Measurement of skin vasoconstrictor response in healthy subjects.

Objectives: Laser Doppler flowmetry enables non-invasive quantification of skin blood flow and its sympathetically mediated change. Four different maneuvers were performed in 60 healthy subjects aged 20-78 years to investigate their variability, reproducibility and to determine the influence of gender, age and height.

Material And Methods: Skin blood flow was measured on the pulp of both index fingers using laser Doppler flowmetry. Vasoconstriction was induced by deep inspiratory gasp, arm dependency, acoustic stimulation and a modified cold pressor test.

Results: More than 95% of normal subjects showed a vasoconstrictor response to cold pressure test and 100% to inspiratory gasp. In all other maneuvers vasoconstrictor response was less reliable. The magnitude of vasoconstrictor responses decreased with age in all maneuvers, while latencies remained unchanged. Only during inspiratory gasp men showed more pronounced vasoconstrictor response compared with women. Body height influenced latencies if peripheral stimuli were applied like in the cold pressor and arm dependency tests.

Conclusions: Inspiratory gasp and the modified cold pressor test were found to be more suitable maneuvers for routine clinical testing than arm dependency and acoustic stimulation. Normal data also for side differences are provided as a base for routine clinical testing in systemic and unilateral neurological disorders.