Prevalence of Tidal Expiratory Flow Limitation in Preschool Children with and without Respiratory Symptoms: Application of the Negative Expiratory Pressure (NEP) Method
Abstract
Negative expiratory pressure (NEP) applied at the mouth during tidal expiration provides a non-invasive method for detecting expiratory flow limitation. Twenty five children with different respiratory symptoms (R) and 17 without any respiratory symptoms (NR) were studied.
Children were examined without any sedation. A preset NEP of -5 cm H2O was applied; its duration did not exceed duration of tidal expiration.
A significance of FL was judged by determining of a flow-limited range (in % of tidal volume). FL was found in 48 % children of R group.
No patient of the NR group elicited FL (P<0.001 R vs. NR).
The frequency of upper airway collapses was higher in R group (12 children) than in NR group (5 children). In conclusion, a high frequency of tidal FL in the R group was found, while it was not present in NR group.
NEP method represents a reasonable approach for tidal flow limitation testing even in non-sedated children.