The use of 2-chloroprocaine for spinal anaesthesia

[Principles of the pharmacology of local anesthetics]

The development of local anesthetics revolutionized the performance of painful interventions. Local anesthetics have an effect on voltage-gated sodium channels in nerve fibers and modulate the conduction of impulses. With respect to the chemical structure, local anesthetics can be divided into amide and ester types. The structural differences of local anesthetics have an influence on the duration of action, the degradation pathways and specific side effects. Severe adverse events include cardiotoxicity and neurotoxicity. In addition to basic measures, such as the monitoring and securing of vital parameters, lipid infusion represents a treatment option in cases of intoxication. The recent developments of local anesthetics are particularly concerned with the reduction of toxicity and prolonging the duration of action.

[Principles of the pharmacology of local anesthetics]

The development of local anesthetics revolutionized the performance of painful interventions. Local anesthetics have an effect on voltage-gated sodium channels in nerve fibers and modulate the conduction of impulses. With respect to the chemical structure, local anesthetics can be divided into amide and ester types. The structural differences of local anesthetics have an influence on the duration of action, the degradation pathways and specific side effects. Severe adverse events include cardiotoxicity and neurotoxicity. In addition to basic measures, such as the monitoring and securing of vital parameters, lipid infusion represents a treatment option in cases of intoxication. The recent developments of local anesthetics are particularly concerned with the reduction of toxicity and prolonging the duration of action.

Comparison of Intrathecal Chloroprocaine With Bupivacaine in Short Gynecological Procedures: A Randomized Double-Blind Study

Background Neuraxial anesthesia, compared to general anesthesia, offers better patient comfort, early ambulation, and discharge with excellent post-operative pain relief for short gynecological procedures. Recently chloroprocaine, a short-acting local anesthetic agent became available for intrathecal use. This study aimed to compare intrathecal chloroprocaine with bupivacaine in short gynecological procedures. Methodology Consecutive patients undergoing short gynecological procedures, patients belonging to the American Society of Anesthesiology (ASA) I and II, between 18 and 60 years of age, and patients with a height between 150 cm and 180 cm were included in the study. Randomization was done using a computer-generated random number table. Patients were allocated to one of the two study groups. Group B received 4 mL of isobaric bupivacaine (0.25%) 10 mg intrathecal, and Group C received 4 mL of isobaric chloroprocaine (1%) 40 mg intrathecal. The primary outcome criteria were time to ambulation and discharge readiness. The secondary outcome criteria were onset, duration, and intensity of sensory and motor blockade, time to voiding, and any adverse effects. Results Patients receiving chloroprocaine had a significantly (p=0.001) faster time (158±31 min) to ambulation compared to bupivacaine (241±23 min). The regression of sensory blockade was substantially faster (p=0.001) with chloroprocaine (60±13 min) than with bupivacaine (94±24 min). Mean time to motor onset was significantly (p=0.05) faster in chloroprocaine (8±3 min) than bupivacaine (12±3 min) group. Significantly faster (p=0.001) recovery of motor blockade was observed with chloroprocaine (130±32 min) than bupivacaine (211±22 min). The time to first voiding was also significantly earlier with stable hemodynamics and no adverse effects in chloroprocaine group. Conclusion Intrathecal chloroprocaine may be an attractive alternative and is superior to isobaric bupivacaine as it provides early ambulation and discharge readiness for daycare anesthesia in short gynecological procedures.

Intrathecal 1% 2-chlorprocaine for short gynecological day care procedures: Prospective, randomized, dose finding study

Background and Aims

Establishing the optimum dose of intrathecal 1% 2-chlorprocaine may reduce the discharge time and encourage more widespread use of spinal anesthesia for day care procedures. The aim of this study was to compare the efficacy and recovery characteristics of three different doses of intrathecal 1% 2-chlorprocaine for short gynecological day care procedures.

Material and Methods

Fifty-one patients scheduled for elective day care gynecological procedures lasting less than 60 min and were randomly divided into three groups of 17 each to receive 35 mg, 40 mg, or 45 mg intrathecal 1% 2-chlorprocaine. Demographic data, time required to achieve readiness for surgery, time required to attain discharge criteria, maximum block height achieved, and adverse effects were recorded in each group.

Results

The time required to achieve readiness for surgery was similar between the three groups (P = 0.306). However, 35 mg group required the shortest time to ambulate and there was a significant difference as compared with both 40 mg (P = 0.012) and 45 mg (P = 0.001). Voiding and the fulfillment of the discharge parameters were also attained more rapidly in the 35 mg group [133 (120,155) min] as compared with both 40 mg [164 (145,175) min, P = 0.000] and 45 mg [160 (150,175) min, P = 0.000]. None of the patients reported neurological symptoms during the follow-up.

Conclusion

The 35 mg intrathecal 1% 2-chlorprocaine not only provides reliable anesthesia for short gynecological procedures but also facilitates faster achievement of the discharge parameters as compared with the 40 mg and 45 mg doses.

Spinal anesthesia in ambulatory surgery

Spinal anesthesia is a safe alternative to general anesthesia but remains underrepresented in the ambulatory setting. Most concerns relate to low flexibility of spinal anesthesia duration and the management of urinary retention in the outpatient setting. This review focuses on the characterization and safety of the local anesthetics that are available to adapt spinal anesthesia very flexibly to the needs of ambulatory surgery. Furthermore, recent studies on the management of postoperative urinary retention provide evidence for safe, but report wider discharge criteria and much lower hospital admission rates. With the local anesthetics that have current approval for usage in spinal anesthesia, most requirements for ambulatory surgeries can be met. The reported evidence on local anesthetics without approval supports clinically established off-label use and can improve the results even further.

Comparing Spinal Chloroprocaine to Hyperbaric and Isobaric Bupivacaine for Total Hip and Knee Arthroplasties: A Retrospective Study

INTRODUCTION

Spinal anesthesia is commonly used for total knee and hip arthroplasties (TKA/THA). The rising popularity of ambulatory TKA and THAs require anesthetic techniques that provide rapid recovery of motor and sensory function while minimizing side effects like postoperative urinary retention. This single-center retrospective observational study compares the recovery profile of patients undergoing TKA and THA under chloroprocaine spinals compared to hyperbaric and isobaric bupivacaine spinals.

METHODS

One hundred and twelve patients undergoing primary TKA and THA under spinal anesthesia at University of Florida Health were identified between September 1, 2019 and February 21, 2020. Their electronic medical records were reviewed. Patients were categorized based on the local anesthetic used in the spinal. Various demographic, intraoperative, and postoperative data were compiled and compared, including duration of surgery, time to physical therapy, time to post-anesthesia care unit (PACU) discharge, and time to spontaneous micturition.

RESULTS

Time to spontaneous micturition and PACU discharge were significantly lower in the chloroprocaine spinal group compared to the hyperbaric bupivacaine group by 193 minutes and 42 minutes, respectively. Fewer patients receiving chloroprocaine spinals had their first physical therapy session limited by residual motor weakness compared to those in both bupivacaine groups. Additionally, mean duration of surgery was shorter in the chloroprocaine group compared to both bupivacaine groups (89 minutes compared to 111 minutes). Time to physical therapy completion was not different. All groups had <10% conversion to general anesthesia.

CONCLUSION

Chloroprocaine spinals can be feasible options for TKAs and THAs with improved postoperative recovery profiles compared to bupivacaine spinals.

A Comparative Study of Dexmedetomidine versus Nalbuphine Used as an Adjuvant to Chloroprocaine for Daycare Surgeries Performed under Subarachnoid Block

Backgrounds and Aims

Nalbuphine or dexmedetomidine when used as an adjuvant to local anesthetic agents may alter the characteristics of subarachnoid block. The study aimed to compare the effect of adding these drugs as an adjuvant to chloroprocaine for spinal anesthesia.

Settings and Design

This prospective, randomized, double-blind study was conducted at a tertiary care center.

Materials and Methods

After obtaining permission from the institutional ethical committee and informed patient consent, patients scheduled for surgeries under subarachnoid block were randomized into three groups of 50 each: Group C: Injection 1% chloroprocaine 40 mg (4 mL) with 1 mL normal saline, Group DC: injection 1% chloroprocaine 40 mg (4 mL) with dexmedetomidine 10 μg diluted to 1 mL in normal saline, and Group NC: injection 1% chloroprocaine 40 mg (4 mL) with nalbuphine 0.4 mg diluted to 1 mL in normal saline. Onset, peak, duration, and time to complete regression of sensory and motor blockade were noted. Side effects, if any, were noted and managed appropriately.

Statistical Analysis

Qualitative data were analyzed using Chi-square test and quantitative data were analyzed using Student's t-test and two-sided Mann-Whitney U-test. P < 0.05 was considered statistically significant.

Results

Group DC had prolonged time to onset, duration, and complete regression of sensory and motor block compared to Group NC and Group C (P < 0.001). Hemodynamic parameters, sedation score, and side effects were comparable in all groups.

Conclusion

Thus, nalbuphine is a better adjuvant to chloroprocaine than dexmedetomidine when administered intrathecally for daycare surgeries performed under spinal anesthesia.

Influence of height on ED95 of intrathecal 2-chloroprocaine for knee arthroscopy: A prospective dose-response clinical trial

BACKGROUND

Plain 2-chloroprocaine , a rapid acting amino-ester-type local anaesthetic, is used in short ambulatory procedures under spinal anaesthesia. The ED 95 of 2-chloroprocaine for lower limb surgery has not yet been defined. Moreover, patients' body height could influence the effects of the administered dose.

OBJECTIVES

The aim of this study was to determine the ED 95 of plain 2-chloroprocaine based on the height of patients undergoing ambulatory knee arthroscopy under spinal anaesthesia using the continual reassessment statistical method (CRM).

DESIGN

Prospective, dose-response, double blind, controlled, bi-center, clinical trial.

SETTING

One university teaching hospital in Brussels and one general teaching hospital, Braine l'Alleud, Belgium. Université libre de Bruxelles.

PATIENTS

ASA I-III (120 patients) scheduled for day-case knee arthroscopy under spinal anaesthesia.

INTERVENTIONS

Patients were divided into three groups of 40, each comprising 10 cohorts of 4 patients, according to their respective heights (Group 1: 150-165 cm, Group 2: 166-180 cm, Group 3: 181-195 cm). Each patient enrolled into one of the 3 groups received an intrathecal dose of plain 2-chloroprocaine determined by the CRM. The starting doses for the first cohorts of four were 40 mg in group 1, 45 mg in group 2 and 50 mg in group 3. The doses for subsequent cohorts were determined by CRM of outcomes in all patients in the previous competed cohorts. Anaesthesia was considered successful when there was a lack of pinprick or cold sensation up to T12, the visual analogue scale score for tourniquet pain was < 2 and no pain during surgery.

MAIN OUTCOMES

The primary outcome was the success or failure of the block. Side effects were also recorded.

RESULTS

ED 95 of 2-chloroprocaine is 40 mg in group 1, 35 mg in group 2, 45 mg in group 3. Groups were different in terms of height and gender ( P  < 0.05) and similar in terms of body mass index and age ( P  > 0.05).

CONCLUSION

The ED95 of intrathecal 2-chloroprocaine for patients undergoing ambulatory knee arthroscopy is between 35 and 45 mg. Height could be a factor involved in the calculation, and patient sex could partly explain the nonlinear relation between height and dose.

TRIAL REGISTRY NUMBER

Clinicaltrials.gov NCT03882489.

Intrathecal pramipexole and selegiline for sensory and motor block in rats

BACKGROUND

The purpose of the study was to investigate spinal sensory and motor block by antiparkinsonian drugs (pramipexole and selegiline), and the combination of pramipexole and the local anesthetic lidocaine.

METHODS

Using a technique of spinal blockade in rats, the effects of pramipexole, selegiline, and coadministration of pramipexole and lidocaine on spinal blockades of motor and sensory function were investigated.

RESULTS

Under a concentration of 100 mM, pramipexole displayed more potent and had a longer duration of nociceptive, proprioceptive, and motor block than selegiline, whereas pramipexole and selegiline were less potent in comparison to lidocaine. Pramipexole produced spinal nociceptive, proprioceptive, and motor blocks in a dose-related manner. On the ED₅₀ (50% effective dose) basis, the rank-order potency on nociceptive, proprioceptive, and motor block was pramipexole < lidocaine. The spinal block duration of pramipexole was greater than lidocaine at every equipotent dose tested (ED₂₅, ED₅₀, and ED₇₅). Coadministration of lidocaine (ED₅₀ or ED₉₅) with pramipexole (4.5 μmol/kg) improved the effect (efficacy) and duration of the spinal block.

CONCLUSIONS

Pramipexole and selegiline were less potent than lidocaine to block sensory and motor responses. The duration of the spinal anesthetic effect of pramipexole was longer than lidocaine. At a non-effective dose, pramipexole increased the duration of efficacy of lidocaine.

ED90 of spinal 2-chloroprocaine 1% in ambulatory knee arthroscopy up to 45 min: a randomized biased-coin- up-and-down sequential allocation trial

Background

A short acting spinal anesthetic facilitates smooth flow since quick recovery of motor function will facilitate unassisted ambulation. The aim of this study was to estimate the effective dose (ED90) of intrathecal 2-chloroprocaine 1% in outpatient knee arthroscopy.

Methods

Two cohorts were included in two different hospitals. In cohort I, a randomized biased-coin up-and-down design with 40 patients was used to find the ED90. Four dose-levels of plain 2-chloroprocaine 1% were used: 25, 30, 35 and 40 mg. The identified primary outcome, the ED90, was validated in 50 patients in cohort II with an open label design. Secondary outcomes included time to complete recovery from motor and sensory block with spinal injection as time zero, peak sensory block level, urine retention and time until hospital discharge.

Results

Forty patients were included in the final analysis in cohort I. The ED90 was estimated at 27.8 mg, successful spinal anesthesia was obtained in 38 patients (95%). Fifty patients were included in the final analysis in cohort II, 49 patients had successful anesthesia with a fixed round dose of 28 mg. In this Cohort, peak sensory block was T10/T11 (range: (L4–T4)). The median time to full recovery of the motor block was 60 min (45–60) and 90 min (75–105) for the sensory block. The mean time to hospital discharge was 2.9 hours (0.7).

Conclusion

The ED90 of 2-chloroprocaine 1% in knee arthroscopy was estimated to be 27.8 mg. In an external population, the ED90 resulted in successful anesthesia in 98% of the patients (95% CI 89% to 100%).

Trial registration number

Netherlands Trial Registry (NL6769).

Spinal or Intravenous Dexmedetomidine for Spinal Anesthesia with Chloroprocaine in Ambulatory Knee Arthroscopies: A Double-Blind Randomized Trial

Purpose

Chloroprocaine provides spinal anesthesia for day-case surgery lasting up to 40 minutes. Intravenous and spinal dexmedetomidine can prolong spinal anesthesia, but no data are available for the combination with chloroprocaine. This double-blind randomized controlled trial compares chloroprocaine with spinal or intravenous dexmedetomidine regarding block characteristics, micturition, and discharge times.

Patients and Methods

After ethical approval and informed consent, 135 patients scheduled for knee arthroscopy were randomized to receive either 40mg spinal chloroprocaine (Chloro-group), 40mg chloroprocaine with 5 mcg spinal dexmedetomidine (Spinal Dex-group) or 40mg chloroprocaine with 0.5 mcg/kg IV dexmedetomidine (IV DEXgroup). Block characteristics, hemodynamic variables and the use of analgesics were registered. Voiding and discharge times were noted. A scoring system was used for micturition problems and sedation. Transient neurological symptoms (TNS) and other late side effects were evaluated after one week.

Results

Demographic data were similar between groups. Block onset times and intensity of motor block were comparable between groups. The time to L2 and Bromage 1 regression was prolonged in the SpinalDEx-group by approximately 30 minutes compared to the other groups (p < 0.01). First voiding as well as discharge from the hospital was prolonged in the Spinal Dex-group by approximately 40 minutes p < 0.01. There was no significant difference between groups regarding treatment of hypotension, sedation, micturition problems or the use of postoperative analgesics (P > 0.8). One patient experienced TNS.

Conclusion

Intrathecal but not intravenous (0.5 mcg/kg) dexmedetomidine can prolong chloroprocaine (40mg) spinal anesthesia when surgery is expected to last over 40 minutes. Despite a similar incidence of adverse effects, this also led to a postponed hospital discharge time.

Evaluation of neurotoxicity and long-term function and behavior following intrathecal 1 % 2-chloroprocaine in juvenile rats

Spinally-administered local anesthetics provide effective perioperative anesthesia and/or analgesia for children of all ages. New preparations and drugs require preclinical safety testing in developmental models. We evaluated age-dependent efficacy and safety following 1 % preservative-free 2-chloroprocaine (2-CP) in juvenile Sprague-Dawley rats. Percutaneous lumbar intrathecal 2-CP was administered at postnatal day (P)7, 14 or 21. Mechanical withdrawal threshold pre- and post-injection evaluated the degree and duration of sensory block, compared to intrathecal saline and naive controls. Tissue analyses one- or seven-days following injection included histopathology of spinal cord, cauda equina and brain sections, and quantification of neuronal apoptosis and glial reactivity in lumbar spinal cord. Following intrathecal 2-CP or saline at P7, outcomes assessed between P30 and P72 included: spinal reflex sensitivity (hindlimb thermal latency, mechanical threshold); social approach (novel rat versus object); locomotor activity and anxiety (open field with brightly-lit center); exploratory behavior (rearings, holepoking); sensorimotor gating (acoustic startle, prepulse inhibition); and learning (Morris Water Maze). Maximum tolerated doses of intrathecal 2-CP varied with age (1.0 μL/g at P7, 0.75 μL/g at P14, 0.5 μL/g at P21) and produced motor and sensory block for 10-15 min. Tissue analyses found no significant differences across intrathecal 2-CP, saline or naïve groups. Adult behavioral measures showed expected sex-dependent differences, that did not differ between 2-CP and saline groups. Single maximum tolerated in vivo doses of intrathecal 2-CP produced reversible spinal anesthesia in juvenile rodents without detectable evidence of developmental neurotoxicity. Current results cannot be extrapolated to repeated dosing or prolonged infusion.

Spinal anaesthesia with Chloroprocaine HCl 1% for elective lower limb procedures of short duration: a prospective, randomised, observer-blind study in adult patients

Background

This prospective, randomised, observer-blinded study has been conducted in patients undergoing procedures of the lower extremities to evaluate the time to complete block resolution of 2-chloroprocaine 1% at three intrathecal doses (30, 40 and 50 mg).

Methods

After informed consent, we enrolled 45 male and female patients, aged 18–65 years, ASA score I-II, BMI 18–32 kg/m², undergoing elective lower limb procedures lasting ≤40 min and with a requested dermatomeric level of sensory block ≥ T12.

The patients were randomised in a 1:1:1 ratio to receive Chloroprocaine HCl 1% at one of the three different intrathecal doses (Group 30 = 30 mg, Group 40 = 40 mg or Group 50 = 50 mg). The progression and regression of both sensory and motor blocks were evaluated blindly. Urine and venous blood samples were collected for pharmacokinetic analysis.

Results

Times to regression of spinal blocks were 1.76 ± 0.35 h, 2.13 ± 0.46 h and 2.23 ± 0.38 h, in Group 30, 40 and 50 respectively: the 30 mg dose showed a significantly faster resolution of spinal block than the 40 mg (p = 0.034) and the 50 mg (p = 0.006). Time to readiness for surgery was significantly reduced with the dose of 50 mg when compared to dose of 30 mg (p = 0.0259).

Conclusions

The doses of 50 mg and 40 mg yielded a longer resolution of spinal block than the dose of 30 mg. Nevertheless, the dose of 30 mg resulted in a higher secondary failure rate.

Trial registration

Registration of clinical trial: clinicaltrials.gov (NCT02481505).

Comparison of analgesic efficacy of intrathecal 1% 2-chloroprocaine with or without fentanyl in elective caesarean section: A prospective, double-blind, randomised study

Background and Aims:

Preservative free 1% 2-chlorprocaine is a short acting local anaesthetic agent suitable for day care surgical procedures. Potentiation of analgesic action of intrathecal local anaesthetics by the addition of opioids is well known. In this study, we investigated the effect of intrathecal fentanyl as an adjuvant to 1% 2-chloroprocaine (2-CP) in parturients undergoing elective lower segment caesarean section (LSCS).

Methods:

This prospective randomised comparative study was performed on 150 healthy, term parturients planned for elective low risk LSCS, divided into two equal groups. The group CS received 1% preservative-free 2-CP 3 ml (30 mg) + 0.5 ml normal saline and group CF received 1% preservative-free 2-CP 3 ml (30 mg) + 0.5 ml fentanyl (25 μg) with a total volume of 3.5 ml intrathecally in both groups. The duration of sensory blockade, duration of motor blockade, maximum height of sensory block, haemodynamic parameters, quality of block, neonatal outcome, patient satisfaction and any side effects were recorded.

Results:

There were no significant differences in demographic characteristics, haemodynamic parameters, onset of sensory block, onset of motor block and duration of motor block between the groups. The duration of sensory block and duration of analgesia was statistically prolonged in group CF than group CS (P value < 0.0001). There was no statistical difference in the Apgar score of newborns in both groups. The adverse effects (hypotension, bradycardia, nausea/vomiting, shivering and transient neurological symptoms) were comparable in both the groups.

Conclusion:

The addition of fentanyl to 1% 2-chloroprocaine intrathecally prolonged the duration of sensory block and postoperative analgesia in patients undergoing LSCS.

Chloroprocaine Provides Safe, Effective, Short-Acting Spinal Anesthesia Ideal for Ambulatory Surgeries: A Retrospective Review

BACKGROUND

The ideal local anesthetic for use in ambulatory spinal anesthesia is safe, with minimal adverse effects, and of a duration that does not impede post-anesthesia care unit (PACU) discharge. Since its approval for use in spinal anesthesia in Europe in 2012, chloroprocaine has seen a resurgence. Recent studies have investigated the safety and efficacy of preservative-free chloroprocaine for use in spinal anesthesia, but few provide the incidence of adverse events such as urinary retention and transient neurologic symptoms.

QUESTIONS/PURPOSES

We sought to assess the safety of chloroprocaine for spinal anesthesia, including the incidence of adverse events and the duration and quality of its use, in the initial 6 months of its use at our institution. We hypothesized that chloroprocaine would provide effective spinal anesthesia for orthopedic cases of short duration, with a low rate of complications.

METHODS

We conducted a retrospective chart review of all patients from June to December 2016 at our institution who had ambulatory knee arthroscopy or foot procedures in which chloroprocaine spinal anesthesia was used. For all 445 charts analyzed, data were collected on anesthesia characteristics, office visits, nursing PACU assessment, and nursing post-operative day 1 follow-up phone calls.

RESULTS

The median chloroprocaine dosage was 44 mg (interquartile range [IQR], 40 to 50). The median duration of sensory block was 156 min (IQR, 128 to 189) and of motor block was 148 min (IQR, 123 to 181). Time to ambulation was 186 min (IQR, 158 to 218) and time to meeting of discharge criteria was 218 min (IQR, 189 to 250). The most common adverse events in the PACU were bradycardia and hypotension. No patients had urinary retention or transient neurologic symptoms.

CONCLUSIONS

In 6 months of use at our institution, chloroprocaine provided safe and effective spinal anesthesia for short orthopedic procedures, with no incidence of transient neurologic symptoms, neuropraxia, or urinary retention.

Amitriptyline Protects Against Lidocaine-induced Neurotoxicity in SH-SY5Y Cells via Inhibition of BDNF-mediated Autophagy

Amitriptyline (AMI) is a traditional tricyclic antidepressant that has been proven to exhibit neuroprotective effects in various neurological disorders. However, the underlying mechanism by which AMI attenuates lidocaine-induced neurotoxicity remains poorly understood. Brain-derived neurotrophic factor (BDNF) is an essential neurotrophin to neuronal development and survival in the brain, and recent studies have suggested that BDNF plays an important role in mediating lidocaine-induced neurotoxicity. The present study was performed to evaluate the protective effect of AMI against the neurotoxicity induced by lidocaine and to explore the role of BDNF-dependent autophagy in this process. The data showed that AMI pretreatment alleviated lidocaine-induced neurotoxicity, as evidenced by the restoration of cell viability, normalization of cell morphology, and reduction in the cell apoptosis index. In addition, autophagy inhibitor 3-methyladenine (3-MA) had a protective effect similar to that of AMI, but autophagy activator rapamycin eliminated the protective effect of AMI by suppressing mTOR activation. Moreover, at the molecular level, we found that AMI-mediated autophagy was involved in the expression of BDNF. The overexpression of BDNF or application of exogenous recombinant BDNF significantly suppressed autophagy and protected SH-SY5Y cells from apoptosis induced by Lido, whereas the neuroprotection of AMI was abolished by either knockdown of BDNF or use of a tropomyosin-related kinase B (TrkB) inhibitor ANA-12 in SH-SY5Y cells. Overall, our findings demonstrated that the protective effect of AMI against lidocaine-induced neurotoxicity correlated with inhibition of autophagy activity through upregulation of BDNF expression.

Comparison of epidural anesthesia with chloroprocaine and lidocaine for outpatient knee arthroscopy

This study aimed to compare clinical efficacy and safety of chloroprocaine and lidocaine in epidural anesthesia for outpatient knee arthroscopy. Eighty patients undergoing knee arthroscopy were randomly allocated to receive 3% 2-chloroprocaine (group C, n = 40) or 2% lidocaine (group L, n = 40) for epidural block. Latency to anesthesia onset, highest block level, time to achieve peak effect, time to complete sensory and motor block regression, vital signs including respiration and hemodynamics, and complications during follow-up were recorded. No significant differences were found in the latency to anesthesia onset and peak effect, duration of anesthesia efficacy, and the time for recovery of sensory function between the two groups. However, the latency to maximal block of pain sensation and the time needed to recover motor function were significantly shorter in group C than in group L (p < 0.05). No adverse effects or neurologic complications were found in both groups. In conclusion, epidural chloroprocaine elicits rapid anesthetic effects, fast sensor and motor block, and faster recovery of motor function compared to lidocaine. These characteristics make chloroprocaine better than lidocaine as the choice of epidural anesthesia in short clinical operations such as knee arthroscopy.

Dexmedetomidine protects against lidocaine-induced neurotoxicity through SIRT1 downregulation-mediated activation of FOXO3a

Lidocaine, a typical local anesthetic, has been shown to directly induce neurotoxicity in clinical settings. Dexmedetomidine (DEX) is an alpha-2-adrenoreceptor agonist that has been used as anxiolytic, sedative, and analgesic agent which has recently found to protect against lidocaine-induced neurotoxicity. Nicotinamide adenine dinucleotide-dependent deacetylase sirtuin-1 (SIRT1)/forkhead box O3 (FOXO3a) signaling is critical for maintaining neuronal function and regulation of the apoptotic pathway. In the present study, we designed in vitro and in vivo models to investigate the potential effects of lidocaine and DEX on SIRT1 and FOXO3a and to verify whether SIRT1/FOXO3a-mediated regulation of apoptosis is involved in DEX-induced neuroprotective effects against lidocaine. We found that in both PC12 cells and brains of mice, lidocaine decreased SIRT1 level through promoting the degradation of SIRT1 protein. Lidocaine also increased FOXO3a protein level and increased the acetylation of SIRT1 through inhibiting SIRT1. Upregulation of SIRT1 or downregulation of FOXO3a significantly inhibited lidocaine-induced changes in both cell viability and apoptosis. DEX significantly inhibited the lidocaine-induced decrease of SIRT1 protein level and increase of FOXO3a protein level and acetylation of FOXO3a. Downregulation of SIRT1 or upregulation of FOXO3a suppressed DEX-induced neuroprotective effects against lidocaine. The data suggest that SIRT1/FOXO3a is a potential novel target for alleviating lidocaine-induced neurotoxicity and provide more theoretical support for the use of DEX as an effective adjunct to alleviate chronic neurotoxicity induced by lidocaine.

Lidocaine vs. Other Local Anesthetics in the Development of Transient Neurologic Symptoms (TNS) Following Spinal Anesthesia: A Meta-Analysis of Randomized Controlled Trials

The use of lidocaine in spinal anesthesia may increase the risk of transient neurological symptoms (TNS) according to previous meta-analyses. However, the previous meta-analyses lacked data on some other local anesthetics and thus, more evaluations are still needed to compare the effect of lidocaine on the development of TNS. The objective of this study was to compare the risk of TNS according to lidocaine versus other local anesthetics in patients undergoing spinal anesthesia. A total of 39 randomized controlled trials with 4733 patients were analyzed. The incidence of TNS was 10.8% in the lidocaine group and was 2.2% in the control groups (risk ratio (RR) 4.12, 95% confidence interval (CI) 3.13 to 5.43, p < 0.001). In subgroup analysis, lidocaine increased the incidence of TNS compared with other local anesthetics except mepivacaine, ropivacaine or sameridine. The risk of TNS was higher in the hyperbaric (p < 0.001) or isobaric lidocaine (p < 0.001) group compared with the control group, but there were no differences found between the two groups when hypobaric lidocaine was administered (p = 1.00). This study confirmed that lidocaine for spinal anesthesia still causes TNS more frequently than most other local anesthetics, especially when hyperbaric or isobaric lidocaine was used.

Impact of Chloroprocaine on the Eligibility for Hospital Discharge in Patients Requiring Ambulatory Surgery Under Spinal Anesthesia: An Observational Multicenter Prospective Study

Introduction

This observational study was designed to assess the use of spinal anesthesia with chloroprocaine in the context of ambulatory surgery.

Methods

A prospective, multicenter, observational study was carried out among 33 private or public centers between May 2014 and January 2015 and adult patients, scheduled for a short ambulatory surgery under spinal anesthesia with chloroprocaine. The primary outcomes were anesthetic effectiveness, defined as performance of the whole surgical procedure without any additional anesthetic agent, and the time to achieve eligibility for hospital discharge. Secondary outcomes were the effect of chloroprocaine on motor and sensory blocks, patients’ satisfaction, and the use of analgesics in the first 24 h after surgery.

Results

Among the 615 enrolled patients, 56% were male, the mean age was 47.2 ± 15.2 years, and most patients had an ASA (American Society of Anesthesiologists) status of 1 (63.7%). Main surgical procedures performed were orthopedic (62.6%) and gynecologic (16.1%), and the mean duration of surgery was 26.7 ± 16.7 min. The overall anesthetic success rate was 93.8% (95% CI [91.5%; 95.6%]) for the 580 patients with available data for primary criteria. The failure rate was lower than 7% for all surgical procedures, except for gynecologic surgery (14.8%; 95% CI [8.1%; 23.9%]). The average times of eligibility for hospital discharge and effective discharge were 252.7 ± 82.7 min and 313.8 ± 109.9 min, respectively. The time of eligibility for hospital discharge is defined as the recovery of the patient’s normal clinical parameters and the time of effective discharge is defined as the time for the patient to leave the hospital after surgery. Eligibility for patient’s discharge was achieved more rapidly in private than public hospitals (236.3 ± 77.2 min vs. 280.9 ± 80.7 min, respectively, p < 0.001).

Conclusions

This study showed positive results on the effectiveness of chloroprocaine as a short-duration anesthetic and could be used to reduce the time to achieve eligibility for hospital discharge.

Trial Registration

ClinicalTrials.gov identifier, NCT02152293. Registered on May 6, 2014. Date of enrollment of the first participant in the trial May 7, 2014.

Chloroprocaine versus prilocaine for spinal anesthesia in ambulatory knee arthroscopy: a double-blind randomized trial

BACKGROUND

In ambulatory lower limb surgery, spinal anesthesia with rapid onset and a short duration of block is preferable. We hypothesized that the use of 2-chloroprocaine would be associated with a faster motor block recovery compared with prilocaine in knee arthroscopy. A difference of 15 min was considered clinically relevant.

METHODS

150 patients were randomly allocated to receive intrathecally either 40 mg of 2-chloroprocaine or 40 mg of prilocaine. The primary outcome was the time to complete recovery from motor blockade. Secondary outcomes included time to full regression of sensory block, peak sensory block level, urine retention needing catheterization, time until hospital discharge, incidence of transient neurologic symptoms and patient satisfaction.

RESULTS

Time to complete recovery from motor blockade was 15 min shorter for 2-chloroprocaine (median: 60 min; IQR: 60-82.5) than for prilocaine (median: 75 min; IQR: 60-90; p=0.004). 2-Chloroprocaine also resulted in faster full regression of sensory block (median: 120 min; IQR: 90-135 compared with median: 165 min; IQR: 135-190, p<0.001) and faster time to hospital discharge (mean difference: 57 min; 95% CI 38 to 77, p<0.001). Peak sensory block was higher in the 2-chloroprocaine group (median: T9; IQR: T6-T12 compared with median: T10; IQR: T8-T12, p<0.008). Patient satisfaction and urine retention needing catheterization were equal in both groups.

CONCLUSIONS

In knee arthroscopy, spinal anesthesia with 2-chloroprocaine results in a faster recovery of motor and sensory block, leading to quicker hospital discharge compared with prilocaine.

TRIAL REGISTRATION NUMBER

NTR6796.

[Evaluation of spinal anesthesia in urological outpatient surgery, comparison between two local anesthetics (Chloroprocaine/Bupivacaine)]

INTRODUCTION

Spinal anesthesia in outpatient urology is controversial (longer hospital stay, risk of urinary retention). The main goal was to evaluate outpatient spinal anesthesia and to compare 2 local anesthetics secondarily.

MATERIAL

Monocentric retrospective study including all patients undergoing surgery in urological ambulatory surgery under spinal anesthesia between December 2011 and May 2015, split into two groups according to the local anesthetic used: bupivacaine (BP) and chloroprocaine (CP). Quantitative variables were compared by Student's t-test, qualitative variables by χ² test.

RESULTS

Seventy-one (95%) out of the 75 patients included have been discharged the same day. Discharge was impossible in these cases: patient alone at home (1), bladder clot (1), JJ intolerance (1), delayed micturition (1). The mean duration of the procedure was 27±19min, the SSPI's was 55±31min, the stay's was 360±91min. A total of 45 patients (60%) received BP and 30 (40%) received CP. The mean residence time in SSPI was significantly reduced in the CP group (47±24min vs. 61±34min, P=0.04). One patient experienced urination delay in the BP group with no significant difference. No significant difference for the other criteria studied despite the mean age, which is higher in the CP group (P=0.02).

CONCLUSION

Spinal anesthesia is adapted to ambulatory urology, and does not increase the risk of urinary retention, especially with CP that would decrease the length of stay in SSPI compared to BP.

LEVEL OF EVIDENCE

4.

Dexmedetomidine protects PC12 cells from lidocaine-induced cytotoxicity via downregulation of Stathmin 1

Background: Understanding of lidocaine-induced neurotoxicity is not complete, resulting in the unsuccessful treatment in some clinical settings. Dexmedetomidine (DEX) has been shown to alleviate lidocaine-induced neurotoxicity in our previous cell model. However, the rationale for DEX combined with lidocaine to reduce lidocaine-induced neurotoxicity in the clinical setting remains to be further clarified in the detailed molecular mechanism. Methods: In this study, we established a cellular injury model by lidocaine preconditioning. Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) proliferation assay kit were used to analyze cell proliferation. Cell apoptosis was measured by flow cytometry and Hoechst 33342 staining. Cell cycle progression was detected by flow cytometry. The protein expression levels were detected by Western blotting and immunofluorescence staining. Results: Our results showed that DEX dose-dependently restored impaired proliferation of PC12 cells induced by lidocaine，as reflected by the increased cell viability and EdU positive cells, which were consistent with the decreased expression of tumor suppressor protein p21 and increased expression of cell cycle-related cyclin D1 and CDK1. In addition, DEX dose-dependently reduced apoptotic PC12 cells induced by lidocaine，as reflected by the decreased expression of apoptosis-related Bax, caspase-3 and caspase-9 and increased expression of anti-apoptotic Bcl-2 compared to the cells only treated with lidocaine. Mechanistically, with gain-or-loss-of-function of STMN1, we showed that DEX-mediated neuroprotection by lidocaine-induced damage is associated with downregulation of STMN1 which might be an upstream molecule involved in regulation of mitochondria death pathway. Conclusion: Our results reveal that DEX is likely to be an effective adjunct to alleviate chronic neurotoxicity induced by lidocaine.

Spinal anaesthesia with chloroprocaine 1% versus total intravenous anaesthesia for outpatient knee arthroscopy: A randomised controlled trial

BACKGROUND

Both general and spinal anaesthesia with short-acting local anaesthetics are suitable and reliable for knee arthroscopy as an ambulatory procedure. Chloroprocaine (CP) 1% seems to be the ideal spinal local anaesthetic for this indication.

OBJECTIVE

The aim of this study was to compare spinal anaesthesia using CP 1% with general for outpatient knee arthroscopy with regard to procedure times, occurrence of pain, patient satisfaction and recovery, and also costs.

DESIGN

A randomised controlled single-centre trial.

SETTING

University Medical Centre Mannheim, Department of Anaesthesiology and Surgical Intensive Care Medicine, Mannheim, Germany. April 2014 to August 2015.

PATIENTS

A total of 50 patients (women/men, 18 to 80 years old, ASA I to III) undergoing outpatient knee arthroscopy were included. A contra-indication to an allocated anaesthetic technique or an allergy to medication required in the protocol led to exclusion.

INTERVENTIONS

Either general anaesthesia with sufentanil, propofol and a laryngeal mask for airway-management or spinal with 40-mg CP 1% were used. We noted procedure times, patient satisfaction/recovery and conducted a 7-day follow-up.

MAIN OUTOMES

Primary outcome was duration of stay in the day-surgery centre. Secondary outcomes were first occurrence of pain, patient satisfaction, quality of recovery and adverse effects. In addition, we analysed treatment costs.

RESULTS

Spinal had faster recovery than general anaesthesia with patients reaching discharge criteria significantly earlier [117 min (66 to 167) versus 142 min (82 to 228), P = 0.0047]. Pain occurred significantly earlier in the general anaesthesia group (P = 0.0072). Costs were less with spinal anaesthesia (cost ratio spinal: general 0.57). Patients felt significantly more uncomfortable after general anaesthesia (P = 0.0096).

CONCLUSION

Spinal anaesthesia with 40-mg CP 1% leads to a significantly earlier discharge and is cheaper compared with general.

TRIAL REGISTRATION

German Clinical Trials Register, www.drks.de, identifier: DRKS00005989.

Intrathecal pramoxine causes long-lasting spinal sensory and motor block in rats

OBJECTIVES

The objective of this experiment was to investigate spinal anaesthetic effects of pramoxine and its comparison with bupivacaine, a long-lasting local anaesthetic.

METHODS

After intrathecal injection, three neurobehavioural assessments, which consisted of nociceptive, proprioceptive and motor block, were constructed in rats. The effects of bupivacaine and pramoxine (four doses of each drug) in a dose-related manner were conducted to obtain the ED₅₀ (50% effective dose). Pramoxine potency and duration at provoking spinal nociceptive, proprioceptive and motor block were compared with those of bupivacaine.

KEY FINDINGS

We manifested that pramoxine provoked dose-relatedly spinal blockades of nociception, proprioception and motor function. Based on the ED₅₀ , the rank potency at producing spinal nociceptive, proprioceptive and motor block was bupivacaine (0.90 (0.82-1.02), 1.00 (0.92-1.08) and 1.16 (1.02-1.34) μmol/kg) greater (P < 0.01 for the differences) than pramoxine (15.47 (14.04-17.05), 16.46 (15.06-17.99), and 17.77 (16.48-19.15) μmol/kg). The spinal block duration created by bupivacaine was not predominantly different (P > 0.05 for the differences) from that created by pramoxine at the equipotent doses (ED₇₅ , ED₅₀ and ED₂₅ ).

CONCLUSIONS

Our preclinical experiment indicated that pramoxine elicited a dose-related spinal block, was less potent than bupivacaine and had a similar duration of spinal block compared with bupivacaine.

Alternative topical anesthesia for bronchoscopy in a case of severe lidocaine allergy

Lidocaine allergy presents a unique difficulty for both patients and providers who undergo/perform bronchoscopy. We present a case of a 73 yo male with severe lidocaine allergy who successfully underwent bronchoscopy with chloroprocaine topical anesthesia and discuss alternative topical anesthetic agents that may be used in this special situation.

Naloxone prolongs cutaneous nociceptive block by lidocaine in rats

We aimed to investigate the local anesthetic properties of naloxone alone or as an adjunct for the local anesthetic lidocaine. After the block of the cutaneous trunci muscle reflex (CTMR) with drugs delivery by subcutaneous infiltration, cutaneous nociceptive block was tested on the ratsꞌ backs. We demonstrated that naloxone, as well as lidocaine, elicited cutaneous analgesia dose-dependently. The relative potency in inducing cutaneous analgesia was lidocaine [22.6 (20.1 - 25.4) μmol/kg] > naloxone [43.2 (40.3 - 46.4) μmol/kg] (P < 0.05). On an equianesthetic basis [50% effective dose (ED₅₀ ), ED₂₅ , and ED₇₅ ], naloxone displayed a greater duration of cutaneous analgesic action than lidocaine (P < 0.01). Coadministration of lidocaine (ED₉₅ or ED₅₀ ) and ineffective-dose naloxone (13.3 μmol/kg) intensifies sensory block (P < 0.01) with prolonged duration of action (P < 0.001) compared with lidocaine (ED₉₅ or ED₅₀ ) alone or naloxone (13.3 μmol/kg) alone on infiltrative cutaneous analgesia. The preclinical data showed that naloxone is less potent than lidocaine as an infiltrative anesthetic, but its analgesic duration was longer than that of lidocaine. Furthermore, naloxone prolongs lidocaine analgesia, acting synergistically for nociceptive block.

Dexmedetomidine Protects PC12 Cells from Lidocaine-Induced Cytotoxicity Through Downregulation of COL3A1 Mediated by miR-let-7b

Safety concerns of some local anesthetics, such as lidocaine, have been raised in recent years due to potential neurological impairment. Dexmedetomidine may protect humans from neurotoxicity, and miR-let-7b is activated by nerve injury; however, the roles of miR-let-7b and its target gene in lidocaine-induced cytotoxicity are not well known. Through bioinformatics and a luciferase reporter assay, COL3A1 was suggested as a direct target gene of miR-let-7b. Here, we confirmed by measuring mRNA and protein levels that miR-let-7b was downregulated and COL3A1 was upregulated in lidocaine-treated cells, an observation that was reversed by dexmedetomidine. Similar to miR-let-7b mimics or knockdown of COL3A1, dexmedetomidine treatment reduced the expression of COL3A1, suppressed cell apoptosis and cell migration/invasion ability, and induced cell cycle progression and cell proliferation in PC12 cells, effects that were reversed by the miR-let-7b inhibitor. Meanwhile, proteins involved in cell apoptosis, such as Bcl2 and caspase 3, were impacted as well. Taken together, dexmedetomidine may protect PC12 cells from lidocaine-induced cytotoxicity through miR-let-7b and COL3A1, while also increasing Bcl2 and inhibiting caspase 3. Therefore, miR-let-7b and COL3A1 might play critical roles in neuronal injury, and they are potential therapeutic targets.

Comparison of 2-Chloroprocaine, Bupivacaine, and Lidocaine for Spinal Anesthesia in Patients Undergoing Knee Arthroscopy in an Outpatient Setting: A Double-Blind Randomized Controlled Trial

BACKGROUND AND OBJECTIVES

Knee arthroscopy is a well-established procedure in day-case surgery, which is frequently performed under spinal anesthesia. It is, however, controversial whether the choice for a specific local anesthetic translates into relevant outcomes. We hypothesized that the use of 2-chloroprocaine would be associated with a faster recovery from sensorimotor block.

METHODS

Ninety-nine patients were included in this prospective, double-blind, randomized controlled trial and randomly allocated to receive either 40 mg 2-chloroprocaine, 40 mg lidocaine, or 7.5 mg bupivacaine. The primary endpoint was the time until complete recovery of sensory block. Secondary endpoints included time to recovery from motor block, failure rates, incidence of hypotension/bradycardia, postoperative pain, first mobilization, voiding and discharge times, and the incidence of transient neurologic symptoms. This clinical trial was registered prior to patient enrollment (EudraCT 2011-003675-11).

RESULTS

Patients in the chloroprocaine group had a significantly shorter time until recovery from sensory block (median, 2.6 hours; interquartile range [IQR], 2.2-2.9 hours) than patients in the lidocaine group (3.1 hours; IQR, 2.7-3.6 hours; P < 0.006) and in the bupivacaine group (6.1 hours; IQR, 5.5 hours to undefined hours; P < 0.0001). Chloroprocaine was associated with a significantly faster recovery from motor block than lidocaine and bupivacaine. Times to first mobilization, voiding, and discharge were significantly shorter for chloroprocaine when compared with bupivacaine, but not with lidocaine. In the bupivacaine group, patients needed significantly less rescue medication for postoperative pain when compared with lidocaine and chloroprocaine. Groups did not differ with respect to patient satisfaction, incidence of bradycardia/hypotension, and transient neurologic symptom rate.

CONCLUSIONS

For spinal anesthesia in patients undergoing ambulatory knee arthroscopy, chloroprocaine has the shortest time to complete recovery of sensory and motor block compared with bupivacaine and lidocaine.

Regional block via continuous caudal infusion as sole anesthetic for inguinal hernia repair in conscious neonates

PURPOSE

The use of general anesthesia in young children has come under increasing scrutiny due to its potential long-term neurotoxic effects. Meanwhile, regional anesthesia for surgical procedures in neonates has many advantages, including preservation of respiratory status and faster return to feeding. We describe the successful use of 3% 2-chloroprocaine administered via continuous caudal infusion as the sole anesthetic agent during elective surgical procedures in infants.

METHODS

A retrospective chart review of all patients who underwent elective surgical procedures under continuous caudal regional anesthetic at a single institution was performed. Thirty patients (27 males, three females) were identified: 28 patients underwent inguinal hernia repairs. Caudal anesthesia was established via continuous infusion of 3% 2-chloroprocaine through an indwelling catheter.

RESULTS

Successful analgesia by regional block alone was achieved in all patients for the duration of each surgical procedure without need for rescue anesthesia. Mean operative time was 49 min. Patients were able to return to feeding immediately after surgery and were ready for discharge home within that day.

CONCLUSION

Continuous caudal infusion of chloroprocaine is a safe and effective way to maintain adequate analgesia for elective surgeries in infants. This successful regional approach obviates the use of general anesthetic which reduces post-operative recovery time and avoids concerns for neurotoxicity.

Adjuvant Agents in Regional Anesthesia in the Ambulatory Setting

PURPOSE OF REVIEW

A majority of surgical practice has involved ambulatory centers with the number of outpatient operations in the USA doubling to 26.8 million per year. Local anesthesia delivery provides numerous benefits, including increased satisfaction, earlier discharge, and reduction in unplanned hospital admission. Further, with the epidemic of opioid mediated overdoses, local anesthesia can be a key tool in providing an opportunity to reduce the need for other analgesics postoperatively.

RECENT FINDINGS

Adjuvants such as epinephrine and clonidine enhance local anesthetic clinical utility. Further, dexmedetomidine prolongs regional blockade duration effects. There has also been a significant interest recently in the use of dexamethasone. Studies have demonstrated a significant prolongation in motor and sensory block with perineural dexamethasone. Findings are conflicting as to whether intravenous dexamethasone has similar beneficial effects. However, considering the possible neurotoxicity effects, which perineural dexamethasone may present, it would be prudent not to consider intravenously administered dexamethasone to prolong regional block duration. Many studies have also demonstrated neurotoxicity from intrathecally administered midazolam. Therefore, midazolam as an adjuvant is not recommended. Magnesium prolongs regional block duration but related to paucity of studies as of yet, cannot be recommended. Tramadol yields inconsistent results and ketamine is associated with psychotomimetic adverse effects. Buprenorphine consistently increases regional block duration and reduce opioid requirements by a significant amount. Future studies are warranted to define best practice strategies for these adjuvant agents. The present review focuses on the many roles of local anesthetics in current ambulatory practice.

Chloroprocaine 10 mg/ml for low-dose spinal anaesthesia in perianal surgery - a randomised dose finding study

BACKGROUND

Low-dose spinal anaesthesia is a safe and reliable anaesthesia technique in outpatient perianal surgery. Regarding its short duration of action and its trend to hyperbaric characteristics, plain chloroprocaine 10 mg/ml seems to be ideal to perform low-dose spinal anaesthesia. The aim of this trial was to determine the optimal dosage of chloroprocaine for this indication.

METHODS

Hundred and twenty patients undergoing perianal surgery were enrolled and randomly allocated to receive 10, 20 or 30 mg of chloroprocaine 10 mg/ml intrathecally. Patients had to sit upright for at least 10 min after injection. We measured the expansion of sensory and motor block and the times until voiding, walking without assistance and home discharge.

RESULTS

The expansion of the sensory (P ≤ 0.0059) and the motor block (P ≤ 0.0086) gained with increasing doses. At a dose of 30 mg the incidence of a profound, clinically relevant motor block was significantly higher compared to 10 and 20 mg (P ≤ 0.0004). In the 10 mg group two patients suffered from nociceptive pain due to an incomplete block and five patients announced discomfort during procedure. Doses of 10 and 20 mg led to a significantly earlier discharge compared to 30 mg (P = 0.0003; P = 0.0406).

CONCLUSION

Plain chloroprocaine 10 mg/ml can successfully be used for low-dose spinal anaesthesia in perianal outpatient surgery. Regarding the unfavourable motor block and later discharge-times in the 30 mg group on the one hand and the block-failures in the 10 mg group on the other, 20 mg can be recommended as the optimal dose.

Prilocaine spinal anesthesia for ambulatory surgery: A review of the available studies

Transient neurologic symptoms (TNS) led to the abandonment of intrathecal lidocaine. We reviewed the published literature for information about the duration of action and side effects of intrathecal prilocaine, which has been recently reintroduced in Europe. Medline and EMBASE databases were searched for the time period from 1966 to 2015. Fourteen prospective and one retrospective study were retrieved. The duration of the surgical block can be adjusted using doses between 40 and 80mg. Hyperbaric prilocaine in doses as low as 10mg can be used for perianal procedures. Four cases of TNS in 486 patients were reported in prospective studies, and none in 5000 cases in a retrospective data set. Spinal prilocaine appears to be safe and reliable for day case anesthesia. However, as chloroprocaine has a shorter duration and a lower risk of TNS and urinary retention, the indications for prilocaine remain to be defined.

Randomised controlled trial of spinal anaesthesia with bupivacaine or 2-chloroprocaine during caesarean section

BACKGROUND

Neuraxial anaesthesia is the desired method for Caesarean section. Bupivacaine is a well-known local anaesthetic. It has a long duration of action and can cause unpredictable levels of anaesthesia with subsequent prolonged discharge time. 2-Chloroprocaine has a rapid onset of action, producing an excellent sensory and motor block and has a rapid hydrolysis in the bloodstream by pseudocholinesterase. We compared bupivacaine and 2-chloroprocaine for spinal anaesthesia during Caesarean section. The primary endpoint was the earliest reversal sign of the motor block.

METHODS

Sixty ASAI/II patients, planned for elective singleton Caesarean section, were equally randomised to three groups. All patients received a combined spinal-epidural anaesthesia. The first group received 2-chloroprocaine (40 mg) without sufentanil, the second group received 2-chloroprocaine (40 mg) with sufentanil (1 μg) and the third group received hyperbaric bupivacaine (7.5 mg) with sufentanil (1 μg) as a spinal anaesthetic. Motor and sensory blockade were assessed at specific time points.

RESULTS

There was no difference between the three groups regarding the time to regression of the motor block. However, at 5 min post spinal injection, the level of sensory block was higher for both groups with 2-chloroprocaine, in comparison with the bupivacaine group.

CONCLUSION

2-Chloroprocaine can be used for low risk Caesarean section in healthy parturients. There is no difference in time to motor block resolution compared to bupivacaine. Motor recovery seems more predictable for 2-chloroprocaine and may be beneficial for the breastfeeding initiation.

Continuous chloroprocaine infusion for thoracic and caudal epidurals as a postoperative analgesia modality in neonates, infants, and children

BACKGROUND

Neonates and infants have decreased metabolic capacity for amide local anesthetics and increased risk of local anesthetic toxicity compared to the general population. Chloroprocaine is an ester local anesthetic that has an extremely short plasma half-life in infants as well as adults. Existing reports support the safety and efficacy of continuous chloroprocaine epidural infusions in neonates and young infants during the intraoperative period. Despite this, continuous chloroprocaine epidural infusion may be an under-utilized method of postoperative analgesia for this patient population. In particular, it may improve pain control in neonates and infants with incisions stretching many dermatomes or those with hepatic impairment.

METHODS

We retrospectively reviewed our experience over 4 years with continuous chloroprocaine epidural infusions in neonates, infants, and children with a focus on the postoperative management of pain.

RESULTS

Twenty-one pediatric patients received continuous 2-chloroprocaine epidural infusions for postoperative pain management from January 2010 to April 2014 for thoracic, abdominal, and limb procedures. The epidural infusion consisted of 1.5% chloroprocaine or 1.5% chloroprocaine with fentanyl. Tabulating the morphine and hydromorphone used for rescue analgesia, the median (interquartile range) opioid consumption (mg·kg(-1) ·day(-1) of intravenous morphine equivalents) for the first, second, and third 24-h postoperative periods were 0.02 (0-0.48), 0.30 (0-0.44), and 0.14 (0-0.29), respectively. Examining the total fentanyl usage, the median (interquartile range) fentanyl consumption (μg·kg(-1) ·day(-1)) for first, second, and third 24-h postoperative periods were 3.89 (0.41-7.24), 0 (0.00-4.06), and 0 (0.00-0.51), respectively. The median N-PASS score assessed every 6 h from 0 to 72 h postoperatively was 0, 1, 2, 0, 0, 1, 0, 0, 0, 0, 1, 0, and 0, respectively. The median FLACC score assessed every 6 h from 0 to 72 h postoperatively was 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, and 0, respectively.

CONCLUSION

The results suggest that chloroprocaine offers an efficacious alternative to the amide local anesthetics for postoperative epidural analgesia in the pediatric population.

Memantine elicits spinal blockades of motor function, proprioception, and nociception in rats

Although memantine blocks sodium currents and produces local skin anesthesia, spinal anesthesia with memantine is unknown. The purpose of the study was to evaluate the local anesthetic effect of memantine in spinal anesthesia and its comparison with a widely used local anesthetic lidocaine. After intrathecally injecting the rats with five doses of each drug, the dose-response curves of memantine and lidocaine were constructed. The potencies of the drugs and durations of spinal anesthetic effects on motor function, proprioception, and nociception were compared with those of lidocaine. We showed that memantine produced dose-dependent spinal blockades in motor function, proprioception, and nociception. On a 50% effective dose (ED50 ) basis, the rank of potency was lidocaine greater than memantine (P < 0.05 for the differences). At the equipotent doses (ED25 , ED50 , ED75 ), the block duration produced by memantine was longer than that produced by lidocaine (P < 0.05 for the differences). Memantine, but not lidocaine, displayed more sensory/nociceptive block than motor block. The preclinical data demonstrated that memantine is less potent than lidocaine, whereas memantine produces longer duration of spinal anesthesia than lidocaine. Memantine shows a more sensory-selective action over motor blockade.

Subcutaneous L-tyrosine elicits cutaneous analgesia in response to local skin pinprick in rats

The purpose of the study was to estimate the ability of L-tyrosine to induce cutaneous analgesia and to investigate the interaction between L-tyrosine and the local anesthetic lidocaine. After subcutaneously injecting the rats with L-tyrosine and lidocaine in a dose-dependent manner, cutaneous analgesia (by blocking the cutaneous trunci muscle reflex-CTMR) was evaluated in response to the local pinprick. The drug-drug interaction was analyzed by using an isobolographic method. We showed that both L-tyrosine and lidocaine produced dose-dependent cutaneous analgesia. On the 50% effective dose (ED50) basis, the rank of drug potency was lidocaine (5.09 [4.88-5.38] μmol)>L-tyrosine (39.1 [36.5-41.8] μmol) (P<0.05). At the equipotent doses (ED25, ED50, and ED75), the duration of cutaneous analgesia caused by L-tyrosine lasted longer than that caused by lidocaine (P<0.01). Lidocaine co-administered with L-tyrosine exhibited an additive effect on infiltrative cutaneous analgesia. Our pre-clinical study demonstrated that L-tyrosine elicits the local/cutaneous analgesia, and the interaction between L-tyrosine and lidocaine is additive. L-tyrosine has a lower potency but much greater duration of cutaneous analgesia than lidocaine. Adding L-tyrosine to lidocaine preparations showed greater duration of cutaneous analgesia compared with lidocaine alone.