Background: Information on the dose of steroid infants inhale from spacer devices and its potential effect on adrenal suppression is limited.
Objective: We sought to determine the total dose of fluticasone propionate (FP) inhaled from a spacer device (Babyhaler) with face mask attachment by infants recovering from acute bronchiolitis and the effect of inhaled FP on the infants' overnight urinary cortisol/creatinine ratios (UCCRs).
Methods: Infants studied were recovering from acute bronchiolitis. In study 1, 22 infants inhaled 150 microg of FP through the Babyhaler. The likely inhaled dose was estimated by trapping it on a filter held within the face mask. In study 2, 40 infants had UCCRs measured before and during 3 months of treatment with either FP (150 microg twice daily, n = 20) or placebo (n = 20).
Results: In study 1 the mean +/- SD dose of captured FP was 12.8 +/- 6.9 microg (ie, 2.1 +/- 1.2 microg/kg). In study 2 the pretreatment UCCR medians (interquartile ranges) were as follows: FP, 22.8 (23.0) nmol/mmol; placebo, 24.0 (28.3) nmol/mmol. Within-group UCCR changes (median and interquartile range DeltaUCCR) were significantly different in the FP group (-8.9 and -20.6 nmol/mmol at 6 weeks and -12.6 and -25.9 nmol/mmol at 12 weeks, respectively; P =.0008) but not in the placebo group ( -5.8 and -10.7 nmol/mmol at 6 weeks and +0.3 and -17.9 nmol/mmol at 12 weeks, respectively; P =.45). Intergroup changes were insignificant in the follow-up period (6 weeks, P =.52; 12 weeks, P =.19).
Conclusion: After bronchiolitis, infants are likely to inhale approximately 8 % of the nominal steroid dose from the Babyhaler. UCCRs can be used to monitor the bioavailability of inhaled steroids in young infants.