Electroencephalogram bispectral index predicts hemodynamic and arousal reactions during induction of anesthesia in patients undergoing cardiac surgery

Abstract

Objective: To evaluate hemodynamic and clinical responses to induction of anesthesia and intubation at 3 different values of the electroencephalogram bispectral index (BIS).

Design: Prospective randomized trial.

Setting: University-affiliated hospital.

Participants: Forty-five patients undergoing elective coronary artery bypass graft surgery.

Interventions: Patients were assigned to 3 groups (n = 15 for each group). Anesthesia was induced with midazolam, sufentanil, and pancuronium. In each group, sufentanil was titrated to a BIS value of 60, 50, or 40 before intubation. Mean arterial blood pressure, heart rate, incidence of coughing, tearing, and need for fluid replacement or injections of norepinephrine were recorded before intubation as well as immediately and 1 and 2 minutes after intubation.

Measurements and main results: Thirteen patients intubated at a BIS value of 60 coughed and 14 experienced tearing after intubation, whereas no patient of the other groups showed signs of arousal. Mean arterial blood pressure remained stable in the BIS 60 and 50 groups, whereas in the BIS 40 group it decreased significantly to lower values before and after intubation. Patients in the BIS 40 group needed significantly more fluid replacement and injections of norepinephrine compared with the other groups. No significant changes in heart rate were detected.

Conclusions: Electroencephalogram BIS predicts hemodynamic and arousal reaction resulting from induction of anesthesia and endotracheal intubation. BIS value should be kept at 50 before intubation to ensure safe hemodynamic conditions during induction of anesthesia in cardiac surgical patients.