Background: Epidural block with bupivacaine alone can provide analgesia in the early post operative period but as the block wears off, systemic analgesics such as non-steroidal anti inflammatory drugs (NASID) or parenteral opioids are frequently required to relieve the pain. Epidural administration of opioids are an effective way of pain control in the post-operative period, but they produce side effects, like delayed respiratory depression. Ketamine when administered epidurally inhibits the nociceptive transmission. The present study was conducted to evaluate the efficacy of epidural 1% ketamine 0.5mg.kg body weight with 0.5% bupivacaine compared with 0.5% bupivacaine plain solution.
Methods: 60 patients were randomly assigned into two groups of 30 patients each. All patients were posted for elective surgery which required a sensory blockade level below T6 dermatome. After standard premedication, single shot lumbar epidurals were administered. Group I received bupivacaine 0.5% plain solution (1.5 ml.spinal segment to be blocked) Group II received bupivacaine 0.5% (1.5 ml.spinal segment to be blocked) plus 1% preservative free ketamine (0.5 mg.kg body weight). Heart rate, blood pressure, sensory and motor blockade, post-operative analgesia and pain score, supplementation during surgery, Intra and postoperative complications were recorded.
Results: Time of onset of sensory blockade and time of onset of the maximum motor blockade is faster in the group of epidural bupivacaine plus ketamine. Quality of motor block did not have a significant change in epidural bupivacaine ketamine group clinically, though the statistical analysis proved to be significant. The epidural bupivacaine plus ketamine group took more time to recover from the motor blockade. Postoperative analgesia was significantly more in the epidural
bupivacaine plus ketamine group. Intraoperatively epidural bupivacaine plus ketamine group showed a
lower incidence of hypotension and bradycardia, None of the patients required supplemental anesthetics during the study. Postoperative pain scores at the first request of analgesia were comparatively lower in the epidural bupivacaine plus ketamine group.
Conclusions: The addition of ketamine to bupivacaine improved significantly both quality and duration of analgesia compared with administration of bupivacaine alone, without increasing the incidence of side effects. Respiratory depression seen with epidural opioids was not seen with epidural ketamine in the present study.
Keywords: Epidural block, Bupivacaine, Ketamine, General anaesthesia, Local anaesthesia