Decreases in cerebral saturation in patients with septic shock are associated with increased risk of death: a prospective observational single center study

Abstract

Background: The mortality rate from septic shock has been declining. Cerebral hypoxia, measured non-invasively with cerebral oximetry, has been correlated with neurologic and non-neurologic sequelae. Whether cerebral desaturations occur in septic shock patients and what consequences these may have is untested.

Methods: Adult patients with septic shock had cerebral saturation monitoring initiated. The primary objective was to determine if the incidence and magnitude of cerebral desaturations in septic shock patients correlated with delirium. We also compared the incidence and magnitude of cerebral desaturations in patients with septic shock with patients undergoing high-risk non-cardiac surgical procedures, a group known to be at high risk for cerebral desaturations.

Results: Fifteen patients were enrolled. Twelve (80 %) patients had a decrease in SctO2 below 65 %. Delirium was not associated with the area under the curve of an SctO2 of 65 % (p = 0.84). Patients who died of septic shock had more significant decreases in SctO2 than those who survived (p = 0.04). Decreased SctO2 was more common in patients with septic shock and was of greater magnitude than those undergoing high-risk non-cardiac surgery.

Conclusions: Cerebral desaturations occur more commonly and are of a greater magnitude in septic shock patients compared with those undergoing high-risk non-cardiac surgery. There did not appear to be a relationship between the incidence or magnitude of decreases in SctO2 and ICU delirium. Patients who died of septic shock had more significant decreases in SctO2 than patients who survived.

Keywords: Cerebral oxygen saturation; Monitoring; Septic shock.

Fig. 1

Graphical representation of the Log AUT SctO₂ of patients who died and survived their septic shock. Patients who died had a higher median AUT S_ctO₂ < 65 % than patients who survived (4.5 [0.0–25.3] vs. 0.0 [0.0–0.6] % min⁻¹ hr⁻¹; p = 0.04)

Fig. 2

Correlation between SctO₂ values and a mean arterial pressure, b norepinephrine dose, and c peripheral oxygen saturation. There was no correlation between any of these variables and SctO₂ (Pearsons r)

Fig. 3

Correlation between a percent time below and b AUT below a SctO₂ of 75 % and post intensive care unit admission day 2 hemoglobin. Decreases in hemoglobin concentration were correlated with both the duration (Pearsons r = −0.46) and magnitude (Pearsons r = −0.41) of cerebral desaturations