Sedative effects of midazolam and xylazine with or without ketamine and detomidine alone following intranasal administration in Ring-necked Parakeets

COMPARISON OF THREE MIDAZOLAM-BASED SEDATION PROTOCOLS IN BUDGERIGARS (MELOPSITTACUS UNDULATUS) AND BLACK-CHEEKED LOVEBIRDS (AGAPORNIS NIGRIGENIS)

This randomized, crossover study evaluated three sedation protocols administered subcutaneously in nine budgerigars (Melopsittacus undulatus) and nine black-cheeked lovebirds (Agapornis nigrigenis). All protocols included midazolam (5 mg/kg), combined with butorphanol (5 mg/kg) (BM), medetomidine (20 lg/kg) (MM), or alfaxalone (13 mg/kg) (AM). Mortalities from suspected cardiorespiratory arrest were observed when AM was used in lovebirds, even after reduction of alfaxalone dosage to 3 mg/kg, and therefore this protocol was excluded from further use in this species. Induction and recovery times were recorded and their quality assessed. Sedation depth and heart and respiratory rates were measured every 5 min and radiographic positioning was attempted at 10 and 20 min. At 30 min, midazolam and medetomidine were reversed with flumazenil (0.05 mg/kg, SC), and atipamezole (0.2 mg/kg, SC), respectively. MM consistently provided deep sedation in both species, with successful radiographic positioning at every attempt. As expected, heart rate was often lower with MM than with other protocols, but no associated complications were noted. In budgerigars, BM had the lowest radiographic positioning success rate (10 min: 5/9, 20 min: 3/9), whereas in lovebirds it provided significantly deeper sedation (P < 0.001), allowing radiographic positioning in all subjects. In both species, BM provided the shortest recovery times. AM resulted in reliable radiographic positioning of all budgerigars at 10 min, but not at 20 min (5/ 9), and provided consistently poor recoveries. This study highlights how differently two psittacine species of similar size may react to the same sedation protocols. AM sedation cannot be fully reversed and produced significant undesirable effects, several of which have been previously reported with alfaxalone administration to avian species. The authors therefore caution against using alfaxalone-midazolam combinations in budgerigars and black-cheeked lovebirds. Both BM and MM provided reliable sedation in these species, and appear to be suitable alternatives to AM.

Evaluation of dexmedetomidine-midazolam sedation in budgerigars (Melopsittacus undulatus)

OBJECTIVE

To evaluate the sedative effects of IM administration of a high or low dose of dexmedetomidine in combination with midazolam in budgerigars (Melopsittacus undulatus).

ANIMALS

20 healthy adult budgerigars.

PROCEDURES

In a prospective, randomized, blinded study, birds were sedated with a high dose (HD; 0.04 mg/kg, IM; n = 10) or low dose (LD; 0.01 mg/kg, IM; 10) of dexmedetomidine in combination with midazolam (3 mg/kg, IM). Twenty minutes later, atipamezole (0.4 mg/kg [HD group] or 0.1 mg/kg [LD group], IM) and flumazenil (0.1 mg/kg, IM) were administered for reversal of sedation.

RESULTS

Times to first effect and to sternal recumbency after administration of the sedatives and times to standing and eating after administration of the antagonists did not differ between groups. Most birds (9/10 in the HD group and 7/10 in the LD group) lost the righting response by 10 minutes after sedative administration, and the peak effect for radiographic positioning was by 15 minutes. Although it was not clinically relevant, most birds showed mild resedation by 60 minutes after administration of the reversal agents. There was no significant cardiorespiratory compromise detected with either protocol.

CLINICAL RELEVANCE

Dexmedetomidine-midazolam can safely and effectively provide a dose-dependent level of sedation in healthy budgerigars. The HD protocol is recommended for radiographic positioning, as it allows for a more reliable, deeper plane of sedation.

Raptor Sedation and Anesthesia

Sedation and/or anesthesia is routinely and successfully used in raptors for a wide variety of procedures from the routine such as physical examination, radiographs, or venipuncture, to the more complex, such as orthopedic surgeries. Understanding the anatomy and physiology of raptor patients who present for care, and being fully prepared before the start of any procedure, can increase the success of anesthetic procedures. Recent advances in raptor sedation and anesthesia continue to improve the health and welfare of these avian patients.

Backyard Poultry and Waterfowl Sedation and Anesthesia

The popularity of backyard poultry (chickens, turkey, guinea fowl) and waterfowl (ducks and geese) is increasing in the United States, and these animals frequently present for veterinary care. Like other birds, these species have unique anatomy that should be clinically considered before anesthesia. A balanced approach to an injectable, inhalational, or combination anesthesia protocol must be taken to ensure a safe outcome for the patient and to achieve the procedural needs. A well-informed clinician may use both sedation and general anesthesia to care for backyard bird patients in practice.

Psittacine Sedation and Anesthesia

Successful management of sedation/anesthesia of psittacine species relies on familiarity with their specific anatomy and physiology, and detailed knowledge of the recent advancements in applied pharmacology of the anesthetics and perianesthetic monitoring of cardiovascular and respiratory functions. Each sedation/anesthetic plan should be patient-specific, developed based on preexisting conditions, size, species, age, and estimated risk. Other key factors to improve safety, quality of perioperative care, and client satisfaction are anticipation of complications, extension of close monitoring to the recovery phase, multimodal analgesic approach, stress prevention/reduction, and transparent communication with the owner.

Avian Sedation

The use of procedural sedation in birds has become a routine practice in veterinary medicine during the past 10 years, with a corresponding increase in avian sedation research. Sedation is most often used in a clinical setting for birds to facilitate examination and/or diagnostic sample collection, splint application, grooming, and minor surgical procedures. Sedation provides several benefits over manual restraint or general anesthesia when performing clinical procedures. This review provides an overview of current studies on avian sedation and discusses common indications, protocols, and adverse effects of sedation in avian patients.

Minimum anesthetic concentration of isoflurane and sparing effect of midazolam in Quaker parrots (Myiopsitta monachus)

OBJECTIVE

To determine the effects of midazolam on the minimum anesthetic concentration (MAC) reduction of end-tidal isoflurane concentration (Fe'Iso) measured using an electrical stimulus in Quaker parrots (Myiopsitta monachus).

STUDY DESIGN

Randomized crossover experimental study.

ANIMALS

A group of six adult Quaker parrots, weighing 98-124 g.

METHODS

Birds were anesthetized with isoflurane in oxygen delivered by mask, then tracheally intubated and mechanically ventilated. Three treatments were applied with a 4 day interval between anesthetic events. Each anesthetized bird was administered midazolam (1 mg kg^-1; treatment MID1), midazolam (2 mg kg^-1; treatment MID2) or electrolyte solution (control) intramuscularly. The treatments were administered using a replicated Latin square design and the observers were blinded. Based on a pilot bird, the starting Fe'Iso was 1.8%. After equilibration for 10 minutes, a supramaximal stimulus was delivered using an electrical current (20 V and 50 Hz for 10 ms) and birds were observed for non-reflex movement. The Fe'Iso was titrated by 0.1% until a crossover event was observed. The MAC was estimated using logistic regression.

RESULTS

The MAC of isoflurane (MAC_ISO) was estimated at 2.52% [95% confidence interval (CI), 2.19-2.85] with a range of 1.85-2.65%. MAC_ISO in MID1 was 2.04% (95% CI, 1.71-2.37) and in MID2 was 1.81% (95% CI, 1.48-2.14); reductions in MAC_ISO from control of 19% (p = 0.001) and 28% (p < 0.001), respectively. Heart rate, temperature, sex and anesthetic time were not different among treatments.

CONCLUSIONS

Midazolam (1-2 mg kg^-1) intramuscularly resulted in a significant isoflurane-sparing effect in response to a noxious stimulus in Quaker parrots without observable adverse effects.

CLINICAL RELEVANCE

Midazolam can be used as part of a balanced anesthetic approach using isoflurane in Quaker parrots, and potentially in other psittacine species.

Effects of Midazolam and Midazolam-Butorphanol on Gastrointestinal Transit Time and Motility in Cockatiels (Nymphicus hollandicus)

Positive contrast gastrointestinal (GI) studies are performed frequently in avian medicine to identify GI obstruction, luminal distension, and intracoelomic mass effects. However, repeated manual restraint and radiographic positioning may result in a stress-response and associated morbidity in birds, which can be attenuated by administration of sedative drugs. In mammals, many sedative drugs have been shown to affect GI transit times and motility. In this randomized, blinded, controlled prospective study, the effects of midazolam (M; 6 mg/kg IM) and midazolam-butorphanol (MB; 3 mg/kg each IM) on GI transit times were evaluated in 12 healthy cockatiels (Nymphicus hollandicus). Iohexol (20 mL/kg) was administered by crop gavage 15 minutes after induction of sedation, and fluoroscopic images were obtained at different time points. Both sedation protocols significantly affected GI transit times and motility, and the MB protocol had more pronounced effects. Overall median (range) GI transit times were 60 (30-120), 90 (30-120), and 120 (120-180) minutes for the control, M, and MB groups, respectively. Ventricular contractions were markedly reduced with both sedation protocols, while esophageal boluses were reduced only in the MB group. Visualization of the GI tract after iohexol administration was graded highest in the control group and poorest in the MB group. Our results show that commonly used sedative drugs have significant effects on GI transit time and motility in birds. Therefore, GI transit times obtained in sedated birds should not be compared to available reference transit times obtained from unsedated animals.

Influence of tramadol on anesthesia times, analgesia and electrocardiogram associated with injection anesthesia in common buzzards (Buteo buteo)

A balanced anesthesia protocol is called perfect when it has fast induction, excellent recovery, the least effect on the cardiopulmonary system and sufficient analgesia. Many of anesthetic combinations have an analgesic effect without opioids. However, at the end of anesthesia, analgesia decreases or is incomplete. The purpose of this study was to evaluate anesthesia times, electrocardiogram (ECG) and analgesic effect of tramadol when administrated with ketamine, ketamine-diazepam, ketamine-midazolam, and ketamine-xylazine and selected a balanced anesthesia protocol in buzzards. Ten adult common buzzards (Buteo buteo) received seven different anesthetic protocols (with or without tramadol). In each protocol, anesthesia times, electrocardiograph parameters and analgesic effect were recorded. Excluding ketamine-tramadol, all protocols produced deep anesthesia in all buzzards. Among of all protocols, no significant differences regarding the amplitude and duration of waves (P, QRS and T) was found. By adding tramadol to anesthetic protocols, response duration to thermal sense increased up 3 hr after recovery. Tramadol did not make considerable effects on anesthesia times and ECG and made analgesic effect up to 3 hr when used with ketamine-benzodiazpins or ketamine-xylazine. Therefore, tramadol can be used with injectable anesthetics to make suitably balanced anesthesia in buzzards.

Overview of Drug Delivery Methods in Exotics, Including Their Anatomic and Physiologic Considerations

Drug delivery to exotic animals may be extrapolated from domestic animals, but some physiologic and anatomic differences complicate treatment administration. Knowing these differences enables one to choose optimal routes for drug delivery. This review provides practitioners with a detailed review of the currently reported methods used for drug delivery of various medications in the most common exotic animal species. Exotic animal peculiarities that are relevant for drug administration are discussed in the text and outlined in tables and boxes to help the reader easily find targeted information.

Low-Stress Medication Techniques in Birds and Small Mammals

Low-stress medication principles and techniques are key aspects of optimal health care delivery for birds and small mammals. When paired with the medical details of patient management, by balancing medication techniques, the probability of clinical success on the highest ethical and welfare criteria can be greatly enhanced. This review addresses both the effects and the disadvantages of using forceful, coercive, and fear-evoking methods as well as the benefits, principles, and possible applications of low-stress medication in the veterinary setting.

Clinical evaluation of intranasal medetomidine-ketamine and medetomidine-S(+)-ketamine for induction of anaesthesia in rabbits in two centres with two different administration techniques

OBJECTIVE

The aim was to compare efficacy and side effects of induction with medetomidine-ketamine or medetomidine-S(+)-ketamine by intranasal (IN) instillation in rabbits and to evaluate both protocols during subsequent isoflurane anaesthesia.

STUDY DESIGN

Prospective, blinded, randomized experimental study in two centres.

ANIMALS

Eighty-three healthy New Zealand White rabbits undergoing tibial or ulnar osteotomy.

METHODS

Medetomidine (0.2 mg kg^-1) with 10 mg kg^-1 ketamine (MK) or 5 mg kg^-1 S(+)-ketamine (MS) was administered IN to each rabbit in a randomized fashion. In Centre 1 (n = 42) rabbits were held in sternal recumbency, and in Centre 2 (n = 41) in dorsal recumbency, during drug instillation. Adverse reactions were recorded. If a rabbit swallowed during endotracheal intubation, half of the initial IN dose was repeated and intubation was re-attempted after 5 minutes. Anaesthesia was maintained with isoflurane. Heart rate, blood pressure, endtidal carbon dioxide concentration and blood gases were recorded. Data were analysed using Student's t-test, Mann-Whitney test and Fisher's exact test.

RESULTS

In all, 39 animals were assigned to the MK group and 44 to the MS group. Two rabbits in the MS group held in dorsal recumbency died after instillation of the drug. Eight (MK) and 11 rabbits (MS) were insufficiently anaesthetized and received a second IN dose. One rabbit in MK and three in MS required an isoflurane mask induction after the second IN dose. There were no significant differences between treatments for induction, intraoperative data, blood gas values and recovery data.

CONCLUSION AND CLINICAL RELEVANCE

This study indicated that medetomidine-ketamine and medetomidine-S(+)-ketamine were effective shortly after IN delivery, but in dorsal recumbency IN administration of S(+)-ketamine led to two fatalities. Nasal haemorrhage was noted in both cases; however, the factors leading to death have not been fully elucidated.

Evaluation of the Sedative Effects of Diazepam, Midazolam, and Xylazine After Intranasal Administration in Juvenile Ostriches ( Struthio camelus )

The sedative effects of diazepam, midazolam, and xylazine after intranasal administration were evaluated in 72 (36 male and 36 female) juvenile healthy ostriches ( Struthio camelus ), weighing 50-61 kg and aged 4-5 months. The birds were randomly divided into 3 groups (n = 24), then each group was further subdivided to 4 subgroups (n = 6). For each drug, 4 different doses were chosen and the total calculated dose was equally administered into either naris of the individual bird. The appropriate dose of each drug to produce standing chemical restraint or sternal recumbency was evaluated based on the onset time, the duration of maximum effect, and the duration of sedation. Midazolam showed significantly shorter onset time (2.9 ± 1.2 minutes) compared with xylazine (4.4 ± 1 minute) and diazepam (4.3 ± 0.4 minutes). Longer duration of sedation was also achieved with midazolam compared with xylazine and diazepam. Moderate sedation was achieved with diazepam (0.8 mg/kg), midazolam (0.4 mg/kg), and xylazine (2 mg/kg) for standing chemical restraint, with the maximum duration effects of 7.0 ± 1.4, 17.7 ± 4.1, and 9.2 ± 2.5 minutes, respectively. Deep sedation was also achieved with midazolam (0.8 mg/kg) and xylazine (4 mg/kg), with sternal recumbency duration of 21.7 ± 4.9 and 13.5 ± 2.6 minutes, respectively. The results of the present study show that intranasal administration can be an effective route for delivery of sedatives in juvenile ostriches. Intranasal midazolam and xylazine could be suggested for standing chemical restraint or inducing sternal recumbency in juvenile ostriches.

EFEITOS ANESTÉSICOS DA ADMINISTRAÇÃO INTRANASAL OU INTRAMUSCULAR DA ASSOCIAÇÃO DE MIDAZOLAM E CETAMINA RACÊMICA OU S+ EM PERIQUITO AUSTRALIANO (Melopsittacus undulatus)

Resumo A anestesia intranasal em aves é considerada uma técnica anestésica segura, simples e eficiente. O objetivo deste estudo foi comparar os efeitos anestésicos da associação de midazolam (5 mg.kg-1) e cetamina (15 mg.kg-1) nas formulações racêmica (R) ou S+ (S) administrados pela via intranasal (IN) ou intramuscular (IM) em periquitos australianos (Melopsittacus undulatus). Foram utilizados oito periquitos em delineamento do tipo crossover, em quatro tratamentos: INR, INS, IMR e IMS. Foram avaliados os tempos de latência, decúbito dorsal, anestesia e recuperação, grau de sedação e qualidade de recuperação. Foi observada diferença significativa no tempo de latência entre INS (40,25±10,55 seg) e IMR (74,32±21,77 seg); entre as vias de administração para o tempo de decúbito dorsal, INS (23,93±7,51 min) e INR (28,68±16,13 min), diferente de IMS (60,08±27,37 min) e IMR (74,3±21,77 min) e para tempo de anestesia, INS (45,48±17,94 min) e INR (39,24±15,62 min), diferentes de IMS (75,84±20,20 min) e IMR (79,4±20,73 min). O tempo de recuperação foi significativamente maior em INS (21,55±18,43 min) comparado a IMR (5,1±3,56 min). Pode-se concluir que as duas vias de administração avaliadas podem ser utilizadas em procedimentos de curta duração e não invasivos e a via intranasal é preferível para procedimentos rápidos.

Midazolam sedates Passeriformes for field sampling but affects multiple venous blood analytes

Feasibility and effect of midazolam administration on blood analytes and for sedation of Passeriformes being collected in a larger study of genetic biodiversity was assessed. Midazolam (5.6±2.7 mg/kg) was administered intranasally prior to sampling, euthanasia, and specimen preparation of 104 passerine birds. Each bird was assessed for sedation score and then multiple analytes were determined from jugular blood samples using the i-STAT® point of care analyzer at "bird side". Most birds were acceptably sedated, sedation became more pronounced as midazolam dose increased, and only a single bird died. Electrolyte concentrations and venous blood gas analytes were affected by midazolam administration while blood pH, packed cell volume, hemoglobin, and calculated hematocrit were not. Intranasal midazolam gives adequate sedation and is safe for short-term use in free-living Passeriformes. Based on venous blood analyte data, sedation of Passeriformes prior to handling appears to reduce stress but also produces venous blood gas differences consistent with hypoventilation relative to birds which were not given midazolam. Further study is recommended to investigate midazolam's continued use in free-living avian species. Studies should include safety, reversal and recovery, effect upon additional endogenous analytes, and compatibility with studies of ecology and toxicology associated with pollution or other environmental degradation in Passeriformes.

Comparison of intranasal administration of xylazine, diazepam, and midazolam in budgerigars (Melopsittacus undulatus): clinical evaluation

Effective sedation methods are important to facilitate safe handling for diagnostic and clinical procedures for small and often delicate birds such as budgerigars (Melopsittacus undulatus). The aim of this study was to directly compare the time of onset and duration of sedation produced by intranasal administration of xylazine, diazepam, or midazolam in budgerigars. Fifteen (seven male, eight female) clinically healthy mature budgerigars weighing 28.9 +/- 6.1 g were involved in the study Each bird was used three times in a randomized crossover study design with 7 days between treatments. Birds received xylazine (25.6 +/- 2.2 mg/kg), diazepam (13.6 +/- 1.1 mg/kg), or midazolam (13.2 +/- 1.3 mg/kg) intranasally (i.n.) using a micropipette. The onset time and dorsal recumbency duration time were measured and recorded. Sedation was produced in all birds after i.n. administration of xylazine, diazepam, and midazolam. Time to onset of sedation was significantly shorter after midazolam (1.3 +/- 0.44 min) compared with that after xylazine (2.6 +/- 0.89 min) and diazepam (2.8 +/- 0.88 min). Xylazine produced significantly longer duration of sedation (286.0 +/- 28.8 min) than that produced by diazepam (165.40 +/- 19.2 min) and midazolam (71.60 +/- 8.9 min). This study demonstrated that i.n. drug administration could provide fast and reliable sedation in budgerigars. Although i.n. midazolam or diazepam can provide adequate sedation for diagnostic and minor therapeutic procedures, xylazine at the dose used in this study is not recommended because the quality of sedation may be insufficient to perform a clinical procedure.