Pediatric Obstructive Sleep Apnea Diagnosis by Respiratory Polygraphy

Overview

Respiratory polygraphy (RP) can be used to detect obstructive sleep apnea syndrome in children (OSA) , but it underestimates the obstructive apnea-hypopnea index (OAHI) because hypopneas associated with cortical arousals are not evaluated. To compensate for this disadvantage, hypopneas linked with autonomic micro-arousals can be calculated from the drop in pulse wave amplitude (obtained dy oximetry), as increased respiratory efforts are related to autonomic nervous system activation, tachycardia, and elevated blood pressure. The aim of this study is to compare OAHI obtained by RP alone or by RP considering hypopneas associated with autonomic micro-arousals with OAHI by polysomnography (PSG).

The diagnosis of obstructive sleep apnea syndrome in children (OSA) requires to perform a polysomnography (PSG) in hospitalization with video surveillance and monitoring by a nurse to put the sensors back on the child if necessary. PSG gives the obstructive apnea-hypopnea index (OAHI) necessary for the diagnosis of OSA and to determine its severity. But PSG is difficult to perform in children, with several sensors and electrodes to install. Respiratory polygraphy (RP) which uses only respiratory signals (without the neurophysiological signals ) can be used for the diagnosis of OSA but it underestimates OAHI because the hypopneas associated with cortical micro-arousals are not taken into account. An alternative to overcome this disadvantage is to determine the presence of autonomic micro-arousals because the increase in respiratory efforts during sleep is associated with activation of the autonomic nervous system and cardiovascular effects, such as tachycardia and an increase in blood pressure. Consequently, these respiratory efforts are associated either with autonomic activation or with cortical micro-arousal. One method to determine autonomic micro-arousals is photo-plethysmography which reflects sympathetic activation. Photoplethysmography is obtained by oximetry signal and is a non-invasive technique based on measuring the relative absorption by the blood of red light and infrared light through the finger. The pulsation of arterial blood flow through the finger arteries modulates light absorption and generates a pulse wave signal. Autonomic micro-arousals will be calculated according to 3 algorithms: reduction of 1) 30%; 2) 40%; 3) 50% of the photoplethysmography signal compared to the baseline and the hypopneas associated with these decreases will be taken into account in the calculation of the OAHI. Consequently, 3 OAHI will be obtained by RP including hypopneas associated with autonomic micro-arousals. The aim of this study is to compare OAHI obtained by RP considering hypopneas associated with autonomic micro-arousals with OAHI by PSG. The hypothesis of this study is that RP by adding hypopneas associated with autonomic micro-arousals can identify OSA in children.