M. Heather Bryan

Human milk feeding in premature infants: Protein,fat, and carbohydrate balances in the first two weeks of life

The nutritional adequacy of the premature infants own mothers milk was assessed during the first two weeks of life. Studies were carried out in three groups (n = 8) of infants of less than 1,300 gm birth weight, matched for gestational age and weight, and fed either pooled breast milk, their mothers own milk, or infant formula (SMA20 or SMA24). Macronutrient balances at the end of the first and second postnatal weeks demonstrated differences in nitrogen and lipid absorption and retention between groups. Nitrogen retentions (mg/kg/day) were similar to normal fetal accretion rates only in the PT and SMA24 groups. Fat absorption was poorest from the heat-sterilized PBM (average of 64.0% of intake) when compared to PT (88.2%) and SMA groups (83.3%). Average gross and metabolizable energy intakes were similar among groups. Nutritional status as measured by plasma total protein and albumin concentrations and weight gain tended to be poorest in the PBM-fed infants. It was concluded that either PT milk or infant formula of a composition similar to SMA24 are more appropriate than pooled banked milk for feeding the premature infant during the first two weeks of life.

The consequences of diaphragmatic muscle fatigue in the newborn infant.

We have previously demonstrated that diaphragmatic muscle fatigue can be diagnosed in infants from spectral frequency analysis of the surface diaphragmatic electromyogram. This requires a digital computer, but the analysis takes several days. Spectral frequency changes, however, can be accurately reflected by band pass filtering and expressing the ratio of high-frequency power to low-frequency power. A fall in this ratio of greater than 20% indicates muscle fatigue. Using a simple analog device to obtain this ratio permits the results to be immediately available; we have used this method to study weaning from mechanical ventilators in ten infants. With a successful weaning step there is no significant change in the ratio, whereas an unsuccessful weaning step invariably leads to a decrease in the ratio of greater than 20%, which precedes CO2 retention and clinical deterioration. These data indicate that diaphragmatic muscle fatigue plays an important role in the infants response to lung disease. Monitoring of the high/low frequency ratio may be helpful in weaning infants from assisted ventilation.

Supplemental intravenous alimentation in low-birth-weight infants

Comparative effects of intravenously administered 10 per cent dextrose solution with and without the addition of 3.5 per cent fibrin hydrolysate were evaluated in the supplemental alimentation of gastric-fed, low-birth-weight infants (

Variations in Intralipid Tolerance in Newborn Infants

Summary: Intravenous Intralipid tolerance tests (IVLTT) were done in 26 newborn infants of 26–40 wk gestational ages. The clearance constants (k2) ranged from 1.2–12.7 (%/min) after bolus injections given within 4.5 h (n = 12) or daily (n = 13). Significant variation (17–31%) occurred, similar to adults, and was unrelated to the time or dose given. Eleven infants received continuous Intralipid infusions for 10–24 h at a rate calculated to maintain a plasma Intralipid plateau concentration of 100 mg/dl. Nine infants did not exceed this optimal plasma level, although four could have tolerated more Intralipid. Two infants exceeded the ideal plasma concentration (> 100 mg/dl). All infants achieved and maintained plateaus within 5 h. Neither day-to-day variations nor the bolus dose used to establish clearance characteristics, accounted for the discrepancies in plateaus achieved. These studies identify some limitations of the IVLTT as a predictor of Intralipid utilization during continuous infusion, and the need for early monitoring of plasma Intralipid concentrations to optimize the therapeutic dose given to newborn infants.

1431 SURFACTANT THERAPY IN HYALINE MEMBRANE DISEASE (HMD)

Three infants with severe HMD were given surfactant with dramatic results. The surfactant phospholipid was extracted from a bovine lung wash by the Folch procedure, all but a trace of protein removed, and autoclaved at 120°C for 30 minutes. Each infant was mechanically ventilated and received 8 ml. of surfactant into the endotracheal tube. The rapid improvement in oxygenation led to a decrease in FiO2 and ventilation as shown in the table.Partial clearing of the chest x-ray was followed by diffuse opacification (atelectasis and edema). The initial marked improvement in oxygenation did not “cure” other aspects of prematurity. Baby 2 had intraventricular hemorrhages on day 2 and later was ventilated for apnea. Baby 3 had a PDA treated conservatively. Post extubation all required supplementary O2 (< 30%) for 10, 2 and 1.5 weeks.

A controlled study of intravenous fibrin hydrolysate supplement in prematures < 1.3 kg

We have compared the effect of early supplemental intravenous 3.5% fibrin hydrolysate plus 10% dextrose to 10% dextrose alone on the mortality, morbidity, weight gain and biochemical changes in 2 equal groups of 15 low birth weight infants of appropriate gestation. The initial alimentation was intravenous with gradual repalcement by oral formula over the first 2 weeks of life. Total fluid intake of 200 ml/kg/day was maintained. Total caloric intake and urinary output did not differ between groups. The amino acid infants received twice the amount of protein (g/kg/day) as the controls. Mortality did not differ between groups when infants were assessed by body weight. In the survivors apnoca was significantly less frequent in those receiving amino acid and regain of birth weight more rapid. Total protein and BUN were higher in those on amino acid reflecting increased N2 intake, and serum PO4 lower. Serum electrolytes, sugar, osmolality, HCO3 did not differ. Fatal cases in the amino acid group, many <1.0 kg, exhibited an excessive rise in BUN, and high plasma osmolality within 3 days of infusion.

1649 HOME APNEA MONITORING IN THE SIBLINGS OF SIDS VICTIMS

Prolonged sleep apnea (> 20 seconds) has been postulated as the final pathway in SIDS. To evaluate this we managed a high-risk group of 50 siblings of SIDS victims, including 11 survivors of 9 multiple pregnancies, on apnea monitors at home.The mean birth weight and gestational age was 3.2±0.6 kg. and 38.4±2.7 weeks respectively. Monitoring started at 3.5±3.6 weeks in the singleton siblings and 16.4±6.6 weeks in the multiple pregnancy survivors. Twelve infants (24%) had at least one definite apneic spell with 8 having >5 episodes. The mean age of the first and last spells were 2.8 and 6.6 months respectively. Clustering in time was noted in 8, and precipitating factors, especially “colds”, were associated with apnea in 9 babies. No deaths occurred, but 9 babies needed vigorous stimulation on at least one occasion. Monitoring ended at an age of 10.2±2.4 months in babies with apnea and 7.1±2.3 months in those without apnea.The apneic babies were no different in respect to sex (X2= 0.01) and prematurity rate (X2=1.46). The incidence of apnea was the same in the survivors of multiple pregnancies as in the singleton siblings (X2=0.08). There was no relationship between the timing of the apnea and the age at death of the sibling.Prolonged apnea in the first 9 months of life is commoner than expected in the siblings of SIDS victims and we speculate that it may be inherited as an autosomal recessive condition.

934 HUMAN MILK: COMPARISON OF NITROGEN (N) COMPOSITION IN MILK FROM MOTHERS GIVING BIRTH PREMATURELY OR AT TERM

Complete 24-hour expressions of human breast milk were collected serially from 7 mothers giving birth at 26-33 wk gestation (Premature,PT) and 8 mothers at 38-40 wk gestation (Full-term,FT) during the first 29 days postpartum. Individual milk samples (69) were analyzed for total N concentration. The regression lines describing the change in N concentration (y) with time in days (d) were y=368 - 4.36d (r=-0.60,p<0.01), and y=310 - 4.15d (r=-0.80,p<0.01), for PT and FT, respectively. Total N concentration in PT milk was significantly higher (p<0.01) than in FT milk over the time studied. The distribution of total N in non-protein N (NPN) and protein N was determined on 7 PT and 8 FT pooled milk samples, representing specific day intervals within each group. NPN as a percent of total N remained constant over the first 29 days of lactation and was similar in the two groups (FT=18.9±0.7,PT=17.8±0.8, mean ± SEM). The proportions of N derived from free amino acid N (FAAN) and urea N(UN) were constant with time and as a percentage of NPN were similar in the FT(7.9±0.4 FAAN;26.8±1.7UN) and PT (8.4±0.7FAAN;25.8±2.0 UN) groups. It is concluded that the higher N concentration of PT milk is due to proportional increments in both the protein and NPN fractions.