Non-Invasive Evaluation of a Carotid Arterial Pressure Waveform Using Motion-Tolerant Ultrasound Measurements During the Valsalva Maneuver

This work details the non-invasive evaluation of a carotid arterial blood pressure (ABP) waveform during the Valsalva maneuver. Unfocused and wide acoustic beams are insonated on the carotid artery to achieve motion-tolerant measurements with a simple two-element ultrasound scanner. Arterial flow and distension waveforms are reliably estimated from spectral Doppler and M-mode ultrasound images whose qualities are consistently maintained in different phases of the maneuver despite possible displacements of the artery. A local pulse wave velocity is estimated using a flow-area method, and it is then combined with the distension waveform to produce the ABP waveform. Human subject validation on seven healthy subjects shows that the bias in pulse pressure estimates across subjects is 0.47 +/- 13.1mmHg. The average root mean square deviations of the ultrasonically measured waveform across subjects is 10.1 +/- 2.43 mmHg, excluding the strain phase of the Valsalva maneuver, and 17.7 +/- 6.30 mmHg in all phases. The mean correlation coefficient between the ultrasonically measured and reference waveform is calculated to be 0.92 +/- 0.04 across subjects. Detailed morphological features and their changes across different phases are observed as reported. This uninterrupted central ABP waveform monitoring under hemodynamics changes supports the idea of a novel stress test to evaluate the health and dynamics of the cardiovascular system at a spot check in clinical settings.

Automated summary

This work presents a non-invasive method for evaluating carotid arterial blood pressure waveforms during the Valsalva maneuver. Using unfocused wide acoustic beams and a two-element ultrasound scanner, the study shows reliable measurements of arterial flow and distension waveforms even with possible artery displacements. The research demonstrates accurate estimation of pulse pressure and consistent waveform quality across different phases of the maneuver.