Intermittent Thoracic Epidural Administration of Ropivacaine-Fentanyl versus Bupivacaine-Fentanyl after Thoracotomy

摘要

Background: Pain relief after thoracotomy can be achieved with thoracic epidural analgesia. The pharmacodynamic profile of ropivacaine was reported to be superior to that of bupivacaine, especially in clinical settings where motor block is undesired. We aimed to compare intermittent thoracic epidural analgesia after thoracotomy using either bupivacaine – fentanyl or ropivacaine – fentanyl. Hemodynamics, ventilation, analgesia and side effects were compared..Methods: After general Anesthesia, 30 patients were randomly allocated to receive intermittent epidural bupivacaine 0.25% plus fentanyl 5 μg/ml (n = 15) or ropivacaine 0.25% plus fentanyl 5 μg/ml (n = 15). Heart rate, mean arterial blood pressure, respiratory rate, arterial blood gases were recorded. Motor power, pain score, analgesic requirements and side effects were evaluated over 24 hours postoperatively.Results: Heart rate, arterial blood pressure, respiratory rate and PaCO2 did not show any between-group differences. At8 and 12 hours in the recovery room, arterial O2 tension was significantly higher in RF group than in BF group, with respective values of 141 (29) mm Hg vs. 122 (26) mm Hg and 138 (22) mm Hg vs. 116 (19) mm Hg (P <0.05). Analgesia and diclofenac requirements were comparable in both groups. Motor power of the upper limbs was preservedin both groups. The incidence of side effects did not significantly differ between the two groups.Conclusion: Ropivacaine–fentanyl thoracic epidural analgesia after thoracotomy is comparable to bupivacaine – fentanyl analgesia in terms of pain control and side effects. Introduction Analgesia after thoracic surgery is of utmost importance. Thoracotomy with its noxious insult contributes to postoperative pulmonary dysfunction (1, 2). Epidural administration of local anesthetics and opioids has been used for post-thoracotomy pain relief (2,3,4). Studies on animals (5, 6) and humans (7, 8) revealed that ropivacaine produces less motor block and less cerebral and cardiotoxic effects than bupivacaine. Epidural ropivacaine produced comparable motor block with bupivacaine during labor (8, 9). However, adding opioid to these local anesthetics demonstrated equal analgesic potency with decreased motor block with ropivacaine-opioid (10, 11). In a clinical setting like thoracotomy, it is pertinent to assure good postoperative analgesia without cardiorespiratory compromise. Epidural ropivacaine-fentanyl may be a better choice than bupivacaine-fentanyl in patients subjected to thoracotomy. To test this hypothesis, we randomly allocated patients subjected to lobectomy to receive intermittent epidural ropivacaine-fentanyl or bupivacaine – fentanyl and blindly observed postoperative analgesia, analgesic requirements, cardio–respiratory variables and side effects. Patients and methods This double-blind study was carried out on thirty one adult patients of either sex. Patients undergoing elective lobectomy under posterolateral muscle cutting, rib retraction thoracotomy were the subject of this study. Approval of the Hospital Research Ethics Committee and informed written consent from all patients were obtained. Patients with known contraindications for epidural analgesia, namely patient refusal, infection at the injection site, bleeding diathesis or neurological disorders, were excluded from the study. Patients with diabetes mellitus and those below 18 years were also excluded. Preoperative evaluation of patients included medical history, clinical examination, routine investigation and chest X-ray. Patients received oral diazepam, 10 mg, and two hours before surgery. After arrival to the operative theatre, an intravenous cannula was inserted and lactated Ringer's solution, 1000 ml, was infused over 30 minutes. Monitoring was established with 3-lead ECG, pulse oximetry and capnography. A radial artery catheter was introduced for serial arterial blood sampling and direct arterial blood pressure monitoring. Perioperative heart rate, mean arterial