Objective: To determine the incidence and time course of blood pressure elevation in dexamethasone-treated premature infants with bronchopulmonary dysplasia.
Methods: In a prospective, self-controlled, consecutive case study, 16 ventilator-dependent very low birth weight neonates treated with dexamethasone were studied. Systolic, diastolic, and mean arterial pressure and heart rate were recorded at three specific times daily. Data were recorded from day 1 of dexamethasone treatment through the duration of therapy and up to 2 weeks after its completion. Retrospective daily data were collected for up to 14 days before therapy.
Results: The 788 daily observations (a systolic and diastolic average of the three blood pressure recordings per day) were recorded for 16 infants, a mean of 49 +/- 11 daily observations each (range, 24 to 67). Systolic and diastolic blood pressures before dexamethasone therapy were correlated to corrected gestational age. At initiation of dexamethasone, blood pressures increased significantly from days 1 to 2. For all observations, mean systolic pressure was 51 +/- 9.5 mm Hg before dexamethasone therapy, compared with 64 +/- 10.2 mm Hg during therapy (p < 0.01); diastolic pressure was 29 +/- 6.7 mm Hg before therapy compared with 41 +/- 8.2 mm Hg during therapy (p < 0.01). After completion of dexamethasone therapy, pressures continued to increase: systolic, 67 +/- 8.8 mm Hg (p < 0.01); diastolic, 42 +/- 6.2 mm Hg (not significant). Both systolic and diastolic pressures increased as a function of weight and age; when we controlled for these covariates, an independent effect of dexamethasone itself on the group was shown. Of the 2182 individual systolic pressure readings, 9.4% were considered in the hypertensive range. The six infants treated with hydralazine had higher mean systolic pressures before dexamethasone therapy than did infants without hydralazine (56 +/- 9.4 mm Hg vs 46 +/- 6.4 mm Hg; p < 0.001) and were 2 weeks older at initiation of therapy.
Conclusions: Blood pressure significantly increases during dexamethasone therapy, particularly within the first 48 hours, and does not return to baseline levels after therapy. Those infants most likely to be labeled hypertensive tend to be older at initiation of therapy but do not appear to have any other significant risk factors.