Observations on gastro-oesophageal reflux, central apnoea and heart rate in infants.

Respiratory movements and heart rate were monitored continuously during the course of 2 h radionuclide studies to detect gastro-oesophageal reflux (GOR) in 22 infants following a milk feed. Twenty infants had GOR, to upper oesophageal/pharyngeal level in 19, and 17 had central apnoea between 3 and 15s. Prolonged central apnoea (greater than 20s) was not observed. Bradycardia, defined as a heart rate less than 80 beats/min for 10s or more, was observed in only 1 infant who did not have GOR. No correlation was found between the number or duration of reflux episodes and the frequency of respiratory pauses between 3 and 17s. When data from individual infants were examined a possible temporal relation between the occurrence of GOR and central apnoea was seen in only two infants; in each case, detailed examination suggested that apnoea was more closely associated with sleep than with GOR. Although the respiratory monitoring system did not include airflow sensors, the almost complete absence of bradycardia suggested that prolonged obstructive apnoeas did not occur. We conclude that any relation between GOR and central apnoeas less than 15 s is not of a direct cause/effect nature.