Sonic vibrational analysis provides continuous measurement of arterial properties

Objective. We describe a new technology for measuring artery mechanical pro perties, called Sonic Vibrational Analysis (SVA). We utilize SVA to study t he changes in radial artery smooth muscle tone caused by intravenous infusi on of vasoactive agents. Methods.Six healthy volunteers were monitored with a radial intra-arterial catheter and an SVA sensor during progressively in creasing doses of nitroglycerin (NTG), phenylephrine, sodium nitroprusside (SNP), dobutamine, and nicardipine. In SVA, the propagation velocity of an audio-frequency vibration is measured over a short segment of the radial ar tery. The measurement has sufficient temporal resolution to track the conti nuous changes in arterial properties that occur due to the natural blood pr essure pulse. Results. Coupled with the measurement of radial blood pressur e, SVA allowed determination of the physiological/mechanical state of the a rtery within a single cardiac cycle. NTG, SNP, and phenylephrine caused sig nificant changes in both blood pressure and the physiological state of the radial artery. Nicardipine and dobutamine altered blood pressure without ch ange in the state of the radial artery. Conclusions. The current results ar e consistent with previous studies of the effects of vasoactive agents on t he radial artery. SVA is non-invasive, continuous, localized to a well-defi ned section of artery, and suitable for the collection of large volumes of time-resolved data in a laboratory or clinical setting.