The effect of ketamine on the MACBAR of sevoflurane in dogs

ObjectiveTo determine the effect of intravenous ketamine on the minimum alveolar concentration of sevoflurane needed to block autonomic response (MAC_BAR) to a noxious stimulus in dogs.Study designRandomized, crossover, prospective design.AnimalsEight, healthy, adult male, mixed-breed dogs, weighing 11.2–16.1 kg.MethodsDogs were anesthetized with sevoflurane on two occasions, 1 week apart, and baseline MAC_BAR (B-MAC_BAR) was determined on each occasion. MAC_BAR was defined as the mean of the end-tidal sevoflurane concentrations that prevented and allowed an increase (≥15%) in heart rate or invasive mean arterial pressure in response to a noxious electrical stimulus (50 V, 50 Hz, 10 ms). Dogs then randomly received either a low-dose (LDS) or high-dose series (HDS) of ketamine, and treatment MAC_BAR (T-MAC_BAR) was determined. The LDS had an initial loading dose (LD) of 0.5 mg kg^?1 and constant rate infusion (CRI) at 6.25 μg kg^?1 minute^?1, followed, after T-MAC_BAR determination, by a second LD (1 mg kg^?1) and CRI (12.5 μg kg^?1 minute^?1). The HDS had an initial LD (2 mg kg^?1) and CRI (25 μg kg^?1 minute^?1) followed by a second LD (3 mg kg^?1) and CRI (50 μg kg^?1 minute^?1). Data were analyzed with a mixed-model anova and are presented as LSM ± SEM.ResultsThe B-MAC_BAR was not significantly different between treatments. Ketamine at 12.5, 25, and 50 μg kg^?1 minute^?1 decreased sevoflurane MAC_BAR, and the maximal decrease (22%) occurred at 12.5 μg kg^?1 minute^?1. The percentage change in MAC_BAR was not correlated with either the log plasma ketamine or norketamine concentration.Conclusions and clinical relevanceKetamine at clinically relevant doses of 12.5, 25, and 50 μg kg^?1 minute^?1 decreased sevoflurane MAC_BAR, although the reduction was neither dose-dependent nor linear.     

脑电双频指数指导七氟醚吸入麻醉在成人心脏手术中的应用

目的观察脑电双频指数指导七氟醚吸入麻醉在成人心脏手术中的应用效果。方法在体外循环下行心脏瓣膜手术的成人患者80例,随机分为治疗组和对照组,均采用七氟醚吸入麻醉。治疗组依据脑电双频指数值调整七氟醚吸入浓度,而对照组根据临床经验来调整。结果治疗组插管时、切皮时和术毕的平均动脉压和心率均较对照组低(P<0.01),术后拔管时间与ICU停留时间都明显短于对照组(P<0.01)。结论在成人心脏手术中,脑电双频指数指导下的七氟醚吸入麻醉可使患者血流动力学更平稳,并缩短术后拔管时间与ICU停留时间。     

Evaluation of intraocular pressure in association with cardiovascular parameters in normocapnic dogs anesthetized with sevoflurane and desflurane

The objective of this study was to determine intraocular pressure (IOP) and cardiac changes in normocapnic dogs maintained under controlled ventilation and anesthetized using sevoflurane or desflurane. Sixteen healthy adult mixed-breed dogs, seven males and nine females, weighing 10-15 kg were used. The dogs were randomly assigned to one of two groups composed of eight animals anesthetized with sevoflurane (SEVO) or desflurane (DESF). In both groups, anesthesia was induced with propofol (10 mg/kg), and neuromuscular blockade was achieved with rocuronium (0.6 mg/kg/h i.v.). No premedication was given. Ventilation was adjusted to maintain end-tidal carbon dioxide partial pressure at 35 mmHg. Anesthesia was maintained with 1.5 minimum alveolar concentration (MAC) of sevoflurane or desflurane. In both groups IOP was measured by applanation tonometry (Tono-Pen) before induction of anesthesia. IOP, mean arterial pressure (MAP), heart rate (HR), cardiac index (CI) and central venous pressure (CVP) were also measured 45 min after the beginning of inhalant anesthesia and then every 20 min for 60 min. A one-way repeated measures anova was used to compare data within the same group and Student's t-test was used to assess differences between groups. P < 0.05 was considered statistically significant. Measurements showed normal IOP values in both groups, even though IOP increased significantly from baseline during the use of desflurane. IOP did not differ between groups. CI in the desflurane group was significantly greater than in the sevoflurane group. Sevoflurane and desflurane have no clinically significant effects on IOP, MAP, HR, CI or VCP in the dog.     

A comparison of recovery times and characteristics with sevoflurane and isoflurane anaesthesia in horses undergoing magnetic resonance imaging

Objective To compare recovery times and quality following maintenance of anaesthesia with sevoflurane or isoflurane after a standard intravenous induction technique in horses undergoing magnetic resonance imaging (MRI). Study design Prospective, randomised, blinded clinical study. Animals One hundred ASA I/II horses undergoing MRI. Materials and methods Pre‐anaesthetic medication with intravenous acepromazine and romifidine was followed by induction of anaesthesia with diazepam and ketamine. The animals were randomised into two groups to receive either sevoflurane or isoflurane in oxygen. Horses were subjectively scored (0–5) for temperament before sedation, for quality of sedation, induction and maintenance and anaesthetic depth on entering the recovery area. Recoveries were videotaped and scored by an observer, unaware of the treatment, using two scoring systems. Times to the first movement, head lift, sternal recumbency and standing were recorded along with the number of attempts to achieve sternal and standing positions. Variables were compared using a Student t‐test or Mann–Whitney U‐test (p < 0.05), while the correlation between subjective recovery score and other relevant variables was tested calculating the Spearman Rank correlation coefficient and linear regression modelling performed when significant. Results Seventy‐seven horses entered the final analysis, 38 received isoflurane and 39 sevoflurane. Body mass, age and duration of anaesthesia were similar for both groups. There were no differences in recovery times, scoring or number of attempts to achieve sternal recumbency and standing between groups. Weak, but significant, correlations were found between the subjective recovery score for the pooled data from both groups and both temperament and time in sternal recumbency. Conclusions No differences in recovery times or quality were detected following isoflurane or sevoflurane anaesthesia after intravenous induction. Clinical relevance Sevoflurane affords no obvious advantage in recovery over isoflurane following a standard intravenous induction technique in horses not undergoing surgery.     

Determination of the minimum alveolar concentration (MAC) and cardiopulmonary effects of sevoflurane in sheep

Objective

To determine sevoflurane’s minimum alveolar concentration (MAC_SEVO) and its cardiopulmonary effects in sheep.

Comparison of the brainstem auditory evoked responses during sevoflurane or alfaxalone anaesthesia in adult cats

Objective

To compare the effects of general anaesthesia using sevoflurane or alfaxalone on the brainstem auditory evoked response (BAER) test in adult healthy cats.

随车乳化器的设计及在495A柴油机上的试验研究

设计了一种随车型乳化器,分析了其工作原理。研究了４９５Ａ柴油机使用该乳化器时工作参数与油耗率的关系,用二次正交回归设计方法建立了油耗率与工作参数之间的数学模型,用优化的方法得到了柴油机的最佳工作参数。台架对比试验结果表明：在最佳参数条件下使用乳化器,在常用工况内,柴油机节油率可达２．１％～６．２％,排气烟度值明显降低。     

菊粉对低脂乳化肠质构及风味品质的影响

为探究菊粉对低脂乳化肠质构及风味品质的影响,本研究以猪后腿肉为原料制作低脂乳化肠,并在肠中添加不同量浓度(0%、1%、2%、3%、4%和5%)的菊粉,以高脂组为对照,研究其对乳化肠基本营养成分、色泽、蒸煮损失、质构特性、微观结构、风味及感官品质的影响。结果表明,随着低脂乳化肠中菊粉添加量的增加,乳化肠水分和蛋白质含量均先增加后显著下降;加入适量菊粉可以降低低脂乳化肠的蒸煮损失;菊粉的加入增加了乳化肠的硬度和咀嚼性,提高了凝聚力。扫描电镜结果表明,菊粉添加量为4%时乳化肠的微观结构孔洞最小且致密;风味及感官评价结果表明,菊粉添加量为5%时醛类和醇类等风味成分含量达到最高,菊粉添加量达到 3%及以上时与对照组相比感官评价总分无显著差异。综上,低脂乳化肠中加入菊粉有利于降低低脂乳化肠的蒸煮损失,改善低脂乳化肠的质构特性及风味和感官品质。本研究结果可为低脂肉制品的生产提供一定的理论依据。