title: Systemic and regional effects of experimental gradual splanchnic ischemia.
abstract: OBJECTIVE
  We evaluated the effects of gradual intestinal ischemia on systemic and regional haemodynamics and oxygen transport.
  
  
  METHODS
  Superior mesenteric artery (SMA) blood flow was decreased by 40%, 70%, and 100% for 60-minute periods and thereafter released in 12 pigs. Hemodynamic changes were monitored continuously, and the intestinal perfusion was evaluated by changes in portal vein-arterial lactate gradient, intramucosal pH, tonometric Pco2, tonometric-portal vein Pco2 gradient, and regional oxygen extraction.
  
  
  RESULTS
  Local signs of intestinal hypoperfusion developed during the SMA occlusion. Intramucosal pH and portal vein pH decreased from 7.18 +/- 0.04 to 6.81 +/- 0.04 (P < .01) and from 7.36 +/- 0.01 to 7.25 +/- 0.03 (P < .05), respectively. Intramucosal Pco2 and tonometric-portal vein Pco2 gradient increased from 12.4 +/- 1.3 to 21.2 +/- 1.8 kPa (P < .01) and from 6.0 +/ 1.3 to 14.0 +/- 1.9 kPa (P < .05), respectively. Portal vein-arterial lactate gradient and splanchnic oxygen extraction increased from 0.02 +/- 0.07 to 2.32 +/- 0.47 mmol/L (P < .01) and from 0.44 +/- 0.03 to 0.60 +/- 0.03 (P < .05), respectively. Systemic changes observed during the SMA occlusion were reduction of cardiac index (161 +/- 12 to 114 +/- 8 mL/min/kg, P < .01) and pulmonary capillary wedge pressure (4 +/- 1 to 3 +/- 1 mm Hg) and increase in heart rate (124 +/- 5 to 173 +/- 11 beats/ min, P < .01) and mean arterial pressure (79 +/- 3 to 104 +/- 5 mm Hg, P > .01). Systemic oxygen extraction increased (P > .05), arterial pH increased (P < .05), and arterial lactate decreased (P < .01) during the SMA occlusion. Splanchnic ischemia defined as an increase in portal vein-arterial lactate gradient above mean +2 SD of the baseline occurred at 93 +/- 15 minutes corresponding 70% SMA occlusion.
  
  
  CONCLUSIONS
  We conclude that signs of tissue hypoperfusion started to develop at 70% SMA occlusion and that regional tissue hypoperfusion in the splanchnic region may develop without any systemic signs of oxygen supply/demand mismatch.
authors.affiliation: Department of Surgery, Kuopio University Hospital, Finland.
authors.forename: A
authors.initials: A
authors.lastname: Heino
authors.forename: J
authors.initials: J
authors.lastname: Hartikainen
authors.forename: M E
authors.initials: ME
authors.lastname: Merasto
authors.forename: E M
authors.initials: EM
authors.lastname: Koski
authors.forename: E
authors.initials: E
authors.lastname: Alhava
authors.forename: J
authors.initials: J
authors.lastname: Takala
mesh_terms: D006439:Hemodynamics; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007413:Intestinal Mucosa / Q000737:chemistry / Q000378:metabolism; D007422:Intestines / Q000098:blood supply; D007511:Ischemia / Q000378:metabolism*; D019344:Lactic Acid / Q000097:blood; D008638:Mesenteric Arteries / Q000503:physiopathology*; D010101:Oxygen Consumption; D011169:Portal Vein / Q000737:chemistry / Q000378:metabolism; D013152:Splanchnic Circulation
chemical_list: D019344:Lactic Acid