Abstract
Reference equations for the RVRTC derived from “in-house” equipment were inappropriate for commercially available devices, although an interim correction factor was developed.1
Aim: to develop equipment specific reference ranges for RVRTC outcomes.
Method: RVRTC data from healthy subjects using Jaeger BabyBody or the 'RASP' systems were collated from 4 centres. Data were excluded if gestational age<37w; birthweight<2.5kg or FEV0.5 not achieved. New reference equations were derived and compared with published references1,2 using recent data from CF infants and controls.
Results: Acceptable RVRTC data from 367 healthy infants (59%boys; 92%White) on 607 tests (age range:2.7-117w) were available from London, Australia, Spain & Portugal. Prediction equations for all data were similar to those limited to White infants or Jaeger data only, thus definitive models were based on all data. When compared with the new equations, abnormalities in FVC & FEV0.5 were increasingly over-estimated with age when using Jones equations2, with a more constant overestimation for FEF25-75(Figs A-C). By contrast, the 'Jones adjusted' equations1 tended to over-estimate abnormalities in younger children but were adequate for older infants(Figs E-F).
Conclusion: This study provides improved prediction equations for RVRTC outcomes which will enhance interpretation of infant lung function results.
1Lum PedPulm 2010
2Jones AJRCCM 2000.
- Copyright ©ERS 2015
