The EC90 of Remifentanil Blunting Hemodynamic Changes to Head Fixation

The EC90 of Remifentanil Blunting Hemodynamic Changes to Head Fixation in the Patients Undergoing Neurosurgery

The purpose of this study is to estimate the EC90 of remifentanil blunting hemodynamic changes to head fixation in the patients undergoing neurosurgery.

Inclusion Criteria:

• patients undergoing neurosurgery that require head fixation with mayfield head holder
• patients who agree to our study

Exclusion Criteria:

• patients who don't agree to our study
• BMI<16.0 or BMI>30
• cardiovascular disease, pulmonary disease, renal disease
• alcoholic abuser or drug abuser
• patients who takes any drug having an influence on cardiovascular system or sympathetic nervous system
• any use of local anesthetics or drugs which have an influence on cardiovascular system from beginning of induction to peri-fixation period