AIR LEAKING THROUGH THE MOUTH DURING NOCTURNAL NASAL VENTILATION - EFFECT ON SLEEP QUALITY

Air leaking through the mouth has been reported in kyphoscoliotic pati ents receiving nasal ventilation via volume-limited ventilators. This study accessed the frequency of occurrence and effect on sleep quality of air leaking through the mouth during nocturnal nasal ventilation i n patients with chest wall and neuromuscular disease using pressure-li mited ventilation. Overnight and daytime polysomnography was performed in six stable experienced users of nocturnal nasal noninvasive positi ve-pressure ventilation (NPPV) who had chronic respiratory failure due to neuromuscular disease or chest wall deformity. All patients used t he BiPAP S/T-D ventilatory support system (Respironics, Inc., Murrysvi lle, PA). Measures included sleep scoring, leak quantitation, diaphrag m and submental electromyograms (EMGs), and tidal and leak volumes.All patients had air leaking through the mouth for the majority of sleep. Sleep quality was diminished because of poor sleep efficiency and red uced percentages of slow-wave and rapid eye movement (REM) sleep. Air leaking through the mouth was associated with frequent arousals during stages 1 and 2 and REM sleep that contributed to sleep fragmentation, but arousals were infrequent during slow-wave sleep. Despite prevalen t leaking, oxygenation was well maintained in all but one patient. Pat ients used a combination of passive and active mechanisms to control a ir leaking. Although nasal ventilation improves nocturnal hypoventilat ion and symptoms in patients with restrictive thoracic disorders, air leaking through the mouth is very common during use. The leaking is as sociated with frequent arousals during lighter stages of sleep that in terfere with progression to deeper stages, compromising sleep quality. Portable pressure-limited ventilators compensate for leaks, maintaini ng ventilation and oxygenation, but further studies are needed to dete rmine which interfaces and ventilator techniques best control air leak ing and optimize sleep quality.