Correspondence: D. Stanescu

ABSTRACT: Inspiratory flow limitation (FL) during sleep has previously been re-ported both in obstructive sleep apnoea (OSA) patients and heavy snorers (HS). Recent results from this laboratory have shown the occurrence both of inspiratory and expiratory flow limitation during muscular relaxation in awake healthy sub-jects and OSA patients. In this study, we have investigated whether expiratory flow limitation occurs during sleep in heavy snorers and in patients with OSA. We studied four nonap-noeic, heavy snorers and five OSA patients. Airflow was measured with a pneumo-tachograph attached to a tight-fitting mask, and supraglottic pressure with a catheter placed at the supraglottic level. Scoring for flow limitation was achieved by visual inspection of 200 breaths recorded during sleep. About 20 % of the respiratory cycles presented isolated inspiratory flow limita-tion. Approximately the same percentage was observed in heavy snorers and OSA patients. Isolated expiratory flow limitation was less frequently recorded. Coup-led inspiratory and expiratory flow limitations were more numerous, especially in heavy snorers. We conclude that both in heavy snorers and obstructive sleep apnoea patients, inspiratory flow limitation is associated with expiratory flow limitation. This sug-gests that upper airway obstruction during sleep is both an inspiratory and expi-ratory event