Evaluating Changes in Pulse Transit Time Drop Index in Patients With Obstructive Sleep Apnea Before and During Cpap Therapy Publisher Pubmed



Kalantari E¹ ; Kalantari F² ; Edalatifard M³ ; Rahimi B³ Show Affiliations
Source: Clinical Respiratory Journal Published:2022

Abstract

Airflow limitation in patients with obstructive sleep apnea (OSA) leads to arousal, increased sympathetic nervous system activity, and elevated blood pressure, which causes a decrease in pulse transit time (PTT). The present study aims to evaluate the effect of CPAP therapy on PTT in patients with moderate to severe OSA. This was a cross-sectional study. Split-night polysomnography (PSG) study was performed for each participant with apnea-hypopnea index (AHI) ≥ 15 before and during CPAP therapy. The PTT was calculated as the time interval between the R wave of the electrocardiogram and the following arrival point in fingertip photoplethysmography. PTT drop was defined as a fall in the PTT curve of ≥15 ms lasting at least for 3 s and at most for 30 s. PTT drop index was defined as the number of drops in PTT that occur per hour of sleep. A total of 30 patients were included. PTT significantly increased, and PTT drop index significantly decreased during CPAP therapy (P < 0.001). PTT was significantly correlated to sleep efficiency (rs = −0.376, P = 0.049) and oxygen desaturation index (ODI) (rs = −0.428, P = 0.018). PTT drop index was strongly correlated to AHI (rs = 0.802, P < 0.001), respiratory disturbance index (RDI) (rs = 0.807, P < 0.001), ODI (rs = 0.693, P < 0.001), arousal index (rs = 0.807, P < 0.001), and periodic leg movement (PLM) index (rs = 0.400, P = 0.035). Overall, the findings from this study indicated that the PTT drop index is a non-invasive and useful marker for evaluating the severity of OSA and the effectiveness of treatment in patients with moderate to severe OSA. © 2022 The Authors. The Clinical Respiratory Journal published by John Wiley & Sons Ltd.