A comparison of 0.1% and 0.2% ropivacaine and bupivacaine combined with morphine for postoperative patient-controlled epidural analgesia after major abdominal surgery

Does epidural morphine loading in addition to thoracic epidural analgesia benefit the postoperative management of morbidly obese patients undergoing open bariatric surgery? A pilot study

BACKGROUND

Insufficient data exist regarding postoperative thoracic epidural analgesia for morbidly obese patients undergoing open bariatric surgery. This study evaluated the effectiveness of morphine loading in a postoperative thoracic epidural analgesic regimen of patient-controlled epidural analgesia (PCEA) with levobupivacaine combined with continuously administered epidural morphine in this patient group.

METHODS

In this prospective randomized controlled trial, 48 superobese patients (body mass index of ≥ 50 kg/m(2)) undergoing open bariatric surgery were randomly allocated to three groups of 16 patients each. Postoperatively, all groups received a continuous epidural morphine infusion of 0.2 mg/h with 0.1 % levobupivacaine via PCEA. Group A did not receive intraoperative epidural morphine loading, while groups B and C received an intraoperative 1- and 2-mg morphine bolus, respectively. Levobupivacaine consumption via PCEA (primary outcome), pain scores at rest and on cough, the time to return of bowel function and ambulation, and arterial blood gas levels (secondary outcomes) were recorded.

RESULTS

The increase in perioperative morphine administration (groups B and C) led to a significantly prolonged return to normal bowel function and delayed ambulation (P<0.05 to 0.01, respectively), without an improvement in postoperative analgesia or a reduction in local anesthetic consumption. Although the prevalence of obstructive sleep apnea (OSA) was high in all groups, no respiratory depression was observed.

CONCLUSIONS

Thoracic PCEA with 0.1 % levobupivacaine combined with continuous epidural morphine administration of 0.2 mg/h without morphine loading is an effective postoperative analgesic regimen that provides adequate pain control, early ambulation, and early return of bowel function in superobese patients, particularly those with OSA.

Epidural ropivacaine -- where are the benefits? A prospective, randomized, double-blind trial in patients with retropubic prostatectomy

BACKGROUND

In comparison with bupivacaine, ropivacaine exhibits comparable anaesthetic effects but with less motor impairment and systemic toxicity. However, the analgesic potency may differ. For example, ropivacaine during obstetric epidural analgesia provides an approximately 40% lower analgesic potency than bupivacaine. Equal visual analogue pain scores require significantly higher dosages of ropivacaine, and general statements about a favourable benefit-risk profile relative to that of bupivacaine may therefore have limited clinical impact. We addressed this topic in a male pain model by evaluating the analgesic efficacy of epidural ropivacaine 0.2% vs. bupivacaine 0.125% after retropubic prostatectomy.

METHODS

Forty patients scheduled for retropubic prostatectomy were randomly assigned to two groups (20 patients per group). In a double-blind prospective design, patient-controlled lumbar epidural analgesia was provided by ropivacaine 0.2% in the ropivacaine group and by bupivacaine 0.125% in the bupivacaine group. The primary endpoint was the total amount of local anaesthetic consumption. The secondary endpoints were the numeric rating scale scores for rest and dynamic pain and the degree of motor impairment.

RESULTS

Ropivacaine consumption was 60% higher (mean +/- standard deviation, 1372.5 +/- 108.3 mg) than that of bupivacaine (852 +/- 75.2 mg) (P < 0.001). There were no significant differences in the numeric rating scale scores and motor impairment.

CONCLUSIONS

In male patients, lumbar epidural administration of ropivacaine 0.2% after retropubic prostatectomy does not appear to provide benefits over bupivacaine 0.125%. Moreover, in view of the significantly higher drug requirements, general statements focusing on the favourable therapeutic index of ropivacaine may require critical analysis, at least during epidural administration.

Low vs. high concentration of levobupivacaine for post-operative epidural analgesia: influence of mode of delivery

BACKGROUND

Although the use of continuous epidural infusion (CEI) and patient-controlled epidural analgesia (PCEA) has become commonplace in pain management, there is still controversy regarding the relative effects of mass, volume and concentration of the local anaesthetic. This prospective study evaluated the influence of two concentrations of levobupivacaine on the quality of analgesia in two modes of delivery after lower abdominal surgery.

METHODS

Eighty-two patients were randomly assigned to four groups to receive combined low thoracic epidural analgesia and general anaesthesia followed by post-operative CEI or PCEA using 1.5 or 5 mg/ml levobupivacaine (15 mg/h in CEI and bolus 5 mg, lockout 20 min in PCEA). Sensory block, pain scores, levobupivacaine and rescue morphine consumption, motor blockade, haemodynamics, side-effects and patient satisfaction were registered within 48 h.

RESULTS

The four groups were similar with regard to demographics, quality of analgesia, morphine consumption and satisfaction rate. No difference in the quality of analgesia was observed for the two modes of delivery with regard to the concentration of levobupivacaine, but the consumption of the local anaesthetic was higher in the CEI groups. The Bromage scores in the PCEA groups were reduced to zero for all except one patient, whereas eight patients presented scores of one or more in the CEI population.

CONCLUSION

Levobupivacaine in thoracic epidurals provides an equal quality of post-operative analgesia in low and high volume independent of the delivery mode, i.e. CEI or PCEA. This is in accordance with the assumption that the total dose of the local anaesthetic determines the quality of analgesia.

Ropivacaine: a review of its use in regional anaesthesia and acute pain management

Ropivacaine (Naropin) is the pure S(-)-enantiomer of propivacaine, and is a long-acting amide local anaesthetic agent, eliciting nerve block via reversible inhibition of sodium ion influx in nerve fibres. Ropivacaine is a well tolerated regional anaesthetic effective for surgical anaesthesia as well as the relief of postoperative and labour pain. The efficacy of ropivacaine is similar to that of bupivacaine and levobupivacaine for peripheral nerve blocks and, although it may be slightly less potent than bupivacaine when administered epidurally or intrathecally, equi-effective doses have been established. Clinically adequate doses of ropivacaine appear to be associated with a lower incidence or grade of motor block than bupivacaine. Thus ropivacaine, with its efficacy, lower propensity for motor block and reduced potential for CNS toxicity and cardiotoxicity, appears to be an important option for regional anaesthesia and for the management of postoperative and labour pain.

Postoperative extradural analgesia with morphine and ropivacaine. A double-blind comparison between placebo and ropivacaine 10 mg/h or 16 mg/h

BACKGROUND

Some controversy exists in the literature on the benefit of epidurals compared to patient-controlled intravenous analgesia (PCA). Also, the dose of ropivacaine for epidural analgesia when combined with morphine remains uncertain. The aim of this study was to compare the epidural vs. PCA technique and high-dose vs. low-dose ropivacaine combined with morphine during knee replacement surgery.

METHODS

In this prospective, randomized, double-blind study, postoperative pain relief with a combination of epidural ropivacaine (Group L: 10 mg h-1, Group H: 16 mg h-1) and morphine (0.16 mg h-1) was evaluated in 30 patients. A placebo group (Group PL) of 15 patients having PCA morphine served as the control. Visual analog pain (VAS), morphine consumption, sensory and motor block and side-effects were recorded during 48 h.

RESULTS

VAS scores at rest were significantly lower in Groups L and H compared to Group PL. On movement, Group H had lower VAS scores than Group PL during 3-27 h (P<0.05) and Group L during 4-9 h (P<0.05), while Group L had lower a VAS than Group PL during 9-18 h (P<0.05). Morphine consumption after 48 h was greater in Group PL (64.6+/-36.3 mg) vs. Group L (23.3+/-33.9 mg) (P<0.001) and Group H (4.3+/-9.6 mg) (P<0.0001). Mild motor block was seen in Group H in 20% and 14% patients at 24 h and 48 h, respectively, but time to mobilization was similar between the groups. Pruritus was more common in the ropivacaine groups (P<0.05).

CONCLUSION

Lumbar epidural analgesia using a combination of ropivacaine (16 mg h-1) and morphine (0.16 mg h-1) provides superior analgesia compared to the PCA technique or ropivacaine (10 mg h-1) and morphine (0.16 mg h-1). Although this resulted in a mild motor block during the first 12 h, patient mobilization was similar in all groups.

The central nervous system and cardiovascular effects of levobupivacaine and ropivacaine in healthy volunteers

We compared the central nervous system (CNS) and cardiovascular effects of levobupivacaine and ropivacaine when given IV to healthy male volunteers (n = 14) in a double-blinded, randomized, crossover trial. Subjects received levobupivacaine 0.5% or ropivacaine 0.5% after a test infusion with lidocaine to become familiar with the early signs of CNS effects (e.g., tinnitus, circumoral paresthesia, hypesthesia). The development of CNS symptoms was assessed at 1-min intervals and study drug administration was terminated when the first CNS symptoms were recognized. Thereafter, symptoms were recorded at 1-min intervals until symptom resolution. Hemodynamic variables were assessed by transthoracic electrical bioimpedance. Continuous 12-lead electrocardiogram monitoring was also performed. There was no significant difference between levobupivacaine and ropivacaine for: the mean time to the first onset of CNS symptoms (P = 0.870), mean total volume of study drug administered at the onset of the first CNS symptom (P = 0.595), stroke index (P = 0.678), cardiac index (P = 0.488), acceleration index (P = 0.697), PR interval (P = 0.213), QRS duration (P = 0.637), QT interval (P = 0.724), QTc interval (P = 0.737), and heart rate (P = 0.267). Overall, fewer CNS symptoms were reported for levobupivacaine than ropivacaine (218 versus 277). This study found that levobupivacaine and ropivacaine produce similar CNS and cardiovascular effects when infused IV at equal concentrations, milligram doses, and infusion rates.

IMPLICATIONS

This study compared directly, for the first time, the toxicity of levobupivacaine and ropivacaine in healthy volunteers. Levobupivacaine and ropivacaine produced similar central nervous system and cardiovascular effects when infused IV at equal concentrations, milligram doses, and infusion rates.