利多卡因、布吡卡因行犬硬膜外阻滞时的药代动力学

为研究利多卡因(lidocaine)和布吡卡因(bupivacaine)行硬膜外阻滞时的药代动力学特征,将16只健康犬随机分成2组(n=8),硬膜外阻滞时按体质量分别注入2%利多卡因6mg/kg和0.5%布吡卡因2mg/kg,在注药后的3、5、8、10、15、20、30、40、50、60、75、90、120、150、180min分别采取股动脉血,用气相色谱法测定血药浓度,比较2组药代动力学指标。结果表明,利多卡因和布吡卡因的药-时曲线均符合一室开放模型,t1/2ka分别为(3.55±0.73)min和(7.76±0.38)min,tpeak分别为(18.8±2.2)min和(35.6±1.5)min,Cmax分别为(4.67±0.37)mg/L和(1.38±0.08)mg/L,AUC分别为(739±73)μg.mL-1.min和(366±45)μg.mL-1.min,CL分别为(12.2±4.6)mL/min和(5.5±0.67)mL/min。     

利多卡因、布吡卡因行山羊硬膜外阻滞的效果比较

选择 30只腹部手术的山羊随机分成 2组 ,每组 1 5例。行硬膜外穿刺后 ,分别注入 2 %利多卡因 8mg/kg和 0 75 %的布吡卡因 2mg/kg ,观察利多卡因、布吡卡因对山羊的阻滞效果。结果表明 :利多卡因、布吡卡因硬膜外阻滞起效时间分别为 (3 3± 1 5)min、 (1 5 5± 4 5)min ;感觉阻滞上界固定时间为 (1 2 0± 1 5)min、 (2 9 2± 8 6)min ;阻滞平面维持时间为 (72 5± 1 0 4)min、 (1 58 0± 2 5 4)min ;阻滞的最高平面为T 9 0± 1 3、T 8 0± 2 1 (T为胸椎 )。肌肉松弛均良好     

利多卡因、布吡卡因行硬膜外阻滞对羊肝、肾功能的影响

为研究利多卡因、布吡卡因硬膜外阻滞对山羊肝、肾功能的影响,将16只成年山羊被随机分成2组(n=8),L3-4之间行硬膜外穿刺、置管后,分别注入2%多利卡因6mg/kg和0.75%布吡卡因2mg/kg。在注药前及注药后的30min、24h、72h和120h采集血样,测定ALT、AST、ALP、γ-GT及LDH的活性和Bilirubin、Grea、UA和Gluc等生化指标。结果表明,利多卡因、布吡卡因行硬膜外阻滞对血清ALT、AST、ALP、γ-GT及LDH活性和Grea、Urea、Gluc和Bilirubin均没有明显影响。     

布比卡因药物体积对犬硬膜外麻醉效果的影响

本次试验旨在探究不同体积布比卡因用于犬硬膜外麻醉对感觉阻滞和运动阻滞的影响,比较盲扎与神经刺激器引导犬硬膜外麻醉的成功率。试验分为6个试验组,BL组(3组)利用解剖结构定位并进行硬膜外麻醉,S组(3组)利用神经刺激器引导进行硬膜外麻醉。注射药物后持续监测犬的体征变化、感觉阻滞(Sensory blockade,SB)、运动阻滞程度(Motor blockade,MB)等指标,直至犬完全恢复。试验结果表明,使用0.5%布比卡因进行犬硬膜外麻醉产生感觉阻滞和运动阻滞的持续时间和阻滞程度随药物体积增加(0.1 mL/kg·bw、0.2 mL/kg·bw、0.4 mL/kg·bw)而增加。盲扎法与神经刺激器法对硬膜外麻醉的成功率无显著影响。     

利多卡因硬膜外麻醉对犬生理指标的影响及镇痛效果评估

为研究利多卡因硬膜外麻醉对犬生理指标的影响,以及分析和评估不同剂量利多卡因硬膜外麻醉对犬的镇痛效果,试验选择健康中华田园犬9只,分为空白组、低剂量(利多卡因,2 mg/kg)组、高剂量(利多卡因,4 mg/kg)组,按体重以适量丙泊酚进行诱导麻醉,于腰椎与荐椎结合处穿刺进入硬膜外腔,并分别注入不同剂量的利多卡因或生理盐水,通过其对痛觉刺激的反应和生理指标(体温、心率、呼吸频率)的变化来评估麻醉效果,最终确定利多卡因硬膜外麻醉剂量。结果表明:麻醉5 min后高剂量组犬的体温显著低于低剂量组和空白组(P0.05);麻醉后25～45 min,高剂量组犬的呼吸频率显著高于低剂量组和空白组(P0.05)。低剂量组犬麻醉5分钟时,对前肢痛觉刺激后心率较刺激前显著升高(P0.05),而此时对后肢进行痛觉刺激发现,刺激前后心率无显著变化(P0.05);至麻醉20分钟时,后肢痛觉刺激后心率较刺激前显著升高(P0.05)。高剂量组犬麻醉10分钟时,前肢痛觉刺激后心率较刺激前显著升高(P0.05),而此时对犬的后肢进行痛觉刺激犬的心率与刺激前无显著变化(P0.05);麻醉45分钟时,对后肢进行痛觉刺激后心率较刺激前显著升高(P0.05),表明高剂量利多卡因硬膜外麻醉对犬后肢的痛觉反射有一定影响,且该影响能维持一定时间。高剂量组犬的后肢痛觉刺激前后心率变化不显著的持续时间要长于低剂量组,而低剂量组长于空白组。三组犬的前肢在麻醉过程中均有痛觉反射,低剂量组后肢在第20分钟开始出现痛觉反射,而高剂量组犬的后肢于麻醉后第40分钟出现痛觉反射。说明4 mg/kg利多卡因进行硬膜外麻醉具有较好的镇痛效果,可用于犬后肢外科手术中疼痛管理。     

氟苯尼考静注及肌注在鸡体内药代动力学研究

健康AA肉鸡 36只 ,随机分成 4组 ,以 15mg/kg和 30mg/kg两种剂量静注、肌注分别给予氟苯尼考。用高压液相色谱法测定血浆中的药物浓度 ,采用 3p97药代动力学程序软件处理药 时数据。静注药 时数据符合二室开放模型 ,主要药代动力学参数 :15mg/kg剂量组Vd(ss) 1 5 7± 0 16L/kg ,T1/2α43 96± 12 2 7min、T1/2 β16 8 18±45 2 4min、CL(s) 0 0 17± 0 0 0 30L/ (kg·min)、AUC886 40± 146 5 3(μg/ml)·min ;30mg/kg剂量组Vd(ss) 1 42±0 2 3L/kg ,T1/2α41 48± 8 6 4min、T1/2 β180 80± 74 97min、CL (s) 0 0 17± 0 0 0 2 9L/ (kg·min)、AUC176 7 15±2 6 8 2 3(μg/ml)·min。肌注药 时数据符合一室开放模型 ,主要药代动力学参数 :15mg/kg剂量组T1/2 (ka) 10 2 5±9 19min、T1/2 (ke) 15 2 41± 73 0 9min、C(max) 3 5 0± 1 13μg/ml、AUC837 88± 16 0 85 (μg/ml)·min、F94 5 3% ;30mg/kg剂量组T1/2 (ka) 11 97± 7 5 9min、T1/2 (ke) 15 2 41± 73 0 9min、C(max) 6 79± 1 38μg/ml、AUC172 5 2 9±35 7 98(μg/ml)·min、F97 6 3%。实验结果表明 :氟苯尼考在鸡体内吸收好 ,分布快 ,消除也快。静注、肌注后曲线下面积AUC与剂量呈比例关系 ,各参数无剂量依赖性。     

犬常用麻醉剂对比格犬血流动力学及肾素-血管紧张素-醛固酮系统的影响

为探讨犬常用麻醉剂对比格犬血流动力学的影响及其作用机制,选用6只实验用比格犬,分两组分别注射两种犬临床常用麻醉剂舒泰和陆眠宁,在注药前及注药后的0、5、10、15 min进行无创血压、心率(HR)监测,并同步采取静脉血样,用ELISA检测肾素、血管紧张素和醛固酮含量。结果发现,血压、HR在注药后5～10 min时发生明显变化。PRA、AⅡ和ALD与收缩压(SBP)、舒张压(DBP)、平均动脉压(MAP)及HR的变化趋势大致相似,且它们之间存在着一定的相关性,其中以SBP、DBP、MAP尤为明显。表明PR A、AⅡ和ALD参与了犬常用麻醉剂引起的犬血流动力学变化过程,肾素-血管紧张素-醛固酮系统的变化可能是犬常用麻醉剂引起血流动力学变化的主要原因之一。     

丙泊酚复合硬膜外阻滞对犬的麻醉效果及其对呼吸系统的影响

本试验采用连续输注丙泊酚配合硬膜外麻醉,研究其对犬的麻醉效果和对呼吸系统的影响.选用成年杂种犬12只,随机分为两组.丙泊酚复合硬膜外阻滞为Ⅰ组(丙泊酚诱导量6 mg/kg体重,镇静维持剂量0.35±0.4 mg/kg体重·min,向硬膜外腔注射6 mg/kg体重的利多卡因);静脉连续输注丙泊酚为Ⅱ组(丙泊酚诱导麻醉6 mg/kg体重,麻醉维持剂量0.71±0.6 mg/kg体重·min).评价犬的麻醉效果和对呼吸系统的影响.单纯连续丙泊酚组镇痛、镇静和肌松效果良好,但是对呼吸系统的影响较大.丙泊酚配合硬膜外麻醉镇痛、肌松和镇静效果良好,对呼吸系统影响较小.连续注射丙泊酚配合硬膜外对犬进行麻醉过程平稳,麻醉效果良好,对呼吸系统影响较小,苏醒较快,未出现不良反应.     

复合麻醉剂KMT对八眉猪呼吸和循环系统的影响

为探讨复合麻醉剂氯胺酮-美托嘧啶-曲马多(KMT)对八眉猪呼吸和循环系统的影响。8只8~10周龄的八眉猪,肌肉注射KMT 0.1m L/kg,并在注药前及注射药后5、10、15、20、30、45、60、90及120 min测定呼吸频率、脉搏血氧饱和度、心率、无创血压及体温等。试验结果表明:注射KMT后,呼吸频率开始增加,10 min时达到最高值,之后开始下降,到45 min时降至最低;动脉血氧饱和度在整个监测过程中均在90%以上;心率与血压在注射KMT后10 min时达到最高值,之后开始下降,到60 min时降至最低;体温从注药后开始下降,在整个监测过程中体温下降幅度在2℃以内。提示:KMT对八眉猪呼吸和循环系统的影响短暂且轻微,证明KMT组方科学合理,临床使用安全。     

硫酸多粘菌素E在猪体内的药代动力学和生物利用度研究

健康断奶仔猪 5头 ,分别进行单剂量肌注 (2 5和 5 0mg/kgb .w .)和静注 (2 5mg/kgb .w .)给药 ,并用微生物学方法对硫酸多粘菌素E在猪体内的药代动力学和绝对生物利用度进行了研究。以 3P97程序处理血药浓度—时间数据 ,结果表明 ,以 2 5和 5 0mg/kgb .w .的剂量肌注给药时 ,其血清中药物的峰浓度 (Cmax)分别为 3 73± 0 2 8μg/ml和 6 40± 0 1 8μg/ml,达峰时间分别为 32 2 2± 1 51min和 34 1 8± 1 76min ,消除半衰期 (t1 / 2 β)为 2 55 99± 1 3 65min和 2 64 0 8± 2 8 57min ;以 2 5mg/kgb .w .的剂量静注给药时 ,其消除半衰期 (t1 / 2 β)为 2 51 2 8± 1 2 53min。静注和肌注在体内的分布均为一级吸收二室模型。肌注 2 5和 5 0mg/kgb .w .剂量的注射液时 ,其平均绝对生物利用度分别为 98 30 %和 88 54 %。     

Caudal epidural injection of lidocaine,tramadol, and lidocaine–tramadol for epidural anesthesia in cattle

Bigham, A. S., Habibian, S., Ghasemian, F., Layeghi, S. Caudal epidural injection of lidocaine, tramadol, and lidocaine–tramadol for epidural anesthesia in Cattle. J. vet. Pharmacol. Therap. 33 , 439–443. Caudal epidural anesthesia is commonly utilized in veterinary medicine to allow diagnostic, obstetrical, and surgical intervention, in the perineal region of large animal. The aim of this study is to directly compare the time of onset and duration of analgesia produced by a tramadol and lidocaine–tramadol combination with that produced by lidocaine administration in the epidural space of Cattle. Five healthy adult Holstein dairy cows were selected to this study. Epidural anesthesia was produced in all cows by lidocaine, with 2 weeks intervals repeated by a combination of lidocaine–tramadol and tramadol. Time to onset and duration of analgesia were recorded. Heart rate, respiratory rate and body temperature were recorded at 0 min and at 5, 10, 15, 30, 60, and 75 min after the epidural administrations of each treatments. The tramadol produced a significant (P < 0.05) longer duration of analgesia (306.8 ± 8.58 min) than lidocaine (69.40 ± 8.96 min) alone and lidocaine–tramadol combination (174 ± 4.84 min). Also, lidocaine–tramadol combination produced a significant (P < 0.05) longer duration of analgesia than lidocaine alone. Complete analgesia began at 14.10 ± 1.57 min in the tramadol treatment, being more delayed than in the treatments with lidocaine–tramadol (4.84 ± 0.68 min) and lidocaine (3.90 ± 0.89 min). Body temperatures, heart rates, and respiratory rates were not significantly different in comparison with baseline values throughout the study in the all treatments. The combination of lidocaine–tramadol produced anesthesia of longer duration than lidocaine and the onset time was approximately same as for the lidocaine group. Utilizing this combination, long duration of anesthesia could commence relatively soon after epidural injection and might be used without re‐administration of anesthetic agent in long‐duration obstetrical and surgical procedures.     

Effect of phentolamine mesylate on regression of lidocaine–epinephrine epidural anaesthesia in sheep

ObjectiveTo determine the impact of epidural phentolamine on the duration of anaesthesia following epidural injection of lidocaine–epinephrine.Study designBlinded randomized experimental study.AnimalsA group of 12 adult ewes weighing 25.7 ± 2.3 kg and aged 8–9 months.MethodsAll sheep were administered epidural lidocaine (approximately 4 mg kg^–1) and epinephrine (5 μg mL^–1). Of these, six sheep were randomized into three epidural treatments, separated by 1 week, administered 30 minutes after lidocaine–epinephrine: SAL: normal saline, PHE1: phentolamine (1 mg) and PHE2: phentolamine (2 mg). The other six sheep were administered only epidural lidocaine–epinephrine: treatment LIDEP. Each injection was corrected to 5 mL using 0.9% saline. Noxious stimuli were pinpricks with a hypodermic needle and skin pinch with haemostatic forceps to determine the onset and duration of sensory and motor block. Heart rate, noninvasive mean arterial pressure (MAP), respiratory rate and rectal temperature were recorded.ResultsThe onset times were not different among treatments. Duration of sensory block was significantly shorter in SAL (57.5 ± 6.2 minutes), PHE1 (60.7 ± 9.0 minutes) and PHE2 (62.0 ± 6.7 minutes) than in LIDEP (81.7 ± 13.4 minutes) (p < 0.05). Duration of motor blockade was significantly shorter in PHE1 (59.4 ± 5.4 minutes) and PHE2 (54.3 ± 4.0 minutes) than in SAL (84.8 ± 7.0 minutes) and LIDEP (91.5 ± 18.2 minutes) (p < 0.01). MAP in PHE2 was decreased at 10 minutes after administration of phentolamine (p < 0.05).Conclusion and clinical relevanceEpidural administration of 5 mL normal saline after epidural injection of lidocaine–epinephrine reduced the duration of sensory but not motor block in sheep. Epidural administration of phentolamine diluted to the final volume of 5 mL diminished both the duration of sensory and motor block in sheep administered epidural lidocaine–epinephrine.     

Epidural analgesia with 0.75% bupivacaine for laparotomy in goats

Epidural nerve block with 0.75% bupivacaine (1 ml/4 kg of body weight) was performed in 17 goats tranquilized by IM administration of acetylpromazine (0.07 mg/kg). For comparison, epidural nerve block with 2% lidocaine containing 1:100,000 epinephrine (1 ml/5 kg) was performed in 7 goats. Transient signs of CNS stimulation were observed during injection of bupivacaine in 5 goats and of lidocaine in 2 goats. Analgesia of the flank was inadequate for laparotomy in 4 goats given bupivacaine (including 1 goat given a two-thirds dose) and in 2 goats given lidocaine. Analgesia for these goats was provided by local infiltration of the operative site with lidocaine. With bupivacaine, the onset of analgesia was up to 40 minutes, and the duration of analgesia was several hours; most goats were unable to stand for at least 11 hours. In comparison, epidural nerve block with lidocaine had a more rapid onset and much shorter duration. For both anesthetic drugs, despite adequate analgesia for laparotomy, response to manipulation of abdominal viscera was observed in 12 goats. Arterial blood pressure and blood gas tensions were measured in 8 goats given bupivacaine; 3 goats had mean arterial blood pressure less than 70 mm of Hg. Seven goats had normal PaCO2 but 2 goats had low PaO2; 1 goat sedated with xylazine had increased PaCO2 and hypoxemia.     

Lignocaine versus bupivacaine for flank anaesthesia using multiport catheters via a caudal epidural approach in cattle

Objective To determine the anaesthetic and systemic effects of dorsolumbar epidural anaesthesia using non-stylet multiport catheters via the caudal approach to administer hypertonic 5% lignocaine (HL) or hypertonic 0.5% bupivacaine (HB) to the flank in standing cattle. Materials and methods Six healthy adult cattle weighing 310–455 kg received 0.2 mg/kg HL or 0.025 mg/kg of HB; control animals received 0.9% saline solution. All drugs were injected into the dorsolumbar epidural space via a caudal approach through a non-stylet multiport catheter. Each animal received each treatment at random. Evaluations of anaesthesia, ataxia, heart rate, arterial pressures, respiratory rate and rectal temperature were obtained at 0 (basal), 5, 10, 15, 30, 45, 60, 75, and 90 min after epidural injection and then at 30-min intervals until loss of anaesthesia. All animals received a standard noxious stimulus and a 4-point scale was used to score the response. A second scale was used to score ataxia. Results The duration of anaesthesia in the upper and lower flanks in cattle was 68 ± 12 and 110 ± 15 min (mean ± SD) after dorsolumbar epidural HL or HB, respectively. Both hypertonic local anaesthetics produced a mild ataxia. The systemic changes were within acceptable limits in these clinically healthy cattle. Conclusion In standing cattle the dorsolumbar epidural injection of hypertonic lignocaine provided faster onset of anaesthesia and fewer cardiovascular effects, but had a shorter duration of anaesthesia than hypertonic bupivacaine.     

Two cases of bradyarrhythmia and hypotension after extradural injections in dogs

OBSERVATIONS: Two healthy obese, seven-year-old, female Rottweilers weighing 40 and 57 kg were submitted for cranial cruciate repair. They were premedicated with intravenous methadone (0.1 mg kg(-1)) and acepromazine (0.01 and 0.02 mg kg(-1)). Anesthesia was induced with propofol (3.6 and 2.5 mg kg(-1)) and maintained with isoflurane in oxygen using a circle breathing system. The dogs were placed in sternal recumbency and epidural injection of lidocaine/bupivacaine or lidocaine/bupivacaine/morphine (0.2 mL/kg, 8 and 11 mL) was carried out over 1.5 and 4 minutes. Epidural pressures were 79 and 72 mmHg at the end of the injections. The first dog's heart rate decreased from 80 to 65 beats minute(-1) with a second degree atrioventricular (AV) block. The arterial pressure decreased from 100 to 50 mmHg. These responded to atropine (0.01 mg kg(-1) IV). The second dog's heart rate decreased from 120 to 60 beats minute(-1) while arterial pressure decreased from 72 to 38 mmHg. No treatment was given and heart rate and arterial blood pressure returned to acceptable ranges. CONCLUSIONS: These cases suggest that large increases in epidural pressure may cause significant cardiovascular effects. This may be avoided by using lower volumes and discontinuing injection if significant back pressure is detected.     

Evaluation of anti-nociceptive effect of epidural tramadol, tramadol-lidocaine and lidocaine in goats

Objective To compare the anti‐nociceptive effect of tramadol, a combination of tramadol‐lidocaine, and lidocaine alone when administered in the epidural space. Study design Experimental randomized cross‐over study. Animals Seven healthy male goats, aged 9–11 months, weight 17.5–25.5 kg. Methods Treatments were lidocaine, 2.86 mg kg^?1, tramadol‐lidocaine (1 mg kg^?1 and 2.46 mg kg^?1, respectively) and tramadol (1 mg kg^?1) given into the epidural space. The volume of all treatments was 0.143 mL kg^?1. Nociception was tested by pin prick and by pressure from a haemostat clamp. Times to the onset and duration of anti‐nociception in the perineal region were recorded. Recumbency and ataxia were noted. Rectal temperature, heart rate and respiratory rate were recorded before and at 15 minute intervals for 2 hours after the administration of each treatment. Statistical comparison used one‐way anova with a post hoc Duncan’s test as a post hoc. Significance was taken as p < 0.05. Results Times (mean ± SD) to onset of and duration of loss of sensation, respectively in minutes were; lidocaine, 3 ± 1 and 85 ± 11), tramadol‐lidocaine 4 ± 1 and 140 ± 2; tramadol 12 ± 1 and 235 ± 18. Onset and duration times were significantly longer with tramadol than the other two treatments. Duration was significantly longer with tramadol‐lidocaine than with lidocaine alone. With lidocaine treatment all goats were severely ataxic or recumbent, after tramadol‐lidocaine mildly ataxic, and after tramadol not ataxic. Rectal temperature, heart and respiratory rates did not differ significantly from baseline after any treatment. Conclusions and clinical relevance The combination of tramadol‐lidocaine given by epidural injection produced an anti‐nociceptive effect in the perineal region, which was rapid in onset and had a longer duration of action than lidocaine alone. This combination might prove useful clinically to provide analgesia in goats for long‐duration obstetrical and surgical procedures but surgical stimuli were not investigated in this study.     

Epidural anaesthesia using lignocaine, bupivacaine or a mixture of lignocaine and bupivacaine in dogs

The time to loss of interdigital reflex, duration of action, duration of muscle relaxation and cardiorespiratory effects were compared after epidural block using lignocaine, bupivacaine or a combination of lignocaine and bupivacaine in dogs. Dogs were pre-medicated with methotrimeprazine, anaesthesia was induced with thiopentone, in order to facilitate epidural puncture, and a lumbosacral epidural block was performed. Body temperature fell after pre-medication, thiopentone and epidural anaesthesia. Minimal changes were observed in arterial O₂ saturation, end tidal CO₂, respiratory rate, heart rate and mean arterial blood pressure. The combination of bupivacaine with lignocaine produced a shorter time to loss of interdigital reflex than bupivacaine alone, longer analgesia than lignocaine alone and longer muscle relaxation than either lignocaine or bupivacaine. The combination appeared to be the best choice when surgical time is prolonged.     

A comparison of the haemodynamic effects of epidurally administered medetomidine and xylazine in dogs

Alpha₂ agonists have a significant role in epidural anaesthetic techniques. However, there are few reports regarding epidural administration of these drugs especially in small animals ( Greene et al. 1995; Keegan et al. 1995; Vesal et al. 1996 ). This study compared the haemodynamic effects of xylazine and medetomidine after epidural injection in dogs. Six dogs (four females and two males) weighing 27.5 ± 3.39 kg, aged 5.6 ± 1.42 years were studied on two separate occasions one month apart. Dogs were sedated with 0.5 mg kg^?1 diazepam IM and 0.1 mg kg^?1 acepromazine IM. After 20 minutes, a lumbosacral epidural injection of 0.25 mg kg^?1 xylazine was administered (group X). One month later, following the same sedation, 15 µg kg^?1 medetomidine was administered epidurally (group M). Haemodynamic variables (ECG and indirect blood pressure (Doppler)), respiratory rate and rectal temperature were recorded before (baseline) and then every 5 minutes after the epidural injection, up to 60 minutes. Differences between groups were compared by a paired t‐test. Within group changes were compared to basal values by anova . A p‐value of < 0.05 was considered statistically significant. Both groups showed significant reductions in heart rate (106.3 ± 7.7 beats minute^?1 baseline versus 67.7 ± 7.6 (group M); 91 ± 3.8 baseline versus 52.3 ± 9 (group X)) and mean arterial blood pressure (113.1 ± 12.3 mm Hg baseline versus 87 ± 11 (group M); 118 ± 7 baseline versus 91 ± 14 (group X)). There were no differences between groups in these variables. After epidural injection, first degree atrioventricular block was recorded significantly more often in group X (50% against 33%) but second degree block was significantly more frequent in group M (66% against 33%). Also 50% of dogs in group X and 66% in group M showed sinus arrest. Respiratory rate decreased significantly in both groups following the epidural injection (20.66 ± 0.66 minute^?1 baseline versus 16.33 ± 4.77 (group M); 37.66 ± 0.56 baseline versus 16.33 ± 1.81 group X), but no differences between groups were observed. Rectal temperature decreased significantly in group X (38.16 ± 0.21) with respect to the basal measurement (39.30 ± 0.14 °C). In group M, there was no significant reduction in temperature, however, no statistical difference in rectal temperature was found between groups. This study shows that 0.25 mg kg^?1 xylazine and 15 µg kg^?1 medetomidine produce similar, significant cardiovascular and respiratory changes following lumbosacral epidural administration in dogs.     

Assessment of brachial plexus blockade in chickens by an axillary approach

ObjectiveTo assess the brachial plexus block in chickens by an axillary approach and using a peripheral nerve stimulator.Study designProspective, randomized, double-blinded study.AnimalsSix, 84-week old, female chickens.MethodsMidazolam (1 mg kg⁻¹) and butorphanol (1 mg kg⁻¹) were administered into the pectoralis muscle. Fifteen minutes later, the birds were positioned in lateral recumbency and following palpation of the anatomic landmarks, a catheter was inserted using an axillary approach to the brachial plexus. Lidocaine or bupivacaine (1 mL kg⁻¹) was injected after plexus localization by the nerve stimulator. Sensory function was tested before and after blockade (carpus, radius/ulna, humerus and pectoralis muscle) in the blocked and unblocked wings. The latency to onset of motor and sensory block and the duration of sensory block were recorded. A Friedman nonparametric one-way repeated-measures anova was used to compare scores from baseline values over time and to compare the differences between wings at each time point.ResultsA total of 18 blocks were performed with a success rate of 66.6% (12/18). The latency for motor block was 2.8 ± 1.1 and 3.2 ± 0.4 minutes for lidocaine and bupivacaine, respectively. The latencies for and durations of the sensory block were 6.0 ± 2.5 and 64.0 ± 18.0 and 7.8 ± 5.8 and 91.6 ± 61.7 minutes for lidocaine and bupivacaine, respectively. There was no statistical difference between these times for lidocaine or bupivacaine. Sensory function was not abolished in nonblocked wings.Conclusions and clinical relevanceThe brachial plexus block was an easy technique to perform but had a high failure rate. It might be useful for providing anesthesia or postoperative analgesia of the wing in chickens and exotic avian species that have similar wing anatomy.