D. Stanescu et al., EXPIRATORY FLOW LIMITATION DURING SLEEP IN HEAVY SNORERS AND OBSTRUCTIVE SLEEP-APNEA PATIENTS, The European respiratory journal, 9(10), 1996, pp. 2116-2121
Inspiratory flow limitation (FL) during sleep has previously been repo
rted both in obstructive sleep apnoea (OSA) patients and heavy snorers
(HS), Recent results from this laboratory have shown the occurrence b
oth of inspiratory and expiratory flow limitation during muscular rela
xation in awake healthy subjects and OSA patients. In this study, we h
ave investigated whether expiratory flow limitation occurs during slee
p in heavy snorers and in patients with OSA, We studied four nonapnoei
c, heavy snorers and five OSA patients, Airflow was measured with a pn
eumotachograph attached to a tight-fitting mask, and supraglottic pres
sure with a catheter placed at the supraglottic level, Scoring for flo
w limitation was achieved by visual inspection of 200 breaths recorded
during sleep. About 20% of the respiratory cycles presented isolated
inspiratory flow limitation, Approximately the same percentage was obs
erved in heavy snorers and OSA patients, Isolated expiratory flow limi
tation was less frequently recorded, Coupled inspiratory and expirator
y flow limitations were more numerous, especially in heavy snorers. We
conclude that both in heavy snorers and obstructive sleep apnoea pati
ents, inspiratory flow limitation is associated with expiratory now li
mitation, This suggests that upper airway obstruction during sleep is
both an inspiratory and expiratory event.