Different dosages of dobutamine in septic shock patients: determining oxygen consumption with a metabolic monitor integrated in a ventilator.
OBJECTIVE
Oxygen consumption (VO2) obtained from respiratory gases by indirect calorimetry (VO2,IC) with a metabolic monitor integrated in a ventilator were to be compared to VO2 obtained by the Fick principle (VO2,Fick) in septic patients following an increase in oxygen delivery (DO2) induced by positive inotropic support.


METHODS
Prospective clinical study.


METHODS
University Hospital, Surgical Intensive Care Unit (ICU).


METHODS
Thirty patients suffering from sepsis.


METHODS
DO2 was increased by dobutamine infusion, starting with an initial dosage of 5 microg x kg x min, increased to a maximum of 10 microg x kg x min.


RESULTS
Dobutamine infusion induced a dosage-related increase in DO2 (from 577 +/- 192 to 752 +/- 202 ml x min x m2, p < 0.01), which was associated with a statistically significant increase in VO2,IC (from 173 +/- 30 to 188 +/- 28 ml x min x m2, p < 0.01) and in VO2,Fick (from 140 +/- 25 to 156 +/- 24 ml x min x m2, p < 0.01). The comparison between VO2,IC and VO2,Fick revealed differences (bias and precision--33 +/- 32 ml x min x m2).


CONCLUSIONS
With a metabolic monitor integrated in a ventilator it was possible to carry out continuous monitoring of calorimetric data under clinical conditions. In contrast to previous studies using indirect calorimetry, this study showed a moderate correlation between VO2 and DO2 in septic patients using either method. The clinical relevance of this finding requires further investigation. Different factors (e. g. injectant temperature, pulmonary VO2) produced substantial differences between VO2,IC and VO2,Fick as previously shown.
Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, Unfallkrankenhaus Berlin, Germany. walters@ukb.de
W
W
Schaffartzik
C
C
Sanft
J H
JH
Schaefer
C
C
Spies
D000328:Adult; D000368:Aged; D015982:Bias; D001784:Blood Gas Analysis; D002153:Calorimetry, Indirect / Q000379:methods*; D002316:Cardiotonic Agents / Q000008:administration & dosage* / Q000494:pharmacology; D004280:Dobutamine / Q000008:administration & dosage* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D016903:Drug Monitoring / Q000379:methods*; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007262:Infusions, Intravenous; D008875:Middle Aged; D010101:Oxygen Consumption / Q000187:drug effects*; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000379:methods; D012772:Shock, Septic / Q000188:drug therapy* / Q000378:metabolism* / Q000503:physiopathology
D002316:Cardiotonic Agents; D004280:Dobutamine