Intrathecal ropivacaine and clonidine for ambulatory knee arthroscopy: a dose-response study

Multimodal Acute Pain Management in the Parturient with Opioid Use Disorder: A Review

The opioid epidemic in the United States has led to an increasing number of pregnant patients with opioid use disorder (OUD) presenting to obstetric units. Caring for this complex patient population requires an interdisciplinary approach involving obstetricians, anesthesiologists, addiction medicine physicians, psychiatrists, and social workers. The management of acute pain in the parturient with OUD can be challenging due to several factors, including respiratory depression, opioid tolerance, and opioid-induced hyperalgesia. Patients with a history of OUD can present in one of three categories: 1) those with untreated OUD; 2) those who are currently abstinent from opioids; 3) those being treated with medications to prevent withdrawal. A patient-centered, multimodal approach is essential for optimal peripartum pain relief and prevention of adverse maternal and neonatal outcomes. Medications for opioid use disorder (MOUD), previously referred to as medication-assisted therapy (MAT), include opioids like methadone, buprenorphine, and naltrexone. These are prescribed for pregnant patients with OUD, but appropriate dosing and administration of these medications are critical to avoid withdrawal in the mother. Non-opioid analgesics such as acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs) can be used in a stepwise approach, and regional techniques like neuraxial anesthesia and truncal blocks offer opioid-sparing options. Other medications like ketamine, clonidine, dexmedetomidine, nitrous oxide, and gabapentinoids show promise for pain management but require further research. Overall, a comprehensive pain management strategy is essential to ensure the well-being of both the mother and the fetus in pregnant patients with OUD.

Effects of fadolmidine, an α2 -adrenoceptor agonist, as an adjuvant to spinal bupivacaine on antinociception and motor function in rats and dogs

α2 -Adrenoceptor agonists such as clonidine and dexmedetomidine are used as adjuvants to local anesthetics in regional anesthesia. Fadolmidine is an α2 -adrenoceptor agonist developed especially as a spinal analgesic. The current studies investigate the effects of intrathecally administered fadolmidine with a local anesthetic, bupivacaine, on antinociception and motor block in conscious rats and dogs. The antinociceptive effects of intrathecal fadolmidine and bupivacaine alone or in combination were tested in the rat tail-flick and the dog's skin twitch models. The durations of motor block in rats and in dogs were also assessed. In addition, the effects on sedation, mean arterial blood pressure, heart rate, respiratory rate and body temperature were evaluated in telemetrized dogs. Concentrations of fadolmidine in plasma and spinal cord were determined after intrathecal and intravenous administration in rats. Co-administration of intrathecal fadolmidine with bupivacaine increased the magnitude and duration of the antinociceptive effects and prolonged motor block without hypotension. The interaction of the antinociceptive effect was synergistic in its nature in rats. Concentration of fadolmidine in plasma was very low after intrathecal dosing. Taken together, these studies show that fadolmidine as an adjuvant to intrathecal bupivacaine provides enhanced sensory-motor block and enables a reduction of the doses of both drugs. The results indicate that co-administration of fadolmidine with intrathecal bupivacaine was able to achieve an enhanced antinociceptive effect without hypotension and could thus represent a suitable combination for spinal anesthesia.

Comparison of Different Doses of Clonidine as an Additive to Intrathecal Isobaric Levobupivacaine in Patients Undergoing Infraumbilical Surgeries

Background:

Spinal anesthesia is a safe, reliable, and inexpensive technique with the advantage of providing surgical anesthesia and prolonged postoperative pain relief, and it also blunts autonomic, somatic, and endocrine responses to surgical stimulus.

Aim:

The aim of this study was to assess the efficacy 15 μg and 30 μg of intrathecal clonidine along with 3 mL of 0.5% isobaric levobupivacaine in comparison with plain 0.5% isobaric levobupivacaine.

Setting and Design:

The prospective, interventional, randomized, comparative, double-blinded study was conducted after obtaining approval from the institutional ethical committee.

Materials and Methods:

Seventy-five patients posted for elective lower-limb orthopedic surgeries were randomly divided into three groups with 25 patients in each group as L (levobupivacaine 0.5%), LC-15 (levobupivacaine 0.5% + clonidine 15 μg), and LC-30 (levobupivacaine 0.5% + clonidine 30 μg). All the patients were given spinal anesthesia using the study drugs, and various parameters were monitored.

Statistical Analysis:

The three groups were compared statistically using analysis of variance and Student's t-test (independent samples t-test). P < 0.05 was considered statistically significant.

Results:

There was a statistically significant difference among the three groups with respect to the onset of time for maximum sensory blockade and duration of analgesia. A statistically significant difference was noted among the three groups with respect to the onset of time for maximum motor blockade.

Conclusion:

Both doses of clonidine produced prolonged sensory block compared to the control. It has been found that 30 μg of clonidine as an adjuvant has produced faster onset and prolonged duration sensory block compared to 15 μg of clonidine.

Randomized Controlled Study Using Ropivacaine with Intravenous Adjuvants in Spinal Anaesthesia In Lower Limb Surgeries

Background

In recent years, several adjuvants have been used to prolong the duration of the subarachnoid block. These adjuvants have either been used via intrathecal route or intravenous (i.v.) route. Dexmedetomidine and clonidine have been used as adjuvants to local anesthetic drugs by intrathecal, epidural, caudal, and i.v. routes and for peripheral nerve blocks. In this study, we endeavored at finding the efficacy of dexmedetomidine and clonidine in improving the analgesia quality and duration of the subarachnoid block.

Setting and Design

A prospective, double-blind, randomized control trial comprising 70 subjects posted for elective lower limb surgeries.

Materials and Methods

Seventy patients were selected at random and were allocated to two groups (Group C and Group D) of 35 each. In Group C, the patients received isobaric ropivacaine with clonidine 1.0 μg.kg^-1 intravenously. In Group D, the patients received isobaric ropivacaine with dexmedetomidine 0.5 μg.kg^-1 intravenously. Perioperatively, heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure, and oxygen saturation were recorded and documented every 5 min till the end of surgery. Time of onset, level of sensory blockade, and duration of sensory blockade were recorded. Motor block was assessed using modified Bromage scale. Data validation and analysis were carried out by SPSS version 16. A P < 0.05 was considered statistically significant.

Results

Time of onset of sensory block in Dexmedetomidine group and Clonidine group was 2.70 ± 1.25 minutes and 3.50 ± 1.23 minutes respectively (P = 0.021). Time of onset of motor block in Dexmedetomidine group and Clonidine group was 3.55 ± 1.60 minutes and 4.30 ± 1.45 minutes respectively (P = 0.034). Time for 2 segment regressions of sensory block in Dexmedetomidine group and Clonidine group was 140.30 ± 12.32 minutes and 125.65±14.33minutes respectively (P = 0.047). Time of regressions of motor blockade to Bromage Scale 1 in Dexmedetomidine group and Clonidine group was 148.65 ± 15.23 minutes and 129.70 ± 19.35 minutes respectively (P = 0.032).

Conclusion

The use of i.v. dexmedetomidine perioperatively prolongs the duration of sensory and motor block significantly when compared to i.v. clonidine.

Pharmacodynamics of intrathecal and epidural fadolmidine, an α2-adrenoceptor agonist, after bolus and infusion in dogs-comparison with clonidine

An α₂-adrenoceptor agonist, clonidine, is extensively used in both anesthesia and intensive care medicine. However, clonidine may produce pronounced hemodynamic side effects such as hypotension and bradycardia which may limit its usefulness in certain conditions. Fadolmidine is a potent α₂-adrenoceptor agonist with different physicochemical properties than clonidine. Here, the effects of fadolmidine and clonidine on analgesia (an increase in thermal skin twitch response latency), sedation, blood pressure, heart rate, respiratory rate, and body temperature were evaluated either up to 8 h after either intrathecal or epidural bolus injections or during a 24-h continuous intrathecal infusion at equipotent analgesic doses in non-anesthetized Beagle dogs. Fadolmidine and clonidine produced a dose-dependent and equipotent maximal antinociception after intrathecal bolus injection (ED₅₀: 67 μg and 78 μg, respectively), but the duration of action of fadolmidine was more long-lasting. During the intrathecal infusion, fadolmidine achieved a good analgesic effect without evoking cardiovascular side effects, e.g., hypotension; these were evident during clonidine infusion. Epidurally, the antinociceptive potency of fadolmidine was weaker (ED₅₀: 128 μg) than when intrathecally administered and weaker than that of epidural clonidine (ED₅₀: 51 μg). At analgesic doses, fadolmidine injection induced moderate initial hypertension concomitantly with a decrease in heart rate whereas clonidine evoked hypotension and bradycardia. These results suggest that especially when non-opioid long-term pain relief is needed, an intrathecal infusion of fadolmidine can provide long-term antinociception with less of the known use-limiting adverse effects associated with clonidine.

The efficacy of ropivacaine and bupivacaine in the caesarean section and the effect on the vital signs and the hemodynamics of the lying-in women

OBJECTIVE

To investigate the efficacy of ropivacaine and bupivacaine in caesarean section and vital signs and the hemodynamics of the lying-in women.

METHODS

A total of 480 lying-in women who were admitted to this hospital for treatment between December 2017 and June 2018 were enrolled into this study as the subjects, which were divided into the experiment group and the control group, with 240 subjects in each group. In the experiment group, subjects received the local anesthesia by infusion of 1.5 mL ropivacaine (0.75%), while those in the control group also took the local anesthesia by infusion of 1.5 mL bupivacaine (0.75%). Thereafter, we observed the differences in the anesthetic efficiency, vital signs and hemodynamics of the lying-in women between two groups.

RESULTS

The excellent and good rates of the anesthesia in two groups were 92.1% and 87.9%, showing no obvious difference; in the experiment group, the average arterial pressures and systolic pressures at 5 min and 10 min after combined spinal and epidural analgesia (CSEA) were all elevated when comparing to the control group (all P < 0.05); in the experiment group, the onset time was obviously extended, while duration of sensory and motor block and the duration of motor block were all shorter than those in the control group (all P < 0.05). During anesthesia, the incidence rate of the adverse reactions in the control group was 2.50%, significantly higher than 0.83% in the experiment group (P < 0.05).

CONCLUSION

Despite that ropivacaine and bupivacaine are efficient in anesthesia in the CSEA in the caesarean section, ropivacaine is more recommended for little influence on the hemodynamics, shorter duration of sensory block and motor block and low incidence rate of adverse reactions, which are conducive to the recovery and also safe to the patients.

The history and progress of local anesthesia: multiple approaches to elongate the action

Analgesia and temporary inhibition of motor activity without interfering with central nervous function have been the essential merits of local anesthesia. Local anesthetics originated from cocaine have played a major role in local analgesia. However, the relatively short duration of action of local anesthetics has been a concern in intra- and post-operative analgesia. From the early age of modern local anesthesia, physicians and medical scientists had been struggling to control the active duration of local anesthetics. Such approach includes: development of long-acting local anesthetics, with physical tourniquet techniques, co-administration of other medicines such as vaso-constrictive agents or analgesics, development of mechanical devices to continuously or intermittently administer local anesthetics, and utilization of pharmaceutical drug delivery systems. In this review, the historical sequence of studies that have been performed in an effort to elongate the action of local anesthetics is presented, referring to epoch-making medical and scientific studies.

Effects of intrathecal dexmedetomidine as an additive to low-dose bupivacaine in patients undergoing transurethral resection of prostate

Background and Aims:

In patients undergoing transurethral resection of prostate (TURP), it is vital to restrict the level of block to T₁₀dermatome during spinal anaesthesia. Low-dose bupivacaine causes minimum haemodynamic alterations, but may provide insufficient surgical anaesthesia. Dexmedetomidine, a selective α₂-adrenoreceptor agonist, is a potent anti-nociceptive agent when given intrathecally. The aim of this study was to compare the adjuvant effects of intrathecal dexmedetomidine with low-dose bupivacaine spinal anaesthesia versus a higher dose of bupivacaine in patients undergoing TURP.

Methods:

The study was designed as a prospective, double-blind, randomised trial that included sixty patients of American Society of Anesthesiologists Grade I–III scheduled for TURP. They were allocated into two groups: Group I receiving only hyperbaric bupivacaine intrathecally and Group II receiving dexmedetomidine with low dose bupivacaine. The time to regression of two dermatomes from the peak sensory block level was the primary outcome of the study.

Results:

With comparable baseline and demographic attributes, both groups had similar peak sensory block levels (T₉). Patients in Group II had quicker onset with the time to reach T₁₀being faster (10.72 ± 3.50 vs. 12.72 ± 3.90 min, P = 0.041), longer duration of motor block (200 ± 18.23 vs. 190 ± 10.15 min, P = 0.011) and increased time to first analgesic requirement (300 ± 25.30 vs. 220 ± 15.12 min, P = 0.0001).

Conclusion:

Intrathecal dexmedetomidine with low-dose bupivacaine provides faster onset, prolonged sensory and motor block and reduced rescue analgesic requirement in patients undergoing TURP.

Evaluation of the neurotoxicity of intrathecal dexmedetomidine on rat spinal cord (electromicroscopic observations)

Background:

Spinal administration of dexmedetomidine has been proposed as an adjuvant in spinal anesthesia. However, there is limited information about its possible neurotoxic effect after its neuraxial administration. Potential spinal neurotoxicity should be investigated in animals before administering drugs through the spinal cord. Our aim was to investigate the neurotoxic effects of intrathecal dexmedetomidine in rats.

Methods:

Two groups were performed: the dexmedetomidine (D) group (n = 10) received 10 μg (0.5 ml), whereas the control (C) group (n = 10) received 0.9% (0.5 ml) sodium chloride through indwelling intrathecal catheter. Seven days after the injection, the medulla spinalis was extracted. Samples were withdrawn from both groups for histologic, electron microscopic examination. The histologic examination was performed separately on each of the four sites. The findings were categorized as follows: 0 - normal neuron; 1 - intermediate neuron damage; and 2 - neurotoxicity.

Results:

Intrathecal administration of dexmedetomidine sensorial block was seen in the dexmedetomidine group and significant differences in the dexmedetomidine group than control group in 15^th and 30^th min (P < 0.05). Histological examination did not show evidence suggestive of neuronal body or axonal lesion, gliosis, or myelin sheath damage in any group. In all animals, there were observed changes compatible with unspecific inflammation at the tip of the needle location. On the four-area scoring histologic examination, the scores of both groups were 0–1, and no statistical difference was observed between the groups.

Conclusions:

A single dose of intrathecal dexmedetomidine did not produce histologic evidence of neurotoxicity.

Adjuvants to local anesthetics: Current understanding and future trends

Although beneficial in acute and chronic pain management, the use of local anaesthetics is limited by its duration of action and the dose dependent adverse effects on the cardiac and central nervous system. Adjuvants or additives are often used with local anaesthetics for its synergistic effect by prolonging the duration of sensory-motor block and limiting the cumulative dose requirement of local anaesthetics. The armamentarium of local anesthetic adjuvants have evolved over time from classical opioids to a wide array of drugs spanning several groups and varying mechanisms of action. A large array of opioids ranging from morphine, fentanyl and sufentanyl to hydromorphone, buprenorphine and tramadol has been used with varying success. However, their use has been limited by their adverse effect like respiratory depression, nausea, vomiting and pruritus, especially with its neuraxial use. Epinephrine potentiates the local anesthetics by its antinociceptive properties mediated by alpha-2 adrenoreceptor activation along with its vasoconstrictive properties limiting the systemic absorption of local anesthetics. Alpha 2 adrenoreceptor antagonists like clonidine and dexmedetomidine are one of the most widely used class of local anesthetic adjuvants. Other drugs like steroids (dexamethasone), anti-inflammatory agents (parecoxib and lornoxicam), midazolam, ketamine, magnesium sulfate and neostigmine have also been used with mixed success. The concern regarding the safety profile of these adjuvants is due to its potential neurotoxicity and neurological complications which necessitate further research in this direction. Current research is directed towards a search for agents and techniques which would prolong local anaesthetic action without its deleterious effects. This includes novel approaches like use of charged molecules to produce local anaesthetic action (tonicaine and n butyl tetracaine), new age delivery mechanisms for prolonged bioavailability (liposomal, microspheres and cyclodextrin systems) and further studies with other drugs (adenosine, neuromuscular blockers, dextrans).

A Comparative Study for the Analgesic Efficacy and Safety Profile of Fentanyl versus Clonidine as an Adjuvant to Epidural Ropivacaine 0.75% in Lower Abdominal Surgeries

CONTEXT

Different adjuvants are coadministered with local anesthetics to improve the speed of onset and duration of analgesia, and to reduce the dose, the selection of which is often left to the choice of an anesthesiologist.

AIM

The aim of this study was to compare the analgesic efficacy and safety profile of fentanyl and clonidine as an adjuvant to epidural ropivacaine anesthesia.

SETTING AND DESIGN

With institutional ethical committee clearance, a prospective, randomized, placebo-controlled double-blind clinical study was conducted at Vivekananda Polyclinic and Institute of Medical Sciences, Lucknow.

MATERIAL AND METHODS

Two groups with thirty patients each were randomly allocated to receive 15-20 ml of 0.75% ropivacaine with 75 μg clonidine or 15-20 ml of 0.75% ropivacaine with 75 μg fentanyl, respectively. Block characteristics such as onset of analgesia, maximum level of sensory blockade, complete motor blockade, hemodynamic, time to two-segment regressions, time for rescue analgesia, time to complete motor recovery, and side effects were analyzed.

RESULTS

Results showed that the onset of blockade is faster when fentanyl is used as additives. Time for two-segment regression was earlier in fentanyl group but time for rescue analgesia was longer in clonidine group.

STATISTICAL ANALYSIS

Two groups were compared by Student's t-test and Chi-square test; ANOVA and significance of mean difference bet were done by Newman-Keuls test.

CONCLUSION

Addition of clonidine to epidural ropivacaine provides superior analgesia than the addition of fentanyl to epidural ropivacaine without much difference in side effect profile.

Comparison of intrathecal versus intra-articular dexmedetomidine as an adjuvant to bupivacaine on postoperative pain following knee arthroscopy: a randomized clinical trial

Background

Postoperative pain is a common, distressing symptom following arthroscopic knee surgery. The aim of this study was to compare the potential analgesic effect of dexmedetomidine after intrathecal versus intra-articular administration following arthroscopic knee surgery.

Methods

Ninety patients undergoing unilateral elective arthroscopic knee surgery were randomly assigned into three groups in a double-blind placebo controlled study. The intrathecal dexmedetomidine group (IT) received an intrathecal block with intrathecal dexmedetomidine, the intra-articular group (IA) received an intrathecal block and intra-articular dexmedetomidine, and the control group received an intrathecal block and intra-articular saline. The primary outcome of our study was postoperative pain as assessed by the visual analogue scale of pain (VAS). Secondary outcomes included the effect of dexmedetomidine on total postoperative analgesic use and time to the first analgesic request, hemodynamics, sedation, postoperative nausea and vomiting, patient satisfaction, and postoperative C-reactive protein (CRP) levels.

Results

Dexmedetomidine administration decreased pain scores for 4 h in both the intrathecal and intra-articular groups, compared to only 2 h in the control patient group. Furthermore, there was a significant reduction in pain scores for 6 h in the intra-articular group. The time to the first postoperative analgesia request was longer in the intra-articular group compared to the intrathecal and control groups. The total meperidine requirement was significantly lower in the intra-articular and intrathecal groups than in the control group.

Conclusions

Both intrathecal and intra-articular dexmedetomidine enhanced postoperative analgesia after arthroscopic knee surgery. Less total meperidine was required with intra-articular administration to extend postoperative analgesia to 6 h with hemodynamic stability.

[Unilateral spinal anesthesia : Literature review and recommendations]

Unilateral spinal anesthesia is a cost-effective and rapidly performed anesthetic technique. An exclusively unilateral block only affects the sensory, motor and sympathetic functions on one side of the body and offers the advantages of a spinal block without the typical adverse side effects seen with a bilateral block. The lack of hypotension, in particular, makes unilateral spinal anesthesia suitable for patients with cardiovascular risk factors e. g. aortic valve stenosis or coronary artery disease. Increasing numbers of surgical procedures are now being performed on an outpatient basis. Until now, spinal anesthesia has been considered unsuitable for this, not only because of the high incidence of intraoperative hypotension and postoperative urinary retention but also because of the prolonged postoperative stay before home discharge. This is not the case with unilateral spinal anesthesia: motor function returns rapidly, the incidence of urinary retention is extremely low, and patients are usually eligible for home discharge sooner than after bilateral spinal anesthesia or general anesthesia. The success of the technique depends on a number of factors. In addition to the local anesthetic, its concentration and dose, and the baricity of the injected solution, the shape of the spinal needle, the injection speed, the patient's position during injection, and the time the patient remains in this position after injection are equally important parameters. A number of intrathecally applied adjuvant drugs are used to give a more intense and/or longer-lasting block. For this review, we collated the published data on unilateral spinal anesthesia from journals with an impact factor greater than 1.0 and defined an optimized method for performing the technique. In order to achieve an exclusively unilateral block one should use 0.5 % hyperbaric bupivacaine injected at a rate of 0.33 ml/min or slower. During the injection and the following 20 min the patient should lie in the lateral decubitus position on the side intended for surgery with knees drawn to the chest. An injection of 5 mg (1 ml) hyperbaric bupivacaine 0.5 % provides an hour-long block to T 12, and a dose of 7.5 to 10 mg (1.5-2.0 ml) extends the block to T 6. Adding clonidine (0.5 to 1.0 µg/kg BW) to the injection prolongs the duration of the block to approximately two to three hours. During the 20-minute fixation period, the cephalad spread of the block can be influenced to a certain extent by raising or lowering the head of the table.

Intrathecal Ropivacaine versus Ropivacaine plus Fentanyl for Out-patient Arthroscopic Knee Surgery

We evaluated the effects of low-dose intrathecal ropivacaine with or without fentanyl for arthroscopic knee surgery. Fifty patients were randomized in equal groups to receive an intrathecal solution (3 ml) containing either 10 mg isobaric ropivacaine or 8 mg isobaric ropivacaine plus 25 μg fentanyl. Complete motor blockade occurred in 22 patients (88%) in both groups. The time taken to reach sensory blockade to T10 and total motor blockade was shorter in the ropivacainetreated group, but differences were not statistically significant. The duration of sensory and motor blockade was shorter in the ropivacaine plus fentanyl-treated group. The cephalad spread of sensory blockade was higher with ropivacaine than with ropivacaine plus fentanyl. We conclude that although 25 μg fentanyl added to 8 mg ropivacaine provided shorter motor and sensory blockade durations than 10 mg ropivacaine alone, small doses of ropivacaine plus fentanyl can be used safely for arthroscopic knee surgery.

Comparative evaluation of intrathecal morphine and intrathecal dexmedetomidine in patients undergoing gynaecological surgeries under spinal anaesthesia: A prospective randomised double blind study

BACKGROUND AND AIMS

Inrathecal opioids like morphine added to local anaesthetic agents have been found to be effective in achieving prolonged post-operative analgesia. Intrathecal dexmedetomidine may be devoid of undesirable side effects related to morphine and hence, this study was designed to evaluate analgesic efficacy, haemodynamic stability and adverse effects of both these adjuvants in patients undergoing gynaecological surgeries.

METHODS

This was a prospective, randomised, double blind study involving 25 patients in each group. Group M received 15 mg of 0.5% hyperbaric bupivacaine with 250 μg of morphine while Group D received 15 mg of 0.5% hyperbaric bupivacaine with 2.5 μg of dexmedetomidine. Characteristics of spinal block, time for first rescue analgesic and total dose of rescue analgesics were noted. Vital parameters and adverse effects were noted perioperatively. Data analysis was done with independent two sample t-test and Mann-Whitney U test.

RESULTS

Time for first rescue analgesic (P = 0.056) and total analgesic demand were similar in both groups. Duration of sensory (P = 0.001) and motor (P = 000) block was significantly higher in dexmedetomidine group. Itching was noticed in 36% and nausea in 52% of patients in the morphine group, either of which was not seen in dexmedetomidine group.

CONCLUSION

Intrathecal dexmedetomidine produces prolonged motor and sensory blockade without undesirable side effects but intraoperative hypotension was more frequent in dexmedetomidine group.

Effects of adding low-dose clonidine to intrathecal hyperbaric ropivacaine: A randomized double-blind clinical trial

Background:

Clonidine added to bupivacaine prolongs the duration of anesthesia and postoperative analgesia with minimal side effects. Ropivacaine has lower lipid solubility and better safety profile as compared to bupivacaine. This study is designed to evaluate the effects of low-dose clonidine when added to hyperbaric ropivacaine.

Materials and Methods:

Ninety patients belonging to American Society of Anesthesiologists-I scheduled for lower limb or lower abdominal surgeries under spinal anesthesia were randomly allocated into three groups (n = 30). Group R: 0.5% hyperbaric ropivacaine 12 mg + saline, Group 15C: 0.5% hyperbaric ropivacaine 12 mg + 15 mcg clonidine and Group 30C: 0.5% hyperbaric ropivacaine 12 mg + 30 mcg clonidine for spinal anesthesia in a total volume of 3.2 ml. Block characteristics, hemodynamic parameters, and side effects were monitored.

Results:

Addition of low-dose clonidine to hyperbaric ropivacaine, significantly prolongs the duration of sensory and motor blockade as well as postoperative analgesia compared with placebo (mean ± standard deviation min; 152.50 ± 15.3, 246 ± 23.5, and 217 ± 37.73, respectively with 15 mcg clonidine, 193 ± 16.59, 284 ± 23.28, and 234.83 ± 36.45, respectively with 30 mcg clonidine, 131 ± 14.7, 211.5 ± 24.39, and 192.33 ± 37.02, respectively with saline). The addition of low-dose clonidine significantly increases the incidence of intra-operative hypotension (46.7% and 83.3%, respectively compared to 16.7%), bradycardia (6.7% and 23.3%, respectively compared to 0%).

Conclusions:

Addition of low-dose clonidine to intrathecal hyperbaric ropivacaine causes a significant prolongation of the duration of sensory and motor blockade as well as postoperative analgesia compared with saline placebo. However, it increases the incidence of hypotension and bradycardia which can be managed with routine clinical measures.

Intrathecal dextmedetomidine to reduce shoulder tip pain in laparoscopic cholecystectomies under spinal anesthesia

BACKGROUND

General anesthesia as a technique for laparoscopic cholecystectomies has disadvantage in terms of the stress response, lack of postoperative analgesia and emesis. Regional anesthesia offers advantages over general anesthesia in terms of cost, postoperative analgesia, intact respiratory control mechanism and early ambulation. Shoulder tip pain remains the main concerns that can be alleviated by adding various adjuvants to local anesthetics.

AIMS AND OBJECTIVES

To study the effect of adding intrathecal dexmedetomidine to bupivacaine to decrease shoulder tip pain, onset and duration of sensory and motor block, hemodynamic changes and side effects if any.

MATERIALS AND METHODS

Totally, 60 patients were divided into two groups of 30 each. Group A received 3 ml of bupivacaine heavy and group B received 5 µg of dexmedetomidine along with 3 ml of bupivacaine diluted to total volume of 3.5 ml in each group.

STATISTICAL ANALYSIS

It was done using Chi-square and Student's t-test.

RESULTS AND CONCLUSIONS

Intrathecal dexmedetomidine provides stable hemodynamics, excellent sedation and analgesia and abolishes shoulder tip pain.

Effect of clonidine and/or fentanyl in combination with intrathecal bupivacaine for lower limb surgery

Background and Aims:

Various adjuncts to local anesthetics have been used with the purpose of improving the quality of subarachnoid block. This randomized double-blind study was conducted to evaluate the efficacy of adding clonidine to bupivacaine and bupivacaine-fentanyl combination.

Material and Methods:

A total of 100 patients scheduled for surgery under spinal anesthesia were randomly allocated into four groups (n = 25 each) to receive intrathecal bupivacaine 7.5 mg plus normal saline 0.5 ml (group BS), intrathecal bupivacaine 7.5 mg, and fentanyl 25 μg (group BF), intrathecal bupivacaine 7.5 mg and clonidine 75 μg (group BC), intrathecal bupivacaine 7.5 mg, clonidine 37.5 μg, and fentanyl 12.5 μg (group BCF). The time of onset and duration of sensory block, highest dermatome level of sensory block, time of onset of motor block, time to complete motor block recovery and duration of spinal anesthesia, intraoperative and postoperative hemodynamics and side effects if any were recorded. VAS, total number of patients who were administered supplemental analgesic in each group and the total amount of supplemental analgesic administered in the next 24 h was quantified and documented in all the groups.

Results:

The time of onset of sensory block (min) in groups BS, BC, BCF, and BF was 10.80 ± 2.26, 10.20 ± 1.00, 10.00 ± 0.00, and 13.80 ± 2.61 respectively, thus onset of sensory block was significantly earlier in groups BC and BCF. Similarly, onset of motor block was also quicker in groups BC and BCF. Time of requirement of supplemental analgesia was 135.20 ± 12.70 min, 199.2 ± 21.92 min, 209.80 ± 26.32 min, and 208.00 ± 26.58 min in groups BS, BF, BC, and BCF respectively. Intraoperative and postoperative changes in heart rate, mean arterial blood pressure, oxygen saturation, and respiratory rate were comparable. Sedation scores were significantly higher in group BC. Pruritus was only observed in groups BF and BCF. Mean nausea vomiting scores were comparable in all groups.

Conclusion:

We conclude that the addition of clonidine in doses of 75 μg and 37.5 μg to low-dose bupivacaine and bupivacaine-fentanyl prolongs the sensory and motor block while increasing the duration of postoperative analgesia without significant side-effects.

Effects of isobaric ropivacaine with or without fentanyl in subarachnoid blockade: A prospective double-blind, randomized study

Background:

The addition of fentanyl to ropivacaine has shown to improve the quality of analgesia without compromising its benefits such as early mobilization and early voiding.

Aim:

The aim of the study was to evaluate the effects of the isobaric ropivacaine in combination with fentanyl and compare it with the isobaric ropivacaine alone in spinal anesthesia for lower abdominal and lower limb surgeries.

Settings and Design:

Double-blinded randomized controlled trial.

Subjects and Methods:

Hundred patients belonging to American Society of Anesthesiologists physical status I and II scheduled for either lower abdominal or lower limb surgery under spinal anesthesia were included. The study was a prospective double-blinded randomized controlled trial where patients were randomly allocated into two groups to receive either 2.5 ml of 0.75% (18.75 mg) isobaric ropivacaine with 25 μg fentanyl (Group RF) or 2.5 ml of 0.75% (18.75 mg) isobaric ropivacaine with 0.5 ml of 0.9% saline (Group R) intrathecally.

Statistical Analysis:

Data analysis was done by Student's unpaired t-test. SPSS version 16 was used. P < 0.05 was considered as statistically significant.

Results:

We found no significant difference in hemodynamics, onset of sensory and motor block, peak level of block, recovery from motor block, return of micturition and incidence of side effects with the addition of fentanyl to ropivacaine. First request for analgesia was required earlier in the control group. There was also a significant prolongation of the duration of sensory block (mean - 341.6 min) and postoperative analgesia in Group RF (mean - 442.2 min) (P < 0.001).

Conclusion:

The addition of fentanyl to ropivacaine significantly prolongs the duration of postoperative analgesia with clinically insignificant influence on hemodynamics and motor blockade with minimal side effects.

Role of Clonidine as adjuvant to intrathecal bupivacaine in patients undergoing lower abdominal surgery: A randomized control study

Background:

Neuraxial anesthesia greatly expands the anesthesiologist armamentarium, providing alternatives to general anesthesia, especially in the lower abdominal surgeries. Clonidine, an alpha-2 adrenergic agonist, has a variety of actions, including potentiation of effects of local anesthetics. This study was undertaken to assess the degree of sensory and motor block and postoperative analgesia provided by low dose (50 mcg) intrathecal clonidine admixed with bupivacaine.

Aims:

The aim of this study is to establish efficacy and safety of intrathecal clonidine as adjuvant to bupivacaine.

Settings and Design:

The type of the study was double-blind randomized trial.

Materials and Methods:

Hundred patients were randomly allocated in two groups, A and B. Group A received bupivacaine 0.5%, 3 ml with placebo (normal saline 0.33 ml) and Group B, bupivacaine 0.5%, 3 ml with clonidine 50 μg (0.33 ml).

Statistical Analysis Used:

Statistical Package for Social Sciences version 15.0 statistical analysis software.

Results:

Mean duration of motor block was significantly higher in Group B (280.80 ± 66.88 min) as compared with Group A (183.60 ± 77.06 min). Significant difference in duration of sensory block was noted between Group B (295.20 ± 81.17 min) and Group A (190.80 ± 86.94 min). Duration of postoperative analgesia was significantly higher in Group B as compared to Group A (551.06 ± 133.64 min and 254.80 ± 84.19 min respectively). Mean visual analog scale scores at different time intervals were significantly lower in the study group (except for 4-h time interval), but the control group had better hemodynamic stability as compared with study group.

Conclusion:

The findings in this study suggested that use of clonidine 50 μg added to bupivacaine for spinal anesthesia effectively increased the duration of sensory block, duration of motor block, and duration of analgesia.

Response to low-dose intrathecal clonidine in septuagenarians undergoing sub-umbilical surgeries: A study

Clonidine, an alpha-2-adrenergic agonist, may have a clinically relevant analgesic action but also a hypotensive action, when administered spinally.

Evaluation of bupivacaine-clonidine combination for unilateral spinal anesthesia in lower limb below-knee orthopedic surgery

Background and Objectives:

The purposes of this study were to evaluate the onset, quality and duration of sensory and motor blockade between hyperbaric bupivacaine and clonidine combination with bupivacaine alone when administered intrathecally for unilateral spinal anesthesia in below-knee orthopedic surgery, efficacy of clonidine for post-operative analgesia and side-effects of clonidine, if any.

Methods:

Sixty ASA I and ASA II patients scheduled for elective surgery with time duration up to 90 min were studied. Patients were randomised in two equal groups by the lottery method. Group A (control group) was given Inj. bupivacaine (hyperbaric) 0.5% - 12.5 mg (2.5 ml) + 0.5 ml of normal saline intrathecally. Group B (clonidine group) was given Inj. bupivacaine (hyperbaric) 0.5% - 12.5 mg (2.5 ml) + 50 mcg clonidine in 0.5 ml volume intrathecally.

Results:

The mean peak sensory block was earlier in Group B (4.7±1.23 min) as compared with Group A (6.27±1.51 min). The mean peak motor block was earlier in Group B (6.17±1.20 min) as compared with Group A (8.63±1.71 min). The two-segment regression of sensory block was longer in Group B (106.23±9.17 min) as compared with Group A (104.43±17.75 min), which is clinically significant. Requirement of rescue analgesia was considerably prolonged in Group B (450.33±95.10 min) as compared with Group A (220±36.36 min), which was also clinically highly significant.

Conclusion:

Intrathecal clonidine potentiates bupivacaine induced spinal sensory block and, motor block and reduces the analgesic requirement in the early post-operative period in unilateral spinal anesthesia for lower limb below knee surgery.

ED50 and ED90 of intrathecal hyperbaric 2% prilocaine in ambulatory knee arthroscopy

PURPOSE

Hyperbaric 2% prilocaine (HP) is increasingly used for spinal anesthesia in day-case surgery. The aim of this prospective double-blind study was to determine the effective dose (ED)50 and the ED90 of HP for patients undergoing knee arthroscopy.

METHODS

Doses of HP were determined using an up-and-down sequential allocation technique. Sequences were analyzed by isotonic regression analysis. A subsequent observational study was performed with the calculated ED90 in 50 patients to confirm the initial result and to describe the induced blockade effects and side effects. Times corresponding to onset and duration of sensory and motor block, surgical data, and side effects were recorded.

RESULTS

The ED50 was estimated at 28.9 mg (95% confidence interval [CI]: 26.5 to 35.3) and the ED90 was estimated to be 38.5 mg (95% CI: 35.7 to 39.5). A 40 mg dose of HP provided efficient anesthesia in 46 patients (92%, 95% CI: 82 to 98). The average (SD) time to effective anesthesia was 14.5 (3.9) min. Complete sensory block at level T12 was obtained after ten minutes in 44 of 50 patients. The average (SD) duration of the sensory block was 205 (36.1) min. Maximal level of sensory block was obtained at the T8-T11 levels in 41 of 50 patients without hemodynamic instability. A Bromage 3 score was obtained in 40 of the 46 patients who achieved successful anesthesia after 30 min. Patients did not experience urinary retention, nor were any signs of transient neurologic symptoms observed.

CONCLUSION

This study determined the ED50 of HP is 28.9 mg and suggests that a 40-mg dose of HP is adequate to provide successful spinal anesthesia for outpatient knee arthroscopy.

Low dose intrathecal clonidine and fentanyl added to hyperbaric bupivacaine prolongs analgesia in gynecological surgery

Background:

We undertook this study to ascertain if a small dose of clonidine (30 μg) when added to a bupivacaine-fentanyl mixture improves spinal analgesia, without producing side effects, as compared to a bupivacaine-fentanyl or a bupivacaine-clonidine mixture.

Materials and Methods:

In this prospective, randomized, double-blind study, 75 (American Society of Anesthesiologists) ASA grade I-II patients, aged between 45 and 65 years, who were scheduled for vaginal hysterectomy with pelvic floor repair or non-descent vaginal hysterectomy under spinal anesthesia were recruited. The patients received hyperbaric bupivacaine (2.3 ml) with fentanyl 15 μg (Group BF) or clonidine 30 μg (Group BC) or both fentanyl (15 μg) and clonidine (30 μg) (Group BCF). The total amount of intrathecal mixture was constant (2.8 ml) in all the groups. Duration of sensory, motor block and effective analgesia, hemodynamic profile, postoperative pain score and analgesic requirements were recorded.

Results:

The duration of effective analgesia, mean time till two-segment regression, and duration of sensory and motor block were significantly longer in group BCF as compared to group BC (P ~ 0.002), and in group BC as compared to group BF (P ~ 0.01). The incidence of intraoperative pain and requirement of postoperative analgesics in the first 24 hours was significantly more in group BF as compared to the other groups (P ~ 0.01). There was no difference in the hemodynamic profile between the groups.

Conclusion:

Low-dose clonidine (30 μg) when added to a bupivacaine-fentanyl mixture increased the duration of effective analgesia and the duration of sensory and motor block in gynecological surgery. The incidence of intraoperative pain and requirement of postoperative analgesics was significantly less when clonidine was added to intrathecal bupivacaine with or without fentanyl.

A comparative study between intrathecal clonidine and neostigmine with intrathecal bupivacaine for lower abdominal surgeries

Background and Aims:

Spinal anaesthesia requires a small volume of drug to produce profound reproducible sensory analgesia and motor blockade, but has limited duration of action. A properly chosen adjuvant to local anaesthetic agent produces the best way to achieve a better quality regional block. Hence, a study was conducted to compare the effect of intrathecal clonidine 75 μg or neostigmine 50 μg added to intrathecal hyperbaric bupivacaine, with regards to sensory characteristics, motor characteristics, haemodynamic stability and side effects.

Methods:

This was a prospective randomized experimental study in 50 patients posted for lower abdominal surgery belonging to ASA I and II status and aged between18 and 60 years. One group received intrathecal clonidine 75 μg and 2.5 ml (12.5 mg) of intrathecal 0.5% hyperbaric bupivacaine (group BC) and second group received neostigmine 50 μg with 2.5 ml (12.5mg) of intrathecal 0.5% hyperbaric bupivacaine (group BN) and they were compared with regards to sensory characteristics, motor characteristics, haemodynamic stability and side effects.

Results:

Addition of 50 μg neostigmine significantly enhanced the onset of sensory block (BN - 90 ± 15 secs, BC-160 ± 20 secs, P value as <0.05) and motor block (BN-110 ± 15 secs, BC-210 ± 20 secs, P value as <0.05) compared to clonidine. Haemodynamics were well maintained in the neostigmine group. Group BC had prolonged analgesia (362 ± 36 mins) compared to BN group (300 ± 25 mins)(P < 0.05) with no serious adverse effects noted perioperatively in either groups.

Conclusion:

Intrathecal clonidine with hyperbaric bupivacaine produces prolonged postoperative analgesia and intrathecal neostigmine with bupivacaine produces a good sensory and motor for the surgical procedure.

Effects of intrathecal dexmedetomidine on low-dose bupivacaine spinal anesthesia in elderly patients undergoing transurethral prostatectomy

Low-dose bupivacaine can limit the spinal block level with minimal hemodynamic effects and yield a rapid recovery, but sometimes it may not provide adequate anesthesia for surgery. Dexmedetomidine, a selective α2-adrenoreceptor agonist, was shown to be a potent antinociceptive agent when given intrathecally in animals and humans. The purpose of this study was to evaluate the adjuvant effects of intrathecal dexmedetomidine in elderly patients undergoing transurethral prostate surgery with low-dose bupivacaine spinal anesthesia. Fifty-four patients undergoing transurethral prostate surgery were randomized into two groups receiving either dexmedetomidine 3 µg (n=27) or normal saline (n=27) intrathecally with 6 mg of 0.5% hyperbaric bupivacaine. The characteristics of the spinal block and postoperative analgesic effects were evaluated. The peak block level was similar for the two groups. However, the dexmedetomidine group demonstrated a faster onset time to the peak block and longer duration of spinal block than the saline group (p<0.01). The motor block scales at the time of peak sensory block and regression of 2-sensory dermatomes were higher in the dexmedetomidine group than in the saline group (p<0.001). There was less analgesic request and the time to the first analgesic request was longer in the dexmedetomidine group than in the saline group (each 487, 345 min, p<0.05). Dexmedetomidine 3 µg when added to intrathecal bupivacaine 6 mg produced fast onset and a prolonged duration of sensory block and postoperative analgesia in elderly patients for transurethral surgery. However, recovery of motor block could be delayed in dexmedetomidine-added patients.

A comparison of intrathecal dexmedetomidine, clonidine, and fentanyl as adjuvants to hyperbaric bupivacaine for lower limb surgery: A double blind controlled study

BACKGROUND

Various adjuvants are being used with local anesthetics for prolongation of intraoperative and postoperative analgesia. Dexmedetomidine, the highly selective 2 adrenergic agonist is a new neuraxial adjuvant gaining popularity.

SETTINGS AND DESIGN

The study was conducted in prospective, double blind manner. It included 120 American Society of Anesthesiology (ASA) class I and II patients undergoing lower limb surgery under spinal anesthesia after approval from hospital ethics committee with written and informed consent of patients.

MATERIALS AND METHODS

The patients were randomly allocated into four groups (30 patients each). Group BS received 12.5 mg hyperbaric bupivacaine with normal saline, group BF received 12.5 mg bupivacaine with 25 g fentanyl, group BC received 12.5 mg of bupivacaine supplemented 30 g clonidine, and group BD received 12.5 mg bupivacaine plus 5 g dexmedetomidine. The onset time to reach peak sensory and motor level, the regression time of sensory and motor block, hemodynamic changes, and side effects were recorded.

RESULTS

Patients in Group BD had significantly longer sensory and motor block times than patients in Groups BC, BF, and BS with Groups BC and BF having comparable duration of sensory and motor block. The mean time of two segment sensory block regression was 147 ± 21 min in Group BD, 117 ± 22 in Group BC, 119 ± 23 in Group BF, and 102 ± 17 in Group BS (P > 0.0001). The regression time of motor block to reach modified Bromage zero (0) was 275 ± 25, 199 ± 26, 196 ± 27, 161 ± 20 in Group BD, BC, BF, and BS, respectively (P > 0.0001). The onset times to reach T8 dermatome and modified Bromage 3 motor block were not significantly different between the groups. Dexmedetomidine group showed significantly less and delayed requirement of rescue analgesic.

CONCLUSIONS

Intrathecal dexmedetomidine is associated with prolonged motor and sensory block, hemodynamic stability, and reduced demand of rescue analgesics in 24 h as compared to clonidine, fentanyl, or lone bupivacaine.

Chloroprocaine 40 mg produces shorter spinal block than articaine 40 mg in day-case knee arthroscopy patients

BACKGROUND

Articaine and chloroprocaine have recently gained interest as short-acting spinal anaesthetics. Based on previous work comparing articaine 60 mg with chloroprocaine 40 mg, we hypothesised that articaine 40 mg and chloroprocaine 40 mg would produce similar spinal anaesthesa regarding block onset, maximal spread, and recovery.

METHODS

In this randomised, double-blind study, adult patients (18-70 years, American Society of Anaesthesiologists physical status I-III, BMI < 36 kg/m(2) ) scheduled for day-case knee arthroscopy received either articaine 40 mg (20 mg/ml) (group A40, n = 16) or chloroprocaine 40 mg (20 mg/ml) (group C40, n = 18) intrathecally. Telephone interviews were performed on the first and seventh postoperative day to disclose possible side effects, e.g. transient neurological symptoms (TNS).

RESULTS

The groups were comparable regarding demographic data, onset and maximal spread of spinal anaesthesia, and duration of surgery. Surgery could be performed successfully under spinal anaesthesia except once in A40 (insufficient block) and once in C40 (prolonged surgery). Complete recovery was significantly slower in A40 vs. C40 for both motor block (105 (94/120) vs. 75 (71/90) min) [P < 0.001, Mann-Whitney U-test (MW-U)] and sensory block [135 (109/176) vs. 105 min (90/124)] (P < 0.02, MW-U), respectively [data are median (25th/75th percentiles)]. One patient from A40 showed mild TNS.

CONCLUSION

Both A40 and C40 provided mainly adequate spinal anaesthesia for day-case knee arthroscopy. While onset and maximal spread were comparable, the recovery from motor block was clearly faster with chloroprocaine after equivalent doses of spinal articaine and chloroprocaine.

The effects of dexmedetomidine added to spinal levobupivacaine for transurethral endoscopic surgery

BACKGROUND

Intrathecal α2 agonists prolong the duration of action of local anesthetics and reduce the required dose. Dexmedetomidine is an α2 receptor agonist and its α2/α1 selectivity is 8 times higher than that of clonidine.

AIMS

In this study, we aimed to investigate the effect of adding dexmedetomidine to intrathecal levobupivacaine on the onset time and duration of motor and sensory blocks.

STUDY DESIGN

Randomized controlled study.

METHODS

Patients were randomly assigned into two groups. Group L (n= 30) patients received 3 mL (15 mg) of 0.5% levobupivacaine +0.3 mL normal saline and Group LD (n= 30) patients received 3 mL (15 mg) of 0.5% levobupivacaine + 0.3 mL (3 μg) dexmedetomidine. Sensory block onset time, block reaching time to T10 dermatome, the most elevated dermatome level, two dermatome regression time, sensory block complete regression time as well as motor block onset time, reaching Bromage 3 and regressing to Bromage 0 were recorded.

RESULTS

Sensory and motor block onset times were shorter in Group LD than in Group L (p<0.001). The regression of the sensory block to S1 dermatome and Bromage 0 were longer in Group LD than Group L (p<0.001). The two dermatome regression time was longer in Group LD than Group L (p< 0.001). There were no statistically significant differences between groups in blood pressure and heart rate. There was no statistically significant difference between groups when adverse effects were compared.

CONCLUSION

We conclude that intrathecal dexmedetomidine addition to levobupivacaine for spinal anaesthesia shortens sensory and motor block onset time and prolongs block duration without any significant adverse effects.

Intrathecal clonidine as an adjuvant to hyperbaric bupivacaine in patients undergoing inguinal herniorrhaphy: A randomized double-blinded study

BACKGROUND

Clonidine is added to intrathecal local anesthetics to improve intraoperative analgesia and to increase the duration of sensory and motor block. Aim of this study was to evaluate and compare the effects of addition of two different doses of clonidine (15 and 30 mcg) to 11 mg hyperbaric bupivacaine in patients undergoing inguinal herniorrhaphy surgery under spinal anesthesia.

MATERIALS AND METHODS

Seventy-five patients enrolled in the study were randomly divided into three groups of 25 each. Group I patients received 11 mg hyperbaric bupivacaine, whereas groups II and III received 15 mcg and 30 mcg clonidine, respectively, as an adjuvant to 11 mg hyperbaric bupivacaine. The volume of solution was kept constant to 2.4 ml by adding saline wherever needed.

RESULTS

Highest level of sensory block, time to achieve this level, and highest Bromage scale recorded were comparable among the groups. The mean time to two-segment regression, regression of sensory block to L3 dermatome, and mean duration of motor block were the greatest in group III followed by group II and group I. There was significant fall in mean arterial pressure (MAP) in groups II and III as compared to group I (P = 0.04). Episodes of hypotension were more in group III than in group II.

CONCLUSION

30 mcg clonidine was associated with more incidence and duration of hypotension than 15 μg of clonidine. 15 mcg clonidine added to 11 mg hyperbaric bupivacaine provides better sensory and motor blockade for inguinal herniorrhaphy.

Prevention of hypotension and prolongation of postoperative analgesia in emergency cesarean sections: A randomized study with intrathecal clonidine

Background and Context:

Different adjuvants been tried out for neuraxial anesthesia in emergency caesarean section so that the dose of the local anesthetic can be reduced and hypotension thereby prevented.

Aims and Objectives:

The present study was carried out in patients presenting for emergency lower segment caesarean section (LSCS) to establish the dose of intrathecal clonidine that would allow reduction of the dose of local anesthetic (thereby reducing the incidence and magnitude of hypotension) while at the same time providing clinically relevant prolongation of spinal anesthesia without significant side effects.

Materials and Methods:

This randomized clinical study was carried out in our institution among 100 pregnant females who underwent emergency caesarean section. The participants were divided randomly into four groups: A, B, C, and D, each comprising 25 parturients. Subarachnoid block was performed using a 26G Quincke needle, with 12 mg of hyperbaric bupivacaine (LA) in group A, 9 mg of LA + 30 μg of clonidine in group B, LA + 37.5 μg of clonidine in group C, and LA + 45 μg of clonidine in group D. The solution was uniformly made up to 2.2 mL with normal saline in all the groups. Onset of analgesia at T₁₀ level, sensory and motor blockade levels, maternal heart rate and blood pressure, neonatal Apgar scores, postoperative block characteristics, and adverse events were looked for and recorded. Statistical analysis was carried out with SPSS^® version 10.0 for Windows^®, using the ANOVA test with post hoc significance, the Chi-square test, and the Mann-Whitney U test. P<.05 was considered significant and P<.0001 as highly significant.

Results:

One hundred patients were enrolled for this study. The four groups were comparable with regard to demographic data and neonatal Apgar scores. Onset and establishment of sensory and motor analgesia was significantly shorter in groups C and D, while hypotension (and the use of vasopressors) was significantly higher in groups A and D. Perioperative shivering, nausea, and vomiting were significantly higher in groups A and D, while incidence of dry mouth was significantly higher in group D.

Conclusions:

The addition of 45 μg, 37.5 μg, and 30 μg of clonidine to hyperbaric bupivacaine results in more prolonged complete and effective analgesia, allowing reduction of up to 18% of the total dose of hyperbaric bupivacaine. From the results of this study, 37.5 μg of clonidine seems to be the optimal dose.

Repeated Intrathecal Administration of Ropivacaine Causes Neurotoxicity in Rats

Previous studies have shown that ropivacaine is the least neurotoxic local anaesthetic. Most of the data derive from short-term ropivacaine injection into the subarachnoid space. Intrathecal administration for a prolonged period, and the histological changes and behavioural effects of repeated intrathecal administration, have not previously been investigated. We studied the possible neurotoxicity of intrathecal injection of ropivacaine in a rat model.

Rats received 0.12 ml/kg body weight of ropivacaine at concentrations of 0.5 or 1%, or normal saline only, via an implanted intrathecal catheter at 90-minute intervals for 12 hours. On days 1, 3, 5, 7, 14 and 28, the spinal cord was examined by light and electron microscopy at the L3 level. We assessed sensory thresholds to noxious stimulation, behavioural change and protein kinase B immunoreactivity for possible neuronal injury within the spinal cord.

Ropivacaine 1% induced thermal hyperalgesia and mechanical allodynia, neuronal injury characterised by tissue oedema, proliferation of glial cells, neuronal morphology changes and degeneration and protein kinase B expression. There were no significant differences in motor function as a result of different concentrations of ropivacaine.

Repeated intrathecal injection of ropivacaine 1% can induce neurotoxicity in rats. Our data suggests that expression of protein kinase B might be involved in this neurotoxicity.

Intrathecal clonidine added to small-dose bupivacaine prolongs postoperative analgesia in patients undergoing transurethral surgery

INTRODUCTION

The aim of this prospective, double-blinded study was to investigate the effects of clonidine in co-administration with bupivacaine during spinal anesthesia, regarding the onset and regression of motor and sensory block, postoperative analgesia and possible side effects.

METHODS

We randomly selected 66 male patients (age 35 to 70), from the American Society of Anesthesiologists (ASA) class I-II; these patients were scheduled for transurethral surgical procedures. These patients were randomly allocated into two groups of 33 patients each: group B (bupivacaine) only received 0.5% isobaric bupivacaine 7.5 mg intrathecally and group BC (bupivacaine + clonidine) received bupivacaine 7.5 mg and clonidine 25 μg intrathecally. We performed the spinal anesthesia at a level of L3-L4 with a 25-gauge needle. We assessed the sensory block with a pin-prick, the motor block using the Bromage scale, analgesia with the visual analog scale and sedation with the modified Wilson scale. We also recorded the hemodynamic and respiratory parameters.

RESULTS

The groups were demographically similar. The mean time of achievement of motor block (Bromage 3) and sensory block at level T9 was significantly shorter in the BC group compared with B group (p = 0.002, p = 0.000, respeectively). The motor block regression time was not significantly different between the two groups (p = 0.237). The postoperative analgesia requirement was significantly longer in group BC compared with group B (p = 0.000). No neurological deficit, sedation or other significant adverse effects were recorded.

CONCLUSION

The intrathecal application of clonidine in combination with bupivacaine improves the duration and quality of spinal anesthesia; it also provides longer duration of postoperative analgesia, without significant side effects.

Dexmedetomidine as an intrathecal adjuvant for postoperative analgesia

Background:

Spinal anaesthesia is the most common approach which is used for lower limb surgery. Dexmedetomidine is the recent drug which acts on α2-adrenergic receptors in the dorsal horn of the spinal cord to produce analgesic effects.

Aim:

Efficacy and safety of intrathecal dexmedetomidine added to ropivacaine.

Setting and Design:

Randomised double blind trial.

Methods:

Sixty patients were randomly allocated to receive intrathecally either 3 ml of 0.75% isobaric ropivacaine + 0.5 ml normal saline (Group R) or 3 ml of 0.75% isobaric ropivacaine + 5 μg dexmedetomidine in 0.5 ml of normal saline (Group D).

Results:

The mean time of sensory regression to S2 was 468.3±36.78 minutes in group D and 239.33±16.8 minutes in group R. Duration of analgesia (time to requirement of first rescue analgesic) was significantly prolonged in group D (478.4±20.9 minutes) as compared to group R (241.67±21.67 minutes). The maximum visual analogue scale score for pain was less in group D (4.4±1.4) as compared to group R (6.8±2.2).

Conclusion:

The addition of dexmedetomidine to ropivacaine intrathecally produces a prolongation in the duration of the motor and sensory block.

Evaluation of analgesic effects of intrathecal clonidine along with bupivacaine in cesarean section

Aims and Context:

The objective of the present study was to evaluate the analgesic and adverse effects of intrathecal clonidine with hyperbaric bupivacaine in spinal anesthesia.

Settings and Design:

Randomized single blind trial.

Methods:

210 ASA I-II pregnant females undergoing emergency cesarean section were randomized in a single-blind fashion to one of the three groups. In group I (n=70) patients received 12.5 mg of 0.5% hyperbaric bupivacaine intrathecally. In group II (n=70) patients received intrathecal mixture of 0.5% hyperbaric bupivacaine (8 mg) and clonidine 50 μg. In group III (n=70), patients received 0.5% hyperbaric bupivacaine (10 mg) intrathecally along with 50 μg of clonidine.

Statistical Analysis Used:

Groups were compared using one-way ANOVA with the Bonferroni multiple comparison post hoc test. The proportion of adverse events was compared using the chi-square test (χ² =57.2410).

Results:

On adding 50 μg clonidine, we were able to reduce intrathecal dose of bupivacaine for cesarean section to 8 mg. Patients receiving intrathecal clonidine along with bupivacaine had significantly long lasting analgesia with lower bupivacaine dose [246.21±5.15 min. (group II) vs 146.0±4.55 min (group I), P=0.021; 95% confidence interval: 238.01-257.40, group II and 134.99-157.0 group I].

Conclusions:

Addition of intrathecal clonidine causes some sedation in the postoperative period, but it provides adequate analgesia and motor paralysis at lower dose of bupivacaine. It also significantly prolongs postoperative pain relief.

Alpha-2-agonists in day case anaesthesia

PURPOSE OF REVIEW

Alpha-2-agonists have long been known to have anaesthetic-sparing, sedative and analgesic properties which are desirable in day case anaesthesia. Their routine use was hampered by a high incidence of undesirable effects, however. In recent years, there have been many attempts to define a role for these unique agents in which their benefits would outweigh their apparent disadvantages.

RECENT FINDINGS

Many recent studies have confirmed the usefulness of alpha-2-agonists in providing sedation and analgesia, although the results have been far from consistent. Some, but by no means all studies have shown advantages over alternative agents, but concerns also remain over acute and possible long-term adverse effects.

SUMMARY

Alpha-2-agonists still have no clearly defined routine role in day surgery. Their most promising application is in limiting recovery agitation in children, but even here, there remain concerns about their routine use.

Local anaesthetic adjuvants: neuraxial versus peripheral nerve block

PURPOSE OF REVIEW

To present a review of the literature on the importance and the clinical characteristics relevant to adjuvants added to local anaesthetics in neuraxial and peripheral nerve blocks.

RECENT FINDINGS

In neuraxial anaesthesia, both opioids and alpha-2 receptor agonists have beneficial effects. Intrathecally, fentanyl and sufentanil not only improve the postoperative analgesia but also make it possible to allow a decrease in the local anaesthetic dose. When clonidine or dexmedetomidine was added to intrathecal local anaesthetics, the regression of sensory, motor block increased dose-dependently and postoperative analgesia was prolonged. The potency of intrathecal clonidine: dexmedetomidine seems to be 10: 1. In peripheral nerve block, when opioid was combined with local anaesthetics, no increased improvement in analgesia was reported in comparison with systemic controls in most of the studies, except buprenorphine. Also clonidine is controversial as an analgesic adjuvant. Special factors, such as type of local anaesthetics, block of upper or lower limb, are important for its the beneficial effect. Other adjuvants, except neuraxial low-dose neostigmine, are of minor importance.

SUMMARY

Opioids and alpha-2 receptor agonists are important as neuraxial adjuvants to improve the quality of peroperative and postoperative analgesia in high-risk patients and in ambulatory procedures. In peripheral nerve blocks, however, some benefit is found only when clonidine is added to local anaesthetics under certain circumstances.

Unilateral spinal anaesthesia for outpatient surgery: a comparison between hyperbaric bupivacaine and bupivacaine-clonidine combination

BACKGROUND

Low-dose hyperbaric bupivacaine has been used to produce unilateral spinal anaesthesia for outpatient surgery. Unilateral spinal anaesthesia is associated with reduction of hypotension, faster recovery and increased patient satisfaction. Small doses of clonidine have shown effectiveness in intensifying spinal anaesthesia. We investigated the effect of adding 15 microg of clonidine to 5 mg hyperbaric bupivacaine on unilaterality.

METHODS

Sixty patients undergoing outpatient knee arthroscopy were randomly allocated to receive either 1.2 ml (6 mg) of hyperbaric bupivacaine or a 1.2 ml solution containing 1.0 ml (5 mg) hyperbaric bupivacaine, 0.1 ml (75 microg) clonidine and 0.1 ml sterile water. The motor block was assessed by a modified Bromage scale and the sensory block by a pinprick.

RESULTS

There was a significant difference in the spread of anaesthesia between the operated and contralateral sides in both groups. Seventy-seven per cent of the blocks were unilateral in group B and 73% in group B-C. There was no significant difference between the groups, in unilaterality. The motor block was prolonged in group B-C but it did not affect home-readiness. Patients receiving clonidine needed more vasopressors. There was a significant difference in blood pressures between the groups, being lower in group B-C after 1 h 45 min.

CONCLUSION

Using 5 mg hyperbaric bupivacaine with 15 microg of clonidine, the unilaterality can be achieved and spinal anaesthesia intensified without affecting home-readiness. More vasopressors are needed in the beginning, but after the surgery patients experienced less pain.

Advances in regional anesthesia for outpatients

PURPOSE OF REVIEW

This review will bring to the reader's attention recent developments in the literature regarding regional anesthesia in the outpatient setting, and allow the reader to evaluate whether these developments are appropriate for inclusion in clinical practice.

RECENT FINDINGS

The most stimulating developments in the area of regional anesthesia for outpatients revolve around the use of continuous analgesic therapy for outpatients after discharge. This is reflected in recent publications describing the use of continuous catheters for peripheral nerve blockade using portable pumps to provide 48-72 h of postoperative analgesia. These devices have raised the hope of opioid-free pain relief for virtually the entire duration of postsurgical pain in the outpatient setting. There are also increasing numbers of suggestions on ways to improve the quality of spinal anesthesia in the outpatient setting, particularly by using lower doses of lidocaine to reduce the problem of transient neurologic symptoms after spinal blockade. Several authors have investigated the cost implications of regional techniques in the outpatient setting, and have concluded that they are very competitive with the general anesthetic techniques that are frequently employed.

SUMMARY

Recent publications suggest additional ways to add regional anesthesia techniques to outpatient surgical practice, particularly with the promise of extensive postoperative pain relief for the ambulatory surgery patient.

Clonidine--a potent analgesic adjuvant

PURPOSE OF REVIEW

The alpha(2)-adrenoceptor agonist clonidine is one of the most widely investigated substances in anaesthesia and pain therapy. Recently, numerous experimental and clinical studies have allowed a better understanding of its underlying mechanisms of action and interactions with other analgesic drugs.

RECENT FINDINGS

Several experimental studies have shown that clonidine may improve the analgesic effect of anti-inflammatory agents and also have significant peripheral antinociceptive effects. Volunteer and clinical studies have demonstrated analgesic effects of clonidine after systemic administration, whereas local administration of plain clonidine (e.g. intra-articular, intravenous regional) showed only limited clinical efficacy. The major clinical place of clonidine may thus be as an adjuvant to other analgesics, as shown in a number of studies in which clonidine has been investigated in combination with local anaesthetics, opioids and ketamine. An increasing number of studies have now investigated clonidine in paediatric patients and have demonstrated that the effects are generally similar to those in adults. Furthermore, it seems that in paediatric patients the side-effects of clonidine are predictable and of limited clinical importance.

SUMMARY

During the past decade clonidine has been investigated as an adjuvant for general and regional anaesthesia and in the postoperative period. There is no doubt that clonidine improves analgesia after systemic, spinal or peripheral opioids, and prolongs the analgesic action of most local anaesthetics. The side-effects of usual doses of clonidine are predictable. Given the clinical experience of an increasing number of hospitals, clonidine should no longer be considered an experimental drug, but a useful addendum to the pharmacological armamentarium.

The elderly outpatient: current anesthetic implications

PURPOSE OF REVIEW

The present overview describes recent contributions to the literature with regard to choice of anesthetic techniques, approaches to anesthetic management of elderly outpatients undergoing arthroscopy and other procedures, reconsideration of the problem of postoperative delirium in the elderly patient, and a general summary of perioperative management and assessment of anesthetic risk in older adults.

RECENT FINDINGS

Major advances in monitoring technology, pharmacology, and comprehensive preoperative assessment have reduced the probability of major adverse outcomes for geriatric surgical patients to low levels. Therefore, it has become difficult to demonstrate clear-cut superiority for any specific anesthetic agent or approach. Nevertheless, the need for prompt and complete recovery of consciousness and rapid discharge after surgery presents additional challenges for the anesthesiologist who is caring for elderly outpatients with regard to prompt recovery of cognitive function and suppression of nausea and vomiting.

SUMMARY

The efficiency and speed with which outpatient surgery and anesthetic recovery can be conducted in older adults continue to improve. Monitors of depth of anesthesia, ultra-short-acting agents, and combined techniques have minimized minor complications such as nausea and vomiting, and have improved the speed with which these patients recover from anesthesia. A small proportion of elderly surgical outpatients remain at risk for residual postoperative cognitive dysfunction.