预注不同剂量米库氯铵对肌松效应的影响

目的 观察预先注射(预注)不同剂量米库氯铵对肌松效应的影响. 方法 选择全身麻醉下行择期手术的患者40例,年龄18 ～60岁,ASA分级Ⅰ、Ⅱ级,按随机数字表法分为4组(每组10例):对照组(A组)、预注20％的95％有效药物剂量(95％ effective dose,ED95)米库氯铵组(B组)、预注30％ED95米库氯铵组(C组)、预注40％ED95米库氯铵组(D组).丙泊酚联合舒芬太尼麻醉诱导后,A组预注生理盐水,B组、C组和D组分别预注米库氯铵0.014 mg/kg(20％ED95)、0.021 mg/kg(30％ED95)和0.028 mg/kg(40％ED95),预注后2 min,给予剩余插管剂量(A组0.210 mg/kg、B组0.196 mg/kg、C组0.189 mg/kg、D组0.182 mg/kg).应用四个成串刺激(train of four stimulation,TOF)-Watch加速仪进行肌松监测.观察肌松起效时间、阻滞维持时间、临床作用时间、体内作用时间和恢复指数. 结果 与A组比较,B组、C组和D组米库氯铵起效时间显著缩短[(183±48)s比(141±18)、(132±30)、(117±21) s](P＜0.05);B组、C组和D组组间比较,起效时间差异无统计学意义(P＞0.05);4组间阻滞维持时间、临床作用时间、体内作用时间和恢复指数差异无统计学意义(P＞0.05). 结论 预注可显著缩短米库氯铵的起效时间,不影响肌松维持和恢复过程,但加大预注剂量未能明显缩短起效时间.     

米库氯铵在无抽搐电休克治疗中的应用

目的观察米库氯铵与琥珀胆碱、阿曲库铵在无抽搐电休克治疗(MECT)中的应用。方法选择精神分裂症患者60例,年龄18~60岁,ASAⅠ或Ⅱ级,随机分为米库氯铵组(A组)、琥珀胆碱组(B组)和阿曲库铵组(C组),每组20例。分别观察记录诱导后肌松药起效时间、MECT后自主呼吸恢复时间、患者完全清醒时间及MECT诱导前和治疗后5 min MAP、HR、SpO2的变化。结果 B组肌松起效时间、自主呼吸恢复时间明显短于A组和C组(P0.05)。A组肌松起效时间、自主呼吸恢复时间明显短于C组(P0.05)。结论在无琥珀胆碱或应用琥珀胆碱禁忌的情况下,米库氯铵是行MECT较好替代药物。     

肝硬化病人乌司他丁预处理对罗库溴铵肌松作用的影响

目的观察肝硬化病人乌司他丁预处理对罗库溴铵肌松作用的影响。方法选择30例患有肝硬化的成年手术病人,随机均分为两组:乌司他丁组(Ⅰ组),静注乌司他丁5000U/kg后1min,静脉给予罗库溴铵0.6mg/kg;生理盐水组(Ⅱ组),静脉给予生理盐水0.1ml/kg后1min,静脉给予罗库溴铵0.6mg/kg。另选15例无肝脏疾患的、ASAⅠ～Ⅱ级择期成年手术病人为对照组(Ⅲ组),处理同Ⅱ组。肌松监测仪检测四个成串刺激(TOF)的变化,记录三组注药后罗库溴铵的起效时间(注药到TOFr=0)、TOF无反应时间(T1=0持续时间)、T1最大抑制程度、临床时效(TOFr恢复至25%时间)、T1恢复至75%时间、恢复指数。结果与Ⅱ、Ⅲ组比较,Ⅰ组插管剂量罗库溴铵的起效时间明显延长(P<0.05)。Ⅱ、Ⅲ组罗库溴铵肌松的起效时间相似。与Ⅱ组比较,Ⅰ、Ⅲ组T1恢复25%时间和恢复指数明显缩短(P<0.05)。Ⅰ、Ⅲ组罗库溴铵肌松的恢复时间相似。结论肝硬化病人乌司他丁预处理延长罗库溴铵的起效时间,但缩短罗库溴铵肌松作用时间。     

不同剂量米库氯铵在眼底日间手术中的应用

目的 比较不同剂量米库氯铵持续输注用于喉罩全麻眼底日间手术中的安全性和对术后残余肌松的影响。

方法 选择择期行喉罩下全麻眼底日间手术患者60例,男35例,女25例,年龄18～65岁,BMI<30 kg/m²,ASA Ⅰ—Ⅲ级。采用随机数字表法将患者分为两组：A组和B组,每组30例。A组喉罩置入后持续输注米库氯铵0.20 mg·kg^-1·h^-1、B组喉罩置入后持续输注米库氯铵0.25 mg·kg^-1·h^-1,维持术中肌松缝结膜时停止输注。记录手术时间、停止输注米库氯铵至拔除喉罩时间。记录入PACU即刻、入PACU后5、10 min的TOFr。记录皮肤潮红、呼吸系统过敏反应、体动、喉罩移位等不良事件的发生情况。

结果 与入PACU即刻比较,入PACU后5、10 min B组TOFr明显升高(P<0.05)。与B组比较,A组停止输注米库氯铵至拔除喉罩的时间明显缩短(P<0.05),入PACU即刻A组TOFr明显升高(P<0.05)。两组均未出现皮肤潮红、呼吸系统过敏反应、体动和喉罩移位等不良事件。

结论 与米库氯铵0.25 mg·kg^-1·h^-1比较,采用米库氯铵0.20 mg·kg^-1·h^-1持续输注用于喉罩全麻眼底日间手术,患者停药至拔除喉罩时间明显缩短、术后残余肌松恢复更快。     

老年患者全麻术后罗库溴铵的残余作用

目的观察老年患者全麻术后罗库溴铵的残余效应(PORC)。方法择期全麻手术患者40例,根据年龄分为中青年组和老年组,每组20例。采用静脉复合全麻,罗库溴铵用量为0.9mg/kg。术中用四个成串刺激(TOF)监测肌松,直至拔管后TOF值(TOFr)≥90%。记录各组TOFr从0恢复到25%(临床时效)、从25%恢复到90%的时间,以及拔管时TOFr<90%(PORC)患者TOFr恢复到90%的时间。监测拔管后及TOFr达90%时的动脉血气。结果老年组罗库溴铵作用时效[(60.70±14.27)minvs.(45.51±7.80)min]及TOFr从25%恢复至90%时间[(46.50±11.56)minvs(34.50±9.56)min]均长于中青年组(P<0.05);老年组PORC发生率高于中青年组(15/20vs12/20),PORC持续时间长于中青年组[(26.00±8.43)minvs(17.20±8.00)min](P<0.05);老年组拔管后CO2蓄积例数多于中青年组(13例vs.6例)(P<0.05)。结论老年患者罗库溴铵的PORC发生率高于中青年患者,应加强围手术期肌松监测,掌握恰当的拔管时机。     

米库氯铵与顺苯磺酸阿曲库铵在婴幼儿唇腭裂手术中的应用比较

目的观察和比较米库氯铵和顺苯磺酸阿曲库铵用于婴幼儿唇腭裂手术中的肌松效应和安全性。方法 2012年9月至2013年9月择期行唇腭裂手术治疗的患儿60例,年龄6个月至3岁,随机分为两组,每组30例。两组均给予咪达唑仑0.1mg/kg、丙泊酚2mg/kg、瑞芬太尼1μg/kg及米库氯铵0.2mg/kg(M组)或顺苯磺酸阿曲库铵0.15mg/kg(C组)行麻醉诱导后气管插管。采用TOF-Guard加速度肌松监测仪连续监测尺神经四个成串刺激(TOF)。观察并记录肌松起效时间、临床作用时间和恢复指数,进行插管评级并观察不良反应情况。结果两组的插管条件评级差异无统计学意义。M组肌松起效时间、肌松临床作用时间以及恢复指数明显短于C组(P0.05);M组不良反应发生率明显低于C组(P0.05)。结论米库氯铵用于婴幼儿唇腭裂手术时起效快、肌松效应时间短,恢复较快。     

老年腰椎结核合并骨质疏松患者麻醉诱导应用顺式阿曲库铵的药效学研究

目的 比较老年腰椎结核合并骨质疏松患者与普通老年腰椎手术患者麻醉诱导时顺式阿曲库铵药效学的差异。方法 选择2012年6月~2013年6月我院骨科老年腰椎结核合并骨质疏松患者（A组）、老年腰椎手术合并骨质疏松的患者（B组）,老年腰椎结核手术患者（C组）和腰椎间盘突出手术患者（D组）各20例进行研究。所有患者均于术前30min肌肉注射阿托品0.5mg。4组患者麻醉诱导均采用静脉注射咪达唑仑0.05mg/kg、丙泊酚2mg/kg、芬太尼5μg/kg和注射单次剂量顺式阿曲库0.15mg/ kg,观察记录诱导期间患者血流动力学变化,同时应用肌松监测仪记录各组起效时间、第一次肌颤搐刺激T1恢复到25%、75%、90%的时间及恢复指数。结果 诱导期间A、B、C、D各组之间的血压、心率变化及肌松药的起效时间之间的差异无统计学意义(P >0.05),A组注射相同剂量的顺式阿曲库铵后神经肌肉阻滞的25%、75%、90%的恢复时间为34.1±9.5min,45.7±5.6 min,51.8±5.1 min;B组注射相同剂量的顺式阿曲库铵后神经肌肉阻滞的25%、75%、90%的恢复时间为32.2±7.4 min,62.4±2.7 min,63.1±6.4 min;C组注射相同剂量的顺式阿曲库铵后神经肌肉阻滞的25%、75%、90%的恢复时间为33.5±5.4 min,43.6±6.1 min, 49.9±6.7 min;D组注射相同剂量的顺式阿曲库铵后神经肌肉阻滞的25%、75%、90%的恢复时间为44.1±7.0 min,58.7±7.6 min,64.9±5.3 min。A组较B、D组的恢复时间显著缩短(P <0.05)。 而A组注射相同剂量的顺式阿曲库铵后神经肌肉阻滞的恢复时间与C组之间差异无统计学意义(P >0.05)。结论 腰椎结核患者麻醉诱导时应用顺式阿曲库铵可显著降低其作用时间,而单纯骨质疏松患者麻醉诱导时不会影响应用顺式阿曲库铵的作用时间。     

罗库溴铵和顺式阿曲库铵用于肝部分切除术肌松效应的比较

目的比较罗库溴铵和顺式阿曲库铵用于肝部分切除术的肌松效应。方法择期全麻下行剖腹单纯肝部分切除术患者40例,随机均分为罗库溴铵组(R组)和顺式阿曲库铵组(C组)。全麻肌松药诱导量R组和C组分别为2倍ED95的罗库溴铵0.6mg/kg及顺式阿曲库铵0.1mg/kg,采用TOF监测肌松程度,当TOFr至25%时追加肌松药。观察两组肌松药起效时间、气管插管条件、临床作用时间、术毕恢复指数、气管拔管时间及不良反应。结果 R组起效时间明显快于、临床作用时间及术毕恢复指数明显长于C组(P0.05);两组气管拔管时间差异无统计学意义。当TOFr为0时,R组气管插管条件为优的例数明显多于C组(P0.05)。R组静脉注射痛发生率为16例(80%),明显高于C组的3例(15%)(P0.05)。两组患者围术期均未发生皮肤潮红、BP降低、HR增快及支气管痉挛等不良反应,未观察到拔管后的肌松残余作用。结论与顺式阿曲库铵比较,应用罗库溴铵具有起效快,作用时间长,虽恢复指数略长,但对拔管时间并无影响,同时未有明显的肌松残余作用,可以安全用于肝部分切除术的患者。     

顺式阿曲库铵闭环注射系统在腹腔镜手术中的应用

目的 探讨顺式阿曲库铵闭环注射在腹腔镜手术中的肌松效果.方法 选择腹腔镜手术患者20例,随机均分成闭环注射组(G组)和对照组(C组).C组持续输注顺式阿曲库铵1.5～2 μg·kg-1·min-1直至手术结束前30 min;G组输注顺式阿曲库铵0.8μg·kg-1 ·min-1,设定肌松深度反馈值T1=15％,近手术结束时由研究实施者根据术中肌松监测指标决定停药时机.记录麻醉时间、顺式阿曲库铵的总用量、恢复指数、TOFr75及TOFr90.结果 G组顺式阿曲库铵总用量均明显少于C组(P＜0.05),恢复指数、TOFr75及TOFr90明显缩短于C组(P＜0.05).结论 与持续输注方式相比,闭环肌松药注射方式肌松药用量更少,恢复指数、TOFr75和TOFr90明显缩短,实现个性化和合理化用药.     

地氟醚七氟醚对糖尿病患者罗库溴铵肌松效应影响的比较

目的 比较地氟醚和七氟醚对糖尿病患者罗库溴铵肌松效应的影响.方法 择期2型糖尿病腹部手术患者60例,年龄45～64岁,ASA分级Ⅱ级,采用随机数字表法分为3组,每组20例:地氟醚组(DD组)、七氟醚组(SD组)和异丙酚组(PD组).静脉注射咪达唑仑、异丙酚和芬太尼行麻醉诱导后启动肌松监测,3组分别用异丙酚、地氟醚和七氟醚维持麻醉.记录肌松维持时间和恢复指数.于静脉注射罗库溴铵后10、20、30、40、50、60、70、80、90、100、110、120 min时记录T1/T0比值及T4/T1比值[四个成串刺激(train-of-four stimulation, TOF)比值].结果 DD组和SD组患者罗库溴铵的维持时间[(61±17),(60±18) min]、恢复指数[(36±12),(35±10) min]之间差异无统计学意义(P＞0.05),且均大于PD组(P＜0.05).DD组、SD组患者静脉注射罗库溴铵后60～120 min时T1/T0比值和TOF比值差异无统计学意义(P＞0.05),且均大于PD组(P＜0.05).结论 地氟醚和七氟醚对糖尿病患者罗库溴铵肌松效应的影响差异无统计学意义.     

Ⅰ-gel喉罩应用于面神经显微血管减压术的临床观察

目的 评价Ⅰ-gel喉罩用于面神经显微血管减压术气道管理的效果.方法 择期行面神经显微血管减压术患者90例,性别不限,年龄20～55岁,BMI 18～25 kg/m2,ASA分级Ⅰ、Ⅱ级,Mallampati分级Ⅰ～Ⅲ级,完全随机分为3组(每组30例):Ⅰ-gel喉罩组(Ⅰ组)、Supreme喉罩组(S组)、气管插管组(Q组).记录3组患者喉罩或插管置入时间、首次置入成功率,两个喉罩组侧卧位时的气道密封压、纤维支气管镜检查评分.记录入室后(T0)、插管前(T1)、插管即刻(T2)、拔管前(T3)、拔管即刻(T4)的生命体征.记录3组患者苏醒时间和拔管时间,术后呛咳、咽痛、恶心呕吐等副作用发生情况.结果 与Q组比较,Ⅰ组、S组置入时间缩短[(12±3)、(16±4)s比(30±6)s](P＜0.05),且Ⅰ组置入时间少于S组(P＜0.05);3组患者置入成功情况差异无统计学意义(P＞0.05);侧卧位时气道密封压Ⅰ组高于S组[(28±3) cmH2O比(24±4) cmH2O(1 cmH2O=0.098 kPa)](P＜0.05).Ⅰ组、S组在T2、T4时点MAP明显低于Q组[(86±10)、(85±9)mmHg(1 mmHg=0.133 kPa)比(105±11)mmHg,(91±11)、(92±12) mmHg比(106±14) mmHg](P＜0.05),HR明显慢于Q组[(75±9)、(76±11)次/min比(89±12)次/min,(83±9)、(82±11)次/min比(93±12)次/min] (P＜0.05).Ⅰ组、S组苏醒时间、拔管时间短于Q组[(2.5±1.4)、(2.8±1.2) min比(5.1±1.8) min,(3.8±1.1)、(3.7±1.0) min比(6.2±1.5) min] (P＜0.05).Ⅰ组、S组呛咳、咽痛发生率明显低于Q组[(0、0比33.3％)、(6.7％、16.7％比30.0％)](P＜0.05);其他副作用发生率差异无统计学意义(P＞0.05).结论 Ⅰ-gel喉罩、Supreme喉罩和气管导管均可安全有效地用于面神经显微血管减压术的气道管理,但Ⅰ-gel喉罩易于置入,气道密封性可靠,术中血流动力学平稳,损伤更小.     

Surgeon-controlled mivacurium administration during elective Caesarean section

We have compared the dose requirements and recovery characteristics of a continuous mivacurium infusion given by the anaesthetist to maintain 95–100% block at the hand muscles with that of a surgeon-controlled, on-demand dosing technique based on the direct assessment of abdominal muscle tone during elective Caesarean section. Twenty-four full term pregnant patients were included. A rapid-sequence induction using thiopentone 3–5 mg· kg^?1 and succinylcholine 1 mg· kg^?1 was used. Anaesthesia was maintained with fentanyl, N₂O and iso-flurane 0.5%. The mechanomyographic response of the adductor pollicis muscle to supramaximal train-of-four (TOF) ulnar nerve stimulation was recorded. Muscle relaxation was achieved initially with mivacurium 0.1 mg· kg^?1 followed either by a continuous infusion of mivacurium to maintain 95–100% block at the adductor pollicis muscle (n = 12) or by surgeon-controlled relaxation (SCR) technique using a syringe pump for patient-controlled analgesia to administer on-demand doses of mivacurium 0.05 mg · kg^?1 (n = 12). The lockout interval was three minutes and the maximum hourly dose of mivacurium allowed was 0.6 mg · kg^?1. The total doses of mivacurium (mean ±SD) were 23.2 ± 10.4 and 12.4 ± 3.5 mg in the infusion and SCR groups, P < 0.01. On-demand, surgeon-controlled doses of mivacurium were injected at a mean of T₁ 42.3 ± 36%. At the end of surgery, T₁ and TOF ratio were respectively 16.7 ± 13%, 5 ± 10% and 48 ± 37%, 30 ± 24% in the infusion and SCR groups. Five patients in the SCR group and one patient in the infusion group did not receive antagonist at the end of surgery. The time to adequate recovery, TOF 75%, after skin closure was 8.2 ± 2.3 and 5.3 ± 4 min in the infusion and SCR groups, P = 0.05. It is concluded that, compared with a continuous mivacurium infusion, the SCR technique is associated with reduced mivacurium requirements, a substantial degree of neuromuscular recovery at the end of surgery and a reduced need for neostigmine reversal in full term pregnant patients undergoing elective Caesarean section.     

Intubating conditions and neuromuscular block after divided dose mivacurium or single dose rocuronium

Purpose

To evaluate the tracheal intubating conditions and neuromuscular blocking charactenstics of divided dose mivacurium or single dose rocuronium.

Methods

Thirty-two patients undergoing elective surgery were studied. Anaesthesia was with propofol 2 mg · kg^?1, followed by an infusion of l50 μg · kg^?1 · min^?1. Patients were randomized to receive either mivacurium-0.15 mg · kg^?1 followed 30 sec later by 0.1 mg · kg^?1, or rocuronium-0.9 mg · kg^?1, followed 30 sec later by placebo. Tracheal intubating conditions were assessed 90 sec after the initial dose of relaxant by an anaesthetist who was unaware of patient group. The electromyographic (EMG) response of the first dorsal interosseus muscle to ulnar nerve train-of-four was measured.

Results

Successful tracheal intubation was performed in all patients after both mivacurium and rocuronium. Intubating conditions (jaw relaxation, open visible vocal cords) were judged to be good-excellent in all but one patient before insertion of the tracheal tube. However, patients receiving mivacunum were more likely to experience coughing and bucking after tracheal tube insertion (10/16 patients) than those receiving rocuronium (3/16 patients, P < 0.05). No patient in the rocuronium group experienced moderately vigorous coughing and bucking after insertion of the tracheal tube vs six patients in the mivacurium group (P < 0.05). Time to 10 and 25% recovery of neuromuscular function was faster (P < 0.05) after divided dose mivacunum (20 ± 1 and 23 ± 1 min, respectively) than after rocuronium (45 ± 5 and 57 ± 8 min, respectively).

Conclusion

The results suggest that, during conditions of the study, divided dose mivacurium is not recommended for a 90-sec tracheal intubation in patients where moderate coughing and bucking is deemed unacceptable.     

The reversal of profound mivacurium-induced neuromuscular blockade

Purpose

Mivacurium is metabolized by plasma cholinesterase catalyzed ester hydrolysis. Acetylcholinesterase antagonists used in the reversal of muscle relaxation may also inhibit plasma cholinesterase and, therefore, delay the hydrolysis of mivacurium. The clinical interaction between acetylcholinesterase antagonists and mivacurium induced neuromuscular blockade was studied.

Method

Intraoperative muscle relaxation was maintained with a mivacurium infusion to achieve a constant intense block (first twitch, T¹, 2–3% of control). Patients were randomly divided into three groups. Patients in Group 1 received no anticholinesterase, in Group 2 neostigmine 0.07 mg · kg^?1, and in Group 3 edrophonium 1 mg · kg^?1. The times between termination of the mivacurium infusion (Group 1) or the administration of the anticholinesterase (Groups 2 and 3) to 25%, 50%, 75% and 95% T₁ recovery, and to 50%, 70% and 90% recovery in the ratio, T₄/T₁ (TR) were recorded.

Result

In the neostigmine Group, T₁ recovery to 25%, 50% and 75% ( 2.32 ± 1.41, 3.90 ± 1.85 and 6.88 ± 2.66 min) was accelerated compared with control (3.36 ± 1.34, 5.78 ± 2.22, and 8.58 ± 3.60, and), but recovery to 95% (18.53 ± 9.09 vs 13.29 ± 5.24 min) was delayed. Also, TR recovery to 50%, 70%, and 90% was slower (14.47 ± 8.73, 21.25 ± 11.06 and 31.37 ± 12.11 min vs 11.75 ± 3.74, 13.78 ± 4.39 and 17.86 ± 6.44 min). However, all T₁ and TR recovery times were decreased in the edrophonium group (0.88 ± 0.51, 2.00 ± 1.50, 4.97 ± 2.96, and 9.35 ± 5.24 min for T₁ and 6.86 ± 3.93, 9.05 ± 4.51 and 12.24 ± 6.66 min for TR).

Conclusion

Neostigmine reversal of intense mivacurium neuromuscular block should be avoided, as this may result in prolongation of the block.     

脑电双频指数-靶控输注注射泵闭环丙泊酚靶控输注应用于妇科腹腔镜手术的安全效益研究

目的 观察BIS-靶控输注(target controlled infusion,TCI)注射泵闭环丙泊酚TCI对妇科腔镜手术患者丙泊酚的节约效应及血流动力学的影响. 方法 纳入ASA分级Ⅰ、Ⅱ级择期行妇科腔镜手术的患者40例,采用计算机随机数字表分组分为闭环组和开环组,每组20例.闭环组采用BIS监测闭环丙泊酚TCI维持全身麻醉,开环组采用BIS监测下人工调整丙泊酚TCI血浆效应浓度2～5 mg/L维持全身麻醉,BIS目标值50±5;瑞芬太尼血浆效应浓度4μg/L TCI.记录两组在入室后5 min(T0)、诱导后气管插管前(T1)、插管后1 min(T2)、插管后5 min(T3)、手术切皮时(T4)、切皮后30 min(T5)、缝皮(T6)、手术结束(T7)、意识恢复(T8)、拔管即刻(T9)及拔管后5 min(T10)等时点MAP、HR、BIS值的变化,同时记录两组患者诱导及维持丙泊酚用药量、苏醒时间及进入PACU时的疼痛数字评分(numerical rating scale,NRS)及Ramsay镇静评分. 结果 术中维持丙泊酚剂量闭环组[(6.2±1.4) mg· kg-1·h-1]较开环组[(6.9±1.0)mg·kg-1·h-1]降低了10％,两组各时点MAP、HR、BIS差异无统计学意义(P＞0.05),闭环组切皮时MAP、HR、BIS波动明显小于开环组(P＜0.05).两组患者苏醒时间、NRS及Ramsay镇静评分差异无统计学意义(P＞0.05). 结论 BIS-TCI注射泵闭环丙泊酚TCI与常规BIS监测下开环丙泊酚TCI可同样安全地应用于临床,可对患者个体化合理给予全身麻醉药物,并可部分降低术中丙泊酚使用剂量,降低麻醉后手术前的循环波动.同时,避免麻醉医师手动调控TCI靶控血浆浓度,极大地降低了麻醉医师的工作量,并使围麻醉期更加平稳安全.     

Mivacurium chloride—a comparative profile

Mivacurium is a new nondepolarizing muscle relaxant of the benzylisoquinoline type. Its short duration of action is due to rapid breakdown by plasma cholinesterase. The dose of mivacurium which produces 95% inhibition of twitch response (ED₉₅) is between 60 and 80 μg/kg. Thus, mivacurium is 0.8 times and four times as potent as vecuronium and atracurium, respectively. With 2–3×ED₉₅, tracheal intubation can be accomplished within 2.5 min of intravenous injection. The ensuing DUR25% (time from injection to 25% recovery of control twitch tension) is twice as long as with suxamethonium and about half as long as with equipotent doses of atracurium or vecuronium. For muscle relaxation during long surgical procedures, mivacurium has been used as a continuous infusion. The average 6-min recovery index after infusion of mivacurium is particularly favourable for flexible control of muscle paralysis, whereas the recovery indices after infusion of atracurium or vecuronium are 15–30 min. In conclusion, mivacurium will close the pharmacodynamic gap between suxamethonium and the nondepolarizing muscle relaxants of intermediate duration of action. It will probably also be a suitable alternative to suxamethonium in elective cases.     

Intubationsbedingungen und Kreislaufverhalten 90 s nach einer geteilten Mivacuriumdosis bei drei unterschiedlichen TIVA-Einleitungsformen

The aim of this study was to compare the intubating conditions of a mivacurium-induced neuromuscular block 90?s after a divided administration with three different methods of induction of anaesthesia. Methods. After approval by the local ethics committee, we investigated 36 ASA I and II patients undergoing a 2-h scheduled, elective surgery, in whom a TIVA was induced by one of three different drugs, edomidate, methohexital or propofol. After stable anaesthesia was reached, 0.15?mg/kg and 0.1?mg/kg of mivacurium, spaced 30?s apart, was injected. Endotracheal intubation was performed 90?s after the first micacurium injection and the intubation conditions were graded (1: excellent, 2: good, 3: poor; 4: impossible). The neuromuscular function was stimulated every 20?s by a nerve stimulator in a train-of-four (TOF) pattern, and the time to complete distinction of a TOF response as well as the time of reoccurrence of the first twitch was taken. A minute prior to injection of the relaxant and every minute for 5?min, the systolic and diastolic blood pressure, mean arterial pressure (MAP) and heart rate were measured. The neuromuscular block was maintained with a mivacurium infusion on a level of one twitch response. After cessation of the mivacurium infusion we recorded the time of reappearance of the second, third and fourth twitch responses. Results. All patients could be intubated 90?s after mivacurium except for one, who was excluded for abnormal difficult intubation conditions. The etomidate group had significantly (χ² test) worse intubation grades than the methohexital group. In none of the groups did we observe any significant cardiovascular response due to the mivacurium injection, neither in blood pressure nor in heart rate. All groups showed similar onset of the maximal neuromuscular block (4±1.8?min) and recovery of the first TOF reaction (11.3±3.4?min). There was no difference in recovery from neuromuscular block maintained by infusion at the end of surgery. Conclusions. A dose of mivacurium 3.57 times the ED₉₅ does not produce any haemodynamic instability, if it is divided into two parts to induce a TIVA. After this dose, all patients could be safely intubated within 90?s. A prolongation of the neuromuscular block after higher mivacurium doses could not be seen, and this dose did not produce a more rapid onset of the maximal block in any group. The time for recovery from a mivacurium infusion did not differ among the groups. Etomidate, due to its short half-life, seems not ideal for induction of a TIVA together with mivacurium in the dosage used. Mivacurium meets the demands of good controllability as required for a TIVA and can be recommended for a 90-s injection-intubation interval as well as for maintenance of the neuromuscular block.     

Neuromuscular and cardiovascular effects of mivacurium chloride in surgical patients receiving nitrous oxide-narcotic or nitrous oxide-isoflurane anaesthesia

The neuromuscular and cardiovascular effects of mivacurium chloride were studied during nitrous oxide-oxygen narcotic (fentanyl) (n = 90) and nitrous oxide-oxygen isoflurane (ISO) anaesthesia (n = 45). In addition, a separate group (n = 9) received succinylcholine during fentanyl anaesthesia to compare its neuromuscular effects with mivacurium. Mivacurium was initially administered as a single bolus in doses from 0.03 mg.kg-1 to 0.25 mg.kg-1 to study the dose-response relationships, as well as the cardiovascular effects of mivacurium. Neuromuscular block (NMB) was measured by recording the twitch response of the adductor pollicis muscle following ulnar nerve stimulation (0.15 Hz, 0.2 ms supramaximal voltage). The ED95 values for mivacurium were estimated to be 0.073 mg.kg-1 and 0.053 mg.kg-1 in the fentanyl and ISO groups respectively. The duration of block (time from injection to 95 per cent recovery) for a dose of 0.05 mg.kg-1 mivacurium was 15.3 +/- 1.0 min and 21.5 +/- 1.3 min for fentanyl and ISO anaesthesia, respectively. The recovery index (25-75 per cent) between initial bolus dose (6.1 +/- 0.5 min), repeat bolus doses (7.6 +/- 0.6 min), mivacurium infusion (6.7 +/- 0.7 min) and succinylcholine infusion (6.8 +/- 1.8 min) were not significantly different. There was minimal change in mean arterial pressure (MAP) or heart rate (HR) following bolus doses of mivacurium up to 0.15 mg.kg-1. Bolus administration of 0.20 mg.kg-1 or 0.25 mg.kg-1 of mivacurium decreased MAP from 78.2 +/- 2.5 to 64.0 +/- 3.2 mmHg (range 12-59 per cent of control) (P less than 0.05). The same doses when administered slowly over 30 sec produced minimal change in MAP or HR.     

Influence of anaesthesia and muscle relaxation on intubating conditions and sympathoadrenal response to tracheal intubation

Background : The study aimed to assess the relative influence of anaesthesia and muscle relaxation on intubating conditions and the haemodynamic and catecholamine responses to tracheal intubation.
Methods : Sixty ASA 1 or 2 patients were randomly assigned to one of four groups (15 patients each) that differed in the depth of anaesthesia (thiopentone plus fentanyl 2.5 μg kg^-1 or thiopentone alone) and the degree of vecuronium–induced neuromuscular block (100% or _>: 65%) at intubation. Muscle relaxation was measured at 0.1 Hz by means of mechanomyography. Heart rate (HR) and mean arterial blood pressure (MAP) were measured before and after induction of anaesthesia, and 1 min and 5 min following intubation, while adrenaline (A) and noradrenaline concentrations (NA) were determined from arterial blood samples.
Results : Intubating conditions were improved primarily by providing complete muscle relaxation at the adductor pollicis muscle (P<0.001) and to a lesser extent by adding fentanyl to thiopentone (P=0.04). The response of HR and MAP to tracheal intubation was attenuated mainly by fentanyl (P<0.001). Complete muscle relaxation further diminished the response of MAP to intubation (P=0.03). Changes in A and NA were dependent on the depth of anaesthesia only (P =>0.01).
Conclusion : The results of the study demonstrate that the sympathoadrenal response to intubation is attenuated by adding fentanyl (2.5 kg^-1) to an induction regimen with thiopentone, whereas provision of complete muscle relaxation at the adductor pollicis muscle is necessary to attain smooth intubating conditions.