title: Decreasing gut wall glucose as an early marker of impaired intestinal perfusion.
abstract: OBJECTIVE
  The aim of this study was to assess the microcirculatory and metabolic consequences of reduced mesenteric blood flow.
  
  
  METHODS
  Prospective, controlled animal study.
  
  
  METHODS
  The surgical research unit of a university hospital.
  
  
  METHODS
  A total of 13 anesthetized and mechanically ventilated pigs.
  
  
  METHODS
  Pigs were subjected to stepwise mesenteric blood flow reduction (15% in each step, n = 8) or served as controls (n = 5). Superior mesenteric arterial blood flow was measured with ultrasonic transit time flowmetry, and mucosal and muscularis microcirculatory perfusion in the small bowel were each measured with three laser Doppler flow probes. Small-bowel intramucosal Pco2 was measured by tonometry, and glucose, lactate (L), and pyruvate (P) were measured by microdialysis.
  
  
  RESULTS
  In control animals, superior mesenteric arterial blood flow, mucosal microcirculatory blood flow, intramucosal Pco2, and the lactate/pyruvate ratio remained unchanged. In both groups, mucosal blood flow was better preserved than muscularis blood flow. During stepwise mesenteric blood flow reduction, heterogeneous microcirculatory blood flow remained a prominent feature (coefficient of variation, approximately 45%). A 30% flow reduction from baseline was associated with a decrease in microdialysis glucose concentration from 2.37 (2.10-2.70) mmol/L to 0.57 (0.22-1.60) mmol/L (p < .05). After 75% flow reduction, the microdialysis lactate/pyruvate ratio increased from 8.6 (8.0-14.1) to 27.6 (15.5-37.4, p < .05), and arterial-intramucosal Pco2 gradients increased from 1.3 (0.4-3.5) kPa to 10.8 (8.0-16.0) kPa (p < .05).
  
  
  CONCLUSIONS
  Blood flow redistribution and heterogeneous microcirculatory perfusion can explain apparently maintained regional oxidative metabolism during mesenteric hypoperfusion, despite local signs of anaerobic metabolism. Early decreasing glucose concentrations suggest that substrate supply may become crucial before oxygen consumption decreases.
authors.affiliation: Department of Anesthesiology, Inselspital, Bern, Switzerland.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Krejci
authors.forename: Luzius
authors.initials: L
authors.lastname: Hiltebrand
authors.forename: Conradin
authors.initials: C
authors.lastname: Büchi
authors.forename: Syed Z
authors.initials: SZ
authors.lastname: Ali
authors.forename: Claudio
authors.initials: C
authors.lastname: Contaldo
authors.forename: Jukka
authors.initials: J
authors.lastname: Takala
authors.forename: Gisli H
authors.initials: GH
authors.lastname: Sigurdsson
authors.forename: Stephan M
authors.initials: SM
authors.lastname: Jakob
mesh_terms: D000818:Animals; D021721:Balloon Occlusion; D015415:Biomarkers / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D004386:Duodenum / Q000098:blood supply / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000098:blood supply / Q000378:metabolism*; D007583:Jejunum / Q000098:blood supply* / Q000378:metabolism*; D019344:Lactic Acid / Q000378:metabolism; D017078:Laser-Doppler Flowmetry; D017538:Mesenteric Artery, Superior / Q000502:physiology*; D008643:Mesentery / Q000502:physiology; D008833:Microcirculation; D009131:Muscle, Smooth, Vascular / Q000098:blood supply; D010101:Oxygen Consumption / Q000502:physiology; D011169:Portal Vein; D011446:Prospective Studies; D019289:Pyruvic Acid / Q000378:metabolism; D012039:Regional Blood Flow; D013552:Swine
chemical_list: D015415:Biomarkers; D002245:Carbon Dioxide; D019344:Lactic Acid; D019289:Pyruvic Acid; D005947:Glucose