title: Greater peripheral blood flow but less bleeding with propofol versus sevoflurane during spine surgery: a possible physiologic model?
abstract: METHODS
  Prospective, randomized, single blind.
  
  
  OBJECTIVE
  To compare the effects of sevoflurane and propofol on lumbar-paraspinal-muscles regional blood flow, as well as bleeding when controlled hypotension is used.
  
  
  BACKGROUND
  Controlled hypotension is the technique of choice to reduce blood loss during spine surgery, but changes in blood flow occurring to lumbar paraspinal muscles during controlled hypotension with propofol and sevoflurane, as well as the entity of bleeding, are unknown.
  
  
  METHODS
  Blood flow was assessed by means of a laser Doppler flowmeter during the prehypotensive and hypotensive (defined as a 15% reduction of baseline mean arterial pressure) period in 28 patients (aged 28-73 years, American Society of Anesthesiologists (ASA) I-II) undergoing lumbar spine surgery. Patients were randomized to receive either sevoflurane or propofol as main anesthetic agent to achieve hypotension. At the end of the surgery, blood loss was calculated and intraoperative bleeding (Visual Analogue Scale ranging from 0 to 100) was evaluated by the surgeon. RESULTS.: Peripheral Blood flow was significantly greater in the propofol group both before and during the hypotensive period (median values of 32.7 FU vs. 7.7 and 38.5 FU vs. 10.5, respectively). Despite this fact, blood loss and intraoperative bleeding were significantly reduced when propofol had been used (P < 0.05).
  
  
  CONCLUSIONS
  Despite the greater blood flow when it is used, propofol causes less bleeding than sevoflurane during spine surgery and could be more indicated to produce hypotension during anesthesia. Moreover, it is possible to explain our findings hypothesizing a selective vasodilation of propofol (postcapillary, venous vasodilation), different from that of sevoflurane (precapillary, arteriolar vasodilation).
authors: Department of Anesthesiology, IRCCS Multimedica, Milan, Italy.
authors: Andrea
authors: A
authors: Albertin
authors: Luca
authors: L
authors: La Colla
authors: Azzurra
authors: A
authors: Gandolfi
authors: Eleonora
authors: E
authors: Colnaghi
authors: Davide
authors: D
authors: Mandelli
authors: Giuseppe
authors: G
authors: Gioia
authors: Gianfranco
authors: G
authors: Fraschini
mesh_terms: D000328:Adult; D000368:Aged; D016063:Blood Loss, Surgical / Q000503:physiopathology / Q000517:prevention & control*; D005260:Female; D006801:Humans; D008161:Lumbosacral Region / Q000098:blood supply* / Q000502:physiology; D008297:Male; D008738:Methyl Ethers / Q000009:adverse effects / Q000494:pharmacology*; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D019635:Neurosurgical Procedures / Q000009:adverse effects / Q000379:methods*; D015742:Propofol / Q000009:adverse effects / Q000494:pharmacology*; D011446:Prospective Studies; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology; D000077149:Sevoflurane; D016037:Single-Blind Method
chemical_list: D008738:Methyl Ethers; D000077149:Sevoflurane; D015742:Propofol