Anesthetic management of a patient with an electroencephalogram phenotype for a "vulnerable brain": a case report

Low frontal alpha power is an electroencephalogram phenotype suggesting vulnerability to anesthetics. This phenotype for a "vulnerable brain" carries risks for burst suppression at lower-than-expected anesthetic concentrations and therefore for postoperative delirium.

A 73-year-old man underwent a laparoscopic Miles' operation. He was monitored with a bispectral index monitor. Before the skin incision, the fraction of age-adjusted minimum alveolar concentration of desflurane was 0.48, and a spectrogram showed slow-delta oscillation despite a bispectral index value of 38-48. Although the fraction of age-adjusted minimum alveolar concentration of desflurane decreased to 0.33, the EEG signature remained unchanged, along with a similar bispectral index value. No burst suppression patterns were observed throughout the whole procedure, and he did not experience postoperative delirium.

This case suggests that monitoring of electroencephalogram signatures is helpful for detecting patients with a "vulnerable brain" and for providing optimal anesthetic depth in such patients.