Spirometry is often normal in children with STRA, and is thus a poor outcome measure (1). Lung Clearance Index is a sensitive, non-effort dependent measure of distal airway gas mixing, which has been shown to be more sensitive than spirometry in Cystic Fibrosis (2). We hypothesised that LCI would be a better marker of steroid response in STRA than spirometry.Patients and Methods
22 STRA children (Mean age 11.9 years, 15 male) had LCI and spirometry measured before and 4 weeks after intramuscular triamcinolone.Results
LCI was elevated in 18/22 prior to triamcinolone and 12/22 at the follow-up; in contrast FEV1 was only abnormal in 10/22 and 6/22 pretriamcinolone and posttriamcinolone respectively. Mean LCI fell from 7.86 to 7.25 (p<0.05) but there was no statistically significant decrease in FEV1 after triamcinolone.Conclusion
LCI is a better discriminant of STRA then FEV1, and is more responsive to steroid treatment. LCI may thus be a better outcome measure in STRA.