Melinda White

Energy expenditure in 100 ventilated, critically ill children: Improving the accuracy of predictive equations

Objective The purpose of this study was to evaluate current methods of predicting energy requirements and to develop and validate new equations derived from energy expenditure measurements of ventilated, critically ill children. Design Prospective, observational, sequential study. Setting Pediatric intensive care unit. Patients A total of 100 ventilated, critically ill children who fit the criteria of energy expenditure measurement. Additional patients (n = 25) were included in the validation study. Intervention An indirect calorimeter was used to measure energy expenditure for a period of 30 mins. Measurements and Main Results The mean measured energy expenditure was 185 ± 51 kJ/kg per day. Predicted energy expenditure from standard equations was compared with measured energy expenditure by using the Bland and Altman “methods comparison procedure,” and poor precision and accuracy were observed. Patient variables were collected at the time of measurement, and multiple regression analysis was performed to determine the independent contribution of each variable to measure energy expenditure. New predictive equations were formulated and validated with additional energy expenditure measurements. Patient variables that did not correlate significantly with energy expenditure were gender, Pediatric Risk of Mortality score, and commencement of nutritional support. An equation was derived from patient variables (age, weight, weight for age Z score, body temperature, number of days after intensive care admission, and primary reason for admission) that correlated significantly (r2 = .898) with measured energy expenditure. A second, simplified equation (energy expenditure kJ/day = {17 × age [months]} + {48 × weight [kg]} + {292 × body temperature °C} − 9677) was produced (r2 = .867). Validation found no significant difference between measured and predicted energy expenditure by the new equations; however, the equations did not predict accurately for patients <2 months of age. Conclusion The new equations provide a more accurate alternative to current predictive methods in assessing energy requirements of ventilated, critically ill children.

Energy Expenditure Measurements in Ventilated Critically III Children: Within- and Between-Day Variability

BACKGROUND Energy expenditure measurement (EEM) by indirect calorimetry is used as a research and clinical tool in pediatric intensive care units. The aims of the study were to determine if a 30-minute EEM is representative of a 24-hour EEM (within-day variation); to determine if there is any diurnal variation during the 24-hour period of EEM; and to determine if there is a clinically significant between day variation of EEMs. METHODS To determine within-day variation, energy expenditure was measured for a period of 24 hours for each subject (n = 11). The 24-hour period was then divided into 30-minute periods. The 30-minute means were compared with the 24-hour means. To determine between-day variation, EEMs were made daily for 30 minutes. RESULTS In the within-day study, the overall mean percent coefficient of variation of the 30-minute measurements was 7.2% +/- 4.5%. There was no significant difference between the 30-minute means and the 24-hour means for each patient (p < .691). In 8 subjects the 30-minute means did not differ from the 24-hour mean by more than 20%. No diurnal variation was observed. The mean percent variation of between day EEM was 21% +/- 16%; the range was 1% to 69%. CONCLUSION In critically ill ventilated children, clinically relevant within-day variations in EEM are uncommon and a single 30-minute EEM gives an acceptable guide to the level of nutrition support required. Between-day variations can, however, be large and daily EEMs are required.

Body composition of children with cancer

BACKGROUND Nutritional status, as represented by body composition, is an important consideration in the treatment of pediatric cancer patients because it is linked to poor outcomes. Little is known about how a childs body composition responds to cancer and treatment. OBJECTIVES We aimed to compare the body composition of children undergoing treatment of cancer with that of healthy controls and to compare body composition between children with hematologic malignancies and children with solid tumors. DESIGN This cross-sectional study measured height, weight, body cell mass, fat-free mass, and fat mass in 48 children undergoing treatment of cancer and blood-related disorders and in age-matched healthy controls. RESULTS Patients with cancer had a significantly lower body cell mass index z score (body cell mass/height raised to the power of 2.5 for females and 3 for males) than did controls (P = 0.0001), and 45% of the patients with cancer were considered malnourished according to body cell mass. Subjects with cancer had a significantly higher percentage of body fat (P = 0.0001) and fat mass (P = 0.0001) than did controls; however, there was no significant difference in fat-free mass (P = 0.09). On the basis of percentage fat, 77% of subjects with cancer were considered obese. No difference in body composition was observed between cancer types. CONCLUSIONS This study showed that children undergoing treatment of all types of cancer have a significantly lower body cell mass and a significantly higher fat mass than do healthy controls. Nutritional support is suggested for all children undergoing treatment of cancer.

Nutritional status and energy expenditure in children pre-bone-marrow-transplant.

Summary:The aims of this study were to establish the nutritional status of children pre-BMT and to determine whether predictive methods of assessing nutritional status and resting energy expenditure (REE) are accurate in this population. We analysed the body cell mass (BCM) (n=26) and REE (n=24) in children undergoing BMT. BCM was adjusted for height (BCM/HTp) and expressed as a Z score to represent nutritional status. To determine whether body mass index (BMI) was indicative of nutritional status in children undergoing BMT, BMI Z scores were compared to the reference method of BCM/HTp Z scores. Schofield predictive equations of basal metabolic rate (BMR) were compared to measured REE to evaluate the accuracy of the predictive equations. The mean BCM/HTp Z score for the subject population was −1.09±1.28. There was no significant relationship between BCM/HTp Z score and BMI Z score (r=0.34; P>0.05); however there was minimal difference between measured REE and predicted BMR (bias=−11±149 kcal/day). The results of this study demonstrate that children undergoing BMT may have suboptimal nutritional status and that BMI is not an accurate indication of nutritional status in this population. However, Schofield equations were found to be suitable for representing REE in children pre-BMT.

The validity of simple methods to detect poor nutritional status in paediatric oncology patients

Poor nutritional status is a major concern for children being treated for an oncology condition. It is vital for optimal prognosis that nutritional concerns are recognised and treated promptly. The majority of oncology treatment centres only use simple methods to screen for poor nutritional status; however, it is unknown whether these simple methods accurately recognise poor nutritional status. We aimed to determine whether commonly used simple nutritional assessment variables could accurately identify poor nutritional status in children being treated for oncological conditions. This cross-sectional study measured height, weight, mid-upper arm circumference, triceps skinfold, albumin levels and body cell mass in forty children being treated for an oncological condition. To determine whether commonly used nutritional variables were suitable determinants, the variables were compared against the reference measure of body cell mass index (BCMI) Z-scores. Using the BCMI Z-score cut-off of - 1.65, 48 % of the study population were considered poorly nourished. Correlational analysis showed that there was no significant biological relationship between the BCMI Z-score and the simple parameters. When divided into two groups based on the nutritional status indicated by the BCMI Z-score, the independent t tests between the well-nourished and malnourished groups demonstrated that there was a significant difference in the BMI Z-score (P = 0.01) between the groups. No simple nutritional measures were found to accurately identify poor nutritional status in children being treated for oncological conditions.

Simple Nutrition Screening Tool for Pediatric Inpatients

BACKGROUND Pediatric nutrition risk screening tools are not routinely implemented throughout many hospitals, despite prevalence studies demonstrating malnutrition is common in hospitalized children. Existing tools lack the simplicity of those used to assess nutrition risk in the adult population. This study reports the accuracy of a new, quick, and simple pediatric nutrition screening tool (PNST) designed to be used for pediatric inpatients. MATERIALS AND METHODS The pediatric Subjective Global Nutrition Assessment (SGNA) and anthropometric measures were used to develop and assess the validity of 4 simple nutrition screening questions comprising the PNST. Participants were pediatric inpatients in 2 tertiary pediatric hospitals and 1 regional hospital. RESULTS Two affirmative answers to the PNST questions were found to maximize the specificity and sensitivity to the pediatric SGNA and body mass index (BMI) z scores for malnutrition in 295 patients. The PNST identified 37.6% of patients as being at nutrition risk, whereas the pediatric SGNA identified 34.2%. The sensitivity and specificity of the PNST compared with the pediatric SGNA were 77.8% and 82.1%, respectively. The sensitivity of the PNST at detecting patients with a BMI z score of less than -2 was 89.3%, and the specificity was 66.2%. Both the PNST and pediatric SGNA were relatively poor at detecting patients who were stunted or overweight, with the sensitivity and specificity being less than 69%. CONCLUSION The PNST provides a sensitive, valid, and simpler alternative to existing pediatric nutrition screening tools such as Screening Tool for the Assessment of Malnutrition in Pediatrics (STAMP), Screening Tool Risk on Nutritional status and Growth (STRONGkids), and Paediatric Yorkhill Malnutrition Score (PYMS) to ensure the early detection of hospitalized children at nutrition risk.

Enteral Nutrition and Bone Marrow Transplantation

This retrospective study evaluated the efficacy of enteral nutrition for pediatric patients undergoing the challenging treatment of allogeneic bone marrow transplantation. During the period from January 1999 to May 2000, 15 patients were transplant recipients. On admission to the hospital, 87% of patients were above the 50th percentile for weight for age. Nasogastric tubes were inserted while platelet counts remained greater than 50 × 10 9 mL/L. A specialized elemental formula for pediatric patients was commenced. These feeds were administered continuously and were titrated until caloric requirement or tolerance level had been achieved. During hospitalization for bone marrow transplantation, enteral nutrition was the major form of nutritional support for all patients. Enteral feeds continued even during maximal gut toxicity and were supported with antiemetics and analgesia. There were insignificant weight fluctuations during hospitalization, with 80% of children above the 50th percentile weight for age being discharged. Enteral nutrition via a nasogastric tube was effective in the provision of nutrition during bone marrow transplantation and continues to have an important role in this unit.

Validation of percent body fat indicators in pediatric oncology nutrition assessment.

Background Given the high prevalence of malnutrition and potential impact nutritional status can have on a child undergoing treatment for cancer, it is vital that oncology centers regularly assess nutritional status. It is important that simple noninvasive anthropometric nutrition assessment measures correlate to more accurate body composition measures. Objectives The aim of this study was to determine the relationship between anthropometric measures and percent body fat determined via air displacement plethysmography in the children being treated in a pediatric oncology and hematology department. Design This cross-sectional study measured height, weight, percent ideal body weight (%IBW), mid arm circumference, triceps skinfolds, and mid upper arm fat area in 23 children. These anthropometric variables were compared against the reference measure of percent body fat via air displacement plethysmography. Results Correlational analysis and general linear models showed that there was a significant statistical relationship between percent body fat and body mass index Z score, %IBW, mid arm circumference, triceps skinfolds, and arm fat area. Conclusions Simple anthropometric measurements of %IBW and triceps skinfolds are good indicators of percent body fat and should be incorporated into regular nutrition assessment of the pediatric oncology patient.

Correlation Between Nutrition Assessment Data and Percent Body Fat via Plethysmography in Pediatric Oncology Patients

BACKGROUND Routine nutrition assessment is a core part of the nutrition management of the pediatric oncology population. The aims of this study were to build on the findings of a previous study to investigate the relationship between nutrition assessment variables and percent body fat (%BF) and to produce an equation to predict %BF in the pediatric oncology population. METHODS The nutrition status assessment criteria for comparison with %BF measures were adapted with permission from the St Jude Childrens Research Hospital nutrition screening system, Department of Clinical Nutrition. Additional measures not part of the screening system included midarm circumference (MAC); triceps, biceps, suprailiac, and subscapular skinfolds; and arm fat area. %BF was determined via air displacement plethysmography and interpreted via percentiles derived from body fat reference curves for healthy children. RESULTS Forty-two children, 22 males and 20 females, participated in the study. Correlational analysis revealed significant correlations with %BF and weight and body mass index z scores, percentage of ideal body weight (%IBW), MAC, skinfolds, arm fat area, and the total nutrition screening score. No relationship was found between height z score, percentage of weight loss over the previous 1 month, serum albumin, diagnosis risk, oral intake, and impending therapy or treatment side effects. Regression analysis found %BF = (1.4 × Biceps Skinfolds (mm) + (0.16 × %IBW) - 1 to have the strongest correlation (r(2) = 0.74). CONCLUSIONS The equation presented here requires validation to estimate %BF in the pediatric oncology population.

Prevalence of malnutrition, obesity and nutritional risk of Australian paediatric inpatients: A national one-day snapshot

Low prevalence rates of malnutrition at 2.5% to 4% have previously been reported in two tertiary paediatric Australian hospitals. The current study is the first to measure the prevalence of malnutrition, obesity and nutritional risk of paediatric inpatients in multiple hospitals throughout Australia.