Noninvasive blood flow measurement over acupuncture points (Gb21): a pilot study

OBJECTIVE: Noninvasive evaluation of the cutaneous (cBF) and subcutaneous (sBF) blood flow over the acupuncture point (AP) Gb21 to assess a characteristically increased microcirculation at AP. BACKGROUND: AP show several anatomic, histologic and physiologic peculiarities that indicate a specifically elevated microcirculation. Nevertheless cBF and sBF over AP have not yet been established by noninvasive measurements. The laser Doppler spectroscope O2C allows a direct and real-time detection of the local cBF (depth: 1 mm) and sBF (depth: 8 mm) in vivo. METHODS: In 28 subjects (41.1+/-9.8 years) the glass fiber probes of the O2C were placed over Gb21 and an adjacent asymptomatic reference point (RP) at the Trapezius Muscle. The relative blood flow was measured over a period of 3 minutes in each case. Microcirculation comparisons over AP and RP were made using multivariate analysis of variance. RESULTS: The results showed significantly higher sBF compared to cBF over Gb21 (F = 89.95, p< 0.01) and RP (F = 88.47, p< 0.01). A significantly higher microcirculation was evaluated for all subjects over Gb21 compared to RP (cBF: F = 7.35, p< 0.05; sBF: F = 8.56, p< 0.01). CONCLUSION: The employment of the O2C permitted for the first time noninvasive evidence of a significantly increased cBF and sBF over AP (Gb21). This evaluation of an initial microcirculatory state of AP should be determined for several AP and larger sampling sizes. The results could be the basis for following controlled acupuncture trials. Regarding a close correlation of AP with myofascial trigger points (TP), further studies in patients with myoskeletal pain could quantify noninvasively a decreased perfusion in the area of TP that might indicate a pathologic condition. The findings of this study encourage the implementation of the laser Doppler spectroscope O2C as a reliable diagnostic tool for various pain syndromes in prevention, therapy, and rehabilitation.