EFFECTS OF DEXAMETHASONE ON BLOOD-PRESSURE IN PREMATURE-INFANTS WITH BRONCHOPULMONARY DYSPLASIA

Objective: To determine the incidence and time course of blood pressur e elevation in dexamethasone-treated premature infants with bronchopul monary dysplasia. Methods: In a prospective, self-controlled, consecut ive case study, 16 ventilator-dependent very low birth weight neonates treated with dexamethasone were studied. Systolic, diastolic, and mea n arterial pressure and heart rate were recorded at three specific tim es daily. Data were recorded from day 1 of dexamethasone treatment thr ough the duration of therapy and up to 2 weeks after its completion. R etrospective daily data were collected for up to 14 days before therap y. Results: The 788 daily observations (a systolic and diastolic avera ge of the three blood pressure recordings per day) were recorded for 1 6 infants, a mean of 49 +/- 11 daily observations each (range, 24 to 6 7). Systolic and diastolic blood pressures before dexamethasone therap y were correlated to corrected gestational age. At initiation of dexam ethasone, blood pressures increased significantly from days 1 to 2. Fo r 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 co mpared with 41 +/- 8.2 mm Hg during therapy (p < 0.01). After completi on of dexamethasone therapy, pressures continued to increase: systolic , 67 +/- 8.8 mm Hg (p < 0.01); diastolic, 42 +/- 6.2 mm Hg (not signif icant). Both systolic and diastolic pressures increased as a function of weight and age; when we controlled for these covariates, an indepen dent effect of dexamethasone itself on the group was shown. Of the 218 2 individual systolic pressure readings, 9.4% were considered in the h ypertensive 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 p ressure significantly increases during dexamethasone therapy, particul arly within the first 48 hours, and does not return to baseline levels after therapy. Those infants most likely to be labeled hypertensive t end to be older at initiation of therapy but do not appear to have any other significant risk factors.