Processed electroencephalography-guided general anesthesia and norepinephrine requirements: A randomized trial in patients having vascular surgery

Processed electroencephalography (pEEG) may help clinicians optimize depth of general anesthesia. Avoiding excessive depth of anesthesia may reduce intraoperative hypotension and the need for vasopressors. We tested the hypothesis that pEEG-guided – compared to non-pEEG-guided – general anesthesia reduces the amount of norepinephrine needed to keep intraoperative mean arterial pressure above 65 mmHg in patients having vascular surgery. Randomized controlled clinical trial. University Medical Center Hamburg-Eppendorf, Hamburg, Germany. 110 patients having vascular surgery. pEEG-guided general anesthesia. Our primary endpoint was the average norepinephrine infusion rate from the beginning of induction of anesthesia until the end of surgery. 96 patients were analyzed. The mean ± standard deviation average norepinephrine infusion rate was 0.08 ± 0.04 μg kg−1 min−1 in patients assigned to pEEG-guided and 0.12 ± 0.09 μg kg−1 min−1 in patients assigned to non-pEEG-guided general anesthesia (mean difference 0.04 μg kg−1 min−1, 95% confidence interval 0.01 to 0.07 μg kg−1 min−1, p = 0.004). Patients assigned to pEEG-guided versus non-pEEG-guided general anesthesia, had a median time-weighted minimum alveolar concentration of 0.7 (0.6, 0.8) versus 0.8 (0.7, 0.8) (p = 0.006) and a median percentage of time Patient State Index was