Heavy snoring with upper airway resistance syndrome may induce intrinsic positive end-expiratory pressure.
We studied eight heavy snorers with upper airway resistance syndrome to investigate potential effects of sleep on expiratory airway and lung resistance, intrinsic positive end-expiratory pressure, hyperinflation, and elastic inspiratory work of breathing (WOB). Wakefulness and non-rapid-eye-movement sleep with high- and with low-resistance inspiratory effort (H-RIE and L-RIE, respectively) were compared. No differences in breathing pattern were seen across the three conditions. In contrast, we found increases in expiratory airway and lung resistance during H-RIE compared with L-RIE and wakefulness (56 +/- 24, 16 +/- 4, and 11 +/- 4 cmH2O . 1(-1) . s, respectively), with attendant increases in intrinsic positive end-expiratory pressure (5.4 +/- 1.8, 1.4 +/- 0.5, and 1.3 +/- 1.3 cmH2O, respectively) and elastic WOB (6.1 +/- 2.2, 3.7 +/- 1.2, and 3.4 +/- 0.7 J/min, respectively). The increase in WOB during H-RIE is partly caused by the effects of dynamic pulmonary hyperinflation produced by the increased expiratory resistance. Contrary to the Starling model, a multiple-element compliance model that takes into account the heterogeneity of the pharynx may explain flow limitation during expiration.
Lofaso
F
F
Service de Physiologie-Explorations Fonctionnelles, Institut National de la Santé et de la Recherche Médicale U 492, Hôpital Henri Mondor, 94010 Créteil, France. frederic.lofaso@hmn.ap-hop-paris.fr
Lorino
A M
AM
Fodil
R
R
D'Ortho
M P
MP
Isabey
D
D
Lorino
H
H
Goldenberg
F
F
Harf
A
A
D000328:Adult; D000368:Aged; D000403:Airway Resistance / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D017286:Polysomnography; D011175:Positive-Pressure Respiration; D012129:Respiratory Function Tests; D012132:Respiratory Muscles / Q000503:physiopathology; D012890:Sleep / Q000502:physiology; D012913:Snoring / Q000503:physiopathology*; D014939:Work of Breathing / Q000502:physiology