Use of radial arterial tonometric continuous blood pressure measurement in cardiovascular reactivity studies

BACKGROUND: Non-invasive continuous blood pressure monitoring has, for the past decade, been performed using the Finapres monitor. Radial tonometry is a new methodology for measuring non-invasive beat-to-beat blood pressure. This technique has been evaluated for other applications, but its use in cardiovascular reactivity testing has not yet been reported. DESIGN: A convenience sample was used to compare a radial tonometric device (Colin Pilot) with intermittent brachial blood pressure measurement (Critikon Dinamap) during reactivity testing. A second comparison was made between an Ohmeda Finapres and a Dinamap. METHODS: Twenty subject-testing sessions during a reactivity protocol were evaluated for blood pressure determination. Separate groups of subjects were used for Pilot versus Dinamap comparisons and Finapres versus Dinamap comparisons. Blood pressure signals from 15 subjects with Pilot and 15 subjects with Finapres data were evaluated for artifacts. Signals were also compared in a subject with Raynaud's phenomenon. RESULTS: Both devices tracked blood pressure well. The Finapres significantly overestimated systolic blood pressure ( P < 0.001). The correlations between the Pilot and Dinamap were consistently higher than those between the Finapres and Dinamap. There were more artifacts (3.2%) with the Finapres than with the Pilot (0.2%). In the subject with Raynaud's phenomenon, the Finapres overestimated blood pressure by more than 40 mmHg and showed more than 75% of artifacts. On the other hand, the Pilot tracked blood pressure in the same subject without error. CONCLUSIONS: Radial tonometric continuous beat-to-beat blood pressure monitoring with the Colin Pilot was associated with a low artifact rating and high accuracy of blood pressure measurement during reactivity testing.