Besides interferencence of esophageal motor function by the nasogastric tube, a decline of the positive gastro-esophageal pressure gradient caused by intermittent positive pressure ventilation seems to have a major role in the pathogenesis of gastroesophageal reflux (GER) in mechanically ventilated preterm infants. The aim of this study was to determine the incidence of GER and associated risk factors in mechanically ventilated preterm infants.

Twenty four hour esophageal pH monitorings were performed using a antimony electrode on 11 mechanically ventilated preterm infants in Neonatal Intensive Care Unit in Pusan National University Hospital. We evaluated the following reflux parameters; reflux index, reflux episodes/hour, reflux episodes ≥5 min/hour, duration of longest episode, and percent episodes ≥5 min. Patients were considered to have significant GER if more than 2 among 5 parameters were satisfied.

The mean gestational age of the patients was 30.9 weeks, mean birth weight was 1,568 g, and mean age at the time of pH monitoring was 2.8 days. Significant GER was detected in 4 patients (36.4%). There was no relationship between the incidence of GER and gestational age, birth weight, postnatal age, or the ventilator settings.

The incidence of GER in mechanically ventilated preterm infants was similar, compared with other previous studies. Associated risk factors of GER in these patients were not detected. Therefore, mechanical ventilation in preterm infants does not seem to be the high risk factor of GER.