title: Dexmedetomidine prevents alterations of intestinal microcirculation that are induced by surgical stress and pain in a novel rat model.
abstract: BACKGROUND
  Anesthesia can become inadequate inadvertently or by misjudgment during surgery or emergence, and the surgical stress and pain stimulation will increase without adequate treatment. Overt stimulation may activate the sympathetic nervous system, increase the blood level of catecholamines, and lead to splanchnic arterial vasoconstriction.
  
  
  METHODS
  We divided 30 male Wistar rats into the following 3 groups: control, surgical stress and pain (SSP), and surgical stress and pain + dexmedetomidine (SSP + Dex). The rats received midline laparotomy to exteriorize a segment of terminal ileum for microcirculation examination by a full-field laser perfusion imager and sidestream dark-field video microscope on mucosa, muscle, and Peyer patch. The inspired concentration of isoflurane was decreased from 1.2% to 0.7% in SSP and SSP + Dex groups. In the SSP + Dex group, the rats received an initial loading dose of dexmedetomidine (0.5 μg/kg) and a maintenance infusion (0.5 μg · kg(-1) · h(-1)).
  
  
  RESULTS
  Dexmedetomidine prevented surgical stress and pain-related tachycardia and hypertension, and it attenuated the reduction of the microcirculatory blood flow intensity in intestinal mucosa (1100 ± 185 perfusion units [PU] vs 800 ± 105 PU, P = 0.001) and muscle (993 ± 208 PU vs 713 ± 92 PU, P < 0.001). Dexmedetomidine restored perfused small vessel density in intestinal mucosa and muscle.
  
  
  CONCLUSIONS
  We established a promising rat model to investigate the effect of surgical stress and pain stimulation on the intestinal microcirculation during light anesthesia. Using this rat model, we found that dexmedetomidine can normalize global hemodynamics and prevent the alteration of intestinal microcirculation.
authors.affiliation: Department of Anesthesiology, Far Eastern Memorial Hospital, No. 21, Sec. 2, Nanya S. Rd., Banciao Dist., New Taipei City, Taiwan, RO China.
authors.forename: Yu-Chang
authors.initials: YC
authors.lastname: Yeh
authors.forename: Wei-Zen
authors.initials: WZ
authors.lastname: Sun
authors.forename: Wen-Je
authors.initials: WJ
authors.lastname: Ko
authors.forename: Wing-Sum
authors.initials: WS
authors.lastname: Chan
authors.forename: Shou-Zen
authors.initials: SZ
authors.lastname: Fan
authors.forename: Jui-Chang
authors.initials: JC
authors.lastname: Tsai
authors.forename: Tzu-Yu
authors.initials: TY
authors.lastname: Lin
mesh_terms: D058647:Adrenergic alpha-2 Receptor Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D018685:Anesthetics, Inhalation / Q000008:administration & dosage; D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D020927:Dexmedetomidine / Q000008:administration & dosage / Q000494:pharmacology*; D004195:Disease Models, Animal; D006339:Heart Rate / Q000187:drug effects; D006973:Hypertension / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D007082:Ileum / Q000098:blood supply*; D007262:Infusions, Intravenous; D007413:Intestinal Mucosa / Q000098:blood supply; D007530:Isoflurane / Q000008:administration & dosage; D008297:Male; D008833:Microcirculation / Q000187:drug effects*; D018715:Microscopy, Video; D009130:Muscle, Smooth / Q000098:blood supply; D010149:Postoperative Pain / Q000209:etiology / Q000503:physiopathology*; D055420:Perfusion Imaging; D051381:Rats; D017208:Rats, Wistar; D012039:Regional Blood Flow / Q000187:drug effects; D013152:Splanchnic Circulation / Q000187:drug effects*; D013312:Stress, Physiological; D013610:Tachycardia / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D013997:Time Factors; D014661:Vasoconstriction / Q000187:drug effects
chemical_list: D058647:Adrenergic alpha-2 Receptor Agonists; D018685:Anesthetics, Inhalation; D020927:Dexmedetomidine; D007530:Isoflurane