Continuous thoracic epidural fentanyl for post‐thoracotomy pain relief: with or without bupivacaine?

Abstract

SummaryTwenty-Jve ASA I or 2 patients undergoing thoracotomy were entered into a prospective, randomised, double-blind study comparing thoracic epidural fentanyl alone and thoracic epidural fentanyl combined with 0.2% bupivacaine. Pain relief, pulmonary function and cardiovascular stability were assessed. Pain relief was superior in the bupivacaine series ( p < 0.05) during the first day after operation and this was accompanied by better oxygenation ( p < 0.05); the difSerence did not persist into the second day. Forced expiratory variables were reduced in both series to 50-60% of the values before operation throughout the study ( p < 0.05) and differences did not occur between the groups. The incidence of side effects attributable to epidural fentanyl was high, but hypotension did not occur. Small doses of bupivacaine administered together with fentanyl into the thoracic epidural space improve analgesia without causing hypotension. Key wordsAnaesthetic technique regional; epidural. Analgesics; fentanyl. Anaesthetics; local bupivacaine.Lateral thoracotomy results in severe pain and deleterious changes in pulmonary physiology.' Shallow breathing during the first day following surgery can lead to atelectasis, pulmonary collapse and hypoxia2 which may continue for some days. Effective postoperative analgesia and physiotherapy can modify this sequence, inhibit changes in forced expiratory variables and prevent the onset of h y p~x i a .~ Postoperative pulmonary function is still reduced even with epidural opioid or local anaesthetic Opioid agents produce no further improvement when given after local anaesthetics,' but the effect of local anaesthetics after epidural opioid treatment remains to be evaluated.Epidural opioid administration provides good postoperative analgesia: and has been used successfully to treat pain and improve pulmonary mechanics after chest t r a~m a .~ Epidural local anaesthetics can also produce effective analgesia, but after thoracic surgery there is considerable risk of hypotension.8 While a combination of local anaesthetic and opioid improves the quality of pain relief,' the problem of cardiovascular instability remains.The purpose of this study was to compare the effect of an epidural infusion of a dilute bupivacaine/fentanyl mixture, against epidural fentanyl alone on pain, cardiovascular stability and postoperative pulmonary function after thoracic surgery. Patients and MethodsThis study was carried out with the approval of the local medical ethics research committee and with informed patient consent. Adult patients of ASA status 1 or 2 undergoing lateral thoracotomy were studied. Patients undergoing pneumonectomy were excluded.The patients were premedicated with temazepam 10 mg. In the theatre, after placement of peripheral venous and radial artery catheters, an epidural cannula was placed at either the T,-T, or T,-T, intervertebral space with 3 cm of the cannula left in the epidural space. Fentanyl 100 pg and bupivacaine 20 mg in a total volume of 10 ml were injected, and after 15 minu...

Side‐effects of epidural infusions of opioid bupivacaine mixtures

“…From these data we calculated approximately equipotent 24-h dosages for each drug. Previous studies have demonstrated superior analgesia with a combination of opioid and bupivacaine with the possible exception of very high dose fentanyl and therefore the use of bupivacaine alone or opioid alone were not considered ethical [10,[24][25][26][27][28].…”

An audit of the safety of an acute pain service

“…It is common practice to infuse a mixture of bupivacaine 0.1-0.25% with an opioid for postoperative analgesia [11][12][13][14]. A relatively low concentration of bupivacaine (0.0625%) plus fentanyl 3.3 mg.ml ¹1 has been chosen as our standard analgesic protocol and most of these patients are monitored in the general ward.…”

Bupivacaine 0.125% improves continuous postoperative epidural fentanyl analgesia after abdominal or thoracic surgery

“…This explanation is supported by previous studies where the addition of bupivacaine 0.25% to epidural morphine showed improved postoperative epidural analgesia following abdominal surgery, 7 and the use of 0.2% bupivaeaine has enhanced continuous epidural fentanyl pain relief following both abdominal aortic surgery,8 and thoracic surgery. 9 There were no differences in the secondary respiratory and alimentary outcome variables which included PaCO2, pH, and times to flatus and po fluids. This is similar to other studies using concentrations of bupivacaine varying from 0.1-0.5% with either fentanyl or morphine.…”

“…[3][4][5][6]8,9,[13][14][15][16][17][19][20][21][22] Dahl et al's work comparing morphine with and without bupivacaine 0.25% 7 showed that differences in analgesia were undetectable at rest but were evident with coughing or exercise. In spite of this, we were able to show the.…”