Prospective evaluation of regional oxygen saturation to estimate central venous saturation in sepsis

Current treatment guidelines for sepsis claim an early goal-directed hemodynamic optimization including fluid resuscitation, use of vasopressors and inotropic agents. We investigated the correlation between the prominent treatment goal central venous saturation (ScvO(2)) and the frontal and the thenar regional oxygen saturation (rSO(2)) measured by near infrared spectroscopy. Secondary, we examined the value of ScvO(2), lactate levels and rSO(2) as surrogate markers of an impaired tissue oxygenation for outcome prediction in sepsis. This prospective, observational study was performed at the surgical intensive care unit of the University Hospital Giessen. A total of 50 patients with sepsis, severe sepsis or septic shock were included. ScvO(2), rSO(2) and lactate were measured at sepsis diagnosis (baseline), 24 and 48 h, thereafter. We investigated the predictive value of frontal and thenar rSO(2) for a decreased SvcO(2) under 70 %. For survivor and non-survivors ScvO(2), rSO(2) and lactate were analysed. Patients with ScvO(2) > 70 % showed a trend to higher levels of fontal rSO(2) (62.81 +/- A 8.06 vs. 53.54 +/- A 15.48; p = 0.058). ROC-analysis revealed a minor prediction of a decreased ScvO(2) by frontal rSO(2) levels at baseline (AUC = 0.687; 95 % CI 0.511-0.863; p = 0.047). Combined measurements of lactate and ScvO2 showed significantly elevated mortality for patients with ScvO2 a parts per thousand yen70 % and lactate levels a parts per thousand yen2.5 mmol/l (log rank test p = 0.004). In the group with ScvO(2) < 70 % and lactate levels < 2.5 mmol/l no patients died during the observation period. Frontal rSO(2) correlates with ScvO(2) but both frontal and thenar rSO2 do not exactly discriminate between patients with high or low ScvO2 in sepsis. The combination of elevated lactate > 2.5 mmol/l and ScvO(2) > 70 % is highly associated with poor outcome in ICU patients with sepsis, severe sepsis and septic shock.