Comparison of the effects of Pethidine plus Lidocaine and Lidocaine alone on depth and duration of post operative analgesia in IV block of upper limb

Background and Objective: One of the alternative methods for general anesthesia that has been used for a long time by means of local anesthetic drugs for brief limbs procedures is intravenous regional block. This research was designed to study the effects of Pethidine plus Lidocaine in intravenous regional anesthesia and comparing it with the conventional method of Lidocaine alone in order to intensity the depth of block and duration of postoperative analgesia in upper limb procedures. Methods: In a prospective and clinical trial, 50 patients (20-60 years old) in ASA class I and II were divided into 2 groups: The patients in group 1 were injected 40ml Lidocaine 0.5% and to the patients in group 2 we added 50ml Pethidine to their 40ml Lidocaine 0.5% regionally. At the end of surgery, along with tourniquet deflation 50mg intravenous Pethidine was injected to group 1. The onset time of tourniquet was recorded and the depth of the block was assessed according to the patient response to painful stimulation just before beginning of the surgery with 5 points scale. All the patients were followed up for 12 hours after procedure to determine the onset of postoperative pain and then it was recorded. Findings: The onset time of tourniquet, pain was 29.45 and 42.41 minutes in group 1 and 2, respectively (P=0.023). The duration of postoperative analgesia in group 2 was 6.83 hours, which was obviously longer than that of group 1 (3.72 hours) (P=0.002). The intensity of the block in group 2 was significantly more than group 1 (P=0.13). Conclusion: According to the results, addition of Pethidine to Lidocaine in upper limb intravenous regional anesthesia, in contrast to the conventional method of Lidocaine alone, not only delays the tourniquet pain and postoperative pain also increases the intensity of block with clear improvement of the perioperative conditions