Assessment of noninvasive tests of cutaneous vascular control in the forearm using a laser Doppler meter and a Finapres blood pressure monitor.
The control of human forearm cutaneous vascular resistance was examined using a combination of laser Doppler perfusion measurement and continuous Finapres blood pressure measurement. Tests which provoke changes in blood flow via different control mechanisms (local and neural) were applied in a group of ten healthy subjects. The purpose was to select from them a suitable (i.e. statistically significant) group to apply in cases where a disease process is suspected of interfering with the control of the skin circulation. Deep inspiration, immersion of the feet in water at 15 degrees C (both eliciting sympathetic vasoconstrictor nerve activity) and arm dependency (eliciting the local veni-arteriolar response) produced statistically significant, symmetrical increases in cutaneous vascular resistance in both arms (p < 0.05, Wilcoxon's test for paired differences). Similarly, post-ischaemic reactive hyperaemia (mediated by local vasodilator mechanisms) and indirect heating of the body (eliciting increased sympathetic vasodilator nerve activity) resulted in significant decreases in cutaneous vascular resistance (p < 0.01). When deep inspiration was repeated from a vasodilated baseline after indirect heating, the increases in cutaneous vascular resistance were smaller than those obtained before heating. Isometric handgrip exercise failed to produce a significant change in contralateral cutaneous vascular resistance (p > 0.05). There were no differences between right and left arms for any test (p > 0.05). The successful tests were subjected to power analysis in order to predict likely patient sample sizes required to demonstrate altered responsiveness at sites of microcirculatory disturbance compared with normal skin.
Stanton
A W
AW
Department of Physiological Medicine, St George's Hospital Medical School, Cranmer Terrace, London, UK.
Levick
J R
JR
Mortimer
P S
PS
D000328:Adult; D001795:Blood Pressure Determination / Q000295:instrumentation; D015924:Blood Pressure Monitors; D005069:Evaluation Studies as Topic; D005260:Female; D005385:Fingers / Q000098:blood supply; D005542:Forearm / Q000098:blood supply*; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008297:Male; D012867:Skin / Q000098:blood supply*; D014655:Vascular Resistance / Q000502:physiology*; D014666:Vasomotor System / Q000502:physiology*