Serial Acid-Base Determinations in Normal Premature and Full-Term Infants During the First 72 Hours of Life

Abstract

have made a serial survey beyond the first 24 hours. It therefore seemed worth while to study the acid-base status on the same infants serially at predetermined times over a period of 72 hours. No such published data are available for premature infants. The opportunity also presented itself to re-evaluate the role ofpH and Pco5 in infants with a respiratory frequency over 60/min. but without respiratory distress (Branning, 1942;Prod'hom et al., 1964. Material and Methods An unselected group of premature and full-term infants was studied in the Peninsula Maternity Hospital. The total number of infants was 36, of whom 20 were premature and 16 were full term. The series of estimations was largely completed on 17 of the premature and all the full-term infants. However, as only normal and healthy infants were to be considered, 3 premature babies who developed respiratory distress were excluded. Seven children were discharged between 48-72 hours and their final readings were, therefore, not obtained. The majority of the group studied were normal vertex deliveries, with 6 caesarean sections and 2 breech extrac-* C.S.I.R. Senior Bursar, Department of Child Health, University of Cape Town. tions, of which equal numbers were premature and full term. The decision as to maturity was made on birth weight alone. The average premature birth weight was 2-25 kg. and for full-term infants it was 3 09 kg. The premature group was not further subdivided because of the small number of cases below 2-0 kg. Premature babies were starved for the first 24 hours. They were then given two 5% dextrose water feeds followed by halfstrength expressed breast milk (EBM). The strength of EBM was increased to 75% on the 3rd day. Full-term infants were given one or two 5% dextrose feeds at about 12 hours and then taken to the mothers for breast feeding. If the mother was not able to breast feed, e.g. after caesarean section, the infant then also received halfstrength EBM which was increased to 75% on the 3rd day. In 15 premature and 6 full-term infants the respiratory rate was recorded every half-hour for the first 18 hours.Arterialized capillary blood was collected from each infant at 2, 4, 6, 12, 24, 48, and 72 hours of age. Blood samples were taken from heel stabs after warming the foot for 15 minutes (Gambino, 1961). 224 acid-base values were immediately determined by means of the Astrup method (Siggaard Andersen, Engel, J0rgensen and Astrup, 1960). The pH and Pco2 were corrected for the temperature of the patient (Rosenthal, 1948; Siggaard Andersen, 1963): this was of importance, as some premature infants had subnormal temperatures. Care was taken to avoid crying before and during the procedure and we were successful on all but 12 of the 224 occasions. The collection of the blood and the determinations were carried out by two of the authors. Throughout the study there was good correlation between the findings of the two operators. Very good blood flow was obtained from these infants compared with experience in ill infants suffering from re...

Acid-base determinations in normal premature infants in the first two months of life.

“…The development of metabolic acidosis after 48-72 hours of age had been previously suspected (Malan et al, 1965) and is confirmed in this study. The 678 Pco2 (mm.…”

“…Group B: babies of gestation 34-36 weeks-19 Group C: babies of gestation over 36 weeks-1. Arterialized capillary blood was collected and acidbase values determined by means of the Astrup method as previously described (Malan et al, 1965).…”

“…In a previous report from this unit (Malan, Evans, and Heese, 1965) it was shown that in the first 72 hours of life there are several differences in acid-base status between premature and full-term infants.…”

Transient respiratory distress syndrome in the newborn.

“…found by Bucci, Scalamandre, Savignoni, and Mendicini (1965) and of about 2 mEq/l. found by Malan, Evans, and Heese (1965). Chest x-ray films obtained in 6 of the TRD infants showed hyperaeration and, in 2 cases, the reticulo-granular pattern usually associated with RDS.…”

“…Four of the RDS infants subsequently died. None of the infants had clinical findings suggestive of aspiration syndrome (Schaffer, 1960), pneumothorax, or pneumomediastinum (Malan and Heese, 1966). S.E.…”