INDIAN JOURNAL OF PEDIATRICS

Vol. 37 January, 1970 No. 264

ORIGINAL ARTICLES

GASTRIC JUICE pH AND BLOOD GLUCOSE IN THE NEWBORN*

MEHARBAN SINGH, C. MONTERIO AND O. P. GHAI

New Delhi

There are very few reports of serial estimation of gastric juice acidity in the neonate (Griswold and Shohl 1925, Huhtikangas 1936, Miller 1941, Thomson 1951, Ebers et al. 1956, Smith 1959). It has been shown that from a relatively neutral state of gastric juice at birth, the acidity rapidly rises and the pH drops to about 1 to 3 at about 4--5 hours (Huhtikangas 1936). This marked post-natal increase in gastric acidity is then followed by a fall in the free acid of the stomach which may altogether be absent at 24 hours though the average is about 1.45 ml of N/10 HC1/100ml (Griswold and Shohl 1925, Ebers et al. 1956, Smith 1959).

There is no satisfactory explanation for fluctuations in gastric acidity in early neonatal life. In the light of the

*From the Department of Pediatrics, All India Imtitute of Medical Sciences, New Delhi.

experimental work of Bachrach (1953), Davis et al. (1965), and Hirschowitz 1967), all of whom demonstrated a fall in the pH of gastric juice following insulin-induced hypoglycaemia, it was postulated that fluctuations in the gastric pH in the newborn may be the result of an instability of carbohy- drate metabolism during this period. The present study was conducted to test this hypothesis.

Material and Methods

Thirty apparently healthy neonates born after uncomplicated normal deliveries at the All-India Institute of Medical Sciences, New Delhi, were taken for the study. The gastric juice samples were collected by naso- gastric intubation at birth and at 3, 6, 24, 48 and 72 hours with a margin of 30 minutes. The gastric aspiration was performed about 3 hours after the last feed. The pH was determined

2 INDIAN JOURNAL OF PEDIATRICS VOL. 37 NO. 264

in the Astrup Micro-equipment (Radiometer Copenhagen). Simul- taneous samples of heel blood were taken for the estimation of blood glucose by the Somogyi--Nelson method.

Ten samples of amniotic fluid were obtained by a puncture of the amniotic sac and their pH was also determined.

Results

The observations are summarized in Table 1. At birth the mean pH of the gastric juice was 7.05. Twenty- three values were above 7.0, four were between 3.0 to 7.0 and only three were below 3.0. At 3,6 and 24 hours, the mean pH values of the gastricjuico

were 2.7, 2.9 and 2.6 respectively and there were no values above 7.0. Subsequently the mean values of pH of the gastric juice rose to 4.08 and 4.60 at the age o f 48 and 72 hours respectively. There were no abnormal clinical findings in any of the seven infants showing high gastric acidity.

The correlation between simul- taneous blood glucose aud gastric juice pH values is shown in Fig.1. It was observed that as the blood glucose dropped to the minimum level at 3 hours, the gastric juice pH also dropped to the lowest level but sub- sequently the correlation between the two parameters was not significant.

The pH of the amniotic fluid ranged between 7.5 and 8.4.

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Gastric juice pH and blood glucose in the newborn.

SING/] ET AL.~GASTRIC JUICE pH AND BLOOD GLUCOSE IN THE NEWBORN 3

Discussion

0nly limited literature is available regarding values of gastric juice pH in the newborn. At birth, the gastric juice was alkaline in 23 out of 30 cases. There was a sharp fall in pH at 3 hours and the minimum mean pH of 2.60 was seen at 24 hours. Sub- sequently the gastric juice pH continued to increase gradually in the next 48 hours. These findings are in agreement with observations made by Huhtikangas (1936). We could not confirm the observations made by Huhtikangas (1936) and Miller (1941) that the gastric acidity falls to zero at 24 hours, although the lowest value of gastric juice pH observed by us was also at 24 hours.

The alkaline pH of the amniotie fluid would support Smith's (1959) hypothesis that the initial low gastric acidity of the newborn at birth could be the result of aspiration of amniotic fluid during the process of birth. However, no satisfactory explanation is available to explain the subsequent alterations in the gastric pH in the newborn.

There was a distinct correlation between the blood glucose and gastric juice pH during the first 3 hours but this correlation was not obtained subsequently. It was not possible to predict the value of gastric juice pH from a given blood glucose value or vice versa. The hypothesis that varia- tions in gastric acidity in the newborn may be a reflection of the instability of the carbohydrate metabolism, has not been proved in this limited study. It is possible that epinephrine release due to hypoglycaemia may not be the only factor influencing gastric secretion in the neonate and the observed fluctua-

tions in gastric acidity may be a manifestation of post-natal develop- mental maturation of the stomach.

Summary Blood glucose and gastric juice pH

were determined simultaneously in 30 apparently healthy newborns from birth to 72 hours of life. The gastric juice at birth was either neutrat or alkaline. There was a sharp fall in the gastric juice pH during the first 3 hours, which was maintained for 24 hours followed by a subsequent rise at 48 and 72 hours. The alkaline pH of the amniotic fluid may explain the initial high pH of the gastric juice at birth but the exact explanation for the subsequent fluctuations in the pH is not yet available. There was no statistically significant and linear cor- relation between simultaneousblood glucose values and gastric juice pH.

References

Bachrach, W . H . (1953). Action of insulin hypoglyeaemia on motor and secretory functions of the digestive tract. Physiol. Rev. 33, 566.

Davis, R. A., Brooks, F. P. and Roberts, C. M . Jr. (1955). Gastric secretory response to graded insulin hypoglycaemia. Arner. J. Physiol. 208, 6.

Ebers, D. W., Smith, D. I. and Gibbs, G . E . (1956). Gastric acidity on the first day of life. Pediatrics, 18, 800.

Griswold, C. and Shohl, A. T. (1925). Gastric digestion in newborn infants. Amer. J. Dis. Child. 30, 541.

Hirschowitz, B. I. (1967). Continuing gastric secretion after insulin hypoglycaemia despite glucose injection. Amer. J. Dig. Dis. 12, 19.

Huhtikangas, H. (1936). Quoted by Smith, C. A. (1959).

Miller, R. A. (1941). Observations on the gas- tric acidity during first month of life. Arch. Dis. Child..16, 22.

Smith, C. A. (1959). The physiology of the Newborn Infant, Blackwell SeientificPublieations, Oxford. 3rd. Ed.

Thomson, J. (1951). The volume and acidity of the gastric contents in the unfed newborn itl- rant. Arch. Dis. Childh. 26, 558,