LACK OF OXYGEN-SUPPLY DEPENDENCY IN PATIENTS WITH SEVERE SEPSIS - A STUDY OF OXYGEN DELIVERY INCREASED BY MILITARY ANTISHOCK TROUSER AND DOBUTAMINE

Background: During severe sepsis, the existence of a pathologic oxygen supply dependency remains controversial. Study objective: To evaluate the relationship between oxygen delivery (DO2) and oxygen consumption (VO2) during severe sepsis and to compare, in this respect, survivors and nonsurvivors and patients with normal or increased concentration of plasma lactate. Study design: Cohort analytic study. Setting: Three European ICUs in university hospitals. Patients: Seventeen mechanical ly ventilated patients with severe sepsis (six with high blood lactate levels) studied within the first day of diagnosis. Interventions and measurements: Pulmonary elimination of carbon dioxide, or carbon dioxi de production (VCO2) and VO2 were measured by indirect calorimetry bef ore and after two interventions designed to increase DO2 (calculated f rom the Fick equation): inflation of a military antishock trouser (MAS T) and infusion of dobutamine. Results: During MAST inflation, DO2 inc reased by 19%, in patients with a normal concentration of plasma lacta te(p <0.01), but remained unchanged in patients with high lactate leve ls. During dobutamine infusion, DO2 increased in both groups by 16%, ( p <0.01) and 20% (p <0.05), respectively. In both groups, we found tha t the VO2 and VCO2 were not affected by either the MAST or the dobutam ine-induced increase in DO2. There was no difference between survivors and nonsurvivors. Conclusion: There was no evidence of a pathologic o xygen supply dependency in patients with severe sepsis, even in those who had an elevated concentration of plasma lactate and in those who u ltimately died. These results do not favor the conclusion that maximiz ing DO2 is a primary therapeutic objective in such patients.