Cardiovascular effects of epidural local anaesthetics

The cardiovascular effects of 20 ml 0.75% bupivacaine with adrenaline 5 micrograms/ml injected epidurally were compared with those of 20 ml 0.75% ropivacaine with adrenaline. Cardiovascular measurements were performed with a transthoracic electrical bioimpedance monitor. The maximum mean arterial blood pressure decreased significantly from baseline values after both solutions, but the decrease after 20 minutes was more pronounced with bupivacaine (21%) than with ropivacaine (9.6%). Stroke volume increased significantly in both groups (52% for bupivacaine and 29% for ropivacaine). Cardiac output increased significantly from baseline values 2 minutes after epidural administration; the mean of the maximum increase was 64% for bupivacaine and 53% for ropivacaine (NS). The mean of the maximum increase of the ejection fraction was 13% in the bupivacaine group and 9% in the ropivacaine group, but was only significantly different from baseline values following bupivacaine. There was no difference in the onset time or height of the sensory block between the groups. The cardiovascular changes can be ascribed to sympathetic blockade and to systemic absorption of the local anaesthetics and adrenaline.     

Post-surgery epidural blockade with local anaesthetics attenuates the catecholamine and thermogenic response to perioperative hypothermia

Core (aural canal) and mean skin (15 sites) temperatures, plasma adrenaline, noradrenaline and metabolites, and gaseous exchange were measured before, during and for 4 h after surgery in sixteen patients scheduled for elective colorectal surgery. All patients received general anaesthesia and no measures were taken to prevent the perioperative loss of body heat. At time of abdominal wall closure, when the core temperature was below 35.0°C, the patients were randomly allocated to receive either 20-30 mg of papaveretum i. v. (papaveretum group, n = 8) or 15 ml of bupivacainc 0.75% via thoracic (T9) epidural route to obtain a T4-S5 sensory blockade (epidural group, n=8). Continuous infusion of either i. v. papaveretum or epidural 0.25% bupivacaine was continued after surgery. During the recovery period of four hours the rate of increase in core and mean skin temperatures was significantly slower in the epidural group compared with the papaveretum group ( P <0.01). Plasma catecholamine concentrations remained elevated after surgery in the papaveretum group, whilst they decreased significantly once epidural blockade was established ( P <0.001). There was a lower trend, however not significant, in the rise of postoperative oxygen consumption and plasma glucose concentration in the epidural group compared with the papaveretum group.     

Asymmetric onset of sympathetic blockade in epidural anaesthesia shows no relation to epidural catheter position

A radiological study was performed of the relation between onset of sympathetic blockade in lumbar epidural anaesthesia and the position of the epidural catheter. In 20 patients scheduled for extracorporeal shock wave lithotripsy (ESWL), the onset of sympathetic blockade after epidural anaesthesia (catheter insertion at the presumed level L2-L3, and injection of 20 ml prilocaine 2% with epinephrine 5 micrograms/ml) was objectively evaluated by photoplethysmography. The onset was asymmetrical in 18 patients, and symmetrical in only two. Just before the start of ESWL, the position of the epidural catheter was checked by radiography after injection of 0.5 ml iohexol 300 mg/ml (Omnipaque 300). The radiopaque contrast medium was found median (n = 2), right (n = 7) and left (n = 11) of the midline. In only 9 patients was the earliest onset of sympathetic blockade correlated with the side of the catheter position, and thus no relation between catheter position and onset of sympathetic blockade was found.     

Comparison of continuous spinal and continuous epidural anaesthesia for lower limb surgery in elderly patients A retrospective study

This retrospective study compared continuous spinal anaesthesia with continuous epidural anaesthesia for lower limb orthopaedic surgery in the elderly. The anaesthetic records of 457 patients who received continuous spinal anaesthesia and 274 who received continuous epidural anaesthesia over a 5-year period were analysed. The patients who had continuous spinal anaesthesia were at a higher anaesthetic risk (ASA 3-4, 76% as compared with 37%, p less than 0.001), but the incidence of failures was significantly lower (1.7%, as compared with 9%, p less than 0.001) and fewer patients showed a decrease in mean arterial pressure of more than 30% (44%, as compared with 65%, p less than 0.001) and (or) received vasopressors (65%, as compared with 77%, p less than 0.01). Our data show continuous spinal anaesthesia to be more reliable and to provide better cardiovascular stability.     

Lumbar epidural diamorphine following thoracic surgery

Twenty-two patients received a single dose of diamorphine 5 mg through a lumbar epidural catheter before thoracic surgery. The patients were transferred after surgery to a high dependency unit where they were allocated randomly to receive either an infusion of epidural diamorphine at a rate of 1 mg/hour (group 1) or bolus doses of epidural diamorphine 5 mg on demand (group 2). There was no statistically significant difference between the groups in visual analogue pain scores in the first 18 postoperative hours. Arterial carbon dioxide tension was elevated in both groups and was consistently higher in group 1 than in group 2, with a statistically significant intergroup difference 12 hours after operation. Respiratory rate was not a useful index of respiratory depression. The commonest nonrespiratory side effect was urinary retention, but the incidences of this and other minor side effects were similar in the two groups.     

Effect of pre- vs postoperative tonsillar infiltration with local anesthetics on postoperative pain after tonsillectomy

Background : Since pre-incisional peritonsillar infiltrations of local anesthetic solutions have been suggested to reduce postoperative pain after tonsillectomy, we compared the efficacy of either pre- or postoperative local anesthetic infiltration upon post-tonsillectomy pain. Methods : After the induction of general anesthesia, 68 consecutive healthy patients, ranging in age from 8 to 65 years, were randomly allocated to either receive peritonsillar infiltration with 0.25% bupivacaine (group 1) or normal saline (group 2) before incision. A third group (group 3) had their peritonsillar region infiltrated with 0.25% bupivacaine after the completion of surgery but before the patients were awakened from anesthesia. All the patients were treated in the same way in the postoperative period: NSAIDs were given intravenously to adults and rectally to children. Acetaminophen was given intravenously or rectally (children aged < 15 yr) if additional analgesic support was requested by the patient. Additional acetaminophen consumption was recorded daily. Pain scores were assessed on every patient with the use of a visual analogue scale (VAS) at rest, 1, 5, 9, 13, 17, 21 and 36 h after surgery, and also on swallowing during the first postoperative day. Results : Global VAS pain scores were lower in the groups treated with bupivacaine infiltration during the first 24 h after surgery (P < 0.05). Supplementary analgesic consumption was lower in group 3 than in group 2 during the 0–9 h interval immediately following surgery (P < 0.05). There were no statistically significant differences for any other parameters between the 3 groups. Conclusion : These results suggest that the timing of peritonsillar infiltration with bupivacaine is not of clinical importance and does not affect the quality of postoperative analgesia in patients undergoing tonsillectomy.     

Effects of intrathecal clonidine on duration of bupivacaine spinal anaesthesia, haemodynamics, and postoperative analgesia in patients undergoing knee arthroscopy

Clonidine, an alpha–2–adrenergic agonist, may have a clinically relevant analgesic action but also a hypotensive action, when administered spinally. In this study, therefore, the analgesic and circulatory effects of intrathecal clonidine were studied in patients undergoing knee arthroscopy under spinal anaesthesia. Forty ASA I–II patients were randomly divided to two groups. One group received clonidine 3 μg–kg^-1 mixed with 15 mg 0.5% bupivacaine and the other group an identical saline volume mixed with bupivacaine as above, in a double–blind fashion. Sensory analgesia, blood pressure, heart rate and sedation were followed during and after the operation. Oxycodone 0.14 mg– kg"' i.m. or ketoprofen 100 mg p.o. was administered when needed. The duration of sensory analgesia (until regression of the block to L2) was longer in the clonidine group (mean 217 min) than in the control group (mean 160 min) ( P < 0.05). Duration of motor blockade was also longer in the clonidine group (mean 215 min) compared to the control group (161 min) ( P < 0.05). Mean arterial pressure and heart rate were significantly lower in the clonidine group compared to the control group. The clonidine patients needed fewer supplemental doses of oxycodone (8 doses) than those in the control group (16 doses) ( P < 0.05). More patients in the clonidine group were sedated 3–6 h after the injection ( P < 0.05). Addition of clonidine prolonged the bupivacaine spinal block. However, marked haemodynamic changes and sedation may limit the usefulness of intrathecal clonidine.     

Does epidural sufentanil provide effective analgesia per-and postoperatively for abdominal aortic surgery?

To assess the efficacy of epidural sufentanil in providing per-and postoperative analgesia, 40 patients undergoing elective abdominal aortic surgery received either 50 μg sufentanil in 10 ml normal saline solution (n=20, ES group) or 10 ml normal saline (n=20, control group) via a thoracic epidural catheter. The study solution was given (double-blind and at random) after the patients had been anaesthetized with i.v. midazolam, sufentanil and vecuronium. Anaesthesia was maintained with 60% nitrous oxide in oxygen and halothane at a 1% inspiratory concentration. When patients showed signs of inadequate analgesia, supplementary doses of 25 μg sufentanil were given i.v. The number of patients requiring additional i.v. sufentanil differed significantly between the two groups: 5 out of 20 patients in the ES group vs 13 out of 20 patients in the control group required additional sufentanil (P<0.05). The mean dose administered i.v. did not differ significantly between the two groups: 105±109.5 μg vs 138.5±126.9 μg (mean±SD) in 5 and 13 patients, respectively. No cardiovascular changes were observed after the epidural bolus dose.
Postoperative analgesia, consisting of a continuous epidural infusion of 50 μg sufentanil in 50 ml bupivacaine 0.125% at a rate of 6–10 ml/h after a bolus dose of 10 ml of this solution, was adequate in the majority of patients, as determined by VAS-scores assessed during the epidural treatment (4.3±1.5 days).     

Comparison of parenteral diclofenac and ketoprofen for postoperative pain relief after maxillofacial surgery

Non-steroidal anti-inflammatory drugs (NSAID) effectively reduce the need for opioid analgesia after various types of surgery. The efficacy of diclofenac and ketoprofen to relieve pain after maxillofacial surgery was compared in the present study. In a randomized and double-blind fashion, 90 ASA I–II patients (16–60 yrs) were studied, divided into three groups: Thirty patients received 1.0 mg · kg^?1 diclofenac i.v. after general anaesthesia induction, before surgical incision, and four hours later the same dose was given i.m. Thirty patients received ketoprofen 1.35 mg · kg^?1 i.v. and i.m., as above, and a third group of 30 patients received a comparable volume of saline i.v. and i.m. The patients received supplemental analgesia using a patient controlled analgesia apparatus; the rescue medication consisted of 0.03 mg · kg^?1 oxycodone i.v. (four-hour maximum dose was 0.4 mg · kg^?1) during the 24-hour follow-up. The three groups were comparable regarding the type of maxillofacial surgery (osteotomies vs. soft tissue surgery). Overall, there was a lower need for i.v. oxycodone during the 24-hour period in the diclofenac group (269 doses) than in the ketoprofen group and in the saline group (388 doses, each) (P<0.01). The significantly lower number of oxycodone administrations in the diclofenac group was a result of a distinguishable difference, particularly during the first four hours after surgery. There was no statistically significant difference in the incidence of side effects of the analgesic therapy between the three groups.     

Intraoperative epidural blockade prevents the increase in protein breakdown after abdominal surgery

BACKGROUND: The aim of this study was to investigate the effect of epidural blockade with bupivacaine, restricted to the intraoperative period, on protein catabolism after major abdominal surgery. METHODS: Fourteen patients undergoing cystoprostatectomy were randomly assigned to receive either general anaesthesia with isoflurane (control group, n=7) or a combination of general anaesthesia and epidural blockade with bupivacaine from segment T4 to S5 (epidural group, n=7). Rates of urea (Ra urea) and glucose production (Ra glucose) were measured three days before and three days after the operation using stable isotope tracers ([15N2]urea, [6,6-2H2]glucose). Protein breakdown was calculated from the urea production rate. Plasma concentrations of metabolic substrates (urea, glucose, lactate, glycerol, amino acids) and hormones (insulin, glucagon, cortisol, adrenaline, noradrenaline) were also determined. RESULTS: Protein breakdown significantly increased after surgery in the control group (P<0.05), while it remained unaltered in the epidural group (control; 66 (54-76), epidural; 43 (29-58) mg x kg(-1) x h(-1), P<0.05, median (range)). Glucose plasma concentration and Ra glucose increased in both groups to a similar extent (P<0.05). Plasma concentration of branched chain amino acids decreased after epidural analgesia to a value significantly lower than in the control group (P<0.05). Glutamine plasma concentration decreased in the control group (P<0.05), but did not change in the epidural group. There were no differences in plasma concentrations of insulin, cortisol and catecholamines between the two groups. Glucagon plasma concentration in the epidural group was significantly lower than in the control group (P<0.05). CONCLUSION: Intraoperative epidural blockade inhibits the increase in protein breakdown after abdominal surgery.     

Introducing epidural fentanyl for on-ward pain relief after major surgery

Background: Epidural opioids have been recommended for analgesia after major surgery. In this report we describe how we introduced a low-cost, on-ward, nurse-based acute pain service using epidural fentanyl after major surgery in the University Hospitals of Oulu and Kuopio.
Methods: In order to evaluate the feasibility of epidural fentanyl infusion administered by ward nurses, we prospectively assessed pain and side effects during fentanyl infusion (median duration 41 h) after major surgery in 305 consecutive patients in Kuopio.
Results: 92% of the patients on the ward who had received epidural fentanyl infusion at 31–54 μg h^-1 reported at most three episodes of severe pain (/ Numerical Rating Scale > 3/10) during the initial postoperative days, but there were some patients (8%) who reported several episodes (>3) of more severe pain (Numerical Rating Scale > 3). Three patients (0.9%) showed a diminished respiratory rate (<10/min), but only one of them (0.3%) was somnolent. One other patient (0.3%) was not arousable until the cessation of infusion. Nausea and pruritus were minor problems in our patients, but a majority needed a urinary catheter.
Conclusion: With well-trained nurses, careful monitoring and appropriate protocols, epidural fentanyl infusion proved to be a feasible method for pain relief after major surgery on a surgical ward.     

Continuous epidural analgesia with bupivacaine-fentanyl versus patient-controlled analgesia with i.v. morphine for postoperative pain relief after knee ligament surgery

BACKGROUND: Both epidural analgesia and intravenous patient-controlled analgesia (PCA) have been found efficacious after various types of surgery. We compared the efficacy, safety, side effects and patient satisfaction of these methods in a randomized double-blind fashion after elective anterior cruciate ligament reconstruction of the knee. METHODS: Fifty-six patients had an epidural catheter placed at the L2-L3 interspace. Spinal anaesthesia with 15 mg of plain bupivacaine 5 mg/ml was performed at the L3-L4 interspace. After surgery the patients were randomly divided into three groups: 19 received a continuous epidural infusion with bupivacaine 1 mg/ml and fentanyl 10 mg/ml (F10), 19 patients received bupivacaine 1 mg/ml and fentanyl 5 microg/ml (F5) and 18 patients received saline (S). The rate of the epidural infusions was 0.1 ml kg(-1) h(-1). Each patient could also use an intravenous (i.v.) PCA device with 40 microg/kg bolus doses of morphine with a lockout period of 10 min and a maximum dose 240 microg kg(-1) h(-1). At the end of surgery ketoprofen 100 mg i.v. was given and continued orally three times a day. Patients were assessed for pain with a visual analogue scale (VAS) at rest and during activity, side effects and satisfaction at 3, 9 and 20 h. RESULTS: Both epidural infusions (F10, F5) provided better analgesia than epidural saline plus i.v. PCA (S) (P<0.05). There was slightly less nausea in the S group (NS). In spite of the difference in the quality of pain relief, there was no difference between the groups in patient satisfaction regarding analgesic therapy. CONCLUSION: Epidural infusion of fentanyl (1 microg kg(-1) h(-1) or 0.5 microg kg(-1) h(-1)) and bupivacaine (0.1 mg kg(-1) h(-1)) provided better pain relief but more side effects than intravenous morphine patient-controlled analgesia after knee ligament surgery. Almost all patients in all groups were satisfied with their pain relief.     

Exaggerated epidural blockade resulting from unusual spread of bupivacaine in a patient with low back pain

A 75-year-old woman with chronic low back pain was given bupivacaine and methylprednisolone epidurally through a catheter in the L1-L2 interspace. An unusual spread of bupivacaine resulted in a block from the C4 to the L1 dermatome with no relief of back pain. Injection of a radiopaque dye and subsequent X rays showed a similar spread. The possible causes are discussed.     

The effect of a priming epidural injection of adrenaline on epidural blockade with bupivacaine

Twenty-four patients receiving epidural anaesthesia were studied to test the hypothesis that 1:200,000 adrenaline administered into the epidural space 5 minutes before 20 ml bupivacaine 0.5% would improve nerve block and delay systemic absorption of the local anaesthetic. Group A/B received 20 ml adrenaline 1:200,000 5 minutes before 20 ml bupivacaine 0.5%, group S/BA 20 ml saline followed by 20 ml bupivacaine 0.5% with 100 micrograms adrenaline, and group S/B saline 20 ml followed by 20 ml plain bupivacaine 0.5%. Mean maximum plasma concentrations of bupivacaine tended to be lower in the adrenaline groups. A delay in the time to peak plasma concentration of bupivacaine was noted in the A/B group; this indicated that priming with adrenaline may be effective at delaying early systemic uptake of the local anaesthetic. In both adrenaline groups a more prolonged epidural block and increased efficacy were noted, although this was only significant for the duration of block at T6 (p = 0.023) and duration of motor block at Bromage level 1 (p = 0.016) in group A/B. There seems little clinical advantage in administering adrenaline 5 minutes before bupivacaine.     

Effects of thoracic vs. lumbar epidural anaesthesia on systemic haemodynamics and coronary circulation in sevoflurane anaesthetized dogs

Background : Although many investigators reported changes in coronary circulation during thoracic epidural anaesthesia (TEA), no previous studies have attempted to compare it with lumbar epidural anaesthesia (LEA) concerning coronary circulation. Our aim was to compare effects of TEA on systemic haemodynamics and coronary circulation with those of LEA in anaesthetized dogs. Methods : In dogs receiving 1.5% sevoflurane, 2% lidocaine (0.1 ml kg^?1)was injected into the epidural space via an epidural catheter inserted at either the T7-T8 (TEA group, n=8) or L5-L6 (LEA group, n=8) interspace, and the same dose was repeated again 30 min later. Results : Heart rate and maximum left ventricular dP/dt decreased in the TEA group but were unchanged in the LEA group. Decreases in mean arterial pressure were found for both groups, and they were more substantial in the TEA than in the LEA group. Decreases in left ventricular minute work index were found for both groups, and they tended to be more substantial in the TEA than in the LEA group. Coronary perfusion pressure and blood flow decreased in both groups. Calculated coronary vascular resistance increased in the TEA group but was unchanged in the LEA group. Conclusion : The most significant difference between TEA and LEA concerning coronary circulation was characterized by an increase in coronary vascular resistance in the TEA group, which was not present in the LEA group. The increase in coronary vascular resistance caused by TEA may be explained by a coronary vasoconstriction caused by a lower myocardial oxygen demand.     

开胸手术后患者肋间神经冷冻镇痛与硬膜外镇痛对凝血功能的影响

目的 比较肋间神经冷冻镇痛和硬膜外术后镇痛对开胸手术患者凝血功能的影响。方 法46例I～Ⅲ级择期行开胸手术的患者,随机分为硬膜外镇痛组(E组,24例)和肋间神经冷冻镇 痛组(C组,22例)。分别于麻醉诱导前(T0)、术毕(T1)、术后1d(T3)、3 d(T3)、5 d(T4)抽取静脉血进行 血栓弹性描记图检测[包括R—time(反应时间)、K—time(凝血时间)、α角、MA(血栓最大幅度)、CI(凝血 指数)]和凝血功能筛选检测[包括凝血酶原时间(PT)、部分凝血酶原时间(APTT)、纤维蛋白原(FIB)], 并于术后4、24、48、72 h采用数字评分法(NRS)进行疼痛评分。术后7～10 d行双下肢B超检查,检测 深静脉血栓形成情况。结果两组间NRS评分差异无统计学意义(P>0．05)。与术前相比,两组T3,4 时K—time缩短,MA、α角增大,FIB升高,T2～4时R—time缩短,CI增大;与E组比较,C组T2-4时CI升高, T3,4时FIB升高(P<0．05),术后各时点PT、APTT差异无统计学意义。两组深静脉血栓形成率[C组 (3／20)、E组(1／20)]比较差异无统计学意义。结论 肋间神经冷冻镇痛和硬膜外镇痛对开胸手术患 者均能产生良好的术后镇痛效果,但与肋间神经冷冻镇痛相比,硬膜外镇痛能降低术后高凝状态。     

Continuous epidural infusion of bupivacaine and morphine for postoperative analgesia after hysterectomy

The analgesic efficacy and side-effects of combined epidural infusion of bupivacaine and morphine, in comparison with these drugs alone, for postoperative analgesia after hysterectomy (60 patients) were evaluated. Before general anaesthesia, all patients had an epidural catheter placed (Th11-12) and 20 ml of 0.5%, bupivacaine was injected. In random order, epidural infusion was continued for 24 h with either 0.25% bupivacaine 4 ml.h-1 (BUPI-group), a bolus of 2 mg of morphine followed by morphine 0.2 mg.h-1 (MO-group), or a combination of the two drugs (COMB-group). A urinary bladder catheter was kept for 24 h. Supplementary postoperative pain medications were i.m. morphine 0.1 mg.kg-1 or rectal indomethacin 50 mg, on request. Immediately after awakening from general anaesthesia and transfer to the recovery room, 18/20 of the BUPI-group patients, 17/20 of the MO-group patients and 19/20 of the COMB-group patients were pain-free. In the postoperative evening and the first postoperative morning, the corresponding figures were 7/20 and 10/20 in the BUPI-group, 15/20 and 15/20 in the MO-group, and 18/20 and 15/20 in the COMB-group (postop, evening; P less than 0.01 BUPI vs. others). The number of patients requiring supplementary analgesics (morphine and indomethacin during the first 24 h was greatest in the BUPI-group P less than 0.01). The number of patients who vomited during the 24-h period was 3 in the BUPI-group, 9 in the MO-group and 5 in the COMB-group.(ABSTRACT TRUNCATED AT 250 WORDS)