Noninvasive Point of Care Device for Assessing Cardiac Response to Acute Volume Changes

Area of Science:

• Cardiovascular Physiology
• Medical Device Technology
• Diagnostic Tools

Background:

• The Valsalva maneuver alters peripheral pulse amplitude, offering insights into volume status.
• Automated quantification of the Valsalva pulse response (VPR) can aid bedside assessment.
• A novel device, Indicor, aims to standardize and automate VPR measurement.

Purpose of the Study:

• To evaluate if the Indicor device's VPR measurement can detect acute central volume changes induced by passive leg raise (PLR).
• To assess the sensitivity of automated VPR in healthy volunteers during a standardized Valsalva maneuver.

Main Methods:

• Healthy volunteers underwent a standardized Valsalva maneuver guided by the Indicor device.
• Photoplethysmography (PPG) signals were recorded during a 10-second expiratory effort (20 mmHg).
• VPR was calculated as the ratio of end-Valsalva to baseline pulse amplitude.

Main Results:

• VPR significantly increased from baseline (0.34 ± 0.13) to PLR (0.60 ± 0.14) in all 30 participants (p < 0.0001).
• Upon returning to upright, VPR decreased significantly (0.33 ± 0.10) compared to PLR (p < 0.0001).
• The device demonstrated sensitivity to acute central volume loading via PLR.

Conclusions:

• The Indicor device reliably and automatically quantifies VPR using PPG during a standardized Valsalva maneuver.
• Automated VPR measurement is sensitive to acute increases in central volume load from PLR in healthy individuals.
• Further research is needed to explore VPR in patient populations with heart failure and altered fluid status.