The Effect Site Concentration of Remifentanil for Conscious Sedation During Awake Nasotracheal Fiberoptic Intubation

The Effect Site Concentration of Remifentanil for Conscious Sedation During Awake Nasotracheal Fiberoptic Intubation

The Effect Site Concentration of Remifentanil for Conscious Sedation During Awake Nasotracheal Fiberoptic Intubation

Remifentanil provides analgesia, suppresses airway reflex, has little effect on cognitive function. It can be used for conscious sedation during awake nasotracheal fiberoptic intubation. Target-controlled infusion is more reliable technique for maintaining optimal infusion rate than manual controlled infusion. The aim of this study is to determine the effect site concentration of remifentanil for successful conscious sedation during awake nasotracheal fiberoptic intubation.

After topical airway anesthesia with 10 % lidocaine in nostril and oropharyx, 1.5~2.0 mg of IV midazolam is injected. Awake nasotracheal fiberoptic intubation is performed with target-controlled infusion of remifentanil. Initial effect site concentration is 3.0 ng/ml. Smooth intubation is defined as absence of persistent cough with head elevation and defensive movement of extremities. In case of smooth intubation, effect site concentration is decreased by 0.5 ng/ml for the subsequent case. If intubation is not smooth, effect site concentration is increased by 0.5 ng/ml for the subsequent case. EC50 of remifentanil is determined using Dixon's up-and-down method.

EC50 of remifentanil for preventing persistent cough and defensive movement using Dixon's up-and-down method

Inclusion Criteria: Patients undergoing cervical spine surgery Age 20-65 American Society of Anesthesiologists physical status classification I or II Exclusion Criteria: Patients' refusal allergy to any drug used unable to cooperate Severe hepatic or renal disease coagulation disorder chronic use of opioids or sedatives increase risk of pulmonary aspiration.