Editor—We read with interest the paper by Nelle at al.1 The authors report that nasogastric bolus feeding in preterm infants provokes a considerable decrease in cerebral blood flow velocity (CBFV) while blood pressure and heart rate remain unchanged. In this study 20 to 40 ml of milk were delivered over 5 minutes to infants with a mean postmenstrual age of 35 weeks.

Was the feeding tube inserted before tube feeding or was it indwelling? Insertion itself could have significantly affected CBFV, heart rate, and oxygen saturation during the feeding period.2-4

What position were the infants in during the study? There are clear differences in oxygen saturation and heart rate between the prone and supine positions.5

Apart from the periods when the infants woke up because of the blood pressure measurements, it is difficult to see how the infants remained in a quiet sleep state throughout the investigation. Behavioural state significantly affects CBFV.6 We recently studied the effects of orogastric feeding with infants in the prone position.7 After feeding (recorded until 20 minutes postprandially), most of the infants were in quiet sleep state, but before or during feeding the quiet sleep state was recorded …