title: Increases in tissue Pco2 during circulatory shock reflect selective decreases in capillary blood flow.
abstract: OBJECTIVE
  Tissue Pco2 reflects metabolic alterations due to circulatory failure during circulatory shock. This study addresses simultaneous changes in gastric and buccal tissue Pco2 with changes in microcirculatory blood flow in a rat model of circulatory shock induced by cecal ligation and puncture.
  
  
  METHODS
  Prospective controlled laboratory study.
  
  
  METHODS
  University-affiliated research laboratory.
  
  
  METHODS
  Male breeder Sprague-Dawley rats.
  
  
  METHODS
  Induction of polymicrobial, abdominal sepsis by cecal ligation and puncture.
  
  
  RESULTS
  Tissue Pco2 was continuously measured with the aid of a miniature carbon dioxide electrode. Using orthogonal polarization spectral imaging, recordings of the microcirculation were taken at baseline and hourly intervals until death and compared with sham-operated animals. Gastric and buccal tissue Pco2 values progressively increased in animals after cecal ligation and puncture and terminated in death. Microcirculatory blood flow in vessels >20 microm was well preserved during progression of shock, whereas there was an early and progressive decrease in microcirculatory blood flow in vessels <20 microm, mostly representing capillaries. Tissue Pco2, the tissue Pco2-Paco2 gradient, and blood flow in vessels <20 microm were highly correlated. This contrasted with sham control animals in which no significant hemodynamic, blood gas, lactate, microcirculatory, and tissue Pco2 abnormalities were observed.
  
  
  CONCLUSIONS
  These observations suggest that microcirculatory failure in capillaries appears as an early defect in close association with anaerobic metabolism during progression of circulatory shock in an animal model of septic peritonitis.
authors.affiliation: Weil Institute of Critical Care Medicine, Rancho Mirage, CA, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Fries
authors.forename: Max Harry
authors.initials: MH
authors.lastname: Weil
authors.forename: Shijie
authors.initials: S
authors.lastname: Sun
authors.forename: Lei
authors.initials: L
authors.lastname: Huang
authors.forename: Xiangshao
authors.initials: X
authors.lastname: Fang
authors.forename: Gianluca
authors.initials: G
authors.lastname: Cammarata
authors.forename: Carlos
authors.initials: C
authors.lastname: Castillo
authors.forename: Wanchun
authors.initials: W
authors.lastname: Tang
mesh_terms: D000818:Animals; D002610:Cheek / Q000098:blood supply; D008297:Male; D008833:Microcirculation / Q000503:physiopathology*; D010101:Oxygen Consumption; D011659:Pulmonary Gas Exchange; D051381:Rats; D017207:Rats, Sprague-Dawley; D012769:Shock / Q000378:metabolism* / Q000503:physiopathology; D013270:Stomach / Q000098:blood supply