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 (ScvO₂) and the frontal and the thenar regional oxygen saturation (rSO₂) measured by near infrared spectroscopy. Secondary, we examined the value of ScvO₂, lactate levels and rSO₂ 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. ScvO₂, rSO₂ and lactate were measured at sepsis diagnosis (baseline), 24 and 48 h, thereafter. We investigated the predictive value of frontal and thenar rSO₂ for a decreased SvcO₂ under 70 %. For survivor and non-survivors ScvO₂, rSO₂ and lactate were analysed. Patients with ScvO₂ >70 % showed a trend to higher levels of fontal rSO₂ (62.81 ± 8.06 vs. 53.54 ± 15.48; p = 0.058). ROC-analysis revealed a minor prediction of a decreased ScvO₂ by frontal rSO₂ 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 ≥70 % and lactate levels ≥2.5 mmol/l (log rank test p = 0.004). In the group with ScvO₂ <70 % and lactate levels <2.5 mmol/l no patients died during the observation period. Frontal rSO₂ correlates with ScvO₂ 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 ScvO₂ >70 % is highly associated with poor outcome in ICU patients with sepsis, severe sepsis and septic shock.