| Summary: | Hypotheses: (1) Nutritional status is impaired in symptomatic congenital heart disease (CHD) in infancy, and this is related to an inadequate positive energy balance. (2) Undernutrition precedes the development of bronchopulmonary dysplasia (BPD) in preterm infants, and there is a subsequent persistent deficit in energy balance, bone mineral content (BMC) and growth. Objectives: To study (1) the effect of CHD on growth and energy balance in infancy (2) macronutrient intake prior to the development of BPD (3) the effect of BPD on energy balance and BMC and the effect of a dexamethasone used to treat BPD on BMC. Background: Poor growth is seen commonly in chronic disease of the heart and lungs (CCPD) and is important because: (a) the disease and its treatment may compromise nutrition (b) good nutrition may influence the outcome of the condition and adult health. Body growth in infants is dependent upon a sufficiently positive balance of protein and energy, and certain micronutrients are important for aspects of specific organ development. Method: CHD - Energy balance measurements were carried out on 21 infants with CHD, post-term age [median (range)] 49 days (-9 to 246) and in 9 controls, post-term age 35 days (-14 to 86). Energy intake (EI) and losses (EL) were measured by bomb calorimetry (18 CHD, 5 control), resting energy expenditure (REE), by indirect calorimetry over several hours (14 CHD, 9 control), and anthropometry performed. BPD - 195 consecutive infants of <32 weeks gestation had weekly anthropometry and a record kept of achieved nutritional intake. 54 of these had dual energy X-ray absorptiometry of the forearm for bone mineral content (BMC). Case control studies were done on nested cohort selected from this group: (1) macronutrient intake and growth in 20 babies with BPD and 20 gestation and birthweight matched controls, (2) EI and EL by bomb calorimetry in 4 infants with BPD and 4 preterm controls, (3) BMC in 10 babies with BPD and 10 gestation and birthweight matched controls, (4) BMC in 15 BPD babies treated with dexamethasone and 15 untreated BPD controls. Conclusions: CHD - There appears to be a progressive postnatal deterioration of nutritional status in hospitalized infants with CHD. This is associated with a tendency to lower energy intake, and in addition raised REE in some infants. Availability of energy appears to be a limiting factor for growth in this group. BPD - There is a shortfall of nutrient intake in the first two weeks, particularly via the enteral route, in preterm infants who later develop bronchopulmonary dysplasia. The subsequent rate of weight gain is slower for several weeks in these babies. There appears to be no abnormality of energy intake or losses. There is a large deficit in BMC in preterm infants at term, with no additional effect of BDP. Systemic steroid treatment slows linear growth, without any apparent effect on bone mineralization.
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