动物全身麻醉方法及用药研究进展

动物麻醉是动物诊疗及手术过程顺利进行的先决条件,动物全身麻醉一般分为吸入性麻醉和非吸入麻醉两类。本文综述了动物全身麻醉的方法及常用麻醉剂的研究进展。     

A comparison of retrobulbar and two peribulbar regional anesthetic techniques in dog cadavers

Objective

To compare injectate distribution and likelihood of regional anesthesia to the orbit following retrobulbar (RB) or peribulbar (PB) injections in dog cadavers.

Ultrasonographic study of a modified axillary approach to block the major branches of the brachial plexus in dogs

ObjectiveTo provide ultrasonographic mapping of the axillary region of dogs to facilitate identification of the major branches of the brachial plexus in relation to the axillary artery.Study designProspective study.AnimalsA total of two dog cadavers and 50 client-owned, healthy dogs weighing >15 kg.MethodsIn Phase 1, anatomical dissections were performed to identify the relation of the major brachial plexus nerves to the axillary artery. In Phase 2, with the dogs in dorsal recumbency with thoracic limbs flexed naturally, the axillary space was scanned using a linear array probe oriented on the parasagittal plane until the axis transverse to nerves was found. Then, the transducer was rotated to a slight lateral angle approximately 30° to midline. The examination aimed to identify the axillary artery and the musculocutaneous, radial, median and ulnar nerves in addition to determining their position and distribution in four predefined sectors.ResultsThe musculocutaneous nerve was observed in all animals cranial to the axillary artery. The radial, ulnar and median nerves were distributed around the axillary artery, with >90% on the caudal aspect of the axillary artery (sectors 1 and 2).Conclusions and clinical relevanceUltrasonography identified the location of the brachial plexus nerves near the studied sectors, providing useful guidance for performing a brachial plexus nerve block.     

A review of ophthalmic local and regional anesthesia in dogs and cats

Objective

Orbital and globe surgeries are commonly performed in companion animals and are considered to cause moderate to severe pain. Regional anesthesia techniques can provide complete sensory blockade, analgesia for painful procedures and improve surgical conditions. The purpose of this review is to summarize local and regional anesthesia techniques for ophthalmic surgery in dogs and cats with emphasis on veterinary publications in the past 12 years.

Retrobulbar and peribulbar regional techniques in cats: a preliminary study in cadavers

ObjectiveTo compare injectate distribution and potential complications of retrobulbar and peribulbar injections in cat cadavers.Study designProspective randomized masked study.AnimalsTen cat cadavers (20 eyes).MethodsA dorsomedial retrobulbar injection (RB) of 1 mL of 0.5% bupivacaine and iopamidol (1:1) was performed in seven eyes. A dorsomedial peribulbar injection (PB‐1) of 4 mL of the same injectate was performed in seven eyes, and two peribulbar injections (PB‐2) of the same injectate, divided equally between the dorsomedial and ventrolateral regions (2 mL each) were performed in six eyes. Intraocular pressure (IOP) was measured before, immediately and 15 minutes after injection. Cadavers underwent computed tomography before and following injections. A radiologist scored injectate distribution within the intraconal space (none, moderate, or large) and around the optic nerve (degrees). An injection was defined as likely to provide adequate regional anesthesia if the volume of distribution of intraconal injectate was ‘large’ and it contacted over 270° of the optic nerve circumference.ResultsThe success rate (95% confidence interval) of RB, PB‐1, and PB‐2 injections was 71% (29.0–96.3%), 86% (42.1–99.6%), and 67% (22.3–95.7%), respectively. With all three techniques, IOP increased significantly after injection, but returned to baseline by 15 minutes following RB injection. No intraocular, intravascular, intrathecal, or intraneural injectate was observed.Conclusion and clinical relevanceThe single‐peribulbar injection technique may be superior to retrobulbar or double‐peribulbar injections, however, all techniques require further studies in live cats to determine safety and efficacy prior to clinical use.     

Ultrasound-guided superficial serratus plane block in dog cadavers: an anatomical evaluation and volume dispersion study

ObjectiveTo evaluate the anatomy of the serratus plane in dogs to establish the optimal landmarks for a superficial serratus plane (SSP) block and evaluate ropivacaine–methylene blue solution dispersion with three volumes of injection.Study designProspective experimental cadaveric study.AnimalsA formaldehyde solution-preserved dog cadaver and 15 frozen/thawed adult dog cadavers.MethodsThe thoracic wall of the formaldehyde-preserved cadaver was dissected. An SSP injection was performed on each hemithorax of the cadavers, with the ultrasound transducer placed over the fourth and fifth ribs, at the level of the shoulder joint. A needle was inserted in-plane in a caudocranial direction until it could be visualized between the serratus ventralis thoracis and latissimus dorsi muscles. Dog cadavers were injected with a ropivacaine–methylene blue solution at 0.3, 0.6 and 1.0 mL kg^–1 and were dissected to determine the spread of the dye.ResultsThe thoracic wall muscles identified in the formalinized cadaver were the cutaneous trunci, latissimus dorsi, external abdominal oblique, serratus ventralis thoracis, scalenus, serratus dorsalis cranialis and external intercostal. The nerves identified in the SSP included the lateral cutaneous branches of intercostal nerves, intercostobrachial nerves and long thoracic nerve. The solution was successfully injected at the SSP in 26 of 29 (89.7%) attempts. Dermatomal dye spread, median (range), was 4 (3–6), 4 (2–5) and 5 (4–8) for 0.3, 0.6 and 1.0 mL kg^–1, respectively, with no significant difference among them.Conclusions and clinical relevanceInjections for an SSP block were easily performed under ultrasound guidance, using the fourth and fifth ribs at the level of the shoulder joint as reference landmarks. An injected volume of 0.3 mL kg^–1 may be sufficient for hemithorax analgesia in dogs. Further studies in dogs are required to determine the utility of this technique.     

Evaluation of the isoflurane‐sparing effects of fentanyl,lidocaine, ketamine,dexmedetomidine, or the combination lidocaine‐ketamine‐dexmedetomidine during ovariohysterectomy in dogs

ObjectiveTo evaluate the isoflurane‐sparing effects of an intravenous (IV) constant rate infusion (CRI) of fentanyl, lidocaine, ketamine, dexmedetomidine, or lidocaine‐ketamine‐dexmedetomidine (LKD) in dogs undergoing ovariohysterectomy.Study designRandomized, prospective, blinded, clinical study.AnimalsFifty four dogs.MethodsAnesthesia was induced with propofol and maintained with isoflurane with one of the following IV treatments: butorphanol/saline (butorphanol 0.4 mg kg^?1, saline 0.9% CRI, CONTROL/BUT); fentanyl (5 μg kg^?1, 10 μg kg^?1 hour^?1, FENT); ketamine (1 mg kg^?1, 40 μg kg^?1 minute^?1, KET), lidocaine (2 mg kg^?1, 100 μg kg^?1 minute^?1, LIDO); dexmedetomidine (1 μg kg^?1, 3 μg kg^?1 hour^?1, DEX); or a LKD combination. Positive pressure ventilation maintained eucapnia. An anesthetist unaware of treatment and end‐tidal isoflurane concentration (Fe′Iso) adjusted vaporizer settings to maintain surgical anesthetic depth. Cardiopulmonary variables and Fe′Iso concentrations were monitored. Data were analyzed using anova (p < 0.05).ResultsAt most time points, heart rate (HR) was lower in FENT than in other groups, except for DEX and LKD. Mean arterial blood pressure (MAP) was lower in FENT and CONTROL/BUT than in DEX. Overall mean ± SD Fe′Iso and % reduced isoflurane requirements were 1.01 ± 0.31/41.6% (range, 0.75 ± 0.31/56.6% to 1.12 ± 0.80/35.3%, FENT), 1.37 ± 0.19/20.8% (1.23 ± 0.14/28.9% to 1.51 ± 0.22/12.7%, KET), 1.34 ± 0.19/22.5% (1.24 ± 0.19/28.3% to 1.44 ± 0.21/16.8%, LIDO), 1.30 ± 0.28/24.8% (1.16 ± 0.18/32.9% to 1.43 ± 0.32/17.3%, DEX), 0.95 ± 0.19/54.9% (0.7 ± 0.16/59.5% to 1.12 ± 0.16/35.3%, LKD) and 1.73 ± 0.18/0.0% (1.64 ± 0.21 to 1.82 ± 0.14, CONTROL/BUT) during surgery. FENT and LKD significantly reduced Fe′Iso.Conclusions and clinical relevanceAt the doses administered, FENT and LKD had greater isoflurane‐sparing effect than LIDO, KET or CONTROL/BUT, but not at all times. Low HR during FENT may limit improvement in MAP expected with reduced Fe′Iso.     

贵州黑山羊胚胎移植手术不同麻醉方法比较

为了筛选适合于贵州黑山羊胚胎移植手术的麻醉方法,试验以贵州黑山羊为试验动物,比较了速眠新Ⅱ注射液2种麻醉方法（肌肉麻醉和静脉麻醉）对山羊生理指标,麻醉山羊的诱导期、麻醉期、苏醒期,麻醉苏醒后山羊的采食、反刍及精神状况的影响。结果表明：2种麻醉方法下,麻醉效果优、良的山羊数量和生理指标无明显差异;速眠新Ⅱ注射液静脉注射麻醉时,山羊的诱导期、麻醉期和苏醒期均较短,在苏醒后0.5 h,90.0%的山羊可以采食,83.3%的山羊可以反刍,93.3%的山羊精神状况良好;苏醒后1 h基本上全部可以恢复正常;采用静脉注射麻醉山羊进行胚胎移植手术,速眠新Ⅱ注射液用药剂量小,且安全、有效,明显优于肌肉注射。     

动物试验中麻醉药物的选择应用研究进展

动物试验中根据试验目的与要求选择适宜、安全、有效的麻醉药是试验成败的关键。动物试验麻醉药物品种繁多,给药途径、方式不尽相同,本文通过阅读相关文献并结合自身研究实践,对动物试验中常用麻醉药特点及应用进行归纳总结,为研究人员进行动物研究麻醉药的选择作以参考,保证试验的顺利进行和研究结果的准确可靠。     

Effects of two continuous infusion doses of lidocaine on isoflurane minimum anesthetic concentration in chickens

ObjectiveTo assess the effect of two intravenous (IV) doses of lidocaine on the minimum anesthetic concentration (MAC) of isoflurane in chickens.Study designBlinded, prospective, randomized, experimental crossover study.AnimalsA total of six adult female chickens weighing 1.90 ± 0.15 kg.MethodsChickens were anesthetized with isoflurane and mechanically ventilated. Isoflurane MAC values were determined (T0) in duplicate using an electrical noxious stimulus and the bracketing method. After MAC determination, a low dose (LD; 3 mg kg^–1 followed by 3 mg kg^–1 hour^–1) or high dose (HD; 6 mg kg^?1 followed by 6 mg kg^?1 hour^–1) of lidocaine was administered IV. MAC determination was repeated at 1.5 (T1.5) and 3 (T3) hours of lidocaine administration and blood was collected for analysis of plasma lidocaine and monoethylglycinexylidide (MEGX) concentrations. Pulse rate, peripheral hemoglobin oxygen saturation, noninvasive systolic arterial pressure and cloacal temperature were recorded at T0, T1.5 and T3. Treatments were separated by 1 week. Data were analyzed using mixed-effects model for repeated measures.ResultsMAC of isoflurane (mean ± standard deviation) at T0 was 1.47 ± 0.18%. MAC at T1.5 and T3 was 1.32 ± 0.27% and 1.26 ± 0.09% (treatment LD); and 1.28 ± 0.06% and 1.30 ± 0.06% (treatment HD). There were no significant differences between treatments or times. Maximum plasma lidocaine concentrations at T3 were 496 ± 98 and 1200 ± 286 ng mL^–1 for treatments LD and HD, respectively, and were not significantly different from T1.5. With treatment HD, plasma concentration of MEGX was significantly higher at T3 than at T1.5. Physiological variables were not significantly different among times with either treatment.Conclusions and clinical relevanceAdministration of lidocaine did not significantly change isoflurane MAC in chickens. Within treatments, plasma lidocaine concentrations were not significantly different at 1.5 and 3 hours.     

Plasma bupivacaine concentrations following orbital injections in cats

Objective

To determine plasma bupivacaine concentrations after retrobulbar or peribulbar injection of bupivacaine in cats.

Evaluation of neuraxial anesthesia in bearded dragons (Pogona vitticeps)

Objective

To assess the feasibility, success rate, onset, duration and extent of motor/sensory block following intrathecal injection of lidocaine in bearded dragons (Pogona vitticeps).

Evaluation of neuraxial administration of bupivacaine in bearded dragons (Pogona vitticeps)

ObjectiveTo assess the success rate, onset, duration and extent of motor/sensory block following neuraxial injection of two dosages of bupivacaine in bearded dragons (Pogona vitticeps).Study designProspective, randomized, blinded, crossover experimental study.AnimalsA total of 10 adult bearded dragons (0.3 ± 0.1 kg).MethodsAfter sedation with alfaxalone (15 mg kg^–1 subcutaneously), neuraxial injections were performed with 1 or 2 mg kg^–1 bupivacaine hydrochloride (0.5%, treatments BUP-1 and BUP-2, respectively) in a randomized treatment sequence with a 7 day washout period. If the initial bupivacaine injection was not successful within 10 minutes, a second injection was performed at the same dose. Mechanical stimulation of limbs, 25%, 50%, 75% of the trunk’s length and cloacal tone were assessed.ResultsSuccess rate following the first neuraxial injection was 95%, which increased to 100% after the second injection. Motor/sensory block were noted by 5 minutes after the injection of bupivacaine at either dose. BUP-2 was associated with more cranial spread. The median (range) duration of cloacal tone loss was longer following treatment BUP-2 [120 (75–225) minutes] than followed treatment BUP-1 [83 (25–135) minutes; p = 0.03]. Duration of pelvic limb motor block was comparable between both doses, lasting a median of 68 minutes in both treatments (p = 0.94). There was a transient, not clinically relevant increase from baseline in heart rate in treatment BUP-1 only. No significant difference from baseline in respiratory rate was noted in either treatment; however, two animals in treatment BUP-2 became apneic (10–20 minutes).Conclusions and clinical relevanceBupivacaine (1 mg kg^–1) is recommended for neuraxial anesthesia in bearded dragons. In treatment BUP-2, extensive cranial spread resulted in apnea and motor block of the thoracic limb in several animals; therefore this dose is not recommended.     

Behavioral responses following eight anesthetic induction protocols in horses

Objective To compare behavioral characteristics of induction and recovery in horses anesthetized with eight anesthetic drug protocols. Study design Randomized prospective experimental study. Animals Eight horses, 5.5 ± 2.4 years (mean ± SD) of age, and weighing 505 ± 31 kg. Methods After xylazine pre‐medication, each of eight horses was anesthetized on four occasions using one of eight different anesthetic induction protocols which incorporated various combinations of ketamine (KET), propofol (PRO), and thiopental (THIO): THIO 8 mg kg^?1; THIO 6 mg kg^?1 + PRO 0.5 mg kg^?1; THIO 4 mg kg^?1 + PRO 1 mg kg^?1; THIO 2 mg kg^?1 + PRO 1.5 mg kg^?1; KET 2 mg kg^?1; KET 1.5 mg kg^?1 + PRO 0.5 mg kg^?1; KET 1 mg kg^?1 + PRO 1 mg kg^?1; KET 0.5 mg kg^?1 + PRO 1.5 mg kg^?1. Quality of induction and recovery were scored from 1 (poor) to 5 (excellent), and time taken to achieve lateral recumbency, first movement, sternal recumbency, and standing were evaluated. Results Time taken to achieve lateral recumbency after drug administration differed significantly (p < 0.0001) among the various combinations, being shortest in horses receiving THIO‐8 (mean ± SD, 0.5 ± 0.3 minutes) and longest in horses receiving KET‐2 (1.4 ± 0.2 minutes). The best scores for induction quality were associated with KET‐1.5 + PRO‐0.5, and the worst scores for induction quality were associated with KET‐2, although the difference was not significant. Time to first movement varied significantly among drug protocols (p = 0.0133), being shortest in horses receiving KET‐2 (12.7 ± 3.6 minutes) and longest in horses receiving THIO‐8 (29.9 ± 1.5 minutes). Horses receiving THIO‐8 made the greatest number of attempts to attain sternal posture (6.5 ± 4.7) and to stand (1.6 ± 0.8). Horses in the THIO‐8 treatment also received the poorest recovery scores (3.3 ± 1.0 and 3.0 ± 0.7 for sternal and standing postures, respectively). The best recovery scores were associated with combinations comprised mainly of propofol. Conclusions Combining propofol with either ketamine or thiopental modifies behaviors associated with use of the individual drugs. Clinical relevance Quality of early anesthesia recovery in horses may be improved by some combinations of propofol with either thiopental or ketamine.     

Effects of intravenous ethyl pyruvate on cardiopulmonary variables and quality of recovery from anesthesia in horses

ObjectiveTo determine the effects of intravenous ethyl pyruvate, an anti-inflammatory with putative benefits in horses with endotoxemia, on cardiopulmonary variables during anesthesia and the quality of anesthetic recovery.Study designRandomized, crossover, blinded experimental design.AnimalsA total of six healthy Standardbred geldings, aged 13 ± 3 years and weighing 507 ± 66 kg (mean ± standard deviation).MethodsHorses were anesthetized for approximately 90 minutes on two occasions with a minimum of 2 weeks apart using xylazine for sedation, ketamine and diazepam for induction, and isoflurane in oxygen for maintenance. Lactated Ringer’s solution (LRS; 10 mL kg^–1 hour^–1) was administered during anesthesia. Treatments were randomized and administered starting approximately 30 minutes after induction of anesthesia and infused over 60 minutes: LRS (1 L) or ethyl pyruvate (150 mg kg^–1 in 1 L LRS). Invasive arterial pressures, heart rate, respiratory rate and end-tidal carbon dioxide tensions were recorded every 5 minutes for the duration of anesthesia. Arterial blood gases, glucose and lactate concentrations were measured every 20 minutes. Anesthetic recovery was video recorded, stored, and subsequently rated by two individuals blinded to treatments. Total recovery time, time to extubation, number of attempts and time to sternal recumbency, number of attempts to stand and time to stand were recorded. Quality of recovery was analyzed. Data between treatments and within a treatment were assessed using two-way repeated-measures anova and a Pearson correlation coefficient, significant at p < 0.05.ResultsAll horses completed the study. No significant differences were detected between the ethyl pyruvate and LRS treatments for either the cardiopulmonary variables or quality of recovery from anesthesia.Conclusions and clinical relevanceThe results suggest that intravenous ethyl pyruvate can be administered to healthy anesthetized horses with minimal impact on the cardiopulmonary variables studied or the quality of recovery from anesthesia.     

Effects of a single intravenous bolus of fentanyl on the minimum anesthetic concentration of isoflurane in chickens (Gallus gallus domesticus)

Objective

To assess the temporal effects of a single fentanyl intravenous (IV) bolus on the minimum anesthetic concentration (MAC) of isoflurane in chickens and to evaluate the effects of this combination on heart rate (HR) and rhythm, systemic arterial pressures (sAP) and ventilation.