Acute Effects of Continuous Positive Airway Pressure (CPAP) on Cardiovascular Responses in Healthy Subjects- A Single-Subject Experimental Design -

Objective: Thus the aim of the present study was to investigate the effects acute cardiovascular of Continuous Positive Airway Pressure (CPAP) utilization in healthy subjects. Materials and methods: On the third day, subjects rested the at the sitting position for 45 min, 15 min a respiratory frequency of 15 breath for minute without CPAP, and then 15 minutes with a positive pressure of 20 cmH2O and PEEP of 15 cmH2O with a face silicone mask. During the last 15 min volunteers rested quietly breathing again without CPAP. Blood pressure (BP) was measured by the auscultatory method every five minutes on the right arm and heart rate (HR) was obtained beat-by-beat by a R-R recorder (S810 Polar®, Finland). HR times series were processed by a specific algorithm developed in MATLAB® for time and frequency domain analysis. A two-way analysis of variance for repeated measures was used verify the effects of CPAP on BP and HR with or without positive pressure, and a Tukey test for post hoc comparisons. Statistical significance was accepted for p