Bispectral Index-Guided Versus Fixed Dose Administration of Desflurane During Balanced Anesthesia With Remifentanil

Bispectral Index-Guided Versus Fixed Dose Administration of Desflurane During Balanced Anesthesia With Remifentanil

Balanced anesthesia combining volatile anesthetics and opioids is commonly used in modern anesthesia. The purpose of this study is to compare two methods of administering desflurane, an volatile anesthetic during balanced anesthesia. The investigators hypothesized that administering desflurane at 1 MAC (minimum alveolar concentration) during balanced anesthesia will be more beneficial in terms of stability of the patient's vital signs and hypnotic depth than administering desflurane according to the patient's BIS (bispectral index) value.

Inclusion Criteria:

• Patients scheduled for operation under balanced anesthesia using desflurane and remifentanil

Exclusion Criteria:

• Refusal of consent
• General anesthesia with agents other than desflurane and remifentanil
• Patients with allergy to neuromuscular blocker, volatile anesthetics, opioids
• History of malignant hyperthermia
• Patients taking CNS stimulants
• Chronic alcohol abuser
• Patients with severe depressed left ventricular function, EF < 30%
• Patients with convulsive disorders
• ASA class IV, V, VI
• Patients with systolic arterial blood pressure lower than 90mmHg before surgery
• Patients needing inotropic infusion during surgery
• Anesthesia time less than 30 minutes