Introduction: The continuous epidural infusion of local anesthetic and fentanyl using a multirate elastomeric infusion pump provides the good analgesic option to treat the postoperative pain following the major abdominal surgery. The aim of the present study is to compare the different infusion rates of 0.1% bupivacaine with fentanyl as continuous epidural infusion using Baxter’s multirate elastomeric infusion pump in patients undergoing laparotomy under general anesthesia.

Materials and Methods: Seventy five patients, in age group of 25–60 year with ASA Grade I and II undergoing intraabdominal surgery under general anesthesia were randomly divided into three groups. The epidural catheter was placed in L1–2 interspace with six cm of catheter length in epidural space before induction of GA. At the time of closure of peritoneum a bolus of 8 ml of 0.1% bupivacaine with fentanyl 2 mcg/ml was given in epidural space and the continuous infusion was started at specified rate depending upon the group. In Gp I the infusion was @ 5 ml/hr while in Gp II and Gp III infusion rate was 7 ml/hr and 12 ml/hr respectively. An independent observer visited the patient at regular intervals to enquire about VAS score in postoperative period, extending up to 48 hours. Statistical Analysis: Parametric and nonparametric data were collected and relevant data of each patient was entered in Microsoft Excel Worksheet© and were analyzed statistically by using IBM SPSS© software. p - value < 0.05 was taken statistically significant.

Results: Analysis of postoperative VAS score showed that all the patients have 0 VAS at the time of extubation. Gp I showed higher VAS scores while Gp II and Gp III had a comparable VAS scores. Mean morphine consumption in Gp I was 0.96 ± 1.136 (total 5.7 mg), in Gp II was 0.48 ± 0.714 (total 2.88 mg) and in Gp III was 0.24 ± 0.663 (total 1.44 mg). All groups demonstrated the height of sensory block at T5 dermatome level in immediate postoperative period and the regression was faster in Gp I and II. The mean height of sensory blockade was much higher in Gp III (T7 dermatome) as compared to Gp I & II (T 9 dermatome). Gp III had mild weakness in hip flexion after 20 hrs of continuous infusion. Statistically higher sedation scores were noted in Gp III, but all patients were responsive to commands at all times. Gp III had higher incidence of bradycardia and hypotension (5/25, 20 %), shivering (13/25, 52%), pruritus (14/25, 56%), nausea and vomiting. The mean hospital stay was 5.106 ± 1.203 days.

Conclusion: For adequate postoperative pain relief following laparotomy under general anesthesia, the administration of bupivacaine 0.1% with fentanyl 2 mcg/ml @7 ml/hr is ideal rate for continuous epidural infusion. The multi rate elastomeric pump used in the study performed satisfactorily and no mal function was reported.