ABSTRACT
In this study we compared the analgesic and heamodynamic effects of continuous extradural bupivacain infusion and intermuscular bupivacain infusion after renal surgery 20 ASA I and II patients undergoining renal surgery through a muscle cutting loin incision were the material of this study. Patients were allocated to receive continuous bupivacain infusion after surgery via either a thoracic extradural catheter [G.I] or via an epidural catheter placed per-operatively between the muscle layers [G.II] for post operative pain relief. Immediately after operation group I patients were given 10 ml of 0.25% bupivacain followed by continuous infusion of 0.25% bupivacain delivered at a rate of up to 6 ml/h for 48 hs post-operatively. In group II patients, immediately after operation, 20ml of 0.25% bupivacain was introduced to the wound followed by continuous infusion commenced at 5ml/h. After operation arterial pressure and heart rate were recorded routinely at 10min intervals for the first hour, and there after at 1 h intervals for 12h, then every 6h for the next 36 hs. The first request for analgesia was treated with systemic morphine administered i.v in 1mg increments until pain was controlled adequately. Further requests for analgesia were treated with morphine 5mg i.m and repeated as required. The total morphine requirements for the initial 48 hs after operation were recorded. Pain scores on a visual analogue scale [VAS] [0 mm= no pain; 100 mm = worst pain imaginable] at rest, during mobilization from the supine into the sitting position and during coughing were assessed 1, 6, 12, 18, 24, 30, 36, 42, and 48hs post-operatively. No bacterially proven wound infection occurred in either group. Mean arterial pressure [MAP] decreased in group I within 30-60 min of administration of the bupivacain, although the differences were not significant between the two groups or compared with the pre-injection values. The mean morphine requirements for group I was 22.9 microg/Kg/h +/- 5.6 and 25.8 microg/Kg/h +/- 5.7 for group II, this difference is not statistically significant. Also there were no significant differences between the two groups in visual analogue pain scores [VAPS] during rest, mobilization from supine into sitting position or during coughing. The data have suggested that a continuous infusion of intermuscular bupivacain is nearly equal to epidural bupivacain infusion in controlling pain after renal surgery. The technique is simple, has few complications and it represents a good alternative when insertion of epidural catheter is contraindicated or difficult to be performed