小型猪乳化异氟醚全身麻醉效果监测

为探讨乳化异氟醚进行小型猪全身麻醉麻醉效果,选取14头巴马猪以2.80 mL· kg-1·h-1进行静脉麻醉,在麻醉过程中对生理反射、镇痛、镇静、肌松,呼吸和循环系统进行监测.结果表明,乳化异氟醚可以使小型猪维持良好外科麻醉状态,麻醉过程中小型猪一般生理指标、循环系统指标未发生显著变化(P＞0.05),呼吸系统指标与正常比较有显著性改变(P＜0.05或P＜0.01),但均在安全范围内,小型猪麻醉过程无异常表现.乳化异氟醚能满足临床手术麻醉需要,可以作为小型猪全身麻醉药物推广应用.     

Effect of dexmedetomidine and xylazine followed by MK-467 on gastrointestinal microperfusion in anaesthetized horses

Objective

To compare the effects of MK-467 during isoflurane anaesthesia combined with xylazine or dexmedetomidine on global and gastrointestinal perfusion parameters.

Effect of oral trazodone on the minimum alveolar concentration of isoflurane in dogs

Objective

To determine the effect of oral trazodone on the minimum alveolar concentration (MAC) of isoflurane in dogs.

The effect of volatile anaesthetics on the relative sensitivity of facial and distal thoracic limb muscles to vecuronium in dogs

ObjectiveTo compare n. facialis-m. nasolabialis (nF-mNL) and n. ulnar-mm. carpi flexorii (nU-mCF) sensitivity to vecuronium during halothane or isoflurane anaesthesia.Study designRandomized, prospective, experimental study.AnimalsForty-four client-owned dogs (19 male, 25 female) undergoing surgery; mean age: 5.0 years; mean body mass: 24.7 kg.MethodsThirty minutes after acepromazine (0.05 mg kg^?1) and morphine (0.5 mg kg^?1), anaesthesia was induced with intravenous (IV) thiopental and maintained with either halothane (n = 22) or isoflurane (randomly allocated) in oxygen. The lungs were mechanically ventilated and end-tidal inhaled anaesthetic (Fe’_IAA) maintained at 1.2 × MAC values. Neuromuscular transmission at nF-uNL and nU-mCF was monitored using the train of four count. Vecuronium (50 μg kg^?1 IV) was injected (t = 0) after 15 trains, 50-60 minutes after inhalational anaesthesia began, when Fe’_IAA had been constant for >15 minutes. Times of the disappearance (-) and reappearance (+) of the fourth (T4) and first twitch (T1) were recorded allowing the calculation of: latent (t = 0 to T4-) and manifest onset times (t = 0 to T1-) duration of blockade (T1- to T1+) and drug effect (T4- to T4+) and recovery time (T1+-T4+). Student’s paired t-test was used to compare simultaneous responses at nF-uNL and nU-mCF. An unpaired t-test was used to compare anaesthetic effects.ResultsLatent and manifest onset times were significantly (p < 0.05) briefer, blockade and drug effects were significantly longer and recovery from blockade were significantly slower in the nF-mNL unit in both halothane and isoflurane recipients. Profound block duration and drug action were significantly longer and recovery from blockade were significantly slower in halothane recipients at both nerve-muscle units.Conclusion and clinical relevanceThe nF-mNL was more sensitive than nU-mCF to vecuronium, particularly in halothane-anaesthetized dogs.     

Isoflurane minimum alveolar concentration sparing effects of fentanyl in the dog

Objective

To characterize the isoflurane-sparing effects of a high and a low dose of fentanyl in dogs, and its effects on mean arterial pressure (MAP) and heart rate (HR).

Effect of transdermally administered fentanyl on the minimum alveolar concentration of isoflurane in cats

OBJECTIVE: To determine the effect of two doses of fentanyl, administered transdermally, on the minimum alveolar concentration (MAC) of isoflurane in cats. STUDY DESIGN: Prospective, randomized study. ANIMALS: Five healthy, spayed, female cats. METHODS: Each cat was studied thrice with at least 2 weeks between each study. In study 1, the baseline isoflurane MAC was determined in triplicate for each cat. In studies 2 and 3, isoflurane MAC was determined 24 hours after placement of either a 25 or 50 microg hour(-1) fentanyl patch. In each MAC study, cats were instrumented to allow collection of arterial blood and measurement of arterial blood pressure. Twenty-four hours prior to studies 2 and 3, a catheter was placed and secured in the jugular vein and either a 25 or 50 microg hour(-1) fentanyl patch was placed in random order on the left thorax. Blood samples for plasma fentanyl determination were collected prior to patch placement and at regular intervals up to 144 hours. After determination of MAC in studies 2 and 3, naloxone was administered as a bolus dose (0.1 mg kg(-1)) followed by an infusion (1 mg kg(-1) hour(-1)) and MAC redetermined. RESULTS: The baseline isoflurane MAC was 1.51 +/- 0.21% (mean +/- SD). Fentanyl (25 and 50 micro g hour(-1)) administered transdermally significantly reduced MAC to 1.25 +/- 0.26 and 1.22 +/- 0.16%, respectively. These MAC reductions were not significantly different from each other. Isoflurane MAC determined during administration of fentanyl 25 micro g hour(-1) and naloxone (1.44 +/- 0.16%) and fentanyl 50 micro g hour(-1) and naloxone (1.51 +/- 0.19%) was not significantly different from baseline MAC (1.51 +/- 0.21%). CONCLUSIONS AND CLINICAL RELEVANCE: Fentanyl patches are placed to provide long-lasting analgesia. In order to be effective postoperatively, fentanyl patches must be placed prior to surgery. Plasma fentanyl concentrations achieved intraoperatively decrease the need for potent inhalant anesthetics in cats.     

Effects of dopamine,norepinephrine or phenylephrine on the prevention of hypotension in isoflurane-anesthetized cats administered vatinoxan or vatinoxan and dexmedetomidine

ObjectiveTo determine the dose of phenylephrine, norepinephrine and dopamine necessary to maintain mean arterial pressure (MAP) within 70–80 mmHg during administration of isoflurane, isoflurane and vatinoxan and isoflurane, vatinoxan and dexmedetomidine at three plasma concentrations.Study designRandomized crossover experimental study.AnimalsA group of five adult healthy neutered male cats.MethodsInstrumentation occurred during anesthesia with isoflurane in oxygen. Isoflurane end-tidal concentration was set to 1.25 × minimum alveolar concentration (MAC). Phenylephrine, norepinephrine or dopamine was administered to maintain MAP 70–80 mmHg. A target-controlled infusion system was used to administer vatinoxan at a target plasma concentration of 1 μg mL^–1 and three dexmedetomidine concentrations (5, 10 and 20 ng mL^–1). Isoflurane concentration was altered to maintain an equivalent 1.25 MAC. Heart rate, arterial blood pressure, central venous pressure, pulmonary artery pressure, pulmonary artery occlusion pressure, body temperature, arterial and mixed venous blood gas, cardiac output and drug concentrations were measured at baseline (isoflurane alone), during vatinoxan administration, and during administration of vatinoxan and dexmedetomidine at the three target concentrations.ResultsMAP < 70 mmHg was observed with vatinoxan alone and in the dopamine treatment with dexmedetomidine concentrations ≤ 10 ng mL^–1. Norepinephrine and phenylephrine maintained MAP 70–80 mmHg during vatinoxan and dexmedetomidine ≤ 10 ng mL^–1. As the target dexmedetomidine concentration increased, the dose of norepinephrine and phenylephrine needed to maintain MAP 70–80 mmHg decreased; no treatment was necessary to maintain MAP > 70 mmHg at the 20 ng mL^–1 target dexmedetomidine concentration in most cats.Conclusions and clinical relevanceNorepinephrine and phenylephrine, but not dopamine, are effective to prevent hypotension in isoflurane-anesthetized cats administered dexmedetomidine and vatinoxan.     

A systematic review of sevoflurane and isoflurane minimum alveolar concentration in domestic cats

ObjectiveThe purpose of this systematic review is to summarize the results of studies which have determined the minimum alveolar concentration (MAC) of isoflurane and sevoflurane in domestic cats.Study DesignSystematic review.AnimalsCats.Methods usedA comprehensive search of research literature was performed without language restriction. The search utilized the Pubmed, Google Scholar, and CAB Abstracts electronic databases using a combination of free text terms ‘Minimum alveolar concentration’, ‘sevoflurane’, ‘isoflurane’, ‘anesthetic’, ‘cat’, ‘cats’ or ‘feline’. The search was conducted from November 2010 to June 2012.ResultsThe MAC for isoflurane ranged from 1.20 ± 0.13% to 2.22 ± 0.35% and the MAC for sevoflurane ranged from 2.5 ± 0.2% to 3.95 ± 0.33%. The average MAC for isoflurane was 1.71 ± 0.07% and for sevoflurane was 3.08 ± 0.4%.Conclusions &; Clinical RelevanceThe average MAC for isoflurane was 1.71 ± 0.07% and for sevoflurane was 3.08 ± 0.4%. Methodology differed among studies, and particular attention should be paid in the future to appropriate reporting of methods to allow sound conclusions to be made from the results.     

Clinical evaluation of the anaesthetic sparing effect of brachial plexus block in cats

ObjectiveTo evaluate the isoflurane sparing effect and the post-surgical analgesia provided by a brachial plexus block (BPB) in cats undergoing distal thoracic limb surgery.Study designProspective randomized blinded clinical study.AnimalsTwenty client-owned cats.MethodsCats were assigned to receive either no BPB (group NB) or a nerve stimulator guided BPB (group BPB) using lidocaine (3.6 mg kg^?1) and bupivacaine (1.2 mg kg^?1). Pre-medication consisted of midazolam and ketamine intravenously (IV). Anaesthesia was induced with propofol IV to effect and maintained with isoflurane delivered in oxygen and a continuous rate infusion of fentanyl (2 μg kg^?1 hour^?1). End-tidal isoflurane concentration (Fe′ISO) was adjusted every 3 minutes guided by changes in cardiorespiratory parameters and reflexes present, to maintain a stable depth of anaesthesia. Five time points were chosen to record all parameters and compare values between groups. Recovery and post-operative pain assessment were performed using a visual analogue scale (VAS) at 15 and 45 minutes after extubation and thereafter at hourly intervals until 5 hours after placement of the BPB.ResultsNo clinically significant differences were seen for heart rate, respiratory rate and non-invasive blood pressure between groups. Mean Fe′ISO was significantly lower in group BPB compared with group NB at all time points. In group NB, all intraoperative measurements of Fe′ISO were significantly higher compared with baseline (3 minutes before start of surgery) measurements. During recovery, VAS scores for group BPB were significantly lower than for group NB. Additional analgesics were needed in all cats within the study period.Conclusion and Clinical relevanceIn cats undergoing orthopaedic surgery of the thoracic limb, BPB reduced intra-operative isoflurane requirement and pain during the early post-operative period when compared with procedures without a BPB. BPB is a useful adjunct to anaesthesia in such cases.