title: Arterial vs venous blood gas differences during hemorrhagic shock.
abstract: OBJECTIVE
  To characterize differences of arterial (ABG) and venous (VBG) blood gas analysis in a rabbit model of hemorrhagic shock.
  
  
  METHODS
  Following baseline arterial and venous blood gas analysis, fifty anesthetized, ventilated New Zealand white rabbits were hemorrhaged to and maintained at a mean arterial pressure of 40 mmHg until a state of shock was obtained, as defined by arterial pH ≤ 7.2 and base deficit ≤ -15 mmol/L. Simultaneous ABG and VBG were obtained at 3 minute intervals. Comparisons of pH, base deficit, pCO2, and arteriovenous (a-v) differences were then made between ABG and VBG at baseline and shock states. Statistical analysis was applied where appropriate with a significance of P < 0.05.
  
  
  RESULTS
  All 50 animals were hemorrhaged to shock status and euthanized; no unexpected loss occurred. Significant differences were noted between baseline and shock states in blood gases for the following parameters: pH was significantly decreased in both arterial (7.39 ± 0.12 to 7.14 ± 0.18) and venous blood gases (7.35 ± 0.15 to 6.98 ± 0.26, P < 0.05), base deficit was significantly increased for arterial (-0.9 ± 3.9 mEq/L vs -17.8 ± 2.2 mEq/L) and venous blood gasses (-0.8 ± 3.8 mEq/L vs -15.3 ± 4.1 mEq/L, P < 0.05). pCO2 trends (baseline to shock) demonstrated a decrease in arterial blood (40.0 ± 9.1 mmHg vs 28.9 ± 7.1 mmHg) but an increase in venous blood (46.0 ± 10.1 mmHg vs 62.8 ± 15.3 mmHg), although these trends were non-significant. For calculated arteriovenous differences between baseline and shock states, only the pCO2 difference was shown to be significant during shock.
  
  
  CONCLUSIONS
  In this rabbit model, significant differences exist in blood gas measurements for arterial and venous blood after hemorrhagic shock. A widened pCO2 a-v difference during hemorrhage, reflective of poor tissue oxygenation, may be a better indicator of impending shock.
authors.affiliation: Kristopher Burton Williams, Ashley Britton Christmas, Brant Todd Heniford, Ronald Fong Sing, Joseph Messick, Department of Surgery, Carolinas HealthCare System, Charlotte, NC 28204, United States.
authors.forename: Kristopher Burton
authors.initials: KB
authors.lastname: Williams
authors.affiliation: Kristopher Burton Williams, Ashley Britton Christmas, Brant Todd Heniford, Ronald Fong Sing, Joseph Messick, Department of Surgery, Carolinas HealthCare System, Charlotte, NC 28204, United States.
authors.forename: Ashley Britton
authors.initials: AB
authors.lastname: Christmas
authors.affiliation: Kristopher Burton Williams, Ashley Britton Christmas, Brant Todd Heniford, Ronald Fong Sing, Joseph Messick, Department of Surgery, Carolinas HealthCare System, Charlotte, NC 28204, United States.
authors.forename: Brant Todd
authors.initials: BT
authors.lastname: Heniford
authors.affiliation: Kristopher Burton Williams, Ashley Britton Christmas, Brant Todd Heniford, Ronald Fong Sing, Joseph Messick, Department of Surgery, Carolinas HealthCare System, Charlotte, NC 28204, United States.
authors.forename: Ronald Fong
authors.initials: RF
authors.lastname: Sing
authors.affiliation: Kristopher Burton Williams, Ashley Britton Christmas, Brant Todd Heniford, Ronald Fong Sing, Joseph Messick, Department of Surgery, Carolinas HealthCare System, Charlotte, NC 28204, United States.
authors.forename: Joseph
authors.initials: J
authors.lastname: Messick
keywords: Arterial blood gases; Base deficit; Hemorrhagic shock; Venous blood gases; pH