title: Oxygen consumption is independent of increases in oxygen delivery by dobutamine in septic patients who have normal or increased plasma lactate.
abstract: We asked whether the relationship between oxygen delivery and oxygen consumption is different between patients who have sepsis and normal (n = 6) or increased (n = 8) concentrations of plasma lactate. We determined oxygen consumption using analysis of respiratory gases while increasing oxygen delivery using a dobutamine infusion. The relationship between oxygen delivery and consumption was y = 124 + 0.043 * x in the normal lactate group and y = 131 - 0.003 * x in the high lactate group (95% CI for differences in slopes, -0.003 to 0.096; p < or = 0.05 for slope, normal versus high lactate). In the normal lactate group, direct oxygen consumption increased by only 8 +/- 6 ml/min/m2 after dobutamine infusion (from 144 +/- 26 to 153 +/- 22 ml/min/m2, p < or = 0.02) despite an average increase of 220 +/- 80 ml/min/m2 in oxygen delivery (from 446 +/- 91 to 666 +/- 90 ml/min/m2, p < or = 0.01). The oxygen extraction ratio fell from 0.27 +/- 0.03 to 0.21 +/- 0.02 after dobutamine (p < or = 0.017). In the high lactate group, direct oxygen consumption decreased by 1 +/- 6 ml/min/m2 after dobutamine (from 131 +/- 33 to 130 +/- 35 ml/min/m2, p > 0.60) despite an average increase of 168 +/- 138 ml/min/m2 in oxygen delivery (from 467 +/- 194 to 635 +/- 300 ml/min/m2, p < or = 0.01). The oxygen extraction ratio fell from 0.30 +/- 0.14 to 0.26 +/- 0.12 after dobutamine (p < or = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Program of Critical Care Medicine, Vancouver General Hospital, University of British Columbia, Canada.
authors.forename: J J
authors.initials: JJ
authors.lastname: Ronco
authors.forename: J C
authors.initials: JC
authors.lastname: Fenwick
authors.forename: B R
authors.initials: BR
authors.lastname: Wiggs
authors.forename: P T
authors.initials: PT
authors.lastname: Phang
authors.forename: J A
authors.initials: JA
authors.lastname: Russell
authors.forename: M G
authors.initials: MG
authors.lastname: Tweeddale
mesh_terms: D000328:Adult; D000368:Aged; D001424:Bacterial Infections / Q000097:blood / Q000378:metabolism*; D004280:Dobutamine / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007773:Lactates / Q000097:blood*; D019344:Lactic Acid; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption
chemical_list: D007773:Lactates; D019344:Lactic Acid; D004280:Dobutamine; D010100:Oxygen