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1.
ObjectiveTo characterise the effects of alfaxalone by intramuscular (IM) injection in red-eared slider turtles and the influence of body temperature on anaesthetic duration and depth.Study designProspective, randomised part-blinded experimental trial.AnimalsTen healthy adult female red-eared sliders.MethodsEach turtle was anaesthetized four times with 10 and 20 mg kg?1 alfaxalone at 20 and 35 °C respectively. Time to maximal effect and plateau and recovery periods were recorded. Skeletal muscle tone, presence of various reflexes, response to noxious stimuli, and heart rate were assessed.ResultsResults are given for protocols 10 mg kg?1 20 °C; 20 mg kg?1 20 °C; 10 mg kg?1 35 °C and 20 mg kg?1 35 °C, respectively: mean time (±SD) to maximal effect was 16 ± 8, 19 ± 6, 5 ± 2 and 7 ± 5 minutes; duration of the plateau phase was 13 ± 12, 28 ± 13, 8 ± 5 and 8 ± 5 minutes and recovery time was 76 ± 20, 126 ± 17, 28 ± 9 and 41 ± 20 minutes. Endotracheal intubation was successful in 80%, 100%, 0% and 30% of turtles, respectively. At 35 °C, all animals retained nociceptive sensation in the front limbs, hind limbs and vent, whereas at 20 °C a few turtles lost peripheral nociceptive sensation. Corneal and tap reflexes were retained in all trials. Mean heart rates were 30 ± 2 and 66 ± 4 beats minute?1 at 20 and 35 °C, respectively.Conclusions and clinical relevanceAlfaxalone administered IM in red-eared sliders provided smooth, rapid induction and uneventful recovery. At 35 °C either dosage provided only short (5–10 minutes) and light sedation. At 20 °C, 10 mg kg?1 provided sedation suitable for short non-invasive procedures. About 20 mg kg?1 provided anaesthesia of approximately 20 minutes duration, appropriate for induction of inhalational anaesthesia or for brief surgical procedures with supplemental analgesia.  相似文献   

2.
ObjectiveTo characterise four different intramuscular (IM) anaesthetic protocols, two with alfaxalone and two with alfaxalone in combination with medetomidine in terrestrial tortoises.Study designBlinded, randomized, cross‐over experimental study.AnimalsNine healthy adult male Horsfield's tortoises (Agrionemys horsfieldii).MethodsEach tortoise was randomly assigned to one of four different protocols: 1) 10 mg kg?1 alfaxalone; 2) 10 mg kg?1 alfaxalone + 0.10 mg kg?1 medetomidine; 3) 20 mg kg?1 alfaxalone; and 4) 20 mg kg?1 alfaxalone + 0.05 mg kg?1 medetomidine. During the experiment, the following variables were recorded: heart rate; respiratory rate; peripheral nociceptive responses; muscle strength; ability to intubate; palpebral, corneal and tap reflexes; and cloacal temperature.ResultsProtocols 1 and 2 resulted in moderate sedation with no analgesia, and moderate to deep sedation with minimal analgesia, respectively. Protocols 3 and 4 resulted in deep sedation or anaesthesia with variable analgesic effect; these two protocols had the longest total anaesthetic time and allowed intubation in 6/9 and 8/9 tortoises respectively. The total anaesthesia/sedation time produced by alfaxalone was significantly increased (p <0.05) by the addition of medetomidine. There were no significant differences regarding time to plateau phase and duration of plateau phase. Baseline heart rate of 53 ± 6 beats minute?1 decreased significantly (p <0.05) with all protocols, and was lower (p <0.05) in protocols 3 and 4. Heart rate increased after atipamezole administration, but the increase was transient. In two tortoises, extreme bradycardia with no cardiac activity for 10 minutes was observed with protocols 3 and 4.Conclusion and clinical relevanceAlfaxalone 10 and 20 mg kg?1 IM can be used for sedation for non‐painful procedures. Alfaxalone in combination with medetomidine can be used for deeper sedation or anaesthesia, but the observed respiratory and cardiovascular depression may limit its use.  相似文献   

3.
ObjectiveTo compare post-operative pain in cats after alfaxalone or ketamine- medetomidine anaesthesia for ovariohysterectomy (OHE) and physiologic parameters during and after surgery.Study designProspective ‘blinded’ randomized clinical study.AnimalsTwenty-one healthy cats.MethodsCats were assigned randomly into two groups: Group A, anaesthesia was induced and maintained with alfaxalone [5 mg kg?1 intravenously (IV) followed by boli (2 mg kg?1 IV); Group MK, induction with ketamine (5 mg kg?1 IV) after medetomidine (30 μg kg?1 intramuscularly (IM)], and maintenance with ketamine (2 mg kg?1 IV). Meloxicam (0.2 mg kg?1 IV) was administered after surgery. Basic physiological data were collected. At time T = -2, 0, 0.5, 1, 2, 4, 6, 8, 12, 16, 20, and 24 hours post-operatively pain was assessed by three methods, a composite pain scale (CPS; 0–24 points), a visual analogue scale (VAS 0–100 mm), and a mechanical wound threshold (MWT) device. Butorphanol (0.2 mg kg?1 IM) was administered if CPS was scored =13. Data were analyzed using a general linear model, Kruskal–Wallis analyses, Bonferroni-Dunn test, unpaired t-test and Fisher's exact test as relevant. Significance was set at p < 0.05.ResultsVASs were significantly higher at 0.5, 1, 2, 4, and 20 hours in group A; MWT values were significantly higher at 8 and 12 hours in group MK. Post-operative MWT decreased significantly compared to baseline in both groups. There was no difference in CPS at any time point. Five cats required rescue analgesia (four in A; one in MK).Conclusion and clinical relevanceAnaesthesia with ketamine-medetomidine was found to provide better post-surgical analgesia than alfaxalone in cats undergoing OHE; however, primary hyperalgesia developed in both groups. Alfaxalone is suitable for induction and maintenance of anaesthesia in cats undergoing OHE, but administration of additional sedative and analgesic drugs is highly recommended.  相似文献   

4.
ObjectiveTo determine the induction doses, then minimum infusion rates of alfaxalone for total intravenous anaesthesia (TIVA), and subsequent, cardiopulmonary effects, recovery characteristics and alfaxalone plasma concentrations in cats undergoing ovariohysterectomy after premedication with butorphanol-acepromazine or butorphanol-medetomidine.Study designProspective randomized blinded clinical study.AnimalsTwenty-eight healthy cats.MethodsCats undergoing ovariohysterectomy were assigned into two groups: together with butorphanol [0.2 mg kg?1 intramuscularly (IM)], group AA (n = 14) received acepromazine (0.1 mg kg?1 IM) and group MA (n = 14) medetomidine (20 μg kg?1 IM). Anaesthesia was induced with alfaxalone to effect [0.2 mg kg?1 intravenously (IV) every 20 seconds], initially maintained with 8 mg kg?1 hour?1 alfaxalone IV and infusion adjusted (±0.5 mg kg?1 hour?1) every five minutes according to alterations in heart rate (HR), respiratory rate (fR), Doppler blood pressure (DBP) and presence of palpebral reflex. Additional alfaxalone boli were administered IV if cats moved/swallowed (0.5 mg kg?1) or if fR >40 breaths minute?1 (0.25 mg kg?1). Venous blood samples were obtained to determine plasma alfaxalone concentrations. Meloxicam (0.2 mg kg?1 IV) was administered postoperatively. Data were analysed using linear mixed models, Chi-squared, Fishers exact and t-tests.ResultsAlfaxalone anaesthesia induction dose (mean ± SD), was lower in group MA (1.87 ± 0.5; group AA: 2.57 ± 0.41 mg kg?1). No cats became apnoeic. Intraoperative bolus requirements and TIVA rates (group AA: 11.62 ± 1.37, group MA: 10.76 ± 0.96 mg kg?1 hour?1) did not differ significantly between groups. Plasma concentrations ranged between 0.69 and 10.76 μg mL?1. In group MA, fR, end-tidal carbon dioxide, temperature and DBP were significantly higher and HR lower.Conclusion and clinical relevanceAlfaxalone TIVA in cats after medetomidine or acepromazine sedation provided suitable anaesthesia with no need for ventilatory support. After these premedications, the authors recommend initial alfaxalone TIVA rates of 10 mg kg?1 hour?1.  相似文献   

5.
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6.
ObjectiveTo quantify induction time, reliability, physiological effects, recovery quality and dart volume of a novel formulation of alfaxalone (40 mg mL?1) used in combination with medetomidine and azaperone for the capture and handling of wild bighorn sheep.Study designProspective clinical study.AnimalsA total of 23 wild bighorn sheep (Ovis canadensis) in Sheep River Provincial Park, AB, Canada.MethodsFree-ranging bighorn sheep were immobilized using medetomidine, azaperone and alfaxalone delivered with a remote delivery system. Arterial blood was collected for measurement of blood gases, physiologic variables (temperature, heart and respiratory rates) were recorded and induction and recovery length and quality were scored.ResultsData from 20 animals were included. Administered dose rates were alfaxalone (0.99 ± 0.20 mg kg?1; 40 mg mL?1), azaperone (0.2 ± 0.04 mg kg?1; 10 mg mL?1) and medetomidine (0.16 ± 0.03 mg kg?1; 30 mg mL?1). The mean drug volume injected was 1.51 mL. The median (range) induction time was 7.7 (5.8–9.7) minutes, and recovery was qualitatively smooth.Conclusions and clinical relevanceAn increased concentration formulation of alfaxalone was administered in combination with medetomidine and azaperone, and resulted in appropriate anesthesia for the capture and handling of bighorn sheep. The dart volume was small, with potential for reducing capture-related morbidity.  相似文献   

7.
ObjectivesTo investigate the character of immobilization given by alfaxalone in juvenile crocodiles at optimal and at suboptimal temperatures.Study designProspective, randomized partial crossover study.AnimalsTwenty captive male estuarine (weight 0.6–2.5 kg) and five captive male freshwater crocodiles (weight 0.2–0.6 kg).MethodsCrocodiles were acclimatized for 24 hours at one of the following environmental temperatures; 32 °C, 27 °C, 22 °C or 17 °C, then received 3 mg kg?1 intravenous (IV) alfaxalone into the dorsal occipital venous sinus. Duration and quality of immobilization was assessed and heart rate (HR) measured. On a separate occasion each crocodile was immobilized at one other environmental temperature.ResultsAlfaxalone, 3 mg kg?1 IV, produced immobilization for 55 (range 15–100 minutes in estuarine, and 20 (range 20–25) minutes in freshwater crocodiles at 32 °C. There was no significant difference overall in immobilization times between temperatures, other than that, in estuarine crocodiles, duration was shorter at 32 °C than 22 °C. The character of immobilization was unpredictable, with animals recovering without warning, or having extended recoveries requiring assisted ventilation. Assisted ventilation was necessary mainly at the lower temperatures. Median HR in all temperature treatments decreased within 5 minutes post–injection, but the change in HR over the duration of immobilization was affected by the temperature, with a progressively smaller range of fall as temperature decreased. At 17 °C, two estuarine crocodiles appeared to re–immobilize after initial recovery, became severely bradycardiac and required ventilation and re–warming.Conclusions and clinical relevanceAlfaxalone IV in small captive estuarine and freshwater crocodiles provides adequate induction of immobilization at various temperatures. However, the unpredictable results following induction mean it is unsuitable for field use and should be restricted to environments where intubation and ventilation are available, where animals can be warmed to optimal temperature, and where access to immersion in water can be restricted for 24 hours.  相似文献   

8.
ObjectiveTo document the effects of two doses of dexmedetomidine on the induction characteristics and dose requirements of alfaxalone.Study designRandomized controlled clinical trial.AnimalsSixty one client owned dogs, status ASA I-II.MethodsDogs were allocated randomly into three groups, receiving as pre-anaesthetic medication, no dexmedetomidine (D0), 1 μg kg?1 dexmedetomidine (D1) intramuscularly (IM) or 3 μg kg?1 dexmedetomidine IM (D3). All dogs also received 0.2 mg kg?1 methadone IM. Level of sedation was assessed prior to induction of anaesthesia. Induction of general anaesthesia was performed with alfaxalone administered intravenously to effect at a rate of 1 mg kg?1 minute?1; the required dose to achieve tracheal intubation was recorded. Anaesthesia was maintained with isoflurane in oxygen. Cardiopulmonary parameters were recorded throughout the anaesthetic period. Quality of intubation, induction and recovery of anaesthesia were recorded. Quantitative data were compared with one-way anova or Kruskal-Wallis test. Repeated measures were log-transformed and analysed with repeated measures anova (p < 0.05).ResultsTreatment groups were similar for categorical data, with exception of sedation level (p < 0.001). The doses (mean ± SD) of alfaxalone required for intubation were D0 1.68 ± 0.24, D1 1.60 ± 0.36 and D3 1.41 ± 0.43, the difference between D0 and D3 being statistically significant (p = 0.036). Heart and respiratory rates during the anaesthetic period were significantly different over time and between groups (p < 0.001); systolic arterial blood pressure was significantly different over time (p < 0.001) but not between groups (p = 0.833). Induction quality and recovery scores were similar between groups (p = 1.000 and p = 0.414, respectively).Conclusions and clinical relevanceThe administration of alfaxalone resulted in a good quality anaesthetic induction which was not affected by the dose of dexmedetomidine. Dexmedetomidine at 3 μg kg?1 IM combined with methadone provides good sedation and enables a reduction of alfaxalone requirements.  相似文献   

9.
ObjectiveTo determine in dogs the effects of medetomidine and butorphanol, alone and in combination, on the induction dose of alfaxalone and to describe the induction and intubation conditions.Study designProspective, randomized, blinded clinical trial.AnimalsEighty-five client-owned dogs (ASA 1 or 2).MethodsSubjects were block randomized to treatment group according to temperament. The treatment groups were: medetomidine 4 μg kg?1 (M), butorphanol 0.1 mg kg?1 (B), or a combination of both (MB), all administered intramuscularly. After 30 minutes, a sedation score was assigned, and alfaxalone 0.5 mg kg?1 was administered intravenously over 60 seconds by an observer who was unaware of treatment group. Tracheal intubation conditions were assessed and, if tracheal intubation was not possible after 20 seconds, further boluses of 0.2 mg kg?1 were given every 20 seconds until intubation was achieved. Induction dose and adverse events (sneezing, twitching, paddling, excitement, apnoea and cyanosis) were recorded; induction quality and intubation conditions were scored and recorded.ResultsThe mean dose of alfaxalone required for induction was similar for groups M and B: 1.2 ± 0.4 mg kg?1. The mean dose requirement for group MB (0.8 ± 0.3 mg kg?1) was lower than groups M and B (p < 0.0001). Induction dose was not influenced by temperament or level of sedation. Induction and intubation scores did not differ between treatment groups. Adverse events were noted in 16 dogs; there was no association with treatment group, temperament or level of sedation.Conclusions and clinical relevanceMedetomidine and butorphanol administered in combination reduce the anaesthetic induction dose of alfaxalone compared to either agent alone. This difference should be taken into account when using this combination of drugs in a clinical setting.  相似文献   

10.
ObjectiveTo characterise the anaesthetic effects of alfaxalone administered intramuscularly (IM) at 10, 20, and 30 mg kg?1.Study designProspective, randomized cross-over study.AnimalsTen juvenile green iguanas (Iguana iguana) of mean body weight (±SD) 480 ± 134 g.MethodsAlfaxalone was administered IM in the triceps of both thoracic limbs. Times for anaesthetic induction, plateau and recovery periods were recorded. Skeletal muscle tone of the jaw, neck, thoracic limbs, pelvic limbs, and tail was scored. The palpebral, corneal and righting reflexes, and the response to painful stimuli were also assessed. Pulse rate and respiratory rate were recorded. Comparisons between different dosages and over time were made using anova.ResultsTimes are given for 10, 20 and 30 mg kg?1 dosages respectively: mean time to maximal effect was 7.7 ± 2.2, 5.4 ± 1.7 and 3.9 ± 1.2 minutes; duration of the plateau phase was 11.3 ± 3.8, 22.1 ± 6.5 and 39.1 ± 11.5 minutes; recovery time was 10 ± 2.4, 17.5 ± 8.6 and 25 ± 7.1 minutes; and total anaesthetic duration was 29 ± 35.7, 45 ± 8.2 and 68 ± 9.8 minutes. Endotracheal intubation was possible in 40% of the subjects given 10 mg kg?1 and in 100% subjects given both 20 and 30 mg kg?1. Loss of response to a painful stimulus was seen in 0/10, 8/10 and 9/10 animals at 10, 20, and 30 mg kg?1 respectively. There was an initial dose-dependent depression of respiration followed by a significant increase in frequency over time. In contrast, pulse rates decreased by 20% over the duration of the anaesthetic events.Conclusions and clinical relevanceIntramuscular administration of alfaxalone is a simple, rapid and reliable means of achieving relatively brief sedation or anaesthesia in healthy green iguanas. A dosage of 10 mg kg?1 provides light sedation, appropriate for examination and venipuncture; 20 mg kg?1 provides a level suitable for minor procedures or for endotracheal intubation and supplementation with inhalational anaesthesia; 30 mg kg?1 produces an anaesthetic plane suitable for surgical procedures of limited duration (up to 40 minutes).  相似文献   

11.
ObjectiveTo describe alfaxalone total intravenous anaesthesia (TIVA) following premedication with buprenorphine and either acepromazine (ACP) or dexmedetomidine (DEX) in bitches undergoing ovariohysterectomy.Study designProspective, randomised, clinical study.AnimalsThirty-eight healthy female dogs.MethodsFollowing intramuscular buprenorphine (20 μg kg?1) and acepromazine (0.05 mg kg?1) or dexmedetomidine (approximately 10 μg kg?1, adjusted for body surface area), anaesthesia was induced and maintained with intravenous alfaxalone. Oxygen was administered via a suitable anaesthetic circuit. Alfaxalone infusion rate (initially 0.07 mg kg?1 minute?1) was adjusted to maintain adequate anaesthetic depth based on clinical assessment. Alfaxalone boluses were given if required. Ventilation was assisted if necessary. Alfaxalone dose and physiologic parameters were recorded every 5 minutes. Depth of sedation after premedication, induction quality and recovery duration and quality were scored. A Student's t-test, Mann–Whitney U and Chi-squared tests determined the significance of differences between groups. Data are presented as mean ± SD or median (range). Significance was defined as p < 0.05.ResultsThere were no differences between groups in demographics; induction quality; induction (1.5 ± 0.57 mg kg?1) and total bolus doses [1.2 (0 – 6.3) mg kg?1] of alfaxalone; anaesthesia duration (131 ± 18 minutes); or time to extubation [16.6 (3–50) minutes]. DEX dogs were more sedated than ACP dogs. Alfaxalone infusion rate was significantly lower in DEX [0.08 (0.06–0.19) mg kg?1 minute?1] than ACP dogs [0.11 (0.07–0.33) mg kg?1 minute?1]. Cardiovascular variables increased significantly during ovarian and cervical ligation and wound closure compared to baseline values in both groups. Apnoea and hypoventilation were common and not significantly different between groups. Arterial haemoglobin oxygen saturation remained above 95% in all animals. Recovery quality scores were significantly poorer for DEX than for ACP dogs.Conclusions and clinical relevanceAlfaxalone TIVA is an effective anaesthetic for surgical procedures but, in the protocol of this study, causes respiratory depression at infusion rates required for surgery.  相似文献   

12.
ObjectiveTo compare the physiological parameters, arterial blood gas values, induction quality, and recovery quality after IV injection of alfaxalone or propofol in dogs.Study designProspective, randomized, blinded crossover.AnimalsEight random-source adult female mixed-breed dogs weighing 18.7 ± 4.5 kg.MethodsDogs were assigned to receive up to 8 mg kg?1 propofol or 4 mg kg?1 alfaxalone, administered to effect, at 10% of the calculated dose every 10 seconds. They then received the alternate drug after a 6-day washout. Temperature, pulse rate, respiratory rate, direct blood pressure, and arterial blood gases were measured before induction, immediately post-induction, and at 5-minute intervals until extubation. Quality of induction, recovery, and ataxia were scored by a single blinded investigator. Duration of anesthesia and recovery, and adverse events were recorded.ResultsThe mean doses required for induction were 2.6 ± 0.4 mg kg?1 alfaxalone and 5.2 ± 0.8 mg kg?1 propofol. After alfaxalone, temperature, respiration, and pH were significantly lower, and PaCO2 significantly higher post-induction compared to baseline (p < 0.03). After propofol, pH, PaO2, and SaO2 were significantly lower, and PaCO2, HCO3, and PA-aO2 gradient significantly higher post-induction compared to baseline (p < 0.03). Post-induction and 5-minute physiologic and blood gas values were not significantly different between alfaxalone and propofol. Alfaxalone resulted in significantly longer times to achieve sternal recumbency (p = 0.0003) and standing (p = 0.0004) compared to propofol. Subjective scores for induction, recovery, and ataxia were not significantly different between treatments; however, dogs undergoing alfaxalone anesthesia were more likely to have ≥1 adverse event (p = 0.041). There were no serious adverse events in either treatment.Conclusions and clinical relevanceThere were no clinically significant differences in cardiopulmonary effects between propofol and alfaxalone. A single bolus of propofol resulted in shorter recovery times and fewer adverse events than a single bolus of alfaxalone.  相似文献   

13.
ObjectiveTo determine the pharmacokinetics and pharmacodynamics of the neurosteroidal anaesthetic, alfaxalone, in horses after a single intravenous (IV) injection of alfaxalone, following premedication with acepromazine, xylazine and guaiphenesin.Study designProspective experimental study.AnimalsTen (five male and five female), adult, healthy, Standardbred horses.MethodsHorses were premedicated with acepromazine (0.03 mg kg?1 IV). Twenty minutes later they received xylazine (1 mg kg?1 IV), then after 5 minutes, guaiphenesin (35 mg kg?1 IV) followed immediately by IV induction of anaesthesia with alfaxalone (1 mg kg?1). Cardiorespiratory variables (pulse rate, respiratory rate, pulse oximetry) and clinical signs of anaesthetic depth were evaluated throughout anaesthesia. Venous blood samples were collected at strategic time points and plasma concentrations of alfaxalone were assayed using liquid chromatography-mass spectrometry (LC/MS) and analysed by noncompartmental pharmacokinetic analysis. The quality of anaesthetic induction and recovery was scored on a scale of 1–5 (1 very poor, 5 excellent).ResultsThe median (range) induction and recovery scores were 4 (3–5) (good: horse slowly and moderately gently attained recumbency with minimal or no rigidity or paddling) and 4 (1–5) (good: horse stood on first attempt with some knuckling and ataxia) respectively. The monitored cardiopulmonary variables were within the range expected for clinical equine anaesthesia. The mean ± SD durations of anaesthesia from induction to sternal recumbency and from induction to standing were 42.7 ± 8.4 and 47 ± 9.6 minutes, respectively. The mean ± SD plasma elimination half life (t1/2), plasma clearance (Clp) and volume of distribution (Vd) for alfaxalone were 33.4 minutes, 37.1 ± 11.1 mL minute?1 kg?1 and 1.6 ± 0.4 L kg?1, respectively.Conclusions and clinical relevanceAlfaxalone, in a 2-hydroxypropyl-beta-cyclodextrin formulation, provides anaesthesia with a short duration of recumbency that is characterised by a smooth induction and satisfactory recovery in the horse. As in other species, alfaxalone is rapidly cleared from the plasma in the horse.  相似文献   

14.
ObjectiveTo evaluate the effect of dexmedetomidine on alfaxalone immobilization in snakes.Study designNonblinded, crossover study.AnimalsA total of eight mature common garter snakes (Thamnophis sirtalis).MethodsSnakes were administered each of three treatments intracoelomically: alfaxalone (30 mg kg–1; treatment A), alfaxalone (30 mg kg–1) combined with dexmedetomidine (0.05 mg kg–1; treatment AD0.05); and alfaxalone (30 mg kg–1) combined with dexmedetomidine (0.10 mg kg–1; treatment AD0.10). A minimum of 10 days elapsed between experimental trials. Times to loss of righting reflex (LRR) and return of righting reflex (RRR) were recorded. Heart rate (HR) was recorded every 5 minutes throughout the period of LRR and averaged for each snake. Times to LRR and RRR, and mean HR in snakes that achieved LRR were reported.ResultsLRR occurred in eight (100%), five (63%) and three (38%) snakes in treatments A, AD0.05 and AD0.10, respectively. For all treatments, time to LRR ranged 3–20 minutes. Median (range) times to RRR were 39 (30–46), 89 (62–128) and 77 (30–185) minutes for treatments A, AD0.05 and AD0.10, respectively. In animals where righting reflex was lost, mean HR was lower in all dexmedetomidine treatments compared with treatment A.Conclusions and clinical relevanceIn this pilot study, alfaxalone resulted in reliable immobilization, whereas dexmedetomidine and alfaxalone combinations resulted in highly variable durations of immobilization with low HR in immobilized animals. For snakes that achieved LRR, the addition of dexmedetomidine (0.05 mg kg–1) to alfaxalone appeared to extend the period of immobilization compared with alfaxalone alone.  相似文献   

15.
ObjectiveTo characterize the physiologic and behavioral effects of a single induction dose and two maintenance doses of alfaxalone delivered by water immersion in the anesthesia of koi (Cyprinus carpio).Study designProspective, within-subject complete crossover design.AnimalsSix adult koi (Cyprinus carpio) with a median body weight of 344.5 g (range 292.0–405.0 g).MethodsKoi were immersed in water containing 10 mg L?1 alfaxalone until immobile and then maintained with alfaxalone at either 1 or 2.5 mg L?1 via a recirculating water system. Times for anesthetic induction and recovery periods were recorded. Physiologic and blood gas parameters were evaluated before, during and after the anesthetic trial. Response to noxious stimuli was also assessed.ResultsMedian anesthesia induction time for all fish was 5.4 minutes. Median recovery time was 11.8 and 26.4 minutes in the 1.0 and 2.5 mg L?1 doses, respectively, which were significantly different (p = 0.04). Cessation of opercular movement occurred in 0/6 and 4/6 fish exposed to 1.0 and 2.5 mg L?1 dose respectively. No difference was observed in median heart rate over the duration of the anesthetic events. Response to noxious stimulation was 4/6 and 0/6 in the 1.0 and 2.5 mg L?1 doses respectively. Oxygenation and ventilation did not change during the experiment, but there was a significant decrease in blood pH along with an increase in blood lactate concentration.Conclusion and clinical relevanceAdministration of alfaxalone, via water immersion, as an induction and maintenance anesthesia agent provided rapid and reliable anesthesia of koi with no mortality. The maintenance dose of 2.5 mg L?1 was sufficient to prevent response to noxious stimuli but was associated with a clinically relevant depression in opercular rate.  相似文献   

16.
ObjectiveTo determine the pharmacokinetics and pharmacodynamics of the neurosteroid anaesthetic, alfaxalone, in neonatal foals after a single intravenous (IV) injection of alfaxalone following premedication with butorphanol tartrate.Study designProspective experimental study.AnimalsFive clinically healthy Australian Stock Horse foals of mean ± SD age of 12 ± 3 days and weighing 67.3 ± 12.4 kg.MethodsFoals were premedicated with butorphanol (0.05 mg kg?1 IV) and anaesthesia was induced 10 minutes later by IV injection with alfaxalone 3 mg kg?1. Cardiorespiratory variables (pulse rate, respiratory rate, direct arterial blood pressure, arterial blood gases) and clinical signs of anaesthetic depth were evaluated throughout anaesthesia. Venous blood samples were collected at strategic time points and alfaxalone plasma concentrations were assayed using liquid chromatography-mass spectrometry (LC/MS) and analysed by noncompartmental pharmacokinetic analysis.ResultsThe harmonic, mean ± SD plasma elimination half life (t½) for alfaxalone was 22.8 ± 5.2 minutes. The observed mean plasma clearance (Clp) and volume of distribution (Vd) were 19.9 ± 5.9 mL minute kg?1 and 0.6 ± 0.2 L kg?1, respectively. Overall, the quality of the anaesthetic inductions and recoveries was good and most monitored physiological variables were clinically acceptable in all foals, although some foals became hypoxaemic for a short period following recumbency. The mean durations of anaesthesia from induction to first movement and from induction to standing were 18.7 ± 7 and 37.2 ± 4.7 minutes, respectively.ConclusionsThe anaesthetic protocol used provided a predictable and consistent plane of anaesthesia in the five foals studied, with minimal cardiovascular depression. In foals, as in the adult horse, alfaxalone has a short elimination half life.Clinical relevanceAlfaxalone appears to be an adequate anaesthetic induction agent in foals and the pharmacokinetics suggest that, with continuous infusion, it might be suitable to provide more prolonged anaesthesia. Oxygen supplementation is recommended.  相似文献   

17.
ObjectiveTo compare anaesthesia induced with either alfaxalone or ketamine in horses following premedication with xylazine and guaifenesin.Study designRandomized blinded cross-over experimental study.AnimalsSix adult horses, five Standardbreds and one Thoroughbred; two mares and four geldings.MethodsEach horse received, on separate occasions, induction of anaesthesia with either ketamine 2.2 mg kg?1 or alfaxalone 1 mg kg?1. Premedication was with xylazine 0.5 mg kg?1 and guaifenesin 35 mg kg?1. Incidence of tremors/shaking after induction, recovery and ataxia on recovery were scored. Time to recovery was recorded. Partial pressure of arterial blood oxygen (PaO2) and carbon dioxide (PaO2), arterial blood pressures, heart rate (HR) and respiratory rates were recorded before premedication and at intervals during anaesthesia. Data were analyzed using Wilcoxon matched pairs signed rank test and are expressed as median (range).ResultsThere was no difference in the quality of recovery or in ataxia scores. Horses receiving alfaxalone exhibited a higher incidence of tremors/shaking on induction compared with those receiving ketamine (five and one of six horses respectively). Horses recovered to standing similarly [28 (24–47) minutes for alfaxalone; 22 (18–35) for ketamine] but took longer to recover adequately to return to the paddock after alfaxalone [44 (38–67) minutes] compared with ketamine [35 (30–47)]. There was no statistical difference between treatments in effect on HR, PaO2 or PaCO2 although for both regimens, PaO2 decreased with respect to before premedication values. There was no difference between treatments in effect on blood pressure.Conclusions and clinical relevanceBoth alfaxalone and ketamine were effective at inducing anaesthesia, although at induction there were more muscle tremors after alfaxalone. As there were no differences between treatments in relation to cardiopulmonary responses or quality of recovery, and only minor differences in recovery times, both agents appear suitable for this purpose following the premedication regimen used in this study.  相似文献   

18.
ObjectiveTo describe the use of intramuscular (IM) premedication with alfaxalone alone or in combination with diazepam in pigs.Study designRandomised‐controlled trial.AnimalsTwelve healthy 2 month‐old Landrace x Large White pigs weighing 21.3 ± 2.4 kg.MethodsAnimals were distributed randomly into two groups: group A (n = 6) 5 mg kg?1 of IM alfaxalone; and group AD (n = 6) 5 mg kg?1 of IM alfaxalone + 0.5 mg kg?1 of IM diazepam mixed in the same syringe. The total volume of injectate was standardized at 14 mL by dilution in 0.9% sodium chloride. Pain on injection, the degree of sedation and the quality of and time to induction of recumbency were evaluated. Once pigs were recumbent, reflexes were evaluated. Pulse and respiratory rates and arterial oxygen saturation were recorded at 5 and 10 minutes after drug administration. Pigs were then moved to another room for subsequent anaesthesia.ResultsTwo animals of group A and one of group AD showed slight pain on drug injection. Time to lateral recumbency (in seconds) was shorter in group AD (mean 203 ± SD 45 range 140–260) than group A (302 ± 75, range 220–420; p < 0.05). In group AD sedation was deeper, and on recumbency there was better muscle relaxation. When moved for anaesthesia, two pigs in Group A showed slight resistance but did not vocalize. There were no differences in physiologic measurements between groups, although in both groups, respiratory rate was significantly lower at ten compared with five minutes post drug injection. There was no apneoa.Conclusions and clinical relevanceIM administration of alfaxalone combined with diazepam resulted in a rapid onset of recumbency and deep sedation, with minimal side effects. The combination might be useful for premedication, but volume of injectate will limit its use to small pigs.  相似文献   

19.
ObjectiveTo determine the alfaxalone dose reduction during total intravenous anaesthesia (TIVA) when combined with ketamine or midazolam constant rate infusions and to assess recovery quality in healthy dogs.Study designProspective, blinded clinical study.AnimalsA group of 33 healthy, client-owned dogs subjected to dental procedures.MethodsAfter premedication with intramuscular acepromazine 0.05 mg kg-1 and methadone 0.3 mg kg-1, anaesthetic induction started with intravenous alfaxalone 0.5 mg kg-1 followed by either lactated Ringer’s solution (0.04 mL kg-1, group A), ketamine (2 mg kg-1, group AK) or midazolam (0.2 mg kg-1, group AM) and completed with alfaxalone until endotracheal intubation was achieved. Anaesthesia was maintained with alfaxalone (6 mg kg-1 hour-1), adjusted (±20%) every 5 minutes to maintain a suitable level of anaesthesia. Ketamine (0.6 mg kg-1 hour-1) or midazolam (0.4 mg kg-1 hour-1) were employed for anaesthetic maintenance in groups AK and AM, respectively. Physiological variables were monitored during anaesthesia. Times from alfaxalone discontinuation to extubation, sternal recumbency and standing position were calculated. Recovery quality and incidence of adverse events were recorded. Groups were compared using parametric analysis of variance and nonparametric (Kruskal-Wallis, Chi-square, Fisher’s exact) tests as appropriate, p < 0.05.ResultsMidazolam significantly reduced alfaxalone induction and maintenance doses (46%; p = 0.034 and 32%, p = 0.012, respectively), whereas ketamine only reduced the alfaxalone induction dose (30%; p = 0.010). Recovery quality was unacceptable in nine dogs in group A, three dogs in group AK and three dogs in group AM.Conclusions and clinical relevanceMidazolam, but not ketamine, reduced the alfaxalone infusion rate, and both co-adjuvant drugs reduced the alfaxalone induction dose. Alfaxalone TIVA allowed anaesthetic maintenance for dental procedures in dogs, but the quality of anaesthetic recovery remained unacceptable irrespective of its combination with ketamine or midazolam.  相似文献   

20.

Objective

To determine the effects of two dexmedetomidine continuous rate infusions on the minimum infusion rate of alfaxalone for total intravenous anaesthesia (TIVA), and subsequent haemodynamic and recovery effects in Greyhounds undergoing laparoscopic ovariohysterectomy.

Study design

Prospective, randomized and blinded clinical study.

Animals

Twenty-four female Greyhounds.

Methods

Dogs were premedicated with dexmedetomidine 3 μg kg?1 and methadone 0.3 mg kg?1 intramuscularly. Anaesthesia was induced with IV alfaxalone to effect and maintained with a TIVA mixture of alfaxalone in combination with two different doses of dexmedetomidine (0.5 μg kg?1 hour?1 or 1 μg kg?1 hour?1; groups DEX0.5 and DEX1, respectively). The alfaxalone starting dose rate was 0.07 mg kg?1 minute?1 and was adjusted (± 0.02 mg kg?1 minute?1) every 5 minutes to maintain a suitable depth of anaesthesia. A rescue alfaxalone bolus (0.5 mg kg?1 IV) was administered if dogs moved or swallowed. The number of rescue boluses was recorded. Heart rate, arterial blood pressure and arterial blood gas were monitored. Qualities of sedation, induction and recovery were scored. Differences between groups were tested for statistical significance using a Student’s t test or Mann–Whitney U test as appropriate.

Results

There were no differences between groups in sedation, induction and recovery quality, the median (range) induction dose of alfaxalone [DEX0.5: 2.2 (1.9–2.5) mg kg?1; DEX1: 1.8 (1.2–2.9) mg kg?1], total dose of alfaxalone rescue boluses [DEX0.5: 21.0 (12.5–38.8) mg; DEX1: 22.5 (15.5–30.6) mg] or rate of alfaxalone (DEX0.5: 0.12 ± 0.04 mg kg?1 minute?1; DEX1: 0.12 ± 0.03 mg kg?1 minute?1).

Conclusions and clinical relevance

Co-administration of dexmedetomidine 1 μg kg?1 hour?1 failed to reduce the dose rate of alfaxalone compared with dexmedetomidine 0.5 μg kg?1 hour?1 in Greyhounds undergoing laparoscopic ovariohysterectomy. The authors recommend an alfaxalone starting dose rate of 0.1 mg kg?1 minute?1. Recovery quality was good in the majority of dogs.  相似文献   

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