Does spinal chloroprocaine pharmacokinetic profile actually translate into a clinical advantage in terms of clinical outcomes when compared to low-dose spinal bupivacaine? A systematic review and meta-analysis

Spinal anesthesia in ambulatory patients

PURPOSE OF THIS REVIEW

To assess current practice in the use of spinal anesthesia in major ambulatory surgery, highlighting its advantages over general anesthesia and identifying potential areas for improvement to facilitate a transition to a sustainable healthcare system.

RECENT FINDINGS

Spinal anesthesia might be preferred in selected populations when compared to general anesthesia providing the highest standards of healthcare quality.The use of local anesthetics with short half-life has proven to be efficient in achieving high anesthesia success rates. Spinal anesthesia does not increase perioperative complications; instead, it has shown a reduction in postoperative nausea and vomiting, an improvement in patient comfort, and a favorable economic impact when compared to general anesthesia.

SUMMARY

Spinal anesthesia is an appropriate method for anesthesia in ambulatory patients, offering advantages over general anesthesia in selected populations.The use of spinal anesthesia is expanding to meet surgical needs. Therefore, it is crucial to plan ahead and anticipate organizational failures in the ambulatory setting to maintain safety and efficiency during outpatient procedures and surgeries.

Total joint replacement in ambulatory surgery

Total joint arthroplasty is one of the most commonly performed surgical procedures in the United States, and projected numbers are expected to double in the next ten years. From 2018 to 2020, total hip and knee arthroplasty were removed from the United States' Center for Medicare and Medicaid Services "inpatient-only" list, accelerating this migration to the ambulatory setting. Appropriate patient selection, including age, body mass index, comorbidities, and adequate social support, is critical for successful ambulatory total joint arthroplasty. General anesthesia and neuraxial anesthesia are both safe and effective anesthetic choices, and recent studies in this population have found no difference in outcomes. Multimodal analgesia, including acetaminophen, nonsteroidal anti-inflammatory drugs, local infiltration analgesia, and peripheral nerve blocks, is the foundation for adequate pain control. Common reasons for "failure to launch" include postoperative urinary retention, postoperative nausea and vomiting, inadequate analgesia, and hypotension.

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.

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.

Current indications for spinal anesthesia-a narrative review

Spinal anesthesia is a commonly performed regional anesthesia technique by most anesthesiologists worldwide. This technique is learned early during training and is relatively easy to master. Despite being an old technique, spinal anesthesia has evolved and developed in various aspects. This review attempts to highlight the current indications of this technique. Understanding the finer aspects and knowledge gaps will help postgraduates and practicing anesthesiologists in designing patient-specific techniques and interventions.

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.

Regional versus general anesthesia for ambulatory total hip and knee arthroplasty

PURPOSE OF REVIEW

With the removal of both total knee and total hip arthroplasty from the Centers for Medicare and Medicaid Services' inpatient-only list, efforts to improve efficiency of the perioperative management of total joint patients have increased recently. The publication of several recent studies examining the impact of anesthesia type on outcomes has prompted the need to review the overall state of evidence for spinal versus general anesthesia for outpatient total joint arthroplasty.

RECENT FINDINGS

Overall complication rates are low in this carefully selected patient population. The majority of patients who are preselected for outpatient total joint arthroplasty appear to successfully achieve this outcome. Some retrospective studies have suggested a benefit for spinal anesthesia in terms of same-day discharge success but direct comparisons in prospective studies are lacking.

SUMMARY

The type of anesthesia used for total joint arthroplasty may have an important effect on outcomes. Until randomized control trials are performed we must rely on existing evidence, which suggests that both spinal and general anesthesia can lead to successful outcomes after ambulatory total joint arthroplasty.

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.

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).

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.

Intrathecal 2-Chloroprocaine 3% Versus Hyperbaric Bupivacaine 0.75% for Cervical Cerclage: A Double-Blind Randomized Controlled Trial

BACKGROUND

Cervical cerclage is a short ambulatory procedure. For spinal anesthesia, local anesthetic agents with rapid postoperative resolution are desired. We hypothesized that in combination with fentanyl, intrathecal 2-chloroprocaine would produce earlier resolution of motor block, resulting in shorter time to meet recovery room discharge criteria than hyperbaric bupivacaine.

METHODS

Women undergoing cervical cerclage with spinal anesthesia were randomized to receive intrathecal 2-chloroprocaine 3% 50 mg or hyperbaric bupivacaine 0.75% 9 mg, both with fentanyl 15 µg. Doses were empirically selected. The onset and resolution of sensory and motor blockade and time to achieve recovery room discharge criteria were monitored. On postoperative day 1, patients rated their satisfaction with the anesthetic and reported on transient neurologic symptoms (TNS), back pain, or headache. The primary outcome was time from spinal injection to motor block resolution. The main secondary outcomes included times from spinal injection to (i) T12 dermatomal level, (ii) sensory block resolution, and (iii) ability to ambulate and void.

RESULTS

Forty-three women were enrolled and randomized to either the chloroprocaine (N = 23) or bupivacaine group (N = 20). The mean (standard deviation [SD]) duration of surgery was 35.3 (11.4) minutes. There was no difference between groups for time to motor block resolution-the median [interquartile range] time for the bupivacaine group (N = 17) was 112 [97-143] minutes versus 109 [88-148] minutes in the chloroprocaine group (N = 22), P = .66, but there was a significant difference in median time to sensory block resolution: 143 [116-162] minutes in the chloroprocaine group versus 198 [152-263] minutes in the bupivacaine group, P = .002. The recovery room discharge criteria, which at our institution include the ability to ambulate unassisted and void urine, were met 76 (95% CI, 33-145) minutes earlier in the chloroprocaine group, P < .0005. One complete block failure occurred with hyperbaric bupivacaine and 2 subjects in each group received treatment for intraoperative discomfort. No patients reported TNS.

CONCLUSIONS

Intrathecal 2-chloropocaine 3% provided similarly effective surgical anesthesia for cerclage placement. Although no difference in time to motor block resolution between groups was observed, the time to sensory block resolution and time to meet recovery room discharge criteria were both significantly shorter among patients who received chloroprocaine than patients who received bupivacaine. Future studies are needed to identify and compare equipotent doses of chloroprocaine and bupivacaine to confirm the superiority of chloroprocaine for this ambulatory obstetric procedure.

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.

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.

Effects of intravenous dexmedetomidine infusion on local anaesthetic block: A spinal anaesthesia clinical model in dogs undergoing hind limb surgery

The aim of this randomised, prospective clinical trial was to determine how the administration of a low dose of dexmedetomidine (DEX) by IV constant rate infusion, modified the duration of the nerve block in dogs undergoing spinal anaesthesia (SA) in a clinical setting. Forty-four dogs undergoing hind limb orthopaedic surgery in a day-surgery regime, maintained under anaesthesia with isoflurane plus SA, were randomly assigned to receive 1 μg/kg/h (IV) of DEX (group D) or not (group C). Spinal anaesthesia was performed with a hyperbaric solution of bupivacaine and morphine at the L_5-6 interspace. Every mean arterial pressure (MAP) increase by 30% above the pre-skin incision value was considered an intraoperative analgesic failure and treated with a bolus of fentanyl as intraoperative rescue analgesia (iRA). Time free from iRA was analysed with a Kaplan-Maier survival curve. The ability to walk at 5 h from SA and the event of bradycardia (HR lower 60 beat per min) and hypotension (MAP value lower 60 mmHg) were recorded. The mean times at which iRA was required were 77.4 (3.2) in group C and 112.2 (8.6) in group D (Logrank test P = 0.038). In groups C and D hypotension incidence was 11/17 (65%) and 2/22 (9%), (P = 0.0004) and bradycardia 3/17 (18%) and 6/22 (27%) (P = 0.704), respectively. The ability to walk 5 h after SA was 14/14 (100%) and 13/14 (93%) in groups C and D, respectively. DEX infusion significantly prolonged the duration of the nociceptive nervous block without prolonging the motor block or increasing the bradycardia events.