How much influence does inspiration have on pulse transit time in sleep apnea?

Abstract

To study how much affect inspiration has on pulse transit time (PTT). Prospective study. Polysomnograms were performed in 51 consecutive patients (male 45, female 6; ages 49.2 +/- 14.7 years) with obstructive sleep apnea. PTT changes during normal breathing, obstructive apnea (OA), and central apnea (CA) were compared, and the correlations between simultaneous changes in PTT and intraesophageal pressure (Peso) were discussed. In comparison with normal breathing, increases in PTT were greater in OA but significantly less in CA. The mean continuous increases in PTT were significantly higher in OA (17.0 +/- 4.9 ms) than those in CA (9.5 +/- 2.7 ms). Simultaneous changes in Peso and PTT correlated significantly but with a lower correlation coefficient in a portion of patients. Inspiration obviously affects PTT, and the linear relationship between simultaneous changes in PTT and Peso might be reflected to some extent.