Ropivacaine: an update of its use in regional anaesthesia

Effect of Dexmedetomidine as an Adjuvant to 0.75% Ropivacaine in Interscalene Brachial Plexus Block Using Nerve Stimulator: A Prospective, Randomized Double-blind Study

BACKGROUND

Ropivacaine, a newer local anesthetic (LA), has been increasingly used nowadays in different concentrations for peripheral nerve blocks. It has lesser cardiac toxicity and higher safety margin when compared to bupivacaine. Dexmedetomidine, a novel α₂ agonist, is widely used as adjuvant to LA in peripheral nerve blocks to decrease the time of onset and increase the duration of the block. In this study, we evaluated the effect of dexmedetomidine as an adjuvant with 0.75% ropivacaine for interscalene brachial plexus block using nerve stimulator.

AIM

This study aims to know the effect of using dexmedetomidine as an adjuvant to 0.75% ropivacaine in interscalene brachial plexuses block using nerve stimulator.

SETTINGS AND DESIGNS

Sixty patients scheduled for elective orthopedic surgery of the upper limb under interscalene block were considered in this prospective randomized controlled double-blind study. The study population was randomly divided into two groups with thirty patients in each group by using computerized randomization.

MATERIALS AND METHODS

Group R received 30 ml of 0.75% ropivacaine with 0.5 ml normal saline and Group RD received 30 ml of 0.75% ropivacaine with 50 μg of dexmedetomidine. The onset of sensory and motor blocks, duration of sensory and motor block, and patient satisfaction score were observed.

RESULTS

Both the groups were comparable in demographic characteristics. The onset of the sensory and motor block is earlier and statistically significant in Group RD (P < 0.05) when compared to Group R. The duration of sensory and motor blockade were significantly prolonged in Group RD (P < 0.0001).

CONCLUSION

Addition of dexmedetomidine to 0.75% ropivacaine in interscalene brachial plexus block significantly shortened the time of onset of the block and prolongs the duration sensory and motor blockade.

Ultrasound-guided continuous femoral nerve block vs continuous fascia iliaca compartment block for hip replacement in the elderly: A randomized controlled clinical trial (CONSORT)

BACKGROUND

Continuous femoral nerve block and fascia iliaca compartment block are 2 traditional anesthesia methods in orthopedic surgeries, but it is controversial which method is better. The objective of this study was to compare the practicality, efficacy, and complications of the 2 modalities in hip replacement surgery in the elderly and to assess the utility of a novel cannula-over-needle set.

METHODS

In this prospective, randomized controlled clinical investigation, 60 elderly patients undergoing hip replacement were randomly assigned to receive either continuous femoral nerve block or continuous fascia iliaca compartment block. After ultrasound-guided nerve block, all patients received general anesthesia for surgery and postoperative analgesia through an indwelling cannula. Single-factor analysis of variance was used to compare the outcome variables between the 2 groups.

RESULTS

There was a significant difference between the 2 groups in the mean visual analog scale scores (at rest) at 6 hours after surgery: 1.0 ± 1.3 in the femoral nerve block group vs 0.5 ± 0.8 in the fascia iliaca compartment block group (P < 0.05). The femoral nerve block group had better postoperative analgesia on the medial aspect of the thigh, whereas the fascia iliaca compartment block group had better analgesia on the lateral aspect of the thigh. There were no other significant differences between the groups.

CONCLUSIONS

Both ultrasound-guided continuous femoral nerve block and fascia iliaca compartment block with the novel cannula-over-needle provide effective anesthesia and postoperative analgesia for elderly hip replacement patients.

Preparation of novel biodegradable ropivacaine microspheres and evaluation of their efficacy in sciatic nerve block in mice

In this study, ropivacaine chitosan-loaded microspheres for subcutaneous administration were developed. The systems were characterized in terms of surface morphology, particle size, encapsulation efficiency, and in vitro release behavior. Results showed that the microspheres had drug loading rate of 7.3% and encapsulation efficiency of 91.2%, and their average diameter was 2.62±0.76 µm. The morphology study revealed that the microspheres are uniform monodispersed spheres and did not form aggregates in aqueous solution. It was clearly observed that the release profile of ropivacaine microspheres exhibited a biphasic pattern: the initial burst release within the first 2 hours and a following slower and sustained release over a long time. In vivo, a greater area under the plasma concentration–time curve from 0 to t (AUC_0–t) was obtained from the microspheres (4.27-fold), than from the injection group, which indicated that there was a significantly improved systemic exposure to ropivacaine. Pharmacodynamics result showed that preparing ropivacaine as microsphere preparation could not only extend the drug effect time but also decrease the administration dosage.

Echo-Guided Differential Popliteal Block in an Obese Patient With Intractable Painful Leg Ulcer for Early Discharge in Day Surgery

Pain management is extremely important in day surgery, and it is one of the limiting factors for this type of procedures. Locoregional anesthesia is strongly recommended for day surgery; nevertheless, it could be very difficult to localize nerve position especially in obese patients. Furthermore, a complete nerve blockade could result in a delayed discharge. We present a case of analgesic ultrasound-guided block of tibial and common peroneal nerves in the popliteal fossa without any motor function involvement in an obese patient undergoing debridement of an infected lower limb ulcer; all previous attempts of surgical debridement in day surgery with topical anesthetics had failed because of discomfort due to pain. Our aim was to ensure an optimal degree of analgesia and, at the same time, to save motor function in order to make early discharge possible. We used 15 mL ropivacaine 0.375% to obtain a differential block, taking advantage of sensitive fibers selectivity of ropivacaine. Surgical debridement was performed successfully. Our peripheral blockade was able to provide significantly prolonged analgesia without motor block that guaranteed a safe and early discharge according to the Post Anesthetic Discharge Scoring System. The satisfaction expressed by the patient and her comfort during the procedure support the choice of this approach for intractable painful ulcers of lower limb.

Single-dose intra-articular ropivacaine after arthroscopic knee surgery decreases post-operative pain without increasing side effects: a systematic review and meta-analysis

PURPOSE

The purpose of this study was to appraise the efficacy and safety of single-dose intra-articular ropivacaine administered for pain relief after arthroscopic knee surgery.

METHODS

PubMed, Embase, and Cochrane Library databases were searched in October 2014 to identify randomized controlled trials of single-dose intra-articular ropivacaine for post-operative pain relief. Post-operative pain intensity, the amount of rescue analgesia required, and side effects including local anaesthetic toxicity were assessed. The relative risk (RR), the weighted mean difference (WMD), and their corresponding 95 % confidence intervals (CIs) were calculated.

RESULTS

Eight randomized controlled trials were included in the analysis. Statistically significant differences in the visual analogue scale for pain intensity value were observed during the immediate post-operative period (WMD -10.35, 95 % CI -17.12 to -3.59, p = 0.003) and the early post-operative period (WMD -11.90, 95 % CI -18.12 to -5.69, p = 0.0002), but not during the late post-operative period (WMD -2.89, 95 % CI -7.46 to 1.68, n.s.). There was no significant difference in the amount of rescue analgesia required (RR 0.76, 95 % CI 0.52-1.11, n.s.). Only two trials reported the incidence of drug-related side effects (including nausea and vomiting): the incidence in the ropivacaine groups was no higher than that in the control groups. Only one trial assessed local anaesthetic toxicity as an outcome, but it was not detected.

CONCLUSIONS

Single-dose intra-articular ropivacaine administered at the end of arthroscopic knee surgery provides effective pain relief in the immediate and early post-operative periods without increasing short-term side effects.

Efficacy and safety of 1% ropivacaine for postoperative analgesia after lower third molar surgery: a prospective, randomized, double-blinded clinical study

OBJECTIVES

The purpose of this study was to investigate postoperative analgesic effect of ropivacaine administered as main or supplemental injection for the inferior alveolar nerve block (IANB) in patients undergoing lower third molar surgery.

MATERIALS AND METHODS

The double-blind randomized study comprised 72 healthy patients. All patients received two blocks, the IANB for surgical procedure + IANB after surgery for postoperative pain control, and were divided into three groups: (1) 2 % lidocaine/epinephrine + 1 % ropivacaine, (2) 2 % lidocaine/epinephrine + saline, and (3) 1 % ropivacaine + saline. The occurrence of postoperative pain, pain intensity and analgesic requirements were recorded. Data were statistically analyzed using chi-square, Fisher, and Kruskal-Wallis tests and analysis of variance (ANOVA) with Bonferroni and Tukey correction.

RESULTS

Ropivacaine was more successful than lidocaine/epinephrine in obtaining duration of postoperative analgesia, reduction of pain, and analgesic requirements whether ropivacaine was used for surgical block or administered as a supplemental injection after surgery.

CONCLUSIONS

Ropivacaine (1 %, 2 ml) resulted in effective postoperative analgesia after lower third molar surgery.

CLINICAL RELEVANCE

Since pain control related to third molar surgery requires the effective surgical anesthesia and postoperative analgesia, the use of 1 % ropivacaine could be clinically relevant in a selection of appropriate pain control regimen for both surgical procedure and early postsurgical treatment.

Does dexmedetomidine improve analgesia of superficial cervical plexus block for thyroid surgery?

Background and Aims:

Bilateral superficial cervical plexus block (BSCPB) is effective in reducing pain following thyroid surgeries. We studied the effect of dexmedetomidine on duration and quality of analgesia produced by BSCPB with 0.5% ropivacaine in patients undergoing thyroid surgeries.

Methods:

In this prospective double-blinded study, 60 adults undergoing thyroid surgeries were randomised into two equal groups to receive BSCPB, either with 20 ml 0.5% ropivacaine (Group A) or 20 ml 0.5% ropivacaine with 0.5 μg/kg dexmedetomidine (Group B) after induction of anaesthesia. Visual analogue scale (VAS) was used to assess analgesia postoperatively at 0, 2, 4, 6, 12 and 24 h and patient satisfaction at 24 h. Haemodynamics were recorded peri-operatively. Wilcoxon signed rank test and Mann–Whitney U-test were applied for VAS and sedation scores. Unpaired t-test was applied for age, weight, duration of surgery and duration of post-operative analgesia.

Results:

There was significantly longer duration of analgesia in Group B (1696.2 ± 100.2 vs. 967.8 ± 81.6 min; P < 0.001) and higher patient satisfaction at 24 h (7 [7–9] vs. 5 [4–6]; P < 0.001). While VAS score for pain were similar up to 6 h, they were lower in Group B at 12 h (0 [0–1] vs. 2 [1–2]; P < 0.001) and 24 h (2 [2–2] vs. 5 [5–6]; P < 0.001). Haemodynamic stability and sedation scores were similar across the groups. There were no adverse events. However, pain during swallowing persisted in both the groups.

Conclusion:

Combination of 0.5% ropivacaine and dexmedetomidine for BSCPB provided significantly prolonged and better quality of postoperative analgesia and patient satisfaction than with 0.5% ropivacaine alone in patients undergoing thyroidectomy.

Comparative analysis of epidural bupivacaine versus bupivacaine with dexmedetomidine for vaginal hysterectomy

Background:

Dexmedetomidine a new drug, which is alpha-two agonist, is recommended by manufacturers as an adjuvant in epidural analgesia and anesthesia.

Aims:

To study the effects of dexmedetomidine on quality and efficacy of the epidural bupivacaine 0.5% for vaginal hysterectomies, by studying the onset of action, duration of action, highest dermatomal level achieved, degree of motor blockade, intraoperative and postoperative anesthesia and analgesia achieved.

Setting and Design:

Prospective randomized study.

Materials and Methods:

In this study, 60 American Society of Anesthesiologists I and II patients requiring vaginal hysterectomy were enrolled. Patients were randomly divided into two groups - Group I: Control group receiving epidural bupivacaine 0.5% 15–20 ml only.

Group II:

Group receiving of epidural bupivacaine 0.5% 15–20 ml with dexmedetomidine 05 mcg/kg. Following parameters were noted: Time to onset of T10 dermatomal level, maximum sensory level achieved, time for complete motor block, time for two segmental dermatomes regression, regression to S1 dermatome, time for first rescue analgesic and total top ups required during study.

Statistical Analysis:

Mean and standard deviation was calculated. We used two independent sample t-test to find the P value. Software used STATA 13.0.

Results:

The demographic profile was comparable between the groups. There was significant difference between two groups (P < 0.001) regarding onset of analgesia to T10 (17.12 ± 2.44 vs. 10.14 ± 2.94), time to achieve complete motor block (27.16 ± 4.52 vs. 22.98 ± 4.78), which was earlier in dexmedetomidine with bupivacaine group. Prolonged postoperative analgesia, less rescue top ups and adequate sedation score was found with dexmedetomidine group. The intraoperative hemodynamic changes were comparable in both the groups. The incidence of dry mouth, shivering and nausea was more with the dexmedetomidine group.

Conclusion:

We conclude that epidural dexmedetomidine 0.5 µg/kg is a good adjuvant providing early onset of sensory and motor block, adequate sedation and prolonged postoperative analgesia with minimal side-effects.

Continuous postoperative pain control using a multiple-hole catheter after iliac bone grafting: comparison between ropivacaine and levobupivacaine

The aim of this study was to compare the analgesic effects of ropivacaine and levobupivacaine in continuous infiltration anaesthesia delivered via a multiple-hole catheter for the purpose of postoperative analgesia after iliac bone grafting. Thirty-four patients scheduled for iliac bone grafting in the maxillofacial region participated in this study. The patients were randomized to a ropivacaine group (Ropi group) and a levobupivacaine group (Levo group). After harvesting the iliac bone for grafting, a multiple-hole catheter was placed on the periosteum of the iliac bone. When surgery was completed, continuous administration was started at 4 ml/h of 0.2% ropivacaine (Ropi group) or 0.25% levobupivacaine (Levo group). Pain was evaluated in the recovery room and at 4h after surgery, as well as at 9:00 and 18:00 on postoperative days 1, 2, and 3, using a visual analogue scale. Side effects were also recorded. No significant difference in the visual analogue scale scores at rest or in motion was observed between the two groups. In addition, there were no side effects in the two groups. Both 0.2% ropivacaine and 0.25% levobupivacaine provided comparable analgesic effects in continuous infiltration anaesthesia delivered via a multiple-hole catheter after iliac bone grafting.

Hyperbaric spinal ropivacaine in lower limb and hip surgery: A comparison with hyperbaric bupivacaine

BACKGROUND AND AIMS

Bupivacaine is more cardiotoxic than ropivacaine. Ropivacaine provides effective spinal anesthesia for lower limb and hip surgeries. This prospective study was designed to compare the efficacy and safety of intrathecal hyperbaric ropivacaine with hyperbaric bupivacaine for patients undergoing limb and hip surgeries.

MATERIAL AND METHODS

Two hundred patients aged 40-75 years, with American Society of Anesthesiologists I and II of either gender were randomly divided into Group R (Ropivacaine) and Group B (Bupivacaine) to receive an intrathecal injection of 3 ml of hyperbaric ropivacaine 0.5% or 3 ml of hyperbaric bupivacaine 0.5%, respectively. Onset and duration of sensory blockade were determined using the pinprick method by a three-point scale at T-10 dermatome. Onset and duration of motor block were assessed by modified Bromage scale. Duration of postoperative analgesia, hemodynamic changes, central nervous system and cardiovascular system toxicity or any adverse effects were observed.

RESULTS

The mean onset of sensory block (6 ± 1.3 min vs. 3 ± 1.1 min; P < 0.001) and motor block (13 ± 1.6 min vs. 9 ± 1.3 min; P < 0.05) was significantly slower in ropivacaine group as compared to bupivacaine group. The total duration of sensory block was significantly shorter in the ropivacaine group (160 ± 12.9 min) than in the bupivacaine group (260 ± 16.1 min; P < 0.05). The mean duration of motor block was also shorter in the ropivacaine group compared to bupivacaine group (126 ± 9.2 min vs. 174 ± 12.6 min; P < 0.05). Quality of anesthesia was comparable in two groups (P = 0.04).

CONCLUSION

We conclude that hyperbaric bupivacaine used intrathecally has a faster onset of sensory block and prolonged duration of analgesia compared to hyperbaric ropivacaine.

Postoperative analgesic efficacy of epidural tramadol as adjutant to ropivacaine in adult upper abdominal surgeries

BACKGROUND

Postoperative pain control after major abdominal surgery is the prime concern of anesthesiologist. Among various methodologies, epidural analgesia is the most preferred technique because of the excellent quality of analgesia with minimum side-effects.

AIM

The present study was designated to compare postoperative analgesic efficacy and safety of epidural tramadol as adjuvant to ropivacaine (0.2%) in adult upper abdominal surgery.

SETTINGS AND DESIGN

Prospective, randomized-controlled, double-blinded trial.

MATERIALS AND METHODS

Ninety patients planned for upper abdominal surgery under general anesthesia were randomized into three equal groups to receive epidural drug via epidural catheter at start of incisional wound closure: Group R to receive ropivacaine (0.2%); Group RT1 to receive tramadol 1 mg/kg with ropivacaine (0.2%); and RT2 to receive tramadol 2 mg/kg with ropivacaine (0.2%). Duration and quality of analgesia (visual analog scale [VAS] score), hemodynamic parameters, and adverse event were recorded and statistically analyzed.

STATISTICAL ANALYSIS

One-way analysis of variance test, Fisher's exact test/Chi-square test, whichever appropriate. A P < 0.05 was considered significant.

RESULTS

Mean duration of analgesia after epidural bolus drug was significantly higher in Group RT2 (584 ± 58 min) when compared with RT1 (394 ± 46 min) or R Group (283 ± 35 min). VAS score was always lower in RT2 Group in comparison to other group during the study. Hemodynamic parameter remained stable in all three groups.

CONCLUSION

We conclude that tramadol 2 mg/kg with ropivacaine (0.2%) provides more effective and longer-duration analgesia than tramadol 1 mg/kg with ropivacaine (0.2%).

Role of regional anesthesia in foot and ankle surgery

Regional anesthesia has increasingly expanded its role in the perioperative care of patients undergoing foot and ankle surgery. In addition to avoiding side effects associated with both general anesthesia and neuraxial anesthetic techniques, especially those related to cardiovascular and pulmonary systems, regional nerve blocks have been shown to improve postoperative pain and reduce hospital stay and associated expenses. The techniques utilized to achieve analgesia of the foot and ankle are diverse, multifaceted, and often incorporate ultrasound guidance. Given the aging of patient populations, and especially the growing incidence of cardiovascular-, pulmonary-, and obesity-related morbidity, the use of regional blocks is likely to expand in these surgical procedures. This review highlights some of the most current developments in the expanding role of regional anesthesia in foot and ankle surgery.

LEVELS OF EVIDENCE

Therapeutic, Level II.

Comparison of ropivacaine and bupivacaine with fentanyl for caudal epidural in pediatric surgery

CONTEXT

Ropivacaine, s-enantiomer of amide local anaesthetic produces differential neural blockade with less motor blockade, cardiovascular and neurological toxicity makes it suitable for day case surgery in children.

AIMS

To compare the effectiveness of Inj. Ropivacaine (0.2 or 0.25%) or Inj. Bupivacaine (0.25%) with fentanyl in caudal block for intra and postoperative analgesia.

SETTINGS AND DESIGN

Double blind retrospective randomized study.

MATERIALS AND METHODS

All the patients (n=112) varying from age group 3.02 ± 3.29 years belonging to ASA I-IV were randomly allocated to receive caudal analgesia Group BF inj. Bupivacaine (0.25%, 2 mg/kg) + Inj. Fentany1 μg/kg (n=70) and group RF: Inj. Ropivacaine (0.25% or 0.2%, 2 mg/kg) + inj. Fentanyl 1 μg/kg (n=42). We monitored vitals and requirement of inhalational gases inraoperatively and also observed pain by pain score (Visual Analogue Score in verbal group and Objective Pain Scale in nonverbal group) and vitals postoperatively. We used rescue analgesics (inj. Paracetamol 5 mg/kg iv) when VAS score ≥4.

STATISTICAL ANALYSIS

Student's t-test.

RESULTS

Duration of analgesia was prolonged in both group RF and BF. Time for first rescue analgesic for group RF (6.1 ± 1.1 hr) compared to group BF (5.6 ± 0.9 hr). Haemodynamic stability and less requirement of inhalation agent intraoperatively with group RF than others.

CONCLUSIONS

Ropivacaine with Fentanyl found to be better combination for pediatric surgeries for below umbilical surgeries as an adjuvant to general anaesthesia or sole technique with chances of less complication with high success rate.

Effects of intrathecal hyperbaric ropivacaine versus hyperbaric bupivacaine for lower limb orthopedic surgery

Background:

Regional anesthesia, increasingly used for infraumbilical surgery, has advantages of decreased stress response to surgery, nausea, vomiting, and cardio-respiratory depression with improved postoperative analgesia, in comparison to general anesthesia. Intrathecal isobaric ropivacaine (RP) had been found, in various clinical studies, to be shorter acting in comparison to bupivacaine (BP). Our present study was, hence, aimed to compare the anesthetic and analgesic efficacy of intrathecal hyperbaric RP relative to hyperbaric BP in lower limb orthopedic surgery.

Materials and Methods:

A total of 100 patients aged ranges between 18 and 60 years of either sex, ASAPS 1 and 2, undergoing elective lower limb orthopedic surgeries were divided into two groups, RP group and BP group receiving intrathecal 0.75% RP 3 ml and glucose 50%, 0.5 ml and 0.5% hyperbaric BP 3 ml and 0.9% normal saline 0.5 ml, respectively. The efficacy in terms of onset and duration of anesthesia and analgesia were assessed along with the heart rate, blood pressure at regular intervals throughout the perioperative period.

Result:

The two study groups were comparable in terms of demography and duration of surgery. Patients in group RP experienced significantly late onset and shorter duration of sensory and motor block in comparison to patients in group BP. There were clinically insignificant differences in perioperative hemodynamics and side-effects noted in each group. Hence, it was observed in this study that equipotent dose of hyperbaric RP had shorter duration of analgesia and anesthesia than with equipotent dose of hyperbaric BP.

Prospective, randomized controlled trial on use of ropivacaine after robotic thyroid surgery: Effects on postoperative pain

BACKGROUND

We evaluated the effects of ropivacaine for pain relief after robotic thyroid surgery.

METHODS

One hundred eight patients scheduled for robotic thyroid surgery were randomized into ropivacaine (n = 54) or control (n = 54) groups. After surgery, 40 mL of 0.25% ropivacaine or 0.9% saline (control) was instilled into the skin flap. Postoperative pain intensity (visual analog scale [VAS]), analgesic requirements (fentanyl), and adverse events were assessed at 1, 2, 4, 8, 16, and 24 hours postoperatively.

RESULTS

One hundred three patients completed the study protocol. VAS scores were lower in the ropivacaine group than the control group (p = .010); however, VAS scores were not significantly different after 8 hours postoperatively. Total analgesic consumption was higher in controls than ropivacaine-treated patients (p = .01). Adverse events did not differ between the 2 groups.

CONCLUSION

Ropivacaine instillation after robotic thyroid surgery reduces acute postoperative pain and analgesic requirements without adverse events. © 2015 Wiley Periodicals, Inc. Head Neck 38: E-E, 2016.

Dose-dependent effect of intrathecal dexmedetomidine on isobaric ropivacaine in spinal anesthesia for abdominal hysterectomy: Effect on block characteristics and hemodynamics

Background and Aims:

Effect of intrathecal dexmedetomidine as an adjuvant to isobaric ropivacaine in spinal anesthesia for abdominal hysterectomy is not much investigated. The objective was to assess the dose dependent effect of dexmedetomidine (3 mcg vs 5 mcg) as an adjunct to isobaric ropivacaine in spinal anesthesia.

Materials and Methods:

Forty selected female patients were randomized to receive intrathecal 0.5% isobaric ropivacaine (15 mg) with dexmedetomidine 3 mcg (Group D3) or 5 mcg (Group D5) in spinal anesthesia for abdominal hysterectomy. Block characteristics, hemodynamic changes, postoperative analgesia, and adverse effects were compared.

Results:

Both groups were comparable regarding sensory-motor block characteristics and postoperative analgesia (P > 0.05). Four (10%) patients of Group D5 and 5 (12.5%) of Group D3 could not achieve desired T6 sensory level and Bromage score of 3(complete motor block) hence were converted to general anesthesia at the outset. Nine (22.5%) patients each in both groups required ketamine supplementation (0.5 mg/kg) for intraoperative pain at the time of uterine manipulation. Incidence of hypotension was comparable (55.56% in Group D5 and 37.14% in Group D3, P = 0.11), but this occurred significantly earlier in Group D5, P < 0.001. Sedation was also significantly more in Group D5 as compared with Group D3, P < 0.01.

Conclusion:

We conclude that spinal anesthesia with isobaric ropivacaine (15 mg) with dexmedetomidine (3 mcg or 5 mcg) did not show much promise for abdominal hysterectomy as one third cases required analgesic supplementation. Both doses of dexmedetomidine produced a similar effect on block characteristic and postoperative analgesia; however, a dose of 5 mcg dose was associated with more hypotension and sedation.

The quest for effective pain control during suture adjustment after strabismus surgery: a study evaluating supplementation of 2% lidocaine with 0.4% ropivacaine

Purpose

To determine whether the addition of 0.4% ropivacaine to the standard 2% lidocaine peribulbar anesthetic block improves pain scores during suture adjustment in patients undergoing strabismus surgery with adjustable sutures.

Methods

Prospective, double-blind study of 30 adult patients aged 21–84 years scheduled for elective strabismus surgery with adjustable sutures. Patients were divided into two groups of 15 patients each based on the local anesthetic. Group A received 2% lidocaine and Group B received 2% lidocaine/0.4% ropivacaine. Pain was assessed using the visual analog scale (VAS) preoperatively and at 2, 4, and 6 hours postoperatively. The Lancaster red-green test was used to measure ocular motility at the same time points.

Results

The pain scores in the two groups were low and similar at all measurement intervals. The VAS for Group A versus Group B at 2 hours (1.7 versus 2.4, P=0.5) and 4 hours (3.5 versus 3.7, P=0.8) showed no benefit from the addition of ropivacaine. At 6 hours, the VAS (3.7 versus 2.7) was not statistically significant, but the 95% confidence interval indicated that ropivacaine may provide some benefit. A repeated measures ANOVA did not find a statistically significant difference in VAS scores over time (P=0.9). In addition, the duration of akinesia was comparable in both groups (P=0.7).

Conclusion

We conclude that the 50:50 mixture of 2% lidocaine with 0.4% ropivacaine as compared to 2% lidocaine in peribulbar anesthetic blocks in adjustable-suture strabismus surgery does not produce significant improvements in pain control during the postoperative and adjustment phases. In addition, ropivacaine did not impair return of full ocular motility at 6 hours, which is advantageous in adjustable-suture strabismus surgery.

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.

Lysine-based surfactants as chemical permeation enhancers for dermal delivery of local anesthetics

The aim of this study is to investigate the efficacy of new, biocompatible, lysine-based surfactants as chemical permeation enhancers for two different local anesthetics, tetracaine and ropivacaine hydrochloride, topically administered. Results show that this class of surfactants strongly influences permeation, especially in the case of the hydrophilic and ionized drug, ropivacaine hydrochloride, that is not easily administered through the stratum corneum. It is also seen that the selected permeation enhancers do not have significant deleterious effects on the skin structure. A cytotoxicity profile for each compound was established from cytotoxicity studies. Molecular dynamics simulation results provided a rationale for the experimental observations, introducing a mechanistic view of the action of the surfactants molecules upon lipid membranes.

Diffuse complex regional pain syndrome in an adolescent: a novel treatment approach

OBJECTIVES

Late diagnosis and management of complex regional pain syndrome (CRPS) can have severe consequences. We report the case of a young adolescent who failed several months of medical and physical therapy for CRPS, which was initially limited to one extremity but then spread to the remaining extremities.

METHODS

At the time of admission to our hospital, she had been unable to independently perform activities of daily living for several months. We placed an epidural catheter and 2 infraclavicular catheters under general anesthesia and ran continuous infusions of local anesthetic and morphine in the epidural catheter (ropivacaine 0.1% and preservative-free morphine [20 μg/mL] at 8 mL/h) and ropivacaine 0.1% 6 mL/h in each infraclavicular catheter.

RESULTS

Patients were started intense physical, occupational, and psychotherapeutic treatments the following day. Color and temperature of extremities normalized within 10 minutes from the time of the bolus of local anesthetic through the catheters. The patient was able to walk and use her hands 48 hours after the placement of the catheters. She was weaned off opioids during her hospital stay and was discharged home 9 days after her initial admission, and was able to walk and attend to her daily living activities.

DISCUSSION

The extensive use of regional anesthesia techniques can greatly benefit patients with CRPS during the acute phase of the rehabilitation process, which includes appropriate physical, and occupational therapy and psychological interventions. It is critical to continue physical therapy and psychological support after discharge from the hospital.

Continuous paravertebral infusion of ropivacaine with or without fentanyl for pain relief in unilateral multiple fractured ribs

Background:

Continuous thoracic paravertebral block (TPVB) provides effective analgesia for unilateral multiple fractured ribs (MFR). However, prolonged infusion of local anaesthetic (LA) in high doses can predispose to risk of LA toxicity, which may be reduced by using safer drugs or drug combinations. This study was conducted to assess efficacy and safety of paravertebral infusion of ropivacaine and adrenaline with or without fentanyl to provide analgesia to patients with unilateral MFR.

Methods:

Thirty adults, having ≥3 unilateral MFR, with no significant trauma outside chest wall, were studied. All received bolus of 0.5% ropivacaine 0.3 ml/kg through paravertebral catheter, followed by either 0.1-0.2 ml/kg/hr infusion of ropivacaine 0.375% with adrenaline 5 μg/ml in group RA or ropivacaine 0.2% with adrenaline 5 μg/ml and fentanyl 2 μg/ml in group RAF. Rescue analgesia was provided by IV morphine.

Results:

Statistical analysis was performed using unpaired Student t-test, Chi-square test and repeated measures ANOVA. After TPVB, VAS scores, respiratory rate and PEFR improved in both groups with no significant inter-group differences. Duration of ropivacaine infusion, morphine requirements, length of ICU and hospital stay, incidence of pulmonary complications and opioid-related side-effects were similar in both groups. Ropivacaine requirement was higher in group RA than group RAF. No patient showed signs of LA toxicity.

Conclusion:

Continuous paravertebral infusion of ropivacaine 0.375% with adrenaline 5 μg/ml at 0.1-0.2 ml/kg/hr provided effective and safe analgesia to patients with unilateral MFR. Addition of fentanyl 2 μg/ml allowed reduction of ropivacaine concentration to 0.2% without decreasing efficacy or increasing opioid-related side-effects.

Interaction of local anesthetics with biomembranes consisting of phospholipids and cholesterol: mechanistic and clinical implications for anesthetic and cardiotoxic effects

Despite a long history in medical and dental application, the molecular mechanism and precise site of action are still arguable for local anesthetics. Their effects are considered to be induced by acting on functional proteins, on membrane lipids, or on both. Local anesthetics primarily interact with sodium channels embedded in cell membranes to reduce the excitability of nerve cells and cardiomyocytes or produce a malfunction of the cardiovascular system. However, the membrane protein-interacting theory cannot explain all of the pharmacological and toxicological features of local anesthetics. The administered drug molecules must diffuse through the lipid barriers of nerve sheaths and penetrate into or across the lipid bilayers of cell membranes to reach the acting site on transmembrane proteins. Amphiphilic local anesthetics interact hydrophobically and electrostatically with lipid bilayers and modify their physicochemical property, with the direct inhibition of membrane functions, and with the resultant alteration of the membrane lipid environments surrounding transmembrane proteins and the subsequent protein conformational change, leading to the inhibition of channel functions. We review recent studies on the interaction of local anesthetics with biomembranes consisting of phospholipids and cholesterol. Understanding the membrane interactivity of local anesthetics would provide novel insights into their anesthetic and cardiotoxic effects.

Comparative Analysis of the Anesthetic Efficacy of 0.5 and 0.75 % Ropivacaine for Inferior Alveolar Nerve Block in Surgical Removal of Impacted Mandibular Third Molars

INTRODUCTION

Ropivacaine belongs to pipecoloxylidide group of local anesthetics. There are reports supporting the use of ropivacaine as a long acting local anesthetic in oral and maxillofacial surgical procedures, with variable data on the concentration that is clinically suitable.

MATERIALS AND METHODS

A prospective randomized double-blind study protocol was undertaken to assess the efficacy of 0.5 and 0.75 % ropivacaine for inferior alveolar nerve block in surgical extraction of impacted mandibular third molars. A total of 60 procedures were performed, of which thirty patients received 0.5 % and thirty received 0.75 % concentration of the study drug.

RESULTS

All the patients in both the study groups reported subjective numbness of lip and tongue. The time of onset was longer for 0.5 % ropivacaine when compared to 0.75 % solution. 90 % of the study patients in 0.5 % ropivacaine group reported pain corresponding to VAS ≥3 during bone guttering and 93.3 % patients reported pain corresponding to VAS >4 during tooth elevation. None of the patients in 0.75 % ropivacaine group reported VAS >3 at any stage of the surgical procedure. The duration of soft tissue anesthesia recorded with 0.75 % ropivacaine was average 287.57 ± 42.0 min.

CONCLUSION

0.75 % ropivacaine was found suitable for inferior alveolar nerve blocks in surgical extraction of impacted mandibular third molars.

Comparative evaluation of dexmedetomidine and fentanyl for epidural analgesia in lower limb orthopedic surgeries

Background and Aims:

Opioids as epidural adjunct to local anesthetics (LA) have been in use since long and α-2 agonists are being increasingly used for similar purpose. The present study aims at comparing the hemodynamic, sedative, and analgesia potentiating effects of epidurally administered fentanyl and dexmedetomidine when combined with ropivacaine.

Methods:

A total of one hundred patients of both gender aged 21-56 years, American Society of Anaesthesiologist (ASA) physical status I and II who underwent lower limb orthopedic surgery were enrolled into the present study. Patients were randomly divided into two groups: Ropivacaine + Dexmedetomidine (RD) and Ropivacaine + Fentanyl (RF), comprising 50 patie nts each. Inj. Ropivacaine, 15 ml of 0.75%, was administered epidurally in both the groups with addition of 1 μg/kg of dexmedetomidine in RD group and 1 μg/kg of fentanyl in RF group. Besides cardio-respiratory parameters and sedation scores, various block characteristics were also observed which included time to onset of analgesia at T10, maximum sensory analgesic level, time to complete motor blockade, time to two segmental dermatomal regressions, and time to first rescue analgesic. At the end of study, data was compiled systematically and analyzed using ANOVA with post-hoc significance, Chi-square test and Fisher's exact test. Value of P<0.05 is considered significant and P<0.001 as highly significant.

Results:

The demographic profile of patients was comparable in both the groups. Onset of sensory analgesia at T10 (7.12±2.44 vs 9.14±2.94) and establishment of complete motor blockade (18.16±4.52 vs 22.98±4.78) was significantly earlier in the RD group. Postoperative analgesia was prolonged significantly in the RD group (366.62±24.42) and consequently low dose consumption of local anaesthetic LA (76.82±14.28 vs 104.35±18.96) during epidural top-ups postoperatively. Sedation scores were much better in the RD group and highly significant on statistical comparison (P<0.001). Incidence of nausea and vomiting was significantly high in the RF group (26% and 12%), while incidence of dry mouth was significantly higher in the RD group (14%) (P<0.05).

Conclusions:

Dexmedetomidine seems to be a better alternative to fentanyl as an epidural adjuvant as it provides comparable stable hemodynamics, early onset, and establishment of sensory anesthesia, prolonged post-op analgesia, lower consumption of post-op LA for epidural analgesia, and much better sedation levels.

Use of reduced-dose periarticular injection for pain management in simultaneous bilateral total knee arthroplasty

We investigated the safety and efficacy of the bilateral periarticular multimodal drug injection (PMDI) at a reduced dosage in patients undergoing simultaneous bilateral total knee arthroplasty (SBTKA). In total, 45 patients undergoing SBTKA received 65 mL PMDI in each knee (reduced-dose group). The incidence of drug-related adverse effects and wound complications were evaluated. Pain levels during the night of the operation and postoperative day 1 and opioid consumption during the first 24 hours after surgery were compared with the regular-dose group of 55 patients undergoing SBTKA who received 100 mL of PMDI in 1 knee. No patient experienced a serious drug-related adverse effect or wound complication. Blood levels of ropivacaine were observed to be lower than a toxic level throughout the monitored period in all patients examined. Patients in the reduced-dose group experienced less pain during the night of operation, but a similar pain level at postoperative day 1.

Postoperative analgesic requirements after subarachnoid or epidural anesthesia with ropivacaine 0.75% in cesarean section. A double-blind randomized trial

OBJECTIVE

Postoperative analgesic requirements and pain scores were compared after subarachnoid versus epidural anesthesia with plain ropivacaine 0.75% for elective cesarean section.

STUDY DESIGN

Ropivacaine 0.75% was randomly administered for subarachnoid or epidural anesthesia in 108 parturients, scheduled for cesarean section. Times for the sensory block to reach T4 level and to regress to T6 level were recorded. At 2, 4, 8 and 24 h postoperatively, pain scores at rest and cough, morphine consumption as well as patient satisfaction, incidence of headache, nausea and/or vomiting were measured.

RESULTS

Median (min-max) time for the sensory block to reach T4 was 7 (3-0) min versus 24 (16-73) min and to regress to T6 was 126 (70-332) min versus 200 (98-439) min in the subarachnoid and epidural groups, respectively (p=0.001). Although the subarachnoid had more analgesic consumption than the epidural group at 2 and 4 h postoperatively (7.3±4.7 vs. 1.8±2.4 mg, p=0.001 and 9±5.7 vs. 3.3±3.8 mg, p=0.001, respectively) no difference was observed at 8 or 24 h postoperatively (p=0.14 and p=0.38, respectively). VAS scores at rest and after cough (p=0.56, p=0.35, respectively), patient satisfaction (p=0.61), incidence of headache (p=1.0), nausea and/or vomiting (p=0.78) did not differ between the two groups.

CONCLUSIONS

Postoperative pain, analgesic requirements, patient satisfaction and adverse effects did not differ when subarachnoid or epidural anesthesia with ropivacaine 0.75% was used for elective cesarean section. Nevertheless, subarachnoid provides faster onset and offset of the block, compared to epidural anesthesia. The key limitation of this study is the lack of postoperative serum ropivacaine measurements taken with concurrent pain score measurements.

Antinociceptive effects of low dose lumbosacral epidural ropivacaine in healthy ponies

The objective of this study was to evaluate the safety and efficacy of low dose lumbosacral epidural ropivacaine in ponies. Antinociceptive effects of epidural ropivacaine were evaluated by means of mechanical nociceptive thresholds (MNTs) at several spinal levels in conscious ponies. The effects of ropivacaine on nociceptive afferent transmission to the spinal cord were also assessed by measuring spinal cord somatosensory evoked potentials (SSEPs) in anaesthetised ponies. Ataxia scores were determined in conscious ponies to assess the effects on motor function. A randomised, placebo controlled, double blind cross-over design was used. Low dose lumbosacral epidural ropivacaine led to increases in MNTs at various anatomical locations with a maximum effect at the lumbosacral and sacrococcygeal regions, both with respect to increase in threshold and duration of effect. Analysis of SSEPs showed that epidural ropivacaine influenced both Aβ- and Aδ-mediated afferent transmission to the spinal cord at the level of the lumbosacral junction. Ponies showed mild ataxia after low dose lumbosacral epidural ropivacaine, but all ponies remained standing. Application of low dose lumbosacral epidural ropivacaine provided safe and efficacious antinociceptive effects in conscious and anaesthetised ponies, and could therefore be a valuable addition to multimodal analgesic protocols in Equidae.

New formulations of local anaesthetics-part I

Part 1 comments on the types of local anaesthetics (LAs); it provides a better understanding of the mechanisms of action of LAs, and their pharmacokinetics and toxicity. It reviews the newer LAs such as levobupivacaine, ropivacaine, and articaine, and examines the newer structurally different LAs. The addition of adjuvants such as adrenaline, bicarbonate, clonidine, and corticosteroids is explored. Comment is made on the delivery of topical LAs via bioadhesive plasters and gels and controlled-release local anaesthetic matrices. Encapulation matrices such as liposomes, microemulsions, microspheres and nanospheres, hydrogels and liquid polymers are discussed as well. New innovations pertaining to LA formulations have indeed led to prolonged action and to novel delivery approaches.

Anesthesia implications in emergency oncologic surgery in a case of untreated Parkinsonism

Oncologic surgery has made tremendous advancements in the last two decades. The prognosis of once thought to be irreversible and incurable diseases has improved dramatically with these advancements, which have given a fresh lease of hope to the general population. But there are certain factors that are still unfavorable for achieving improved outcome of surgery in various cancers. The associated comorbid diseases do determine to a large extent the actual outcome of all the interventions to treat oncologic disease. The untreated coexisting disease makes the task of the attending anesthesiologist very challenging as numerous complications are anticipated, especially during emergency surgery. We are describing a case of a patient with endometrial carcinoma who presented with unstoppable bleeding per-vaginum and was suffering from Parkinson disease since 1½ years, for which no treatment was ever sought. Vaginal hysterectomy was performed under graded epidural anesthesia; and after a smooth and uneventful postoperative period of 8 days, she was referred to radiotherapy unit for further management.

Comparison of epidural ropivacaine and ropivacaine clonidine combination for elective cesarean sections

Background and Aim:

Neuraxial adjuvants augment the action of local anesthetics. The aim is to determine the qualitative and quantitative aspects of epidural block of ropivacaine 0.75% versus ropivacaine 0.75% with clonidine for elective cesarean section.

Settings and Design:

A randomized double-blind study was conducted among 51 healthy parturients, scheduled for elective cesarean section, at Gian Sagar Medical College and Hospital, Banur, Punjab, India.

Materials and Methods:

Epidural block was administered with 20 ml of ropivacaine 0.75% (group R) and ropivacaine 0.75% and clonidine 75 µg (group RC) and anesthetic level was achieved minimum until T6–T7 dermatome. Onset time of analgesia, sensory and motor block levels, maternal heart rate and blood pressure, neonatal Apgar scores, postoperative analgesic dose and adverse events were recorded.

Results:

Fifty one patients were enrolled in this study and were subjected to statistical analysis. Groups were comparable with regard to demographic data, neonatal Apgar scores and incidences of side effects except for the higher incidence of dry mouth in patients of RC group. Onset of analgesia was much shorter in RC group along with prolonged duration of analgesia. The incidence of bradycardia and hypotension was more in RC group as compared to R group which was statistically significant. The dose requirement for postoperative pain relief was significantly lesser in RC group.

Conclusions:

The addition of 75 µg clonidine to isobaric epidural ropivacaine results in longer, complete and effective analgesia with similar block properties and helped to reduce the effective dose of ropivacaine when compared with plain ropivacaine for cesarean delivery.

Efficacy of thoracic epidural anesthesia for laparoscopic cholecystectomy

BACKGROUND

Laparoscopic cholecystectomy is performed to minimize the postoperative morbidity and early return to work. This study was planned to evaluate the efficacy and feasibility of thoracic epidural anesthesia for laparoscopic cholecystectomy, so that it can be later used as anesthetic technique in patients when general anesthesia is not feasible.

MATERIALS AND METHODS

Forty-eight adult consented patients of ASA grade I and II of either sex scheduled for elective laparoscopic cholecystectomy were enrolled for thoracic epidural anesthesia with 15 ml of 0.75% ropivacaine and 50 μg fentanyl. Intraoperative hemodynamic parameters and respiratory efficiency were recorded. Intra-operatively patient anxiety, pain, vomiting, hypotension or any other adverse event was managed with appropriate drug regime. Postoperative pain management with epidural analgesia, and bowel recovery were also recorded.

RESULTS

The thoracic epidural anesthesia was effective for laparoscopic cholecystectomy in all except in two patients where conversion to general anesthesia was required. The hemodynamic parameters and respiratory efficiency were maintained within physiological limits. Only 4 patients required treatment for hypotension with vasopressor and 15 patients experienced shoulder pain, which was effectively managed with small doses of ketamine. The midazolam was required only in 11 patients for anxiety. The mean surgical time was 56.8±51.6 min. The 24-hour postoperative epidural infusion for analgesia was effective with limited effects on bowel and bladder function. Postoperatively only 3 patients had an episode of vomiting. There was good surgeon and patient's satisfaction.

CONCLUSIONS

The thoracic epidural anesthesia with 0.75% ropivacaine and fentanyl for elective laparoscopic cholecystectomy is efficacious and has preserved ventilation and hemodynamic changes within physiological limits during pneumoperitoneum with minimal treatable side effects.

[Maternal hypotension with low doses of spinal bupivacaine or levobupivacaine and epidural volume expansion with saline for cesarean section]

BACKGROUND AND OBJECTIVE

Epidural volume extension (EVE) with saline solution can contribute to greater cephalad spread of drugs injected into the subarachnoid space during cesarean section. We studied the incidence of material hypotension with spinal bupivacaine or levobupivacaine (L-bupivacaine) and the spread after epidural saline injection.

MATERIAL AND METHODS

After ethics committee approval, we randomized women scheduled for cesarean section to 4 groups to receive 5 mg of 0.25% bupivacaine with (n=51) or without (n=6) saline EVE; 5 mg of 025% L-bupivacaine (n=50); or 6 mg of 03% L-bupivacaine (n=50). All patients also received 25 microg of fentanyl per 2 mL of local hyperbaric spinal anesthetic. In all except the non-EVE group, 10 mL of saline was infused through an epidural catheter 5 minutes after anesthetic infusion. We recorded patient demographic data, procedural and anesthetic times, incision-clamping times, occurrence of hypotension, ephedrine dose required, motor and sensory blockade, requirement for rescue analgesics, and neonatal outcome.

RESULTS

After 6 patients had been randomized to the non-EVE group, no further patients were assigned because all the women required rescue analgesics. Demographic data, duration of procedure, time between. incision and delivery, and Apgar scores were similar in all the groups. The incidence of hypotension was lower in the group receiving 5 mg of L-bupivacaine (26% vs. 52.9% in the bupivacaine 5-mg group, and 56% in the 6-mg L-bupivacaine group, P = .04). More women given 5 mg of L-bupivacaine required rescue analgesia (46%) than did those receiving 5 mg of bupivacaine (235%) or 6 mg of L-bupivacaine (28%) (P = .039). Hypotension was associated with a lower umbilical cord pH (P = .001). Ephedrine doses over 20 mg were also associated with a lower umbilical cord pH (P = .031).

CONCLUSIONS

The incidence of hypotension was lowest in the group anesthetized with 5 mg of L-bupivacaine, but the need for rescue analgesia was greater in this group. Doses of 5 mg and 6 mg may be sufficient for cesarean section, as they provide a good level of sensory blockade.

The effect of warmed ropivacaine to body temperature on epidural sensory block characteristics

STUDY OBJECTIVE

To determine whether warmed (body temperature) ropivacaine increases the speed of onset of sensory block of epidural anesthesia.

STUDY DESIGN

Prospective, randomized, double-blind study.

SETTING

University hospital.

PATIENTS

180 ASA physical status I and II patients, aged 18 to 64 years, undergoing elective anal surgery.

INTERVENTIONS

Patients were randomly divided into 6 groups defined by ropivacaine temperature [room temperature (RT) or body temperature (BT)] and concentration (0.5%, 0.75%, or 1.0%).

MEASUREMENTS

Sensory block was evaluated by pinprick at the T10, T12, L3, and the perianal region (S4, S5) dermatomes. pH values and adverse events were also recorded.

MAIN RESULTS

There were no differences in baseline demographics, pH, or upper sensory level between groups. Mean onset time of T12 and L3 sensory block was significantly faster for each BT than RT ropivacaine concentration. Anal region (S4, S5) sensory block was significantly faster after BT 0.75% versus RT 0.75% ropivacaine.

CONCLUSIONS

Warmed ropivacaine shortens the onset of sensory block of epidural anesthesia.

Maxillary infiltration anaesthesia by ropivacaine for upper third molar surgery

The main purpose of this study was to assess the clinical efficacy and haemodynamic effects of ropivacaine for infiltration anaesthesia in patients undergoing surgical removal of upper third molars. The safety profile of ropivacaine was also studied by investigating the maximal venous plasma concentration of ropivacaine and the reactivity to ropivacaine of isolated human infraorbital arteries. Ropivacaine in concentrations of 0.5, 0.75 and 1% achieved dose-dependent parameters of maxillary infiltration aneasthesia, clinically relevant in concentrations 0.75 and 1%. Postoperative needs for analgesics were observed in 67-100% of patients. Haemodynamic parameters were stable during surgery with significant changes occuring 10 min after surgery. After maxillary infiltration of 2.0 ml 1% ropivacaine, the maximum venous plasma concentration (Cmax) was 82+/-15 microg/l. On isolated human infraorbital artery, ropivacaine (10(-4)M) induced endothelium-independent contraction. This study suggests that 0.75 and 1% ropivacaine offers adequate and safe intraoperative analgesia but not successful postoperative pain control for the surgical removal of upper third molars.

Initial development and characterization of PLGA nanospheres containing ropivacaine

Local anesthetics are able to induce pain relief by binding to the sodium channels of excitable membranes, blocking the influx of sodium ions and the propagation of the nervous impulse. Ropivacaine (RVC) is an amino amide, enantiomerically pure, local anesthetic largely used in surgical procedures, which present physico-chemical and therapeutic properties similar to those of bupivacaine but decreased toxicity and motor blockade. The present work focuses on the preparation and characterization of nanospheres containing RVC; 0.25% and 0.50% RVC were incorporated in poly(d,l-lactide-co-glycolide (PLGA) 50:50) nanospheres (PLGA-NS), prepared by the nanoprecipitation method. Characterization of the nanospheres was conducted through the measurement of pH, particle size, and zeta potential. The pH of the nanoparticle system with RVC was 6.58. The average diameters of the RVC-containing nanospheres was 162.7 +/- 1.5 nm, and their zeta potentials were negative, with values of about -10.81 +/- 1.16 mV, which promoted good stabilization of the particles in solution. The cytotoxicity experiments show that RVC-loaded PLGA-NS generate a less toxic formulation as compared with plain RVC. Since this polymer drug-delivery system can effectively generate an even less toxic RVC formulation, this study is fundamental due to its characterization of a potentially novel pharmaceutical form for the treatment of pain with RVC.