Effects of epidural clonidine added to lidocaine solution upon the requirements of sedatives during epidural anesthesia

The authors studied 34 patients undergoing abdominal total hysterectomy in order to evaluate whether epidural clonidine added to lidocaine solution could alter the requirements of sedatives during epidural anesthesia. Patients were randomly assigned to one of four groups; 18 ml of 2% lidocaine with 1:200,000 clonidine (n = 6), 1:100,000 clonidine (n = 7), 1:200,000 epinephrine (n = 13), or neither (plain, n = 8). The requirements of sedatives (diazepam, thiamylal) and analgesic (butorphanol) prior to the second epidural injection were compared among the four groups. The dose of intravenous diazepam or thiamylal required for sedation in the patients receiving lidocaine with 1:100,000 clonidine had a tendency to be smaller as compared with those in other three groups. There was a significant difference (P less than 0.05) in the requirement of diazepam between the patients given lidocaine with 1:100,000 clonidine and those given plain lidocaine. The present results suggest that the addition of clonidine to lidocaine solution could reduce the requirements of sedatives in epidural anesthesia.     

不同剂量可乐定复合罗哌卡因硬膜外麻醉的效应

目的 评价不同剂量的可乐定复合罗哌卡因硬膜外麻醉的临床效应。方法 60例ASAⅠ-Ⅱ级妇科手术患者，硬膜外随机双盲接受不含或含50、100、150μg可乐定的0.75%罗哌卡因25ml，分为R、R－C50、R－C100、R－C150四组。记录感觉镇痛、运动阻滞起效时间及持续时间，术中镇痛质量及不良反应。结果 R－C100组、R－C150组运动阻滞起效时间缩短，术中内脏牵拉痛发生率及氯胺酮需要量减少，镇痛持续时间延长，寒战发生率降低。然而，R－C150组低血压发生率、麻黄碱需要量及输液量增加。结论 可乐定100μg与0.75％罗哌卡因25ml合用于硬膜外麻醉，可改善罗哌卡因阻滞特征而不增加低血压、心动过缓等副作用。     

硬膜外麻醉时可乐定和肾上腺素对麻醉效果和血清利多卡因浓度的影响

目的　研究硬膜外麻醉时 ,利多卡因溶液中加用可乐定或肾上腺素对血清利多卡因浓度和硬膜外麻醉效果的影响。方法　将 3 0例 ASA ～ 级下腹或下肢择期手术患者随机分为三组 :1组为利多卡因空白对照组 ,单纯 2 %利多卡因 6mg· kg- 1 硬膜外注射 ;2组为肾上腺素对照组 ,2 %利多卡因 6m g· kg- 1 加肾上腺素 5μg· ml- 1 硬膜外注射 ;3组为可乐定试验组 ,2 %利多卡因 6mg·kg- 1 加可乐定 5μg· m l- 1 硬膜外注射。测定感觉和运动阻滞的起效和恢复时间 ,并采集动脉血检测血清利多卡因浓度。结果　利多卡因溶液中加用可乐定 ( 1∶ 2 0万 ) ,可使硬膜外麻醉起效加快、作用间期延长 ,并能降低血清利多卡因浓度 ,其作用类似于利多卡因溶液加用同等浓度的肾上腺素。结论　可乐定作为一种血管活性因子可应用于硬膜外麻醉 ,以减少利多卡因的毒副作用     

Effect of epidural clonidine added to epidural sufentanil for labor pain management

Labor analgesia with intrathecal sufentanil has been shown to be prolonged by the addition of intrathecal clonidine. The current study was designed to determine if epidural clonidine would prolong labor analgesia provided by epidural sufentanil. Forty laboring primiparous women at less than 5 cm cervical dilation requesting epidural analgesia were enrolled. Following a 3 mL test dose of lidocaine with epinephrine, patients were randomized to receive 10 mL of either sufentanil 20 microg (S) or sufentanil 20 microg with clonidine 75 microg (SC). After administration of the analgesic, pain scores and side-effects were recorded for each patient at 5, 10, 15, 20 and 30 min, and every 30 min thereafter, by an observer blinded to the technique used. There were no demographic differences between the two groups. Pain relief was rapid for all patients. The mean duration of analgesia was similar between the S group (153 +/- 78 min) and the SC group (178 +/- 55 min). Side-effects were similar between the two groups. There was no difference between the two groups in time from sufentanil administration to delivery, incidence of operative or assisted delivery, or cervical dilation at the time of redose. For early laboring patients, epidural sufentanil 20 microg after a lidocaine test dose provides analgesia comparable to that of sufentanil 20 microg with clonidine 75 microg; there was no significant difference in analgesic duration between the two groups.     

Tramadol added to lidocaine for intravenous regional anesthesia

Sixty volunteers, divided into four groups of 15 each, received IV regional anesthesia of the upper limb with 40 mL tramadol 0.25%, sodium chloride 0.9%, lidocaine 0.5%, or 100 mg tramadol-containing lidocaine 0.5%. By using a double-blinded method, we tested the onset and recovery of sensory block at six sites of the forearm and hand as well as onset of complete motor block. The symptoms after deflation of the tourniquet were recorded. The onset and recovery of sensory block and the onset of motor block were similar in the tramadol and saline groups. However, in the Tramadol-Lidocaine Group, the speed of onset of sensory block was faster than in the Lidocaine Group. In the Tramadol and the Tramadol-Lidocaine Groups, the incidence of skin rash and painful or burning sensation at the injection site was increased. We conclude that tramadol 0.25% does not have a local anesthetic effect when used as a sole drug for IV regional anesthesia, but might modify the action of local anesthetic, providing a shorter onset time of sensory block. Implications: Tramadol, a centrally acting analgesic, might have local anesthetic properties, as do some opioid drugs. We demonstrated that 0.25% tramadol solution containing 100 mg tramadol is not effective as a sole drug, but may improve the action of 0.5% lidocaine for intravenous regional anesthesia. The increased incidence of side effects may limit the clinical use of tramadol.     

Addition of clonidine to 0.5% lidocaine for intravenous locoregional anesthesia

OBJECTIVE: Evaluate the effect of the addition of clonidine to lidocaine on postoperative pain after intravenous regional anaesthesia. STUDY DESIGN: Double blind prospective study. PATIENTS AND METHODS: Forty-five patients were randomly allocated to two groups: group 1 (n = 25) receiving 3 mg.kg-1 of lidocaine 0.5% added to saline and group 2 (n = 20) receiving 3 mg.kg-1 of lidocaine 0.5% added to clonidine (150 micrograms). Postoperative analgesia was assessed using a visual analogue pain score (VAPS) and the time to first analgesic request. The incidence of side effects after tourniquet release was noted. Analysis of variance, Kruskall Wallis and chi 2 tests were used for statistical analysis. A p-value of < 0.05 was considered significant. RESULTS: Age, ASA class, duration and type of surgery, tourniquet time and sensory block duration were comparable for the two groups. The time to first antalgic request after deflation of tourniquet was similar in the two groups (38 +/- 15 min versus 44 +/- 19 min), while VAPS score was lower (p < 0.05) in the clonidine group (5.2 versus 6.8). The incidence of side effects was comparable in the two groups. CONCLUSION: The addition of clonidine (150 micrograms) to lidocaine for intravenous regional anaesthesia improved postoperative analgesia but in a limited and short-lasting manner.     

Plasma lidocaine concentrations during continuous thoracic epidural anesthesia after clonidine premedication in children.

There is no report concerning oral clonidine's effects on epidural lidocaine in children. Therefore, we performed a study to assess the concentrations of plasma lidocaine and its major metabolite (monoethylglycinexylidide [MEGX]) in children receiving continuous thoracic epidural anesthesia after oral clonidine premedication. Ten pediatric patients, aged 1-9 yr, were randomly allocated to the Control or Clonidine 4 microg/kg group (n = 5 each). Anesthesia was induced and maintained with sevoflurane in oxygen and air (FIO2 40%). Epidural puncture and tubing were carefully performed at the Th11-12 intervertebral space. An initial dose of 1% lidocaine (5 mg/kg) was injected through a catheter into the epidural space, followed by 2.5 mg x kg(-1) x h(-1). Plasma concentrations of lidocaine and MEGX were measured at 15 min, 30 min, and every 60 min for 4 h after the initiation of continuous epidural injection. The concentrations of lidocaine and MEGX were measured using high-pressure liquid chromatography with ultraviolet detection. Hemodynamic variables were similar between members of the Control and Clonidine groups during anesthesia. The Clonidine group showed significantly smaller lidocaine concentrations (p < 0.05) and the concentration of MEGX tended to be smaller in the plasma of the Clonidine group for the initial 4 h after the initiation of epidural infusion. In conclusion, oral clonidine preanesthetic medication at a dose of 4 microg/kg decreases plasma lidocaine concentration in children. IMPLICATIONS: Oral clonidine decreases the plasma lidocaine concentration in children. Our finding may have clinical implications in patients receiving continuous epidural anesthesia. Additionally, perhaps an additional margin of safety regarding lidocaine toxicity is gained through the use of oral clonidine in children who will receive epidural lidocaine.     

The dose-sparing effect of clonidine added to ropivacaine for labor epidural analgesia

To determine the effects of clonidine with ropivacaine during epidural labor analgesia, we studied 66 nulliparous women in early active labor. Women were randomized to receive ropivacaine 0.1% 8 mL plus 75 microg of clonidine (Group 1), ropivacaine 0.2% 8 mL plus 0.5 mL of NaCl 0.9% (Group 2), or ropivacaine 0.2% 8 mL plus 75 microg of clonidine (Group 3) 5 min after a bupivacaine 7.5 mg with epinephrine 15 microg test dose. Upon request, additional analgesia with ropivacaine 0.1% 8 mL followed by ropivacaine 0.2% 8 mL/h was administered. With clonidine, duration of analgesia was increased (132 +/- 48 min [Group 1] and 154 +/- 42 min [Group 3] versus 91 +/- 44 min [Group 2]; P < 0.05), and total ropivacaine dose over the first 4 h was significantly reduced (40.5 +/- 15 mg [Group 1] and 47.0 +/- 16 mg [Group 3] versus 72.5 +/- 18 mg [Group 2]; P < 0.01). The incidence of more profound motor block was more frequent in Group 2 (P < 0.05). Although there was a trend for more women receiving clonidine to require ephedrine for treatment of hypotension, this did not seem to have an impact on fetal outcome or incidence of cesarean deliveries for nonreassuring fetal heart rate tracings. This study demonstrates the dose-sparing effect of clonidine when added to ropivacaine. IMPLICATIONS: The effect of adding 75 microg of clonidine to ropivacaine for epidural labor analgesia was studied. Clonidine increased analgesia duration and produced dose sparing compared with ropivacaine alone. Despite a tendency for hypotension in women receiving clonidine, there was no apparent effect on delivery mode or neonatal outcome.     

Comparison of pH-adjusted lidocaine solutions for epidural anesthesia

One hundred forty-eight adult patients having epidural anesthesia for cesarean section, postpartum tubal ligation, lower extremity orthopedic procedures, or lithotriptic therapy were assigned to five groups. Group 1 patients were given a commercially prepared 1.5% lidocaine solution with 1:200,000 epinephrine plus 1 ml of normal saline per 10 ml of lidocaine; the solution pH was 4.6. Group 2 patients were given commercially prepared 1.5% lidocaine solution plus 1:200,000 epinephrine, with 1 mEq (1 ml) NaHCO3 per 10 ml of lidocaine; the solution pH was 7.15. Group 3 patients received the commercial solution of 1.5% lidocaine with 1:200,000 epinephrine; the solution pH was 4.55. Group 4 patients were given a mixture of 18 ml of 2% lidocaine with 30 ml of 1.5% lidocaine, both commercially packaged with 1:200,000 epinephrine, plus 1 mEq (1 ml) of NaHCO3 added per 10 ml of solution; the solution pH was 7.2. Group 5 patients received 1.5% plain lidocaine to which epinephrine was added to a final concentration of 1:200,000; the solution pH was 6.35. Times of onset of analgesia (time between the completion of the anesthetic injection and loss of scratch sensation at the right hip (L-2 dermatome] and of surgical anesthesia (time between completion of injection and loss of discomfort following tetanic stimulation produced by a nerve stimulator applied to skin on the right hip) were significantly more rapid in the groups that received the pH-adjusted solutions (groups 4 and 2). Group 4 had the fastest mean onset time, 1.92 +/- 0.17 min, followed by group 2, 3.31 +/- 0.23 min.(ABSTRACT TRUNCATED AT 250 WORDS)     

Adding clonidine to lidocaine for intravenous regional anesthesia prevents tourniquet pain.

Tourniquet pain often complicates the use of the pneumatic tourniquet during surgical procedures performed under IV regional anesthesia. Clonidine-containing local anesthetic solutions have better analgesic properties than plain solutions when used for spinal, epidural, or peripheral blocks. We tested the hypothesis that the addition of clonidine may improve the quality of IV regional anesthesia, especially tourniquet tolerance. Forty patients were allocated randomly in a double-blinded, randomized study to receive 40 mL of 0.5% lidocaine and either 1 mL of isotonic saline or clonidine (150 microg). A double-cuffed tourniquet was kept inflated until patients complained of pain, leading to release of the distal cuff. Pain at the tourniquet site, at the surgical site, and in the distal part of the arm was rated on a visual analog scale (VAS) and a verbal rating scale (VRS) every 15 min during tourniquet placement and every 15 min for 1 h after tourniquet deflation. Motor blockade, sedation, arterial pressure, and heart rate were also recorded. VAS and VRS scores were significantly lower in the clonidine group 30 and 45 min after tourniquet inflation. The tolerance for the distal tourniquet was also significantly longer in the clonidine group (median [range]: 22 [10-40] vs 10 [5-20] min; P < 0.05); motor blockade was comparable between the two groups. Pain was not different in the two groups after tourniquet release. The clonidine group experienced a higher degree of sedation. We conclude that clonidine improves tourniquet tolerance when added to a local anesthetic solution. IMPLICATIONS: A 150-microg dose of clonidine added to lidocaine improved tourniquet tolerance during IV regional anesthesia.     

利多卡因椎管内麻醉的安全性问题

椎管内麻醉使用利多卡因的安全性问题影响着其临床应用,现就近年来利多卡因应用于椎管内麻醉产生神经系统后遗症的临床及实验研究作了综述,并提出了其应用于椎管内麻醉的临床安全剂量作为参考。     

Intravenous regional anesthesia using lidocaine and clonidine.

BACKGROUND: Clonidine has been added to local anesthetic regimens for various peripheral nerve blocks, resulting in prolonged anesthesia and analgesia. The authors postulated that using clonidine as a component of intravenous regional anesthesia (IVRA) would enhance postoperative analgesia. METHODS: Forty-five patients undergoing ambulatory hand surgery received IVRA with lidocaine, 0.5%, and were assigned randomly and blindly to three groups. The control group received intravenous saline, the intravenous clonidine group received 1 microg/kg clonidine intravenously, and the IVRA clonidine group received 1 microg/kg clonidine as part of the IVRA solution. After their operations, the patients' pain and sedation scores and analgesic use were recorded. RESULTS: Patients in the IVRA clonidine group had a significantly longer period of subjective comfort when they required no analgesics (median [range]) for 460 min (215-1,440 min), compared with 115 min (14-390 min) for the control group and 125 min (17-295 min) for the intravenous clonidine group (P<0.0001). The patients who received IVRA with clonidine reported significantly lower pain scores 1 and 2 h after tourniquet deflation compared with the other groups, and they required no fentanyl in the postanesthesia care unit. They also required fewer analgesic tablets (325 mg acetaminophen with 30 mg codeine) in the first 24 h (2+/-1, mean +/- SD) compared with the other two groups, 5+/-1 tablets (control) and 4+/-2 tablets (intravenous clonidine) (P<0.0001). No significant postoperative sedation, hypotension, or bradycardia developed in any of the patients. CONCLUSION: The addition of 1 microg/kg clonidine to lidocaine, 0.5%, for IVRA in patients undergoing ambulatory hand surgery improves postoperative analgesia without causing significant side effects during the first postoperative day.     

右美托咪定和可乐定硬膜外给药对硬膜外罗哌卡因麻醉效果的影响

目的 比较右美托咪定(dexmedetomidine,Dex)和可乐定硬膜外给药对罗哌卡因阻滞效果的影响. 方法 全组75例患者美国麻醉医师协会(ASA)分级Ⅰ或Ⅱ级,年龄55岁～65岁,拟行阴式子宫切除术.按随机数字表法分为硬膜外给予0.75％罗哌卡因15 ml含100 μg Dex组(RD组)、硬膜外给予0.75％罗哌卡因15ml含100 μg可乐定组(RC组)和硬膜外给予0.75％罗哌卡因15ml含生理盐水组(C组). 结果 RD组麻醉平面到达T10起效时间[(8.5±2.4)min]短于RC组和C组[(10.4±3.4) min和(12.7±4.3)min],RD组在较短的时间内[(13±4)min]达到最高阻滞平面,明显短于RC组和C组[(15±4) min和(18±4) min];RD组完全运动阻滞时间[(18±5)min]短于RC组和C组[(21±4) min和(24±4)min;(P＜0.05和P＜0.01)].RD组术后24 h曲马多用量[(87±17)mg]也显著少于RC组和C组[(101±21) mg和(146±19) mg;(P＜0.01)].RD组和RC组寒战发生率明显低于C组(P＜0.01),未发现1例呼吸抑制. 结论 硬膜外给予Dex可增强罗哌卡因硬膜外阻滞效果,与可乐定比较麻醉起效快、围术期呼吸循环稳定,减少术后镇痛药的应用.     

Reversal of lidocaine with epinephrine epidural anesthesia using epidural saline washout

BACKGROUND AND OBJECTIVES: Prolonged motor and sensory block following epidural anesthesia can be associated with extended postoperative care unit stays and patient dissatisfaction. Previous studies have demonstrated a more rapid motor recovery following the administration of epidural crystalloids in patients who had received plain bupivacaine and lidocaine epidural anesthesia. However, epinephrine is commonly added to local anesthetics to improve the quality and prolong the duration of the epidural block. The objective of this study was to determine the relationship of 0.9% NaCl epidural catheter flush volume (i.e., washout) to the recovery of motor and sensory block in patients undergoing 2% lidocaine with epinephrine epidural anesthesia. METHODS: A prospective, randomized, double-blind study design was utilized. Thirty-three subjects scheduled for elective gynecologic or obstetrical surgical procedures underwent epidural anesthesia using 2% lidocaine with epinephrine (1:200,000). A T4 dermatome level of analgesia, determined by toothpick prick, was maintained intraoperatively. Following surgery, subjects were randomized to 1 of 3 treatment groups. Group 1 (control, n = 11) received no epidural 0.9% NaCl (normal saline [NS]) postoperatively. Group 2 (15 mL NS x 1, n = 10) received an epidural bolus of 15 mL NS. Group 3 (15 mL NS x 2, n = 12) received an epidural bolus of 15 mL NS postoperatively and a second 15-mL NS bolus 15 minutes later. Assessment of motor and sensory block was performed at 15-minute intervals until complete motor and sensory recovery. RESULTS: Times to partial and full motor and sensory recovery were significantly faster in the epidural NS groups than in the control group. Full motor recovery was more rapid in subjects receiving two 15-mL NS epidural NS boluses (30 mL total) compared with those receiving a single 15-mL NS bolus (108 +/- 9 min v 136 +/- 13 min) and significantly faster than control group subjects (153 +/- 14 min). Both NS x 1 and NS x 2 epidural bolus groups experienced significantly reduced times to complete sensory recovery when compared with the control group (NS x 1 = 154 +/- 13 min, NS x 2 = 153 +/- 9 min, control 195 +/- 14 min). CONCLUSIONS: A more rapid recovery of motor and sensory block in patients undergoing 2% lidocaine with epinephrine epidural anesthesia can be achieved with the use of 30 mL NS epidural washout. Reg Anesth Pain Med 2001;26:246-251.     

The analgesic effect of nitroglycerin added to lidocaine on intravenous regional anesthesia

We evaluated the analgesic effect of nitroglycerine (NTG) when added to lidocaine in IV regional anesthesia. Thirty patients undergoing hand surgery were randomly assigned to two groups. The control group (group C, n = 15) received a total dose of 40 mL with 3 mg/kg of lidocaine diluted with saline, and the NTG group (group NTG, n = 15) received an additional 200 mug NTG. Hemodynamic variables, tourniquet pain measured before and 1, 5, 10, 20, and 30 min after tourniquet inflation, and analgesic requirements were recorded during the operation. After the tourniquet deflation, at 1 and 30 min and 2 and 4 h, visual analog scale (VAS) score, time to first analgesic requirement, total analgesic consumption in the first 24 h after operation, and side effects were noted. Shortened sensory and motor block onset time (3.2 +/- 1.1 versus 4.5 +/- 1.2 min; P = 0.01 and 3.3 +/- 1.6 versus 5.2 +/- 1.8; P = 0.009 in group NTG and group C, respectively), prolonged sensory and motor block recovery times (6.8 +/- 1.6 versus 3.1 +/- 1.2 min P < 0.0001 and 7.3 +/- 1.3 versus 3.6 +/- 0.8 P < 0.0001 in group NTG and group C, respectively), shortened VAS scores of tourniquet pain (P = 0.023), and improved quality of anesthesia were found in group NTG (P < 0.05). VAS scores were lower in group NTG after tourniquet release and in the postoperative period (P = 0.001). First analgesic requirement time was longer in group NTG (225 +/- 74 min versus 39 +/- 33 min) than in group C (P < 0.0001). Postoperative analgesic requirements were significantly smaller in group NTG (P < 0.0001) but the side effects were similar in both groups. We conclude that the addition of NTG to lidocaine for IV regional anesthesia improves sensory and motor block, tourniquet pain, and postoperative analgesia without side effects.     

The dose-response relationship for clonidine added to a postoperative continuous epidural infusion of ropivacaine in children.

Epidurally administered clonidine enhances the quality and duration of postoperative analgesia when it is used as an adjunct to local anesthetics in children. We investigated the dose-response relationship for epidural clonidine when added to a continuous postoperative epidural infusion of ropivacaine. By use of an observer-blinded design, 55 pediatric patients (1-4 yr old) were randomly given a postoperative epidural infusion of plain ropivacaine 0.1% 0.2 mg. kg(-1). h(-1) (Group R), ropivacaine 0.08% 0.16 mg. kg(-1). h(-1) plus clonidine 0.04 microg. kg(-1). h(-1) (Group RC1), ropivacaine 0.08% 0.16 mg. kg(-1). h(-1) plus clonidine 0.08 microg. kg(-1). h(-1) (Group RC2), or ropivacaine 0.08% 0.16 mg. kg(-1). h(-1) plus clonidine 0.12 microg. kg(-1). h(-1) (Group RC3). A clear dose-response relationship could be identified for a continuous infusion of epidural clonidine, with clonidine dosages in the 0.08-0.12 microg. kg(-1). h(-1) range providing improved postoperative analgesia (reduced Children's Hospital of Eastern Ontario pain score, increased time to first supplemental analgesic demand, and a reduced total number of doses of supplemental analgesics during the first 48 h after surgery). Analgesia was improved without any signs of increased sedation or other side effects. The adjunct use of epidural clonidine in the dosage range of 0.08-0.12 microg. kg(-1). h(-1) appears effective and safe for use in children. Implications: The addition of clonidine (0.08-0.12 microg.kg(-1).h(-1))to a continuous epidural infusion of ropivacaine was found to improve postoperative pain relief in children. No clinically significant signs of sedation or other side effects were observed.