The purpose of this study is to determine whether changes in perfusion index can be used for detecting intravascular injection of an epinephrine in anesthetized adults and to compare its reliability with criteria using changes in heart rate, systolic blood pressure or T-wave amplitude.

Intravenous injection of local anesthetics could result in life-threatening complications during general anesthesia. Physicians usually use local anesthetics containing epinephrine to detect intravascular injection. Existing methods including heart rate, systolic blood pressure and T-wave amplitude are unreliable to detect intravascular injection during anesthesia and a method using changes in perfusion index was recently suggested. This study was designed to determine whether perfusion index is a reliable method to detect intravascular injection of epinephrine containing local anesthetics and to compare its reliability with conventional criteria in sevoflurane anesthetized adults.

We will randomize patients to 2 groups: a saline group and an epinephrine group. Changes in perfusion index, systolic blood pressure, heart rate and T-wave amplitude will be measured during 5 minutes after injection of 3 mL of saline or 1% lidocaine containing epinephrine. we will determine sensitivity, specificity, positive predictive value and negative predictive value.

Inclusion Criteria:

• ASA physical status 1 patients undergoing general anesthesia for elective surgery

Exclusion Criteria:

• emergent operation
• those who are taking anticoagulant medication, calcium channel blockers, or b-blockers
• laparoscopic operation
• history of smoking