Randomized double-blind comparison of ropivacaine-fentanyl and bupivacaine-fentanyl for spinal anaesthesia for urological surgery

Intrathecal ropivacaine versus bupivacaine in a non-obstetric population- A meta-analysis and trial sequential analysis

Background and Aims

Intrathecal bupivacaine is used for anaesthesia and analgesia but is associated with hypotension. Ropivacaine is an alternative drug that may have fewer cardiotoxic and neurotoxic events. This meta-analysis investigated whether intrathecal ropivacaine is associated with reduced hypotension as compared to bupivacaine.

Methods

The meta-analysis is registered in the International Prospective Register of Systematic Reviews (PROSPERO). The databases PubMed, Cinahl Plus, Google Scholar, and Scopus were searched, and papers from January 1980 to January 2023 were deemed eligible and filtered using predetermined inclusion and exclusion criteria. The primary outcome was the incidence of hypotension. Secondary outcomes were the duration of sensory block, duration of motor block, incidence of bradycardia, ephedrine usage, and duration of analgesia. Jadad scores were used to evaluate the quality of the papers. RevMan statistical software® utilised inverse variance and a random effect model to calculate the standardised mean difference with 95% confidence intervals for continuous variables and the Mantel-Haenszel test and the random effect model to calculate the odds ratio for dichotomous variables.

Results

Thirty-three papers, including 2475 patients in total, were included. The Jadad score was between 1 and 5. The incidence of hypotension was significantly higher with intrathecal bupivacaine than with ropivacaine (P = 0.02). The duration of sensory block (P < 0.001) and motor block (P < 0.001) was prolonged with intrathecal bupivacaine. The duration of analgesia favoured intrathecal bupivacaine (P = 0.003).

Conclusion

Intrathecal ropivacaine has a reduced incidence of hypotension and a reduced duration of sensory block compared to bupivacaine.

Effect of intrathecal lipophilic opioids on the incidence of shivering in women undergoing cesarean delivery after spinal anesthesia: a systematic review and bayesian network meta- analysis of randomized controlled trials

Background

Shivering is a common side effect in women having cesarean delivery (CD) under spinal anesthesia, which can be bothersome to the patient, and it can also interfere with perioperative monitoring. In several studies, the intrathecal (IT) addition of a lipophilic opioid to local anesthetics has been shown to decrease the incidence of shivering.

Objective

We performed this network meta-analysis to evaluate the effects of intrathecal lipophilic opioids in preventing the incidence of shivering in patients undergoing CD.

Methods

This review was planned according to the PRISMA for Network Meta-Analysis (PRISMA-NMA) guidelines. An English literature search of multiple electronic databases was conducted. We included randomized controlled trials (RCTs) that reported on the incidence of shivering, with study groups receiving either IT fentanyl, sufentanil, or meperidine in women undergoing CD under spinal anesthesia. Quality of the studies was assessed using the modified Oxford scoring system. Using random-effects modeling, dichotomous data were extracted and summarized using odds ratio (OR) with a 95% credible interval (CrI). Statistical analysis was conducted using R studio version 1.0.153 - Inc.

Results

Twenty-one studies consisting of 1433 patients (Control group: 590 patients in twenty-one studies; Fentanyl group:199 patients in seven studies; Sufentanil group: 156 patients in five studies; Meperidine group: 488 patients in ten studies) met the inclusion criteria for this systematic review investigating the effect of intrathecal lipophilic opioids in preventing the incidence of shivering in women undergoing cesarean delivery under spinal anesthesia. Methodological validity scores ranged from 3 to 7. The Bayesian mixed network estimate showed the incidence of shivering was significantly lower with IT fentanyl (pooled odds ratio (OR): 0.13; 95% credible interval (CrI): 0.04 to 0.35; P = 0.0004) and IT meperidine (OR: 0.12; 95% CrI: 0.05 to 0.29; P < 0.00001), but not with IT sufentanil (OR: 0.37; 95% CrI: 0.11 to 1.22; P = 0.23). The IT fentanyl group had a significantly lower incidence of intraoperative discomfort [Risk Ratio (RR): 0.19; 95% CI: 0.10–0.35; P < 0.00001], the IT sufentanil group had a significantly higher incidence of pruritus (RR: 6.18; 95% CI: 1.18–32.46; P = 0.03) The IT meperidine group had a significantly lower incidence of intraoperative discomfort (2.7% vs. 13.6%; RR: 0.22; 95% CI: 0.09–0.55; P = 0.001), but there was a significant increase in nausea and vomiting (IT meperidine group vs. Control group: 42.7% vs. 19.4%; RR: 2.56; 95% CI: 1.14–5.75; P = 0.02). Meta-regression analysis based on the opioid dose and quality of the study did not impact the final inference of our result.

Conclusion

IT fentanyl significantly decreased the incidence of shivering in women undergoing CD under spinal anesthesia without increasing maternal adverse events, confirming that routine use in this patient population is a good choice. IT sufentanil did not decrease the incidence of shivering. IT meperidine decreased the incidence and severity of shivering, but its use was also associated with significant nausea and vomiting.

ED 50 and ED 95 of intrathecal bupivacaine coadministered with sufentanil for cesarean delivery under combined spinal-epidural in severely preeclamptic patients

Background:

Spinal anesthesia was considered as a reasonable anesthetic option in severe preeclampsia when cesarean delivery is indicated, and there is no indwelling epidural catheter or contraindication to spinal anesthesia. However, the ideal dose of intrathecal bupivacaine has not been quantified for cesarean delivery for severe preeclamptic patients. This study aimed to determine the ED₅₀ and ED₉₅ of intrathecal bupivacaine for severely preeclamptic patients undergoing elective cesarean delivery.

Methods:

Two hundred severely preeclamptic patients are undergoing elective cesarean delivery under combined spinal-epidural anesthesia enrolled in this randomized, double-blinded, dose-ranging study. Patients received 4 mg, 6 mg, 8 mg, or 10 mg intrathecal hyperbaric bupivacaine with 2.5 μg sufentanil. Successful spinal anesthesia was defined as a T6 sensory level achieved within 10 minutes after intrathecal drug administration and/or no epidural supplement was required during the cesarean section. The ED₅₀ and ED₉₅ were calculated with a logistic regression model.

Results:

ED₅₀ and ED₉₅ of intrathecal bupivacaine for successful spinal anesthesia were 5.67 mg (95% confidence interval [CI]: 5.20–6.10 mg) and 8.82 mg (95% CI: 8.14–9.87 mg) respectively. The incidence of hypotension in Group 8 mg and Group 10 mg was higher than that in Group 4 mg and Group 6 mg (P < 0.05). The sensory block was significantly different among groups 10 minutes after intrathecal injection (P < 0.05). The use of lidocaine in Group 4 mg was higher than that in other groups (P < 0.05). The use of phenylephrine in Group 8 mg and Group 10 mg was higher than that in the other two groups (P < 0.05). The lowest systolic blood pressure before the infant delivery of Group 8 mg and Group 10 mg was lower than the other two groups (P < 0.05). The satisfaction of muscle relaxation in Group 4 mg was lower than other groups (P < 0.05). There was no significant difference in patients’ satisfaction and the newborns’ Apgar score and the blood gas analysis of umbilical artery serum (P > 0.05).

Conclusion:

Our study showed that the ED₅₀ and ED₉₅ of intrathecal bupivacaine for severely preeclamptic patients undergoing elective cesarean delivery were 5.67 mg and 8.82 mg, respectively. In addition, decreasing the dose of intrathecal bupivacaine could reduce the incidence of maternal hypotension.

Sparing effects of sufentanil on epidural ropivacaine in elderly patients undergoing transurethral resection of prostate surgery

PURPOSE

This study examined the sparing effect of sufentanil on the median effective concentration (EC₅₀) of epidural ropivacaine in elderly patients undergoing elective transurethral resection of prostate (TURP).

MATERIALS AND METHODS

This was a prospective randomized double-blind dose-response study. Fifty eight elderly patients with American Society of Anesthesiologists physical status I-II who were scheduled for TURP surgery under epidural anesthesia were randomly allocated to a group receiving 15 mL of ropivacaine (group R) or a group receiving ropivacaine plus 5 μg of sufentanil (group RS). The concentration of ropivacaine was determined by a Dixon's up-and-down sequential allocation. The first participant received 0.3% of ropivacaine in both groups and subsequent concentrations were determined by the response of the previous patient in the same group. The EC₅₀ of epidural ropivacaine was analyzed using the Dixon and Massey method.

RESULTS

The EC₅₀ of ropivacaine during TURP surgery was 0.186% (95% confidence interval, 0.173-0.200%) in group R, and 0.136% (95% confidence interval, 0.127-0.144%) in group RS (p<0.01). No differences in Bromage scale of motor block examination and the onset time of sensory block were observed.

CONCLUSION

Administration of 5 μg of epidural sufentanil caused a 37% reduction in the EC₅₀ of epidural ropivacaine in elderly patients who underwent TURP surgery. Thus, sufentanil addition during surgery of TURP can decrease the dose of ropivacaine anesthesia required.

Ropivacaine: Anesthetic consideration in elderly patients for transurethral resection of prostrate a clinical trial

Background:

Ropivacaine has less systemic toxicity and greater differentiation of sensory and motor blockade after subarachnoid block. This study was aimed to evaluate the anesthetic efficacy of intrathecal 0.75% isobaric ropivacaine alone or with fentanyl in elderly patients undergoing transurethral resection of prostrate.

Materials and Methods:

Fifty four elderly consented patients of ASA grade I-III scheduled for transurethral resection of prostrate under the subarachnoid block were randomized to receive either intrathecal 4 mL of 0.75% isobaric ropivacaine (Group R, n = 27) or 3.5 mL of 0.75% isobaric ropivacaine with 0.5 mL (25 μg) of fentanyl (Group RF, n = 27). The characteristics of sensory and motor blockade, intraoperative hemodynamic changes, and secondary effects were noted for evaluation.

Results:

There was no significant difference in the demographic profile of patients. The surgical anesthesia was adequate for TURP surgery in all patients. The median time to achieve the sensory blockade at T10 dermatome was 3.2 ± 1.5 min in Group R and 3.5 ± 1.3 min in Group RF. The median duration of sensory blockade at T10 was 130.6 ± 10.2 min in Group R and 175.8 ± 8.6 min in Group RF. The median duration of complete motor block was significantly shorter than the duration of sensory blockade (P < 0.001). There were fewer episodes of manageable hypotension in 5 patients of Group R and 11 patients of Group RF. No secondary effects have occurred in any patients.

Conclusion:

The intrathecal 0.75% isobaric ropivacaine alone or with fentanyl has provided effective surgical anesthesia for transurethral resection of prostrate and hemodynamic stability in elderly patients.

Update on the clinical utility and practical use of ropivacaine in Chinese patients

We reviewed the Chinese and English literature for efficacy and tolerability data as well as pharmacological properties of ropivacaine in Chinese patients. Ropivacaine is a long-acting amide local anesthetic agent that elicits nerve block via reversible inhibition of sodium ion influx in nerve fibers. The available evidence in the literature on anesthesia practice indicates that ropivacaine produces equally surgical sensory block and postoperative and obstetrics analgesia with good maternal and fetal outcome to those of bupivacaine or levobupivacaine. It appears to be associated with comparable onset, quality, and duration of sensory block, but with a lower incidence or grade of motor block, compared to bupivacaine. The satisfaction of both patients and surgeons is high when ropivacaine is used. Thus, ropivacaine appears to be an important option for regional anesthesia and for the management of postoperative and labor pain, with its enhanced sensorimotor differentiation blockage at lower concentrations and enhanced safety at higher concentrations.

Comparison of intrathecal ropivacaine-fentanyl and bupivacaine-fentanyl for major lower limb orthopaedic surgery: A randomised double-blind study

Background and Aims:

Intrathecal bupivacaine results in complete anaesthetic block of longer duration than ropivacaine. Fentanyl as an adjuvant may improve the quality of spinal block of ropivacaine while maintaining its advantage of early motor recovery. In this study, we proposed to compare the efficacy and safety of intrathecal ropivacaine-fentanyl (RF) with bupivacaine-fentanyl (BF) for major lower limb orthopaedic surgeries.

Methods:

Sixty patients were randomly allocated to receive either intrathecal 15 mg 0.5% ropivacaine with 25 mcg fentanyl (Group RF) or 15 mg 0.5% bupivacaine with 25 mcg fentanyl (Group BF). The onset, duration, spread of sensory and motor block, haemodynamic parameters and side effects were recorded. Statistical Package for Social Sciences 20 software was used for statistical analysis.

Results:

Time to reach highest sensory level and complete motor block were comparable. Sensory regression to L1 dermatome was 226 ± 46.98 min in Group RF and 229.33 ± 50.51 min in Group BF, P = 0.36. The motor recovery to Bromage scale 1 was faster in Group RF (242.8 ± 47.06 min) than Group BF (268 ± 49.9 min) P = 0.023. Time for rescue analgesia was prolonged in Group BF (263.33 ± 63 min) when compared to Group RF (234.44 ± 58.76 min), P = 0.021. The haemodynamic stability was better in Group RF than Group BF.

Conclusion:

Intrathecal RF provided satisfactory anaesthesia with haemodynamic stability for major lower limb orthopaedic surgery. It provided similar sensory but shorter duration of motor block compared to BF which is a desirable feature for early ambulation, voiding and physiotherapy.

Drug therapy for preventing post-dural puncture headache

BACKGROUND

Post-dural (post-lumbar or post-spinal) puncture headache (PDPH) is one of the most common complications of diagnostic, therapeutic or inadvertent lumbar punctures. Many drug options have been used to prevent headache in clinical practice and have also been tested in some clinical studies, but there are still some uncertainties about their clinical effectiveness.

OBJECTIVES

To assess the effectiveness and safety of drugs for preventing PDPH in adults and children.

SEARCH METHODS

The search strategy included the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2012, Issue 5), MEDLINE (from 1950 to May 2012), EMBASE (from 1980 to May 2012) and CINAHL (from 1982 to June 2012). There was no language restriction.

SELECTION CRITERIA

We considered randomised controlled trials (RCTs) that assessed the effectiveness of any drug used for preventing PDPH.

DATA COLLECTION AND ANALYSIS

Review authors independently selected studies, assessed risks of bias and extracted data. We estimated risk ratios (RR) for dichotomous data and mean differences (MD) for continuous outcomes. We calculated a 95% confidence interval (CI) for each RR and MD. We did not undertake meta-analysis because participants' characteristics or assessed doses of drugs were too different in the included studies. We performed an intention-to-treat (ITT) analysis.

MAIN RESULTS

We included 10 RCTs (1611 participants) in this review with a majority of women (72%), mostly parturients (women in labour) (913), after a lumbar puncture for regional anaesthesia. Drugs assessed were epidural and spinal morphine, spinal fentanyl, oral caffeine, rectal indomethacin, intravenous cosyntropin, intravenous aminophylline and intravenous dexamethasone.All the included RCTs reported data on the primary outcome, i.e. the number of participants affected by PDPH of any severity after a lumbar puncture. Epidural morphine and intravenous cosyntropin reduced the number of participants affected by PDPH of any severity after a lumbar puncture when compared to placebo. Also, intravenous aminophylline reduced the number of participants affected by PDPH of any severity after a lumbar puncture when compared to no intervention, while intravenous dexamethasone increased it. Spinal morphine increased the number of participants affected by pruritus when compared to placebo, and epidural morphine increased the number of participants affected by nausea and vomiting when compared to placebo. Oral caffeine increased the number of participants affected by insomnia when compared to placebo.The remainder of the interventions analysed did not show any relevant effect for any of the outcomes.None of the included RCTs reported the number of days that patients stayed in hospital.

AUTHORS' CONCLUSIONS

Morphine and cosyntropin have shown effectiveness for reducing the number of participants affected by PDPH of any severity after a lumbar puncture, when compared to placebo, especially in patients with high risk of PDPH, such as obstetric patients who have had an inadvertent dural puncture. Aminophylline also reduced the number of participants affected by PDPH of any severity after a lumbar puncture when compared to no intervention in patients undergoing elective caesarean section. Dexamethasone increased the risk of PDPH, after spinal anaesthesia for caesarean section, when compared to placebo. Morphine also increased the number of participants affected by adverse events (pruritus and nausea and vomiting)There is a lack of conclusive evidence for the other drugs assessed (fentanyl, caffeine, indomethacin and dexamethasone).These conclusions should be interpreted with caution, owing to the lack of information, to allow correct appraisal of risk of bias and the small sample sizes of studies.

Low-dose ropivacaine or levobupivacaine walking spinal anesthesia in ambulatory inguinal herniorrhaphy

PURPOSE

The purpose of our study was to compare the equipotent doses of ropivacaine and levobupivacaine for walk-out criteria and the characteristics of spinal anesthesia in inguinal herniorrhaphy surgery.

METHODS

Combined spinal-epidural anesthesia was performed. Adult patients were randomly allocated to receive 5 mg 0.5% ropivacaine plus 25 μg fentanyl (group RF, n = 25) or 3.75 mg 0.75% levobupivacaine plus 25 μg fentanyl (group LF, n = 25). Each solution was hypobaric, and the same volume, 3 ml, was administered. Sensory and motor block characteristics, hemodynamic changes, side effects, number of patients having ability to stand and walk at the end of the operation, time to first analgesic requirement, time to urination, time to getting out of bed (ambulation), and time to home discharge were determined.

RESULTS

Sensory block onset time and time to reach the T6 dermatome were significantly shorter in group LF, whereas time to the two-segment regression and time to first analgesic requirement were significantly shorter in group RF. All patients in group LF were Bromage 0. Time to home discharge was shorter in group LF, but this difference was not statistically significant.

CONCLUSION

We suggest that both local anesthetics can be used in walking spinal technique. Levobupivacaine may be an alternative local anesthetic for walking spinal anesthesia as it provides minimum motor block and a long duration of postoperative analgesia, even if its use is not associated with a shorter home discharge time.

Intrathecal sufentanil decreases the median effective dose (ED50) of intrathecal hyperbaric ropivacaine for caesarean delivery

BACKGROUND

The addition of opioid to local anaesthetics has become a well-accepted practice of spinal anaesthesia for caesarean delivery. Successful caesarean delivery anaesthesia has been reported with the use of a low dose of intrathecal hyperbaric ropivacaine coadministered with sufentanil. This prospective, double-blinded study determined the median effective dose (ED50) of intrathecal hyperbaric ropivacaine with and without sufentanil for caesarean delivery, to quantify the sparing effect of sufentanil on the ED50 of intrathecal hyperbaric ropivacaine.

METHODS

Sixty-four parturients undergoing elective caesarean delivery with combined spinal-epidural anaesthesia were randomized into two groups: Group R (ropivacaine) and Group RS (ropivacaine plus sufentanil 5 microg). The initial dose of ropivacaine was 13 mg in Group R and 10 mg in Group RS. The effective dose was defined as a T(6) level attained within 10 min and no supplemental epidural anaesthetic required during surgery. Effective or ineffective responses determined, respectively, a 0.3 mg decrease or increase of the dose of ropivacaine for the next patient using an up-down sequential allocation.

RESULTS

The ED50 of intrathecal ropivacaine was 11.2 mg [confidence interval (CI) 95%: 11.0-11.6] in Group R vs. 8.1 mg (CI 95%: 7.8-8.3) in Group RS. Motor block was markedly more intense in Group R than in Group RS, and the incidence of shivering was lower in Group RS than in Group R. There were no differences in the onset time of sensory block or motor block, in the incidence of hypotension, nausea and vomiting.

CONCLUSION

Intrathecal sufentanil 5 microg produced a 28% reduction of ED50 of intrathecal hyperbaric ropivacaine for caesarean delivery.

Comparison of equipotent doses of ropivacaine-fentanyl and bupivacaine-fentanyl in spinal anaesthesia for lower abdominal surgery

The aim of this randomised, double-blind study was to compare equipotent doses of plain ropivacaine and bupivacaine (19.5 mg and 13 mg respectively), both with fentanyl 20 microg, for spinal anaesthesia in lower abdominal surgery. After written informed consent had been obtained, 52 ASA I to II male patients scheduled for lower abdominal surgery were randomly assigned to receive intrathecal plain ropivacaine 19.5 mg with fentanyl 20 microg (group R, n =26) or plain bupivacaine 13 mg with fentanyl 20 microg (group B, n =26) in 3 ml. The level and duration of sensory block, intensity and duration of motor block, time to mobilise and patient satisfaction were recorded. All patients achieved sensory block to T10 or higher The level of sensory block was significantly higher in group B (T4 [T3 to T7] vs T7 [T4 to T9], P <0.05). There was no difference in the onset time of motor block. The duration of motor block (Bromage score >0) was shorter in group R (139+/-39 minutes vs group B 182+/-46 minutes, P <0.05). The duration and intensity of complete motor block (Bromage score=3) were also shorter in group R (90+/-25 minutes vs 130+/-40 minutes, P <0.05). We conclude that plain ropivacaine 19.5 mg plus fentanyl 20 microg is associated with a lower level of sensory block and a shorter duration of motor block when compared to bupivacaine 13 mg plus fentanyl 20 microg for spinal anaesthesia in lower abdominal surgery.

The median effective dose of bupivacaine, levobupivacaine, and ropivacaine after intrathecal injection in lower limb surgery

BACKGROUND

Intrathecal anesthesia is commonly used for lower limb surgery. Bupivacaine, levobupivacaine, and ropivacaine have all been used as intrathecal drugs, but their relative potency in this context has not been fully determined. In this study, we determined the median effective dose (ED(50)) of these three local anesthetics for intrathecal anesthesia in lower limb surgery and hence their relative potencies.

METHODS

Seventy-five patients scheduled for lower limb surgery under combined spinal-epidural anesthesia were randomly allocated to one of three groups receiving intrathecal bupivacaine, levobupivacaine, or ropivacaine. The dose of local anesthetic was varied using up-down sequential allocation technique. The dose for the first patient in each group was 8 mg, and the dosing increment was set at 1 mg. Subsequent doses in each group were determined by the outcome in the previous patient using success or failure of the spinal anesthesia as the primary end point. A success was recorded if a bilateral T12 sensory block to cold was attained within 20 min after intrathecal injection, and the surgery proceeded successfully until at least 50 min after the intrathecal injection without supplementary epidural injection. The ED(50) was calculated using the method of Dixon and Massey.

RESULTS

The ED(50)s were 5.50 mg for bupivacaine (95% confidence interval [CI]: 4.90-6.10 mg), 5.68 mg for levobupivacaine (95% CI: 4.92-6.44 mg), and 8.41 mg for ropivacaine (95% CI: 7.15-9.67 mg) in intrathecal anesthesia. The relative anesthetic potency ratios are 0.97 (95% CI: 0.81-1.17) for levobupivacaine/bupivacaine, 0.65 (95% CI: 0.54-0.80) for ropivacaine/bupivacaine, and 0.68 (95% CI: 0.55-0.84) for ropivacaine/levobupivacaine.

CONCLUSION

This study suggests that in intrathecal anesthesia for lower limb surgery, ropivacaine is less potent than levobupivacaine and bupivacaine, whereas the potency is similar between levobupivacaine and bupivacaine.

Low-dose ropivacaine-sufentanil spinal anaesthesia for caesarean delivery: a randomised trial

BACKGROUND

It is well known that intrathecal opioids have a synergic effect with spinal local anaesthetics. The aim of this study was to evaluate whether low-dose ropivacaine in combination with sufentanil could produce effective spinal anaesthesia with less maternal hypotension and vomiting than ropivacaine alone.

METHODS

80 ASA I and II parturients undergoing elective caesarean delivery under combined spinal-epidural anaesthesia were randomly allocated to two groups. Group R15 received intrathecal hyperbaric ropivacaine 15 mg and group SR10 hyperbaric ropivacaine 10 mg with sufentanil 5 micrograms. Characteristics, efficacy and side effects of spinal anaesthesia in each group were measured.

RESULTS

There was no significant difference in the quality of intraoperative analgesia and muscle relaxation between groups. The incidence of hypotension was significantly higher (55% vs. 20%, P < 0.005) and the need for ephedrine less in group R15 than in group SR10. In group SR10, the onset of motor block was delayed (2.9 +/- 1.1 vs. 4.6 +/- 2.5 min, P < 0.005), the duration was shorter (65.9 +/- 15.1 vs. 125.4 +/- 26.4 min, P < 0.005). The duration of effective analgesia was longer (260 +/- 32.5 vs. 143 +/- 22.1 min, P < 0.005), the incidence of shivering (20% vs. 60%, P < 0.005) and vomiting (5% vs. 30%, P < 0.005) were lower in group SR10.

CONCLUSIONS

The combination of hyperbaric ropivacaine 10 mg with sufentanil 5 lg produced effective spinal anaesthesia for caesarean delivery with significantly less hypotension, vomiting and shivering, shorter duration of motor blockade and longer lasting analgesia than hyperbaric ropivacaine 15 mg.

Spinal Ropivacaine for Lower Limb Surgery: A Dose–Response Study

BACKGROUND

The dose-response relationship for spinal ropivacaine in patients undergoing surgery of the lower extremity has not been fully determined.

METHODS

We performed a prospective, randomized, double-blind study of 60 patients scheduled for lower limb surgery under combined spinal-epidural anesthesia. Patients were assigned to receive 1 of 5 doses of intrathecal ropivacaine: 2, 4, 7, 10, or 14 mg diluted to 2.8 mL with normal saline. A dose was considered successful if a sensory block to cold was achieved bilaterally at the T12 dermatome within 20 min and surgery proceeded without supplementation for at least 50 min.

RESULTS

Anesthesia was successful in 0, 0, 42, 83, and 100% of the 2, 4, 7, 10, and 14 mg groups, respectively. The derived value for ED(50) was 7.6 mg (95% CI: 6.2-8.7 mg) and for ED(95) was 11.4 mg (95% CI: 9.7-18.3 mg). The cephalic level of sensory block and the degree of motor block increased with larger doses of ropivacaine.

CONCLUSION

The ED(50) and ED(95) for spinal ropivacaine in lower limb surgery of 50 min duration or less were 7.6 and 11.4 mg, respectively. This provides a useful guide for clinicians to choose the optimal dose of spinal ropivacaine under different clinical situations.

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.