title: Effects of fluid challenge on gastric mucosal PCO2 in septic patients.
abstract: OBJECTIVE
  To determine the effects of fluid challenge on systemic hemodynamic variables and gastric intramucosal partial pressure of carbon dioxide (PCO(2)) in septic patients.
  
  
  METHODS
  Short-term interventional study.
  
  
  METHODS
  Medical-surgical intensive care unit in a university hospital.
  
  
  METHODS
  Twenty-four adult patients with severe sepsis or septic shock requiring volume replacement. All patients were studied within 24 h of onset of severe sepsis or septic shock.
  
  
  METHODS
  Five hundred milliliters of a 6% hydroxyethyl starch (HES) solution were administered in 30 min.
  
  
  RESULTS
  Complete hemodynamic data, blood samples, and gastric mucosal PCO(2) (automatic gas capnometry) determinations were obtained at baseline and 15 min after the end of fluid infusion. After fluid challenge, cardiac index (CI) increased from 3.8 (range 2.9-4.2) to 4.2 (range 3.1-4.9) l/min m(-2) ( p<0.05). The PCO(2) gap decreased from 9.8 (range 6.9-26.0) to 8.5 (range 6.6-17.4) mm Hg ( p<0.05), but important individual variations were observed. We failed to observe significant relationships between changes in CI and in PCO(2) gap, or between indices of preload (pulmonary artery occluded pressure, right atrial pressure, and pulse pressure variations) and changes in PCO(2) gap. In addition, changes in PCO(2) gap and in (v-a) CO(2) were not related; however, changes in PCO(2) gap were related to baseline PCO(2) gap ( p=0.003), PEEP ( p=0.02), and cumulative doses of vasopressors ( p=0.02).
  
  
  CONCLUSIONS
  The effects of fluid challenge on gastric mucosal PCO(2) are variable and related to baseline PCO(2) gap rather than to systemic variables. In general, rapid volume infusion decreases PCO(2) gap, but this effect is more pronounced in patients with presumably impaired mucosal perfusion.
authors.affiliation: Department of Intensive Care, Erasme University Hospital, Route de Lennik 808, 1070 Brussels, Belgium.
authors.forename: Eliézer
authors.initials: E
authors.lastname: Silva
authors.forename: Daniel
authors.initials: D
authors.lastname: De Backer
authors.forename: Jacques
authors.initials: J
authors.lastname: Creteur
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Vincent
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002245:Carbon Dioxide / Q000378:metabolism*; D005260:Female; D005440:Fluid Therapy / Q000379:methods*; D005753:Gastric Mucosa / Q000378:metabolism*; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000627:therapeutic use; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010313:Partial Pressure; D010952:Plasma Substitutes / Q000627:therapeutic use; D011446:Prospective Studies; D012772:Shock, Septic / Q000628:therapy*; D018746:Systemic Inflammatory Response Syndrome / Q000628:therapy*
chemical_list: D006895:Hydroxyethyl Starch Derivatives; D010952:Plasma Substitutes; D002245:Carbon Dioxide