Introduction: For possible use as a predictor of wheezing illnesses in routine care, we evaluated the feasibility and variability of measurement of passive respiratory mechanics in a large, open population of healthy neonates and infants.
Methods: As part of the ongoing Wheezing Illnesses Study Leidsche Rijn, respiratory compliance (Crs), respiratory resistance (Rrs), and time constant (taurs) were measured during natural sleep in 450 healthy term neonates and infants using the single-occlusion technique (SOT). Interobserver and intraobserver variability of data sampling and the subsequent selection and analysis of occlusions as well as intra-measurement variability were examined.
Results: Technically acceptable lung function measurements could be performed in 328 infants (73%). Low intraobserver and interobserver variability was found for both data sampling (intraclass correlation coefficient [ICC] > or = 0.87) and for selection and analysis of occlusions (ICC > or = 0.99). Intra-measurement variability was low, with a mean intra-measurement coefficients of variation for Crs, Rrs, and taurs of 8.5%, 10.4%, and 15.4%, respectively. Averaging three or more occlusions resulted in stable values of Crs, Rrs, and taurs.
Conclusion: Results of this study indicate that feasibility and variability of lung function testing using the SOT is acceptable for use in large populations of healthy neonates and infants in routine care.