Normal values of SvO2 as therapeutic goal in patients with multiple injuries

To determine whether maintaining normal levels of mixed venous oxygen saturation (SvO2) in patients with multiple injuries is more relevant to survival than maintaining above-normal levels of oxygen transport.

Non-randomised, retrospective control study over a 38-month period.

Multidisciplinary intensive care unit in a university hospital.

40 patients with multiple injuries divided in to group A (23 patients) and group B (17 patients).

In group A patients, we maintained normal SvO2 by manipulation of oxygen transport variables: oxygen delivery (DO2) was increased only if SvO2 decreased or the dobutamine test was positive. In group B patients, DO2 was routinely maintained at above-normal levels by aggressive use of fluids and dobutamine.

In group A we measured SvO2 continuously and performed the dobutamine test. Oxygen transport-related variables were recorded every 12 h in the first 5 days after injury in both groups, as well as lactate concentrations. Survival was significantly greater in group A than in group B (p < 0.01). Multiple organ failure was less frequent in group A than in group B (p < 0.01). The average DO2 in group A was significantly lower than in group B from day 2 onwards (p < 0.05-0.01). Average values of DO2 of 605-688 ml/ min per m2 were required to maintain normal SvO2 and aerobic metabolism in group A; 10 patients required dobutamine 2.5-5 micrograms/kg per min. The average DO2 in group B was 622 ml/ min per m2 on day 1 and then it increased to 835 ml/min per m2 on day 5 after trauma.

Our results indicate that for patients with multiple injuries maintaining normal SvO2 values and increasing DO2 only if required are more relevant for survival than routine maintenance of above-normal oxygen transport values.