Is impaired cerebrovascular autoregulation associated with outcome in patients admitted to the ICU with early septic shock?

Objective: To investigate the correlation between early changes in cerebrovascular autoregulation (CVAR) and neurological outcome and mortality in patients admitted to the intensive care unit with septic shock. Design, setting and participants: A prospective observational study in a tertiary, university-affiliated ICU, of 28 patients with septic shock (median age, 66 years; interquartile range [IQR], 56-74 years), with a median APACHE III score of 86 (IQR, 55-119). Main outcome measures: We used the correlation in time between cerebral tissue oxygenation (measured with near infrared spectroscopy) and mean arterial pressure to determine the tissue oxygenation reactivity index (TOx) as a measure of CVAR. Low TOx represents intact CVAR and high TOx represents impaired CVAR. We performed the measurements in the first 3 days after admission to the ICU. Survival and neurological outcomes, measured using the modified Rankin Scale and the Cerebral Performance Category scale, were censored 3 months later. Results: All survivors of septic shock had a good neurological outcome. The TOx for Days 1-3 was higher (P < 0.001) in non-survivors (median, 0.04 [IQR, 0.12- 0.24]) compared with survivors (median, -0.02 [IQR, -0.13 to 0.05]). The TOx was independently associated with survival at 3 months (odds ratio, 0.13 [95% CI, 0.01-0.69]; P < 0.05) using logistic regression analysis. Conclusions: CVAR is impaired early in septic shock and is independently associated with mortality at 3-month follow-up. Information based on bedside monitoring of CVAR in the ICU could form a valuable adjunct to guide haemodynamic optimisation in patients with septic shock.