Estimation of spontaneous baroreflex sensitivity using transfer function analysis: effects of positive pressure...

Area of Science:

• Cardiovascular Physiology
• Respiratory Medicine
• Medical Engineering

Background:

• Spontaneous baroreflex sensitivity (BRS) is crucial for cardiovascular homeostasis.
• Non-invasive positive pressure ventilation (PPV) is increasingly used in cardiorespiratory management.
• Understanding PPV's acute effects on BRS is vital for optimizing its clinical application.

Purpose of the Study:

• To investigate the short-term impact of non-invasive positive pressure ventilation (PPV) on spontaneous baroreflex sensitivity (BRS) in healthy adults.
• To quantify changes in heart rate variability (HRV) and blood pressure variability (BPV) under PPV.
• To assess the influence of PPV on baroreceptor reflex gain and phase shift.

Main Methods:

• Fifty-five healthy volunteers underwent breathing tests with and without 5 mbar PPV at 12 and 15 breaths/min.
• Beat-to-beat blood pressure and RR interval time series were recorded.
• Spectral and transfer function analyses were used to assess HRV, BPV, and baroreflex parameters (alpha-index, Phi) in LF and HF bands.

Main Results:

• PPV significantly increased mean RR interval and blood pressure compared to control.
• The high-frequency (HF) band alpha-index, reflecting baroreflex gain, showed a significant increase with PPV at both respiratory frequencies.
• No significant changes in phase shift (Phi) were observed in response to PPV.

Conclusions:

• Short-term application of PPV effectively enhances the high-frequency component of baroreflex gain in healthy subjects.
• These findings suggest PPV can modulate autonomic cardiovascular control.
• The results provide insights into the physiological mechanisms and potential therapeutic benefits of PPV strategies for cardiorespiratory disorders.