title: Subcutaneous blood flow in man during sleep with continuous epidural anaesthesia.
abstract: BACKGROUND
  Subcutaneous blood flow increases during sleep and we evaluated if this increase is affected by epidural anaesthesia.
  
  
  METHODS
  Lower leg subcutaneous blood flow was determined by 133Xenon clearance in ten subjects during continuous epidural anaesthesia at L2-L3 including eight hours of sleep, while the upper abdominal subcutaneous blood flow served as control.
  
  
  RESULTS
  Epidural anaesthesia to the level of the umbilicus was followed by an increase in the lower leg subcutaneous blood flow from 3.4 (1.8-6.3) to 7.8 (3.6-16.9) ml min-1 100 g-1 (median and range; P < 0.001) and returned to 3.5 (2.4-7.6) ml min-1 100 g-1 after 88 (45-123) min. In contrast, until the period of sleep the upper abdominal region blood flow remained at 5.2 (3.2-6.4) ml min-1 100 g-1. During sleep, lower leg subcutaneous blood flow did not change significantly, but the upper abdominal flow increased to 6.2 (5.2-7.2) ml min-1 100 g-1 after 34 (29-70) min (P < 0.01), and it remained elevated for 125 (100-164) min.
  
  
  CONCLUSIONS
  The results indicate that although epidural anaesthesia induced only a temporary increase in lower leg subcutaneous blood flow, it hindered the rise in subcutaneous blood flow normally manifest during early sleep.
authors.affiliation: Department of Clinical Physiology, Bispebjerg Hospital, Denmark.
authors.forename: J H
authors.initials: JH
authors.lastname: Sindrup
authors.forename: L J
authors.initials: LJ
authors.lastname: Petersen
authors.forename: J
authors.initials: J
authors.lastname: Kastrup
authors.forename: H
authors.initials: H
authors.lastname: Wroblewski
authors.forename: N H
authors.initials: NH
authors.lastname: Secher
mesh_terms: D000009:Abdominal Muscles; D000328:Adult; D000767:Anesthesia, Epidural; D001783:Blood Flow Velocity; D005260:Female; D006801:Humans; D007866:Leg; D008297:Male; D012867:Skin / Q000098:blood supply*; D012890:Sleep / Q000502:physiology*