OXYGEN-TRANSPORT PATTERNS IN PATIENTS WITH SEPSIS SYNDROME OR SEPTIC SHOCK - INFLUENCE OF TREATMENT AND RELATIONSHIP TO OUTCOME

Objective: To investigate the relationship between oxygen transport pa tterns and outcome in patients with sepsis syndrome or septic shock ma naged according to two different treatment regimens. Design: Retrospec tive study of a subgroup of patients with sepsis syndrome or septic sh ock taken from a randomized, prospective, controlled trial. Setting: G eneral intensive care units in a teaching and a district general hospi tal. Patients: Seventy-eight patients classified according to predeter mined criteria as having sepsis syndrome or septic shock were drawn re trospectively from a larger study group of 109 consecutive patients co nsidered to be at risk for developing multiple organ failure. Interven tions: Ail patients received volume expansion to an optimal pulmonary artery occlusion pressure. If the therapeutic goals (cardiac index of >4.5 L/min/m(2), oxygen delivery [Do(2)] of >600 mL/min/m(2), and oxyg en consumption [Do(2)] of >170 mL/min/m(2) were not achieved with flui ds alone, patients were randomized to either a control group or a trea tment group, in the treatment group, dobutamine (5 to 200 mu g/kg/min) was administered to increase cardiac index and Do(2) until all three goals were simultaneously achieved. In the control group, dobutamine w as administered only if the cardiac index was <2.8 L/min/m(2). In both groups, norepinephrine was infused to maintain mean arterial pressure at 80 mm Hg. Measurements and Main Results: Hemodynamic, oxygen trans port, and lactate measurements were made at the time of admission to t he study, at the time of optimal volume administration, at 1, 2, 4, 8, 12, 16, 20, and 24 hrs, then every 6 hrs for the next 24 hrs, and at least every 8 brs thereafter. The time at which all therapeutic goats were first achieved simultaneously or the time of maximal Do(2) was id entified and termed ''tmax''. Survivors from both the control and trea tment groups significantly (p < .001) increased cardiac index and Do(2 ) in response to maximal resuscitation, and despite an associated decr ease in oxygen extraction (p < .01), there was a significant (p < .01) increase in Vo(2). In nonsurvivors from both groups, despite signific ant increases in cardiac index (p < .05) and Do(2) (p < .01) at tmax, oxygen extraction decreased (p < .01) and Vo(2), remained unchanged. D o(2) and Vo(2) were significantly lower (p < .05) at tmax in nonsurviv ors than in survivors from both groups. Persistently high lactate conc entrations were characteristic of nonsurvivors. Conclusions: Survivors of sepsis syndrome or septic shock are characterized by an ability to increase both Do(2) and Vo(2). In contrast, nonsurvivors typically ha ve reduced cardiac reserve, they fail to increase Vo(2) following resu scitation, and when delivery is enhanced with aggressive inotropic sup port, oxygen extraction falls. These patterns of response were similar in both treatment and control groups, although the magnitude of the c hanges was exaggerated in the treatment group. These observations may help to explain the findings by some investigators that treatment aime d at achieving survivor Values of cardiac index, Do(2), and Vo(2) fail s to improve outcome when instituted following admission to intensive care.