Arterial tonometry and assessment of cardiovascular alterations with chiropractic spinal manipulative therapy

To (a) introduce arterial tonometry, which may offer a greater opportunity to detect alterations of the cardiovascular system with spinal manipulative therapy, (b) discuss the limitations of standard blood pressure measurements and (c) discuss factors that govern the contour of arterial pressure pulses.

Information was obtained from peer-reviewed medical and chiropractic journal articles and medical textbooks written in English (mainly from 1980 to 1995).

Arterial tonometry is a noninvasive method to continuously measure the contour of arterial pressure pulses. Pulses can be simultaneously measured from several arterial sites because vessel occlusion is not required. Arterial tonometry supplements standard blood pressure measurements that measure only the systolic and diastolic pressures by permitting the investigation of additional parameters of cardiovascular functions. Changes in large artery function can be inferred through alterations of pulse contour, wave velocity and harmonic transmission ratios. Analysis of the beat-to-beat fluctuations of arterial pressure and heart rate can be used to determine whether SMT alters the autonomic nervous system. Reductions of arterial pressure in central vessels may not be apparent from standard blood pressure measurements at peripheral vessels. The contour of a pressure pulse depends on the magnitude and timing between incident and reflected pressure waves from the upper and lower body, body shape and size, the duration and pattern of ventricular systole, and dispersion and attenuation. Therefore, arterial tonometry may improve the ability to detect alterations of the cardiovascular system in chiropractic research.