title: Effect of alpha(alpha)-cross-linked hemoglobin and pyridoxalated hemoglobin polyoxyethylene conjugate solutions on gastrointestinal regional perfusion in hemorrhagic shock.
abstract: BACKGROUND
  Hemoglobin-based blood substitutes may cause vasoconstriction, which could limit organ perfusion during trauma resuscitation. We investigated the effect of two hemoglobin solutions on regional blood flow and mucosal perfusion in the gastrointestinal tract in a hemorrhagic shock model.
  
  
  METHODS
  Twenty-four swine were bled 30% of blood volume over 1 hour. Six additional animals were anesthetized and monitored but did not undergo hemorrhage. Bled animals were resuscitated with alpha(alpha)-hemoglobin (alpha(alpha)Hb), pyridoxalated hemoglobin polyoxyethylene conjugate (PHP), shed blood, or lactated Ringer's solution. Regional blood flow was measured by radiolabeled microspheres. Gastric mucosal perfusion was estimated by measuring intramucosal pH (pHi) by tonometry.
  
  
  RESULTS
  PHP and shed blood restored small-bowel flows to sham values, whereas lactated Ringer's solution and alpha(alpha)Hb did not. Shed blood and PHP, but not alpha(alpha)Hb, restored cardiac index (CI) to baseline (p < 0.05). Mean pulmonary artery pressure was elevated over baseline with alpha(alpha)Hb and PHP and remained elevated with alpha(alpha)Hb (p < 0.05). pHi was significantly lower after resuscitation with PHP than with other fluids.
  
  
  CONCLUSIONS
  PHP was efficacious in restoring CI and small-bowel flow, but the pHi remained low, indicating possible continued mucosal ischemia. Alpha(alpha)Hb led to limited recovery of CI and small-bowel blood flow but restored pHi close to baseline. Shed blood was efficacious in restoration of pHi, gastrointestinal blood flows, and systemic hemodynamics.
authors.affiliation: Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA.
authors.forename: R B
authors.initials: RB
authors.lastname: Noone
authors.forename: M G
authors.initials: MG
authors.lastname: Mythen
authors.forename: S N
authors.initials: SN
authors.lastname: Vaslef
mesh_terms: D000818:Animals; D001802:Blood Substitutes / Q000494:pharmacology*; D004064:Digestive System / Q000098:blood supply*; D006439:Hemodynamics; D006441:Hemoglobin A / Q000494:pharmacology*; D006454:Hemoglobins / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D007668:Kidney / Q000098:blood supply; D010100:Oxygen / Q000378:metabolism*; D011092:Polyethylene Glycols / Q000494:pharmacology*; D012039:Regional Blood Flow; D012771:Shock, Hemorrhagic / Q000378:metabolism*; D013552:Swine
chemical_list: D001802:Blood Substitutes; D006454:Hemoglobins; C050907:pyridoxalated-hemoglobin-polyethylene glycol conjugate; C028672:hemoglobin AA; D011092:Polyethylene Glycols; D006441:Hemoglobin A; D010100:Oxygen