Input for baroreflex analysis: which blood pressure signal should be used?

Area of Science:

• Physiology
• Cardiovascular Regulation
• Systems Biology

Background:

• The baroreflex (BR) is a key physiological regulator of blood pressure.
• Previous BR analysis primarily used systolic (SBP) or diastolic (DBP) blood pressure variability.
• The utility of mean blood pressure (MBP) as an input for BR analysis requires further investigation.

Purpose of the Study:

• To investigate the optimal blood pressure input signal (SBP, DBP, or MBP) for baroreflex (BR) analysis.
• To assess how coupling strength varies between different BR arms (cardiac vs. vascular) and physiological states.
• To determine if MBP is a more sensitive indicator for cardiac BR analysis.

Main Methods:

• Employed partial spectral decomposition to analyze causal coupling in the frequency domain.
• Recorded noninvasive beat-to-beat RR intervals, SBP, MBP, DBP, and peripheral vascular resistance (PVR).
• Evaluated BR coupling during rest, orthostatic stress (head-up tilt), and cognitive load (mental arithmetic).

Main Results:

• At rest, MBP showed the strongest coupling with RR intervals.
• For the vascular resistance BR arm, SBP, DBP, and MBP showed similar importance.
• During orthostasis, SBP became a more important input for the cardiac BR arm, while MBP-RR gain was more sensitive to physiological changes.

Conclusions:

• Baroreflex coupling strength is influenced by the specific BR arm, the chosen blood pressure input signal, and the physiological state.
• Mean blood pressure (MBP) is recommended as a more frequently utilized input signal for cardiac baroreflex analysis.
• The findings highlight the dynamic nature of baroreflex regulation and the importance of selecting appropriate input signals for accurate assessment.