Background Pulse transit time (PTT) represents a
noninvasive marker of sleep fragmentation in patients with
obstructive sleep apnea–hypopnea syndrome (OSAHS).
Little is known regarding changes in PTT in patients with
excessive daytime sleepiness associated with nocturnal
inspiratory flow limitation (IFL) without apneas or
desaturation.
Patients and methods A total of 20 patients with nocturnal
IFL were age and sex matched with a group of patients with
OSAHS and another without significant breathing disorders
during sleep [nonflow limited (NFL)]. PTT arousal index (PTT
Ar) is the number of PTT arousals per hour.
Results Overall, 20 patients with IFL were age and sex
matched with two groups: one with OSAHS and another
without significant sleep-disordered breathing (SDB) (NFL).
There was a significant increase in the median BMI of the IFL
group compared with the NFL group (40 vs. 30; P0.05). The PTT Ar in
the IFL group (36.5/h) was significantly higher than that in the
NFL group (16.3/h) and lower than that observed in the
OSAHS group (60/h; P