Table 34-9
- Local anesthetic drug (principal determinant of duration)
- Dose (increasing dose results in increased duration and density)
- Age (conflicting results)
- Adrenergic agonists (epinephrine 1:200,000)
- Prolongs duration of lidocaine and mepivacaine > bupivacaine and etidocaine
- Mechanism may reflect decreased absorption from epidural space or direct inhibitory effect of epinephrine on sensory and motor neurons