Immediate hemodynamic stabilization with positive airway pressure: PTT-derived nocturnal blood pressure fluctuations during split-night polysomnography

Study objectives To evaluate the immediate hemodynamic effect of positive airway pressure (PAP) therapy on pulse transit time (PTT)-derived nocturnal blood pressure fluctuation (NBPF) during split-night polysomnography and to determine whether this effect differs between hypertensive and non-hypertensive individuals.Methods This retrospective cohort study included 464 adults undergoing split-night polysomnography between 2015 and 2023. NBPF was defined as the standard deviation of systolic blood pressure (SBP) derived from PTT calibrated using manufacturer-validated algorithms. Within-group changes were assessed using paired t-tests, between-group comparisons used independent t-tests, and multivariable linear regression adjusted for age and baseline NBPF. Effect sizes (Cohen's d) and 95% confidence intervals (CI) were calculated.Results NBPF decreased significantly after PAP therapy in both hypertensive (mean reduction 20.71 ± 24.25 mmHg, p Conclusions PAP therapy during split-night studies produces immediate hemodynamic stabilization, reflected by a large and significant reduction in nocturnal BP variability in both hypertensive and non-hypertensive patients. These findings support early PAP initiation to mitigate nocturnal BP lability regardless of baseline hypertension status.