Monitoring of sleep apnea in children using pulse transit time

Abstract

Aim of this study was to validate the use of pulse transit time (PTT) as a method to monitor sleep apnea in children. PTT was estimated as the interval between between the ECG R-wave and the point at which the pulse wave at the finger reached 90% amplitude. First, we assessed changes in the PTT during breathing against known resistances in 15 awake children; resistance was applied with a modified nose and mouth two-way non rebreathing face mask, having the inhalation valve port fitted with drilled plastic cylinders. Second, we analyzed 20 events of obstructive apnea and 90 events of central apnea during sleep in 10 children. Our data showed a good correlation between the inspiratory effort and the PTT oscillations amplitude. In addition PTT oscillations amplitude tuned out to successfully discriminate central from obstructive apnea.