title: Myocardial ischemia in intestinal postischemic shock: the effect of hypoxemic reperfusion.
abstract: OBJECTIVE
  The circulatory shock following intestinal ischemia-reperfusion injury has been attributed to hypovolemia. The purpose of the current study is to clarify the pathophysiology of this type of shock and to test the hypothesis that hypoxemic compared with normoxemic reperfusion improves hemodynamics.
  
  
  METHODS
  Randomized animal study.
  
  
  METHODS
  Medical school laboratory.
  
  
  METHODS
  Twenty-one pigs.
  
  
  METHODS
  Pigs were subjected to 120 mins of intestinal ischemia by clamping the superior mesenteric artery. Upon declamping, the animals were randomized into two groups: a group that received hypoxemic reperfusion (HR group, n = 8) with a PaO2 = 30-35 and a control group reperfused with PaO2 = 100 mm Hg (control group, n = 13).
  
  
  RESULTS
  Measurements included mean arterial pressure, cardiac index, pulmonary artery occlusion pressure, and requirements for fluids and epinephrine. Biopsies from the terminal ileal mucosa were taken for malondialdehyde measurements at baseline, at 120 mins of ischemia, and at 30 and 60 mins of reperfusion. A piece of left ventricle was obtained after 120 mins of reperfusion for histologic studies. Five of 13 animals of the control group died in intractable shock; no animal of the HR group died (p =.11). The decrease in the mean arterial pressure during reperfusion was more pronounced in the control group (p <.008) despite the larger doses of epinephrine administered, compared with the HR group (p <.02). During reperfusion, both groups exhibited a decrease in cardiac index; this was more pronounced in the control group (p =.0007). Pulmonary artery occlusion pressure increased during reperfusion in both groups and was more pronounced in the control group (p =.04 at 60 mins). Although mixed venous blood oxygen saturation of the control animals was higher at 30 mins of reperfusion (p =.005), it declined after 60 mins and became lower than that of HR animals at the end of reperfusion (p <.02). The myocardial histopathologic injury score was higher in the control group (2.0 +/- 0.69 and 3.4 +/- 0.89 for the HR and control groups, respectively; p <.03). The concentrations of intestinal mucosa malondialdehyde were significantly higher in the control group at 60 mins of reperfusion (p <.03).
  
  
  CONCLUSIONS
  Acute myocardial ischemia and left heart failure significantly contribute to the circulatory shock that follows intestinal ischemia/reperfusion injury and are attenuated by hypoxemic reperfusion.
authors.affiliation: Departmentof Critical Care, University of Athens medical School, Greece. edouzin@cc.uoa.gr
authors.forename: Emmanuel E
authors.initials: EE
authors.lastname: Douzinas
authors.forename: Marinos T
authors.initials: MT
authors.lastname: Pitaridis
authors.forename: Efstratios
authors.initials: E
authors.lastname: Patsouris
authors.forename: Spyridon
authors.initials: S
authors.lastname: Kollias
authors.forename: Vasilios
authors.initials: V
authors.lastname: Boursinos
authors.forename: Dimitrios I
authors.initials: DI
authors.lastname: Karmpaliotis
authors.forename: Yiannis
authors.initials: Y
authors.lastname: Gratsias
authors.forename: Evangelos
authors.initials: E
authors.lastname: Evangelou
authors.forename: Apostolos
authors.initials: A
authors.lastname: Papalois
authors.forename: Anastasia E
authors.initials: AE
authors.lastname: Konstantinidou
authors.forename: Charis
authors.initials: C
authors.lastname: Roussos
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D006439:Hemodynamics; D007082:Ileum / Q000098:blood supply; D007413:Intestinal Mucosa / Q000098:blood supply; D008297:Male; D017202:Myocardial Ischemia / Q000503:physiopathology*; D010101:Oxygen Consumption; D011897:Random Allocation; D015424:Reperfusion; D015427:Reperfusion Injury / Q000503:physiopathology*; D012769:Shock / Q000503:physiopathology*; D013552:Swine