Acute Variations in Blood Pressure and Pulse Transient Time in Obstructive Sleep Apnea Patients Receiving Continuous Positive Airway Pressure Treatment

Obstructive sleep apnea (OSA) is strongly associated with cardiovascular morbidity, particularly hypertension. While continuous positive airway pressure (CPAP) is the gold-standard treatment, its effects on blood pressure (BP) dynamics and alternative monitoring methods like pulse transit time (PTT) require further investigation. This cross-sectional study at Bamdad Respiratory Research Center (2020) enrolled 33 adults (mean age 55±15.24 years; 42.4% female) with moderate-to-severe OSA (AHI>15). Participants underwent split-night polysomnography with CPAP titration. BP was measured hourly using Holter monitoring before, during, and after CPAP, while PTT was derived from ECG R-waves and fingertip photoplethysmography. Statistical analysis employed paired t-tests and Bonferroni correction. CPAP significantly reduced systolic BP (SBP) from 130.64±4.13 mmHg to 121.23±3.29 mmHg (p<0.001), though diastolic BP (DBP) changes (78.11±1.69 to 75.39±1.97 mmHg) were non-significant (p>0.05). PTT values increased during CPAP (baseline: 243.54±6.79 ms; post-CPAP: 245.31±8.69 ms), correlating with BP reductions but without statistical significance in pairwise comparisons (p>0.05). CPAP effectively lowers SBP in OSA patients, with PTT showing promise as a non-invasive BP monitoring tool. While PTT trends mirrored BP improvements, further research is needed to establish its clinical utility.