-2.9 kcal/kg, p < .05). CONCLUSIONS: The effect of Pseudomonas colonization on metabolic demand in children with CF can be accurately assessed by expressing resting energy expenditure as kilocalorie per kilogram of LBM, the active metabolic component of the body. The 50% increase in REE/LBM seen in the children colonized with Pseudomonas species represents the metabolic demand from the inflammatory burden and work of breathing resulting from the effects of the Pseudomonas colonization. The trend of a lower LBM in the children colonized with Pseudomonas species makes this finding even more dramatic.     

机械通气危重患儿的连续性静息能量消耗测定

目的　探讨机械通气危重患儿的静息能量消耗变化,比较公式估算与间接测热法（IC）所测得的能量消耗之间的差异,分析影响危重患儿代谢状态的可能因素。方法　前瞻性收集2012年9月至2013年9月入住上海儿童医学中心重症监护室、行呼吸机辅助通气、满足IC要求的内科危重症患儿共56例,于机械通气第1、4、7、10天应用代谢车测定其静息能量消耗,并记录患儿的一般临床资料。结果　对56例患儿行IC测定130次,所测得的静息能量消耗值（MREE）在机械通气第1、4、7、10天间比较差异无统计学意义（P=0.379）。MREE与Schofield及WHO公式估算值（PEE）比较差异虽无统计学意义（P值分别为0.917和0.995）,但一致性较差（R2值分别为0.185和0.322）。患儿在机械通气第1天的代谢状态仅与年龄（P=0.000）和身高（P=0.027）相关,与疾病严重程度和临床结局均无关联。结论　机械通气危重患儿的静息能量消耗IC法实测值随机械通气时间变化并不显著,预测公式估算的静息能量消耗值与IC法实际测量值之间一致性较差。建议将IC应用于重症监护病房,指导危重患儿个体化营养支持治疗,以改善患儿临床结局。     

Longitudinal investigation of energy expenditure in infants with cystic fibrosis

OBJECTIVE: To determine when energy expenditure becomes elevated in infants with cystic fibrosis (CF). DESIGN: Longitudinal studies of total energy expenditure (TEE) using doubly labeled water were conducted in infants identified with CF by newborn screening through the first year of life. SETTING: Hospital and community based studies in Denver, Colorado, USA and Cambridge, UK. RESULTS: Eight of the 12 infants enrolled had begun enzyme therapy but were clinically asymptomatic. Four of the 12 infants were heterozygous for the delta F508 mutation, however no difference was seen in TEE from the remaining homozygous infants. TEE was compared to control cohorts at 2, 6 and 12 months of age. There was no difference from the control groups in TEE/kg fat free mass (FFM)/day at 2 months. However, by 6 months of age TEE/kg FFM/day in infants with CF exceeded that of age-matched controls by 25% (P<0.001). This elevation in TEE continued at 12 months of age exceeding that of controls by 30% (P<0.05). CONCLUSIONS: These results indicate that infants with CF have increased energy needs by 6 months of age and that early diagnosis alone does not prevent the development of increased caloric requirements. These findings emphasize the need for close nutritional monitoring to prevent suboptimal growth during infancy in this population. SPONSORSHIP: This research was supported by grant number 5 MO1 RR00069, General Clinical Research Centers Program, National Center for Research Resources, NIH.     

Total energy expenditure in stable patients with cystic fibrosis.

BACKGROUND AND AIMS: Undernutrition is a common problem in patients with cystic fibrosis and is associated with a poor prognosis. The two aims of this study were to assess and compare the two main field techniques in the measurement of total energy expenditure and, secondly, to assess total energy expenditure in stable patients and compare with healthy controls. METHODS: Resting energy expenditure was measured using indirect calorimetry and total energy expenditure was measured using 24-h heart rate (HR) methodology and doubly isotopically labelled water. RESULTS: Seventeen patients, mean age 23 years and FEV(1)52% predicted and thirteen controls were recruited. Resting energy expenditure was higher in patients 0.24 (0.03) MJ/kg Fat-Free Mass (FFM) compared to controls 0.22 (0.02) MJ/kg FFM, P=0.02. Twenty-four hour heart rate underestimated total energy expenditure, 9.49 (1.85) MJ/day in patients compared to 11.69 (2.79) MJ/day using doubly labelled water. There was no difference in total energy expenditure in patients and controls using both methods, 11.69 (2.79) MJ/day compared to 11.38 (2.71) MJ/day using doubly isotopically labelled water. CONCLUSIONS: In clinically stable young adult patients with moderately severe respiratory disease total energy expenditure is comparable to that an a control population despite in increase in resting energy expenditure and both 24-h HR and doubly isotopically labelled water are suitable for use in patients with cystic fibrosis.     

Adolescent development and energy expenditure in females with cystic fibrosis

BACKGROUND AND AIMS: Poor nutrition and growth status are common in people with cystic fibrosis (CF), and females often have a worse clinical course. Relationships between sexual maturity, nutrition, resting energy expenditure (REE), and pulmonary status in females with CF and pancreatic insufficiency (PI) were evaluated. METHODS: Pre- and post-menarcheal females with CF and PI (8-29 yr) were compared to healthy females. Z-scores for growth and body composition, anthropometry and DEXA were assessed. REE was measured in all subjects and pulmonary function in CF. RESULTS: Compared to healthy females (n=28, 14.6+/-4.1 yr), females with CF (n=16, 14.7+/-4.4 yr) had lower height Z (-0.1+/-0.9 versus -0.9+/-0.9, P=0.009) and muscle area Z (0.8+/-1.3 versus -0.4+/-1.2, P=0.007), and higher REE (100+/-10 versus 110+/-11% predicted, P=0.008). Difference in REE was more pronounced for post-menarcheal girls. REE adjusted for fat and fat-free mass was significantly higher with CF (+110 calories/day), and declined with menarcheal age in all subjects. FEV1 was positively associated with BMI Z score, and negatively associated with age at menarche. CONCLUSIONS: Height and muscle stores were reduced and REE elevated in subjects with CF compared to healthy controls. Poorer growth and nutritional status and delayed menarche were associated with poorer pulmonary function in CF and were likely related to the cumulative effect of energy imbalance on growth and body composition.     

Comparison of energy prediction equations with measured resting energy expenditure in children with sickle cell anemia

OBJECTIVE: To determine the accuracy of energy prediction equations when compared with measured resting energy expenditure (REE) in children with sickle cell anemia. To develop a modified equation that more accurately estimates the energy needs of children with sickle cell anemia and to cross-validate these on a different set of patients (test patients). DESIGN: REE was measured in children using indirect calorimetry and compared with predicted values using the Harris-Benedict and the Food and Agriculture Organization/World Health Organization/United Nations University equations (WHO). SUBJECTS/SETTING: Eighteen patients participated in the original sample that compared predicted with measured energy expenditure. The modified equations were developed using the original 18 patients. A test population of 20 different patients was used to validate the modified equations. STATISTICAL ANALYSIS: Wilcoxon signed-rank test was performed to compare measured with predicted REE. The correlation analysis method and multiple linear regression method were used to develop 2 modified versions for the Harris-Benedict and WHO prediction equations. RESULTS: When compared with the mean predicted REE using the Harris-Benedict and WHO equations, the mean measured REE was 14% and 12% greater than both (P=.005 and P=.014, respectively). Two modified equations were developed from the Harris-Benedict and WHO equations. Based on the data from the test patients, the mean measured REE was 15% greater than the mean predicted REE based on the Harris-Benedict and WHO equations (P=.0001 for both). When the modified Harris-Benedict and WHO equations were used, there was almost no difference in the mean measured REE and the mean predicted REE (mean difference using Harris-Benedict = 14, P = .9273; mean difference using WHO = -13, P = .6215). CONCLUSION: Both energy prediction equations underestimated REE in children with sickle cell anemia. The 2 modified versions of the energy prediction equations that we propose predicted the energy needs of these children much more accurately; however, the modified equations need to be validated through application to other children with sickle cell anemia.     

Improving oral energy intake in older children with cystic fibrosis

The effect of intensive dietary counselling in 28 older children and adolescents with cystic fibrosis was monitored over a one-year period, assessing dietary intake and nutritional status. There was a significant improvement in energy intake ( P <0.01) and fat intake ( P <0.01) in the group as a whole, including control patients. The most significant improvement was in the group who received intensive counselling and standard pancreatic enzyme supplements ( P <0.02). Correlation with change in nutritional status was poor.
We conclude that energy intake can be improved in this difficult group of patients but that more individualization of intake to achieve normal growth is required.     

Variability in results from predicted resting energy needs as compared to measured resting energy expenditure in Korean children

Energy needs are influenced by many factors, including ethnicity. Multiple studies have shown that the accuracy of an energy prediction equation varies with the ethnic background of the study population. Therefore, it is crucial to identify the most accurate energy prediction equation to use for a given population. This study compared measured resting energy expenditure to results from commonly-used energy prediction equations to identify the most accurate equation to use for Korean children. Based on previous literature showing wide variation in accuracy of energy prediction equations in different ethnic groups, we hypothesized that results from measured- vs. predicted energy needs would be significantly different in this population. Subjects were 92 South Korean children (38 boys, 54 girls) age 7.7 ± 2.7 years (mean ± SD). Measurements included: resting metabolic rate (TrueOne 2400 metabolic cart), weight/height (digital scale/stadiometer); body fat (BIA, Inbody720), blood pressure (sphingomanometer), triceps skinfold thickness (MD-500 skinfold calipers), muscle mass (Heymsfield's formula) and body surface area (Dubois formula) calculations. Resting energy needs were predicted using the Harris-Benedict, WHO/NAO/FAO, Altman and Dittmer, Maffeis, and Schofield-HW equations, and the Dietary Reference Intake recommendations. Measured and predicted energy needs were significantly correlated (P < .001 for all; range R² = 0.54-0.56), yet significantly different for all equations studied (P < .05) except the Maffeis and Schofield-HW equations. Differences (means ± SD) between measured vs. predicted energy needs ranged from 9.5 ± 123.2 (Schofield-HW) to 199.6 ± 132.7 (WHO/NAO/FAO) kcal/day, where a value closer to zero indicates increased accuracy of the prediction equation to correspond to measured energy needs. Although results from equations studied were significantly correlated with measured resting energy needs, notable discrepancies existed which, over time, could produce undesirable weight changes in Korean children.     

Prediction of resting energy expenditure in a large population of obese children

BACKGROUND: Recommendations for energy intake in obese children rely on accurate methods for measuring energy expenditure that cannot be assessed systematically. OBJECTIVE: The aim was to establish and validate new equations for predicting resting energy expenditure (REE), specifically in obese children. DESIGN: REE (indirect calorimetry) and body composition (bioelectrical impedance analysis) were measured in 752 obese subjects aged 3-18 y. The first cohort (n=471) was used to establish predictive equations, the second (and independent) cohort (n=211) was used to validate these equations, and the third cohort, a follow-up group of children who lost weight (n=70), was used to examine predictive REE in the postobese period. REE values predicted with the use of various published equations and the new established equation were compared with measured REE by using the Bland-Altman method and Student's t tests. RESULTS: In cohort 1, significant determinants of the new prediction equations were fat-free mass in boys (model R2=0.79) and age and fat-free mass in girls (model R2=0.76). External validation conducted by using the Bland-Altman method and Student's t tests, in cohort 2, showed no significant difference between measured REE and predicted REE with the new equation. When already published equations were applied, systematical bias appeared with all published equations except for that of the World Health Organization. In cohort 3, the children who lost weight, almost all equations significantly underestimated REE. CONCLUSIONS: These new predictive equations allow clinicians to estimate REE in an obese pediatric population with sufficient and acceptable accuracy. This estimation may be a strong basis for energy recommendations in childhood obesity.     

Predicting resting energy expenditure in patients with musculoskeletal deformities

The aim of this study was to assess the validity of the commonly used equations (Harris-Benedict (HB), Schofield (S) and equations based on midarm circumference (MAC) and midarm muscle circumference (MAMC) in predicting resting energy expenditure (REE) in a population of patients with musculoskeletal deformities. 20 kyphoscoliotic patients (15 female (F); 5 male (M); mean age 59.6 years) and 10 controls (7 F; 3M; 59.8 years) were studied. REE measured by indirect calorimetry (IC) with a ventilated canopy system (Deltatrac metabolic monitor) was not significantly different between patients and controls (Mean (SD) REE (MJ/24 h): Patients: 5.48 (1.1); controls: 5.28(0.8)). In patients with deformities the Schofield equation gave values which were closest to measured REE (mean difference and limits of agreement IC vs S: 0.098 MJ/24 h; -0.822 and 1.018). The Harris-Benedict equation using height (Ht) and armspan (AS) in lieu of height also gave acceptable results (IC vs HB (Ht): 0.34; -0.638 and 1.318; IC vs HB (AS): 0.255; -0.683 and 1.253). Equations based on MAC and MAMC compared poorly (IC vs MAC equation: 0.398; -1.530 and 2.326; IC vs MAMC equation 0.687; -0.911 and 2.285). On regression analysis the equation REE = 0.295 (MAMC) + 0.0483 (AS) -0.0324 (age) -6.25 predicted REE best in the patient population (r(2) = 0.861).     

Energy expenditure, nutrition status, and body composition in children with cystic fibrosis

OBJECTIVE: Undernutrition is a frequent complication in patients with cystic fibrosis (CF). Elevated energy requirements have been found to be 4% to 33% higher than in controls in some studies. Whether or not this is caused by a primary defect or energy metabolism is still a matter of controversy. To this end, we assessed energy expenditure, nutrition status, and body composition of clinically stable CF outpatients. METHODS: Fifteen clinically stable CF patients, ages 2 to 15 y, were paired with 15 healthy control children. Measurements consisted of anthropometry and body composition. Plasma tocopherol, retinol, and hair zinc content were measured. Resting energy expenditure was determined by indirect calorimetry. Physical activity and dietary intake were recorded by recall methods. RESULTS: Two children were nutritionally at risk according to the weight/height index, eight were normal, three were overweight, and two were obese. Body composition was similar in both groups. Zinc, tocopherol, and retinol levels were low in three, two, and three patients, respectively. Resting energy expenditures were 4.7 MJ/d (1127 +/- 220 kcal/d) in CF children and 4.63 MJ/d (1108 +/- 191 kcal/d) in control children (P = not significant). Physical activity level was sedentary in 86.6% of CF patients; the rest had a light physical activity pattern. Energy intake represented 141% of the estimated daily energy expenditure. CONCLUSIONS: Non-oxygen-dependent CF children, without acute respiratory infection, had resting energy expenditures comparable to those of matched controls. Total energy expenditure was similar to or slightly lower than that in healthy children. Dietary recommendations for CF patients need to be reassessed.     

Changes in resting energy expenditure among children undergoing allogeneic stem cell transplantation

BACKGROUND: Because of the effects of chemotherapy and radiotherapy, patients undergoing stem cell transplantation (SCT) are commonly provided nutritional support with parenteral nutrition. The energy and nutrient needs of these patients have not been well studied. OBJECTIVE: The objective was to measure resting energy expenditure (REE), dietary intake, and biochemical and anthropometric changes in children before and after allogeneic SCT. DESIGN: This was a prospective cohort study of 37 children aged 9.1 +/- 6.4 y ( +/- SD) undergoing SCT who were enrolled in an open-label trial of a unique supportive care intervention that included the routine use of oral leucovorin, vitamin E, and ursodeoxycholic acid. Parenteral nutrition was provided to match 100% of measured or estimated REE. REE was measured weekly via indirect calorimetry. RESULTS: Baseline REE was 95% of the predicted age- and sex-matched norms and was significantly correlated with midarm muscle area (r = 0.82, P < 0.001). REE fell to a nadir of approximately 80% of the predicted levels by week 3 after SCT, with a gradual increase in weeks 4 and 5. Arm anthropometric measurements showed no change in triceps skinfold thickness but significant declines in midarm muscle area after SCT. Serum vitamin E remained in the normal range. CONCLUSIONS: Children undergoing SCT show significant declines in REE after transplantation. These changes may be due to alterations in lean body mass. Standard nutritional regimens may lead to overfeeding.     

Whole-body protein turnover and resting energy expenditure in obese, prepubertal children

BACKGROUND: Obesity is becoming more frequent in children; understanding the extent to which this condition affects not only carbohydrate and lipid metabolism but also protein metabolism is of paramount importance. OBJECTIVE: We evaluated the kinetics of protein metabolism in obese, prepubertal children in the static phase of obesity. DESIGN: In this cross-sectional study, 9 obese children (x +/- SE: 44+/-4 kg, 30.9+/-1.5% body fat) were compared with 8 lean (28+/-2 kg ,16.8+/-1.2% body fat), age-matched (8.5+/-0.2 y) control children. Whole-body nitrogen flux, protein synthesis, and protein breakdown were calculated postprandially over 9 h from 15N abundance in urinary ammonia by using a single oral dose of [15N]glycine; resting energy expenditure (REE) was assessed by indirect calorimetry (canopy) and body composition by multiple skinfold-thickness measurements. RESULTS: Absolute rates of protein synthesis and breakdown were significantly greater in obese children than in control children (x +/- SE: 208+/-24 compared with 137+/-14 g/d, P < 0.05, and 149+/-20 compared with 89+/-13 g/d, P < 0.05, respectively). When these variables were adjusted for fat-free mass by analysis of covariance, however, the differences between groups disappeared. There was a significant relation between protein synthesis and fat-free mass (r = 0.83, P < 0.001) as well as between protein synthesis and REE (r = 0.79, P < 0.005). CONCLUSIONS: Obesity in prepubertal children is associated with an absolute increase in whole-body protein turnover that is consistent with an absolute increase in fat-free mass, both of which contribute to explaining the greater absolute REE in obese children than in control children.     

A six-month study of growth and energy expenditure in children with cystic fibrosis taking a pulmonary inhalation medication (rhDNase)

OBJECTIVE: To characterize the effects of recombinant human deoxyribonuclease (rhDNase) on growth velocity, body composition, resting energy expenditure (REE) and food intake in children with cystic fibrosis (CF). METHODS: A prospective, six-month pilot study was conducted in twenty-one subjects with CF (twelve male, nine female, ages 11.5+/-3.1 years) measured at baseline, two and six months post-baseline. Repeated measures ANOVA was used to examine the change in variables across time. RESULTS: The majority (75%) of subjects had minimal lung disease at baseline (FEV1: 80%-119% predicted). As expected for growing children, weight and height gains (1.6 kg and 2.5 cm) were observed between baseline and six months (p=0.0001). No change was observed in weight z-scores from six months prior to initiation of rhDNase therapy to six months post, though a significant decline (p=0.049) in Ht z-score was observed over this twelve-month period. Triceps skinfolds and mid-arm muscle circumference increased from baseline to six months (p<0.01); respective z-scores remained stable. Energy intake remained constant during the period it was studied from baseline to two months of therapy: 120%+/-27% RDA. REE, though slightly elevated compared to healthy children (baseline 106%+/-8% predicted), remained stable throughout the study and at a level which may be expected for children with minimal lung disease. A trend (p=0.057) towards a decrease in the number of subjects requiring hospitalization for pulmonary exacerbations during the trial period was observed. CONCLUSIONS: In summary, these pilot data from younger children with milder CF-related lung disease do not confirm anecdotal reports of improved rate of weight gain, caloric intake or decreases in the elevated REE. Future research might focus on documentation of the possible nutritional effects of rhDNase in clinical trials of children with more severe lung disease.     

Estimation of resting energy expenditure by anthropometry

The role of anthropometry in estimating resting energy expenditure (REE) has been assessed in 142 clinically stable patients. Ninety eight patients had cancer (54 weight stable, 44 weight losing) and 44 patients had nonmalignant illness (27 weight stable, 17 weight losing). Mid-arm muscle circumference (MAMC) measurements correlated significantly with REE measured by indirect calorimetry in each of the groups studied. Weight loss significantly affected this correlation whereas cancer did not. The correlation in weight stable patients was poorer than that in weight losing patients, possibly reflecting inaccuracy of anthropometric measurements due to subcutaneous adipose tissue. Significant correlations were also observed between mid-arm circumference (MAC) and REE, and between MAMC and whole body oxygen consumption.REE can be estimated from MAMC measurements in weight stable and weight losing patients with benign or malignant disease. This simple method may be of value in estimating REE where indirect calorimetry facilities are unavailable.     

Increased resting energy expenditure in patients with end-stage renal disease

BACKGROUND: Protein-calorie malnutrition is a significant problem for patients with end-stage renal disease. Increased resting energy expenditure may be an important contributing factor. We postulate that resting energy expen diture in the different stages of renal disease and treatments may be different. METHODS: Resting energy expenditure was measured using a whole-room indirect calorimeter (metabolic chamber) along with nutritional parameters and body composition after 12-hour fasting in 15 patients with advanced chronic renal failure patients, 15 patients on chronic hemodialysis, and 10 patients on peritoneal dialysis. Patients on hemodialysis were assessed on a non-dialysis day. A 2-day dietary recall was used to assess energy intake. RESULTS: Resting energy expenditure, adjusted for fat-free mass, was similar in patients on hemodialysis and peritoneal dialysis but significantly higher than in patients with chronic renal failure (p < .05). Resting energy expenditure in all patients were generally higher (10% to 20%) than predicted values using standard equations derived in normal and obese populations, whereas daily energy intake was less (26% to 34%) than energy expenditure for all groups, adjusted for light daily activity. CONCLUSIONS: End-stage renal disease patients displayed increases in resting energy expenditure over the predicted values derived using normal populations. Resting energy expenditure was significantly higher in patients receiving dialysis, regardless of the modality, than patients with chronic renal failure. Daily energy intake was substantially less than required in all patient groups studied, suggesting that patients with renal failure could develop protein-calorie malnutrition because of increased resting energy expenditure, which is exacerbated by dialysis.