title: Effects of sympathetic nerve blockades on low-frequency oscillations of human earlobe skin blood flow.
abstract: Earlobe skin blood flow measured by laser Doppler flowmetry often shows low-frequency oscillations with a frequency around 0.1 Hz. We evaluated the effects of different sympathetic blocking techniques on the oscillations. Power spectrum of 5-min time series of beat-to-beat peak earlobe skin blood flow showed a distinct spectral peak at a frequency around 0.1 Hz (mean +/- SD, 0.107+/-0.016 Hz). The power of the spectral peak measured as coefficient of component variance (CCV) was diminished with total spinal anesthesia (TSA, n = 4) and cervicothoracic epidural anesthesia (CTEA, n = 4; P<0.05 for both). The CCV was unchanged significantly with bilateral thoracic sympathetic ganglionic excision (TSGE, n = 5). Right stellate ganglion block (RSGB, n = 6) caused a trend towards an increase in the CCV on the right (blocked)-side (P = 0.072) but no change on the left (intact)-side. Cross-spectrum analysis revealed that the low-frequency oscillations were not coherent between the right- and left-side earlobes or with low-frequency oscillations in systolic blood pressure either before or after RSGB. TSA and CTEA are known to cause extensive sympathetic nerve blockade in a broad area, while TSGE and RSGB are known to cause local and partial sympathetic blockade. Our results suggest that although the low-frequency oscillations in earlobe skin blood flow may be mediated non-neurally, magnitude of the oscillations may be modified by sympathetic vasomotor tone.
authors.affiliation: Department of Anesthesiology and Resuscitology, Nagoya City University Medical School, Nagoya, Japan. hsasano@med.nagoya-cu.ac.jp
authors.forename: H
authors.initials: H
authors.lastname: Sasano
authors.forename: J
authors.initials: J
authors.lastname: Hayano
authors.forename: T
authors.initials: T
authors.lastname: Tsuda
authors.forename: H
authors.initials: H
authors.lastname: Katsuya
mesh_terms: D000328:Adult; D000767:Anesthesia, Epidural; D000779:Anesthetics, Local / Q000008:administration & dosage; D004431:Ear, External / Q000098:blood supply* / Q000294:innervation; D005260:Female; D005728:Ganglia, Sympathetic / Q000187:drug effects / Q000502:physiology*; D005730:Ganglionic Blockers / Q000008:administration & dosage*; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008012:Lidocaine / Q000008:administration & dosage*; D008297:Male; D010507:Periodicity; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology; D012867:Skin / Q000098:blood supply* / Q000294:innervation
chemical_list: D000779:Anesthetics, Local; D005730:Ganglionic Blockers; D008012:Lidocaine