Upper airway collapsibility during sleep in upper airway resistance syndrome.
OBJECTIVE
To compare upper airway collapsibility during sleep between patients with upper airway resistance syndrome (UARS), normal subjects, and patients with obstructive sleep apnea/hypopnea syndrome (OSA/H).


METHODS
A descriptive study of a series of clinical patients and a cohort of normal control subjects.


METHODS
Two academic sleep-disorders centers.


METHODS
One hundred six adult patients with sleep-disordered breathing evaluated at the SUNY Sleep Disorders Center-Medicine and 12 adult subjects without habitual snoring or daytime sleepiness and with an apnea/hypopnea index (AHI) < 5/h evaluated at the Johns Hopkins Pediatric Sleep Disorders Center.


METHODS
All subjects underwent full-night polysomnography and a determination of pharyngeal critical pressure (Pcrit). All patients had a determination of therapeutic level of nasal continuous positive airway pressure (Ptherapeutic).


RESULTS
The mean +/- SD Pcrit of the 12 normal subjects was - 15.4 +/- 6.1 cm H(2)O; the mean Pcrit of the 22 UARS patients was - 4.0 +/- 2.1 cm H(2)O; the mean Pcrit of the 37 patients with mild-to-moderate OSA/H (AHI > or = 10/h and < 40/h) was - 1.6 +/- 2.6 cm H(2)O; and the mean Pcrit of the 47 patients with moderate-to-severe OSA/H (AHI > or = 40/h) was 2.4 +/- 2.8 cm H(2)O. The Pcrit of each group differed from that of all other groups (p < 0.01). The mean Ptherapeutic of patients with UARS was 6.9 +/- 1.7 cm H(2)O; the mean Ptherapeutic of patients with mild-to moderate OSA/H was 7.9 +/- 1.9 cm H(2)O (p = 0.08 compared with the Ptherapeutic of UARS patients); and the mean Ptherapeutic of patients with moderate-to severe OSA/H was 10.5 +/- 2.4 cm H(2)O (p < 0.0001 compared to each of the other patient groups).


CONCLUSIONS
UARS is a syndrome of increased upper airway collapsibility during sleep. The upper airway collapsibility during sleep of patients with UARS is intermediate between that of normal subjects and that of patients with mild-to moderate OSA/H.
Gold
Avram R
AR
Division of Pulmonary/Critical Care Medicine, SUNY-Stony Brook, School of Medicine, DVA Medical Center, Northport, NY 11768, USA.
Marcus
Carole L
CL
Dipalo
Francis
F
Gold
Morris S
MS
D000328:Adult; D000402:Airway Obstruction / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D000403:Airway Resistance; D006801:Humans; D010614:Pharynx / Q000503:physiopathology*; D017286:Polysomnography; D011175:Positive-Pressure Respiration; D012890:Sleep / Q000502:physiology*; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D013577:Syndrome