Catherine A Leitch

Total But Not Resting Energy Expenditure Is Increased in Infants With Ventricular Septal Defects

Objective. The purpose of this study was to determine the effect of left-to-right shunting on the resting energy expenditure (REE), total energy expenditure (TEE), and energy intake in a group of 3- to 5-month-old infants with moderate to large unrepaired ventricular septal defects (VSDs) compared with age-matched, healthy infants. Methods. Eight infants with VSDs and 10 healthy controls between 3 to 5 months of age participated in the study. Indirect calorimetry was used to measure REE and the doubly-labeled water method was used to measure TEE and energy intake. An echocardiogram and anthropometric measurements were performed on all study participants. Daily urine samples were collected at home for 7 days. Samples were analyzed by isotope ratio mass spectrometry. Data were compared using analysis of variance. Results. No significant differences were found in REE (VSD, 42.2 ± 8.7 kcal/kg/d; control, 43.9 ± 14.1 kcal/kg/d) or energy intake (VSD, 90.8 ± 19.9 kcal/kg/d; control, 87.1 ± 11.7 kcal/kg/d) between the groups. The percent total body water was significantly higher in the VSD infants and the percent fat mass was significantly lower. TEE was 40% higher in the VSD group (VSD, 87.6 ± 10.8 kcal/kg/d; control, 61.9 ± 10.3 kcal/kg/d). The difference between TEE and REE, reflecting the energy of activity, was 2.5 times greater in the VSD group. Conclusions. REE and energy intake are virtually identical between the two groups. Despite this, infants with VSDs have substantially higher TEE than age-matched healthy infants. The large difference between TEE and REE in VSD infants suggests a substantially elevated energy cost of physical activity in these infants. These results demonstrate that, although infants with VSDs may match the energy intake of healthy infants, they are unable to meet their increased energy demands, resulting in growth retardation.

Increased energy expenditure in infants with cyanotic congenital heart disease.

Infants with cyanotic congenital heart disease (CCHD) often have reduced weight gain compared with infants in control groups. Our purpose was to conduct a longitudinal study of energy intake, resting energy expenditure (REE), and total energy expenditure (TEE) of a group of infants with CCHD. We hypothesized that increased REE and TEE and decreased energy intake in these infants would lead to reduced growth. Ten infants with uncorrected CCHD and 12 infants in a control group were studied at 2 weeks of age and again at 3 months. Indirect calorimetry was used to determine REE; the doubly labeled water method was used to determine TEE and intake. At 2 weeks and 3 months of age, infants with CCHD weighed significantly less than infants in the control group. No significant difference was seen in energy intake or REE between groups during either period. TEE was slightly but not statistically increased in the CCHD group at 2 weeks (72.6 +/- 17.4 vs 59.8 +/- 10.9 kcal/kg/d) and significantly increased at 3 months (93.6 +/- 23.3 vs 72.2 +/- 13.2 kcal/kg/d, P </=.03). We conclude that increased TEE but not increased REE is a primary factor in the reduced growth in infants with CCHD.

Energy expenditure and energy intake during dexamethasone therapy for chronic lung disease.

Dexamethasone is commonly administered to ventilator-dependent preterm infants with chronic lung disease. Infants receiving dexamethasone therapy frequency exhibit decreased rates of weight gain. The purpose of this investigation was to determine whether decreased growth in infants receiving dexamethasone therapy is caused by increased energy expenditure. Twelve infants were studied: 6 received dexamethasone treatment at 2 wk of age and crossed over to receive placebo treatment at 4 wk; the treatment order was reversed in the other 6 infants. The doubly labeled water method was used to determine energy expenditure for a 1-wk period during each treatment phase. The rate of weight gain during dexamethasone treatment was 6.5 ± 10.6 and 20.0 ± 5.7 g/kg/d during placebo treatment. Energy expenditure was 93.1 ± 34.6 kcal/kg/d during dexamethasone treatment and 88.3 ± 37.1 kcal/kg/d during placebo treatment. Energy intake was 119.2 ± 29.0 kcal/kg/d during dexamethasone treatment and 113.8 ± 23.7 kcal/kg/d during placebo treatment. The difference between intake and expenditure, or the energy available for growth, was 26.2 ± 36.8 kcal/kg/d during dexamethasone treatment and 25.5 ± 37.4 kcal/kg/d during placebo treatment. No significant differences were found in energy expenditure or energy intake between the treatment phases. The reduced growth seen in infants receiving dexamethasone treatment cannot be explained by increased energy expenditure or decreased energy intake, but may be due to differences in the composition of newly accreted tissue.

Acute changes in leucine and phenylalanine kinetics produced by parenteral nutrition in premature infants

To determine the effect of parenteral nutrition on the balance and catabolism of leucine (by oxidation) and phenylalanine (by hydroxylation) and to assess any acute changes in proteolysis and/or protein synthesis, leucine and phenylalanine kinetics were measured by stable isotope tracer infusions in nine 32-wk gestation premature infants under both basal conditions and in response to an i.v. infusion of glucose, lipid, and amino acids. Leucine and phenylalanine balance both changed from negative to positive during parenteral nutrition. However, leucine and phenylalanine catabolism were differently affected by parenteral nutrition; the rate of leucine oxidation increased 2-fold, whereas the rate of phenylalanine hydroxylation was unchanged from basal values. Phenylalanine utilization for protein synthesis and leucine utilization for protein synthesis (based on both plasma leucine andα-ketoisocaproic acid enrichments) increased significantly during parenteral nutrition. The endogenous rates of release of leucine (based on plasma leucine enrichment) and phenylalanine (both reflecting proteolysis) were significantly reduced during parenteral nutrition. The endogenous rate of release of leucine (based on α-ketoisocaproic acid enrichment) was slightly but not significantly lower during parenteral nutrition. The substantial increase in leucine oxidation without changes in phenylalanine hydroxylation suggests a possible limitation in the phenylalanine/tyrosine supply during parenteral nutrition. In addition, these results suggest that premature infants respond to parenteral nutrition with acute increases in whole body protein synthesis as well as a probable reduction in proteolysis.

Growth, nutrition and energy expenditure in pediatric heart failure

Disturbances in growth are often a consequence of congenital heart disease during infancy and childhood. The magnitude of the growth disturbance is generally related to the anatomical lesion and is most severe in infants and children with congestive heart failure. Presently, surgical repair in this population is often delayed in order to permit increased weight gain. Surgery is preformed when a patient reaches an ideal weight and age, or failure to thrive precludes further waiting. The available data indicate that caloric intake in these infants and children may be nearly adequate for age, but is inadequate to permit normal growth rates. Energy expenditure appears to be significantly elevated in this population relative to that of age-matched infants and children. Therefore, while caloric intake may be appropriate for age, increased energy expenditure leaves the infant or child with congenital heart disease with little energy available for growth. More information is needed on energy intakes and expenditures of specific patient populations, and especially of patients with congestive heart failure, before accurate predictions of their metabolic needs are possible. This knowledge may allow us to better meet the nutritional needs of these populations and decrease the risk of malnutrition and failure to thrive, in turn decreasing surgical risk for these patients.

ENERGY EXPENDITURE IN THE EXTREMELY LOW-BIRTH WEIGHT INFANT

Information about energy requirements of extremely low-birth weight infants is sparse, despite the rapidly improving survival rates of this population. Metabolizable energy intake can be estimated from energy balance studies and the percentage of caloric intake that is actually absorbed by these infants is approximately 87%. Data on energy expenditure in extremely premature infants is limited; however, energy expenditure has been shown to increase with postnatal age. Because both intake and expenditure are affected by multiple factors, there is significant variability in estimates of the energy requirements in extremely low-birth weight infants. At present, no valid recommendations can be made regarding optimal energy requirements for the extremely low-birth weight infant, except that their requirements probably exceed those of stable, growing very low-birth weight infants, currently estimated at 105 to 135 kcal.kg-1d-1.

Large left-to-right shunts and congestive heart failure increase total energy expenditure in infants with ventricular septal defect ☆

T purpose of the present study was to determine the effect of congestive heart failure (CHF) and/or left-to-right shunting on resting and total energy expenditure, energy intake (caloric intake), and the energy expenditure of physical activity in a group of 3to 4-month-old infants with ventricular septal defect (VSD) and a group of healthy age-matched controls. We hypothesized that infants with VSD being treated for CHF would exhibit significantly higher rates of total energy expenditure (TEE) than infants with VSD without CHF or healthy infants. We also hypothesized that the magnitude of left-to-right shunting (Qp:Qs) would positively correlate with TEE. • • • Threeto 5-month old infants with VSD were identified in the cardiology clinic, confirmed by echocardiography, and recruited for the study population. This age group was chosen because pulmonary vascular resistance in these infants with heart defects had generally decreased enough so that a large left-to-right shunt should be apparent and growth problems may have been manifested, but most did not have surgical intervention. Seventeen infants (6 males and 11 females) with VSD and 13 (8 males and 5 females) healthy control infants were studied. Infants with other heart lesions or chromosomal defects were excluded. Infants who had undergone palliative procedures (pulmonary artery banding) or other surgical procedures, or who had been hospitalized within 6 weeks from the study were also excluded. The patient group was subdivided into 2 groups. Ten patients were being treated for CHF (CHF group) and 7 patients were not (non-CHF group). The diagnosis of CHF was based on clinical parameters such as tachypnea, hepatomegaly, or increases in medications to control symptoms. The study was approved by the institutional review board of Indiana University-Purdue University at Indianapolis. Written informed consent was obtained from parents or guardians before enrollment in the study. Infant characteristics are listed in Table 1. There were no significant differences between birth weight, gestational age, or age at the time of the study. However, there was a significant difference between weights at the time of the study. All 10 patients in the CHF group received lasix and digoxin; 4 infants also received aldactone. None of the infants in the control group was taking medications. Five of the CHF group infants received higher calorie formula or fortified breast milk (25 to 30 cal/oz); the non-CHF group infants received 20 cal/oz of formula, and all control infants received regular 20 cal/oz of formula or breast milk. Anthropometric measurements were obtained on day 1 of the study. Weight, crown-heel length, head and mid-arm circumference, triceps, and subscapular skinfold thicknesses were measured in each infant. All measurements were taken in triplicate and mean value was used. Open circuit indirect calorimetry was used to measure resting energy expenditure (REE). This was performed on day 1 of the study for approximately 30 minutes while the infants were asleep and within 1 hour of the last feeding. Infants were not sedated. A Plexiglas hood (Rohm and Haas Co., Philadelphia, Pennsylvania) was placed over the infant’s head, and a suction pump was used to draw air through the hood. Oxygen consumption and carbon dioxide (CO2) production were determined from the oxygen and CO2 gradients across the face during a steady-state period, correcting for room temperature and atmospheric pressure.1 The respiratory quotient was calculated as respiratory quotient 5 CO2/oxygen consumption [VCO2/VO2], where VCO2 and VO2 are the volumes of CO2 produced and oxygen consumed, respectively. REE was calculated using the modified Weir formula.2 The doubly labeled water method was used to measure TEE, energy intake, and total body water over a 1-week period. This method is based on the premise that oxygen exits the body as water and CO2, while hydrogen exits solely as water. The difference between the elimination rates of O and H reflects the rate of CO2 production. From the rate of CO2 production and the respiratory or food quotient, the TEE can be calculated from the Weir formula.2 After collection of a baseline urine sample, an oral dose of Oand H-labeled water was administered to the infant (2.0 g H2 O/kg and 0.08 g H2O/kg).3 Serial urine samples were obtained over the next 24 hours to measure the total body water pool size. Daily urine samples were collected over the next 7 days to measure elimination rates of O and H. Samples were From the Section of Pediatric Cardiology and Neonatal-Perinatal Medicine, Department of Pediatrics, James Whitcomb Riley Hospital for Children, Indiana University Medical Center, Indianapolis, Indiana. This work was supported in part by Grants S10-RR-07269 and M01RR-750 from the National Institutes of Health, Bethesda, Maryland, and the James Whitcomb Riley Memorial Association, Indianapolis, Indiana. Dr. Leitch’s address is: Indiana University School of Medicine, Department of Pediatrics, Riley Hospital for Children, 699 West Drive, RR 208, Indianapolis, Indiana 46202-5210. E-mail: cleitch@ iupui.edu. Manuscript received August 31, 2000; revised manuscript received and accepted November 22, 2000.

Energy expenditure in extremely low birth weight infants near time of hospital discharge.

OBJECTIVE To test the hypothesis that total energy expenditure is significantly higher in extremely low birth weight (ELBW) infants compared with healthy term infants near the time of discharge. STUDY DESIGN This study was designed to determine total energy expenditure and body composition in a group of ELBW infants nearing discharge receiving full-volume enteral feedings of fortified breast milk or postdischarge formula (Neosure) (n = 10; mean birth weight, 0.8 +/- 0.1 kg; mean gestational age, 26 +/- 0.8 weeks; mean age at study, 68 +/- 9 days; mean postconceptional age, 36 +/- 1 weeks) and compare them with healthy term newborns all receiving breast milk (n = 14; mean birth weight, 3.5 +/- 0.5 kg; mean gestational age, 39.0 +/- 1.4 weeks; mean age at study, 2.3 +/- 1 days). Body composition and total energy expenditure were measured using the doubly labeled water method over a 7-day period. RESULTS Mean total energy expenditure was significantly higher in the ELBW infants compared with the term infants (89 +/- 22 kcal/kg/day vs 58 +/- 19 kcal/kg/day; P <or= .001). Total energy expenditure normalized to fat-free mass was also significantly greater in the ELBW infants (98 +/- 3 kcal/kg/day vs 73 +/- 20 kcal/kg/day; P <or= .01). CONCLUSIONS The rate of total energy expenditure is greater in ELBW infants nearing discharge compared with normal healthy term infants. In the ELBW infants, higher energy intake compensates for their higher total energy expenditure.

Effect of late-onset sepsis on energy expenditure in extremely premature infants.

The purpose of this study was to compare total energy expenditure (TEE) in extremely premature infants during and after an episode of sepsis. We hypothesized that TEE in the sepsis group (SEP) would be higher during the septic period and higher than an age-matched control group (CTL). We further hypothesized that the TEE of the SEP group during the recovery period would be similar to that of the CTL group. The doubly labeled water method was used to determine TEE in both groups. Infant characteristics were as follows: SEP group, n = 10, gestation = 26 ± 1 wk, birth weight = 854 ± 218 g; CTL group, n = 10, gestation = 26 ± 1 wk, birth weight = 880 ± 158 g. TEE of the SEP group during the septic period was significantly greater than during the recovery period (96 ± 25 kcal/kg/d versus 55 ± 17 kcal/kg/d) and significantly greater than the CTL group during the first study period (96 ± 25 kcal/kg/d versus 67 ± 12 kcal/kg/d). TEE in the SEP group during the recovery period was similar to the CTL group. These increases in TEE may contribute to impaired growth and need to be considered when providing nutritional support for extremely premature infants.

Effect of enteral versus parenteral feeding on leucine kinetics and fuel utilization in premature newborns

ABSTRACT: To determine whether the route of nutrient delivery affects whole-body protein kinetics and fuel utilization, eight premature newborns were studied during both a 4-h period of enteral intake and a 4-h period of parenteral nutrition. The kinetics of the essential amino acid leucine were measured using a constant tracer infusion of 1–13C-leucine, and fuel utilization and energy expenditure were assessed by respiratory calorimetry. All leucine kinetic parameters were similar during enteral or parenteral nutrition (in mean ± SD μmol/kg/h, flux = 233 ± 51 enteral versus 258 ± 42 parenteral, leucine from protein breakdown = 177 ± 50 enteral versus 200 ± 41 parenteral, leucine oxidation = 57 ± 26 enteral versus 63 ± 20 parenteral, and leucine used for protein synthesis = 176 ± 63 enteral versus 196 ± 50 parenteral). In addition, overall rates of energy expenditure (∼52 kcal/kg/d) and pattern of fuel utilization (∼70% carbohydrate, 13% fat, 17% protein) were unaltered by the route of feeding. Thus, as reflected by leucine kinetics, overall rates of protein turnover, synthesis, oxidation, and breakdown as well as energy expenditure and fuel utilization are similar when nutrition is provided to premature newborns by either the enteral or parenteral route. These results suggest that short-term provision of parenteral nutrition may be able to substitute appropriately for enteral intake, at least with regard to the utilization of one essential amino acid and the overall pattern of fuel utilization.