Sevoflurane-Remifentanil Interaction: Multiple Response Surfaces, Validation of Calibration Stimuli, Validation of the Intraoperative Isobole Concept and Investigating Remifentanil Induced Opioid Tolerance

Sevoflurane-Remifentanil Interaction: Multiple Response Surfaces, Validation of Calibration Stimuli, Validation of the Intraoperative Isobole Concept and Investigating Remifentanil Induced Opioid Tolerance

During this study, the pharmacodynamic interactions between sevoflurane and remifentanil will be studied.

Inclusion Criteria:

• American Society of Anesthesia class I and II patients
• Aged 18-60 years
• Scheduled for surgery under general anesthesia

Exclusion Criteria:

• Weight less than 70% or more than 130% of ideal body weight
• Neurological disorder
• Diseases involving the cardiovascular system (hypertension, coronary artery disease, prior acute myocardial infarction (AMI), any valvular and/or muscular disease involving decrease of the ejection fraction, arrhythmias, which are either symptomatic or require continuous medication/pacemaker/automatic implantable cardioverter defibrillator [AICD])
• Pulmonary disease including asthma, severe chronic obstructive pulmonary disease (COPD), etc.
• Gastric diseases including reflux, endocrinological diseases
• Recent use of psycho-active medication, including alcohol.