Propofol, an intravenous sedative agent, frequently produces pain during injection. This study was designed to investigate whether transcutaneous electrical nerve stimulation could reduce pain during propofol injection.

in minimizing propofol injection pain.

Twenty min after transcutaneous electrical nerve stimulation, the electrodes were removed and propofol 0.5 mg/kg was administered at the rate of 0.5 ml/sec using syringe pump. Propofol injection pain was evaluated by a study blinded anesthesiologist using a four point scale: 0=no (negative response to questioning), 1=mild pain (pain reported only in response to questioning without any behavioral sings), 2=moderate pain (pain reported in response to questioning and accompanied by a behavioral signs or pain reported spontaneously without questioning, 3=severe pain (strong vocal response or response accompanied by facial grimacing, arm withdrawal or tears).

Inclusion Criteria:

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Exclusion Criteria:

• American Society of Anesthesiologists physical status classification > 3
• Patient with a history of allergy to drugs
• Patient who takes opioid, sedative, anticonvulsant
• Patient with a history of neurologic disease and psychological disorders
• patient with skin problem
• Patient with pacemaker or electric medical device
• pregnancy

Two electrodes were attached to the radial side of dominant forearm. In the placebo group the TENS device had no current output although the power "on" indicator light remained active.