Blood pressure responses to care procedures in ventilated preterm infants.

Responses of mean aortic blood pressure to sequences of routine care procedures in 22 ventilated, preterm infants were studied daily for the first 3 days of life. In the first 11 infants standard care procedures were used, whereas the next 11 infants were preoxygenated by a preceding 10% increase in inspired oxygen concentration; in these infants, chest physiotherapy was entirely omitted while the frequency of endotracheal suctioning was reduced. A total of 259 blood pressure responses were recorded. In general, responses were biphasic, consisting of an initial blood pressure drop followed by a greater blood pressure rise of longer duration. Baseline blood pressure, as well as the minimum and maximum blood pressure during the care procedures, increased with gestational age and with postnatal age. The blood pressure drop was most pronounced in the infants requiring the most intensive ventilatory support and was reduced by modifying the care procedures. The blood pressure rise was the least in the infants receiving pancuronium and phenobarbitone. Eight infants, 4 in each group, had intraventricular haemorrhage; in these infants, the care procedures induced more pronounced blood pressure drops in the first day of life when compared to the infants without haemorrhage.