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.