Epinephrine Improves Epidural Postoperative Analgesia Produced By A Small-dose Infusion Of Ropivacaine And Fentanyl

BACKGROUNDThere is severe pain after major thoracic or abdominal surgery. Epidural infusion of ropivacaine and fentanyl is a effective way to control this postoperative pain.But side effects(motor block, systemic and CNS toxicity, nausea, vomiting, pruritus) limits their use. The addition of epinephrine can decrease these side effects. Because of its vasoconstrictive properties, systemic absorption of other components of the epidural solution—typically local anesthetics and opioids—is reduced. This is expected both to decrease side effects and to enchane the analgesia of local anesthestic and opioids. Furthermore, epinephrine produces analgesia through an α₂-adrenergic mechanism in the substantia gelatinosa of the spinal cord dorsal horn.Epinephrine,fentanyl and ropivacaine do have separate pharmacodynamic mechanisms of effect in modulation of the nociceptive impulse transmission in the spinal cord, supraadditive analgesic interactions may occur.Up to now, there is few study reported the analgesicefficacy and safty of epinephrine epidural infusion.OBJECTIVETo investigate the influence of epinephrine on thoracic epidural anelgesia producedby a small-dose infusion of ropivacaine and fentanyl after major thoracic orabdominal surgery.MATERIALS AND METHODS30 ASA â… - â…¡ patients scheduled for major thoracic or abdominal surgery weredouble-blinding and randomly divided into Group A and GroupB. All patients weregoing under combined epidural and general anethesia.Before the induction of generalanesthesia, an epidural catheter was inserted at an appropriate level between the 6thand 11th thoracic interspace,depending on the site of surgery. After operation allepidural catheter were connected a GRASEBY 9500 PCA pump, which containedmixture consisting of ropivacaine 1mg/ml, fentanyl 2μg/ml and epinephrine 2μg/ml, and started as a continuous infusion at a rate of 4-5ml/h, self-adminster one4ml bolus up to twice per hour. At 8:00AM-11:00 AM on the first postoperativeday epinephrine was omitted from epidural infusion in group A. At 8:00AM-11:00 onthe second postoperative day,this experiment was reperted in group B andepinephrine was omitted from epidural infusion in group B. when pain intensityincreased , morphine l-5mg was titrated IV. VAS when coughing and at rest, extentof sensory blockade,amounts of epidural infusion and IV morphine,vital signs andside effects were recorded per hour from 8:00 AM to 16:00 PM.RESULTPain increased and hypoesthetic dermatomal segments decrease (p<0.01) whenepinephrine was omitted from the triple epidural infusion.Consumption of epiduralstudy-drug and IV morphine was significantly higher during the period withoutepinephrine compare with the period with epinephrine (p<0.01). Nause increasedsignificantly (p<0.01).After restarting the triple rpidural mixture with the epinephrine,pain was again reduce and the sensory blockade was restored.CONCLUSIONEpinephrine markedly improves the pain-relieving effect and increased the sensoryblockade of ropivacaine and fentanyl and reduces side effects.