Urine Output Monitoring and Acute Kidney Injury in Non-mammalian Exotic Animal Critical Care

Acute kidney injury (AKI) is a sudden, severe decrease in kidney function which can occur in any species. There are various causes of AKI, some of which are seen in domestic species and some that are unique to birds, reptiles, and amphibians. These species present unique challenges with AKI management, such as differences in anatomy and physiology, intravenous and urinary catheterization, repeated blood sampling, and their tendency to present in advanced states of illness. This article will discuss AKI, diagnosis, treatment, and prognosis for non-mammalian exotic species.

Treatment of Pain in Birds

This article provides an overview of the current understanding of evidence-based clinical analgesic use in birds. The field of avian analgesia has dramatically expanded during the last 20 years, affording more options for alleviating both acute and chronic pain. These options include opioids, nonsteroidal anti-inflammatory drugs, local anesthetics, and/or other drugs like gabapentin, amantadine, and cannabinoids, acting at different points in the nociceptive system thereby helping to provide greater pain relief while reducing the risk of adverse effects when combined.

Pharmacokinetics of intravenous meloxicam, ketoprofen and tolfenamic acid in chukar partridge (Alectoris chukar)

1. The aim of this study was to determine the pharmacokinetics of meloxicam (MLX, 1 mg/kg body weight (BW)), ketoprofen (KETO, 2 mg/kg BW), and tolfenamic acid (TA, 2 mg/kg BW) in chukar partridge (Alectoris chukar) following intravenous (IV) administration.2. Twenty-four healthy chukar partridges were randomly divided into three equal groups (n = 8) as MLX, KETO and TA. Plasma concentrations of MLX, KETO and TA were measured using high-performance liquid chromatography-ultraviolet detection and analysed using non-compartmental analysis.3. No adverse effects were determined in chukar partridges after IV administration of MLX, KETO and TA. MLX, KETO and TA were detected in plasma up to 10, 12 and 12 h, respectively. The terminal elimination half-life of MLX, KETO and TA was 1.22, 1.77 and 1.95 h, respectively. MLX, KETO and TA exhibited volumes of distribution at a steady-state of 0.03, 0.23 and 0.41 l/kg BW, respectively. The total plasma clearance of MLX, KETO and TA was 0.02, 0.11 and 0.15 l/h/kg, respectively. The extraction ratios for MLX, KETO and TA were calculated as 0.002, 0.011 and 0.016, respectively.4. MLX, KETO and TA offer treatment in chukar partridges for various conditions with an absence of adverse reactions and properties such as short elimination half-life and low volume of distribution. However, there is a need to establish the safety and adverse effects of repeated administration, pharmacokinetics of other administration routes and pharmacological efficacy of MLX, KETO and TA in chukar partridges.

Local and Regional Anesthesia in Zoological Companion Animal Practice

Local anesthetics provide analgesia and can be incorporated into multimodal anesthetic protocols. They work by blocking the voltage-dependent sodium ion channels along neurons that mediate nociception. Systemically, these drugs can be cardiotoxic in a dose-dependent manner. Lidocaine and bupivacaine are the most commonly used local anesthetics and their use has been reported in all classes of vertebrates. Despite anecdotal reports to the contrary, zoologic companion animals are unlikely to be more susceptible to the cardiotoxic effects of local anesthetics than domestic small animals. Local anesthetics can be clinically useful for analgesia and anesthesia in zoologic companion animal practice.

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.

The high-altitude bird chronicles: lessons from field work with Frapps

Over the past decade, Peter Frappell, aka Frapps, has been an integral part of an international group studying birds that migrate or reside at altitude. This research has taken the extended group from Terkhiin Tsagaan Lake on the Mongolian plateau to Chilika Lake in eastern India, Koonthankulum bird sanctuary in southern India, Lake Qinghai in Chinese Tibet, Summer Lake Wildlife and Malheur National Wildlife Refuge in Oregon, and San Pedro a Marca, Vichaycocha and Lake Titicaca National Reserve in Perú. It has been a productive project producing over 30 manuscripts, 15 of which were based on research in the field. What has not been published are the stories behind the research and the critical lessons learned along the way. Some of these are chronicled here.

Comparison of Anesthetic Efficacy of Lidocaine and Bupivacaine in Spinal Anesthesia in Chickens

Lidocaine is used for epidural and spinal anesthesia in various animal species. The ideal drug for epidural and spinal anesthesia should have a long effective duration in addition to a fast onset of action, and adequate analgesia and muscle relaxation. Despite the delayed onset of action, bupivacaine provides a longer duration of anesthesia than lidocaine. The purpose of this study was to compare the onset to effect and duration of action between lidocaine and bupivacaine for spinal anesthesia in broiler chickens. Thirty-two, 8-week-old, female Ross broiler chickens were randomly divided into 4 groups of 8: 1) 2 mg/kg lidocaine (L); 2) 0.1 mg/kg bupivacaine (B0.1); 3) 0.25 mg/kg bupivacaine (B0.25); and 4) 0.5 mg/kg bupivacaine (B0.5). After aseptic preparation, a 23-gauge spinal needle was inserted into the synsacrococcygeal space of the chickens with correct needle placement confirmed by a sudden loss of resistance. Spinal anesthesia was performed with the aforementioned doses of lidocaine and bupivacaine. The respiratory rate and cloacal temperature were measured every 10 minutes in each chicken until the anesthetic effect was no longer present. The onset to effect and the duration of action were calculated for each bird based on the pinch test at predetermined time intervals. The results are demonstrated as mean ± SD. The onset of action for bupivacaine (9 ± 1.41, 4.33 ± 1.15, and 3.33 ± 1.23 minutes in B0.1, B0.25, and B0.5 groups, respectively) was significantly delayed compared with that of lidocaine (1.37 ± 0.52 minutes). The duration of action of B0.5 (54 ± 6.08 minutes) was significantly longer than that of any other group (17.87 ± 3.18, 11 ± 1.41, and 18 ± 4.36 min in L, B0.1, and B0.25 groups, respectively). The results showed that a spinal injection of 0.5 mg/kg bupivacaine produces approximately 55 minutes of spinal anesthesia in these broiler chickens, which is much longer than the 18 minutes of anesthesia provided by 2 mg/kg lidocaine. Considering the various disease conditions that affect the cloacal area of birds, one can use each of these anesthetic drugs for either short-term or long-term spinal anesthesia in chickens and possibly other avian species.

Diseases of the Avian Urinary System

Diseases of the renal system can be caused by infectious and noninfectious processes. Creating a relevant differential diagnosis for kidney disease in the live or dead bird requires a structured approach where the list of differentials is narrowed based on the signalment of the bird; its history, including its diet and management; physical findings; and other diagnostic findings. This article aims to provide the reader not only a list of the diseases that occur in birds but also the guidelines on when a disease should be considered in a differential.

Cardiovascular tolerance of intravenous bupivacaine in broiler chickens (Gallus gallus domesticus) anesthetized with isoflurane

OBJECTIVE

To determine the median effective dose (ED₅₀) of intravenous (IV) bupivacaine associated with a 50% probability of causing clinically relevant cardiovascular effects [defined as 30% change in heart rate (HR) or mean arterial pressure (MAP)] in chickens anesthetized with isoflurane.

STUDY DESIGN

Randomized up-and-down study.

ANIMALS

A total of 14 Ross-708 broiler chickens (Gallus gallus domesticus) weighing 1.70-2.75 kg.

METHODS

Anesthesia was induced and maintained with isoflurane. Monitoring included the electrocardiogram and invasive arterial pressures. Chickens were administered bupivacaine IV over 2 minutes using a dose based on the response of the previous animal. Dose was decreased when HR and/or MAP in the previous animal increased or decreased ≥30% after bupivacaine administration, or increased when HR or MAP changed <30%. The ED₅₀ was defined as the dose resulting in ≥30% variation in HR or MAP in 50% of the population studied.

RESULTS

The IV ED₅₀ of bupivacaine was 1.94 mg kg^-1 using Dixon's up-and-down method and 1.96 mg kg^-1 by logistic regression.

CONCLUSIONS AND CLINICAL RELEVANCE

These results suggest that 1.33 and 1.96 mg kg^-1 of IV bupivacaine are associated with a respective 1 or 50% probability of a clinically significant change in MAP in isoflurane-anesthetized chickens. Identification of the cardiovascular changes associated with different doses of bupivacaine can be used as the basis for studies of therapeutic applications in the domestic chicken. Further studies are required to determine interspecies variation.

BEST-PRACTICE GUIDELINES FOR FIELD-BASED SURGERY AND ANESTHESIA OF FREE-RANGING WILDLIFE. I. ANESTHESIA AND ANALGESIA

Field anesthesia is often necessary for both invasive and noninvasive procedures on wild animals. We describe basic principles of safe anesthetic delivery, monitoring, and recovery for application in procedures involving free-ranging wildlife. For invasive procedures, the potential for immediate and lasting pain must be addressed and appropriate analgesia provided. In situations where the minimum standard of safe anesthesia and effective analgesia cannot be provided, the investigator and approving bodies should rigorously evaluate the risk to the patient against the value of the data obtained. This document is intended to serve as a resource for Institutional Animal Care and Use Committees, biologists, veterinarians, and other researchers planning projects that involve free-ranging wildlife in field conditions.

Pharmacokinetics after intravenous administration of flunixin meglumine in budgerigars (Melopsittacus undulatus) and Patagonian conures (Cyanoliseus patagonus)

OBJECTIVE

To investigate the disposition kinetics of flunixin meglumine when administered IV to budgerigars (Melopsittacus undulatus) and Patagonian conures (Cyanoliseus patagonus).

DESIGN

Prospective cohort study.

ANIMALS

8 adult Patagonian conures and 24 adult budgerigars.

PROCEDURES

Injectable flunixin meglumine (50 mg/mL) was diluted to 10 and 1. 0 mg/mL and administered IV at a dose of 5.0 mg/kg (2.3 mg/lb) to Patagonian conures and budgerigars, respectively.

RESULTS

In budgerigars, the elimination half-life was 0.72 hours and the mean residence time was 0.73 hours. In Patagonian conures, the elimination half-life was 0.91 hours and the mean residence time was 1.20 hours. The concentration of flunixin was below the assay's limit of quantification (0.5 μg/mL) at 3 and 6 hours in budgerigars and Patagonian conures, respectively. A single budgerigar developed adverse effects (lethargy and signs of depression) for approximately 15 minutes following drug administration.

CONCLUSIONS AND CLINICAL RELEVANCE

The half-life of flunixin in Patagonian conures and budgerigars was short following IV administration; however, results of this study suggested that IV administration of injectable flunixin meglumine at 5.0 mg/kg resulted in plasma concentrations that could potentially be anti-inflammatory and analgesic in budgerigars and Patagonian conures.

Does ketoprofen or diclofenac pose the lowest risk to fish?

Ketoprofen and diclofenac are non-steroidal anti-inflammatory drugs (NSAIDs) often used for similar indications, and both are frequently found in surface waters. Diclofenac affects organ histology and gene expression in fish at around 1 μg/L. Here, we exposed rainbow trout to ketoprofen (1, 10 and 100 μg/L) to investigate if this alternative causes less risk for pharmacological responses in fish. The bioconcentration factor from water to fish blood plasma was <0.05 (4 for diclofenac based on previous studies). Ketoprofen only reached up to 0.6 ‰ of the human therapeutic plasma concentration, thus the probability of target-related effects was estimated to be fairly low. Accordingly, a comprehensive analysis of hepatic gene expression revealed no consistent responses. In some contrast, trout exposed to undiluted, treated sewage effluents bioconcentrated ketoprofen and other NSAIDs much more efficiently, according to a meta-analysis of recent studies. Neither of the setups is however an ideal representation of the field situation. If a controlled exposure system with a single chemical in pure water is a reasonable representation of the environment, then the use of ketoprofen is likely to pose a lower risk for wild fish than diclofenac, but if bioconcentration factors from effluent-exposed fish are applied, the risks may be more similar.

Avian analgesia

Avian analgesia is now recognized as a critical component of avian medicine and surgery. The need to recognize pain and to provide pain relief is the first step, and many anecdotal therapeutic doses have been extrapolated from other companion animals. Several published research investigations, using several species of birds, have begun to provide avian analgesia therapeutic information for clinical application. The challenge is to continue pushing this research forward with appreciation that there are approximately 10,000 known species of birds, perhaps 200 species commonly kept as pets, and that each species has a range of behaviors as varied as their species-specific PKs and PDs to each analgesic drug.

Geriatric psittacine medicine

This article investigates geriatric psittacine medicine; it identifies how to recognize and treat pain, and describes disease conditions by system, administration of medicine, and examination techniques.

Toxicity of non-steroidal anti-inflammatory drugs to Gyps vultures: a new threat from ketoprofen

Three Gyps vulture species are on the brink of extinction in South Asia owing to the veterinary non-steroidal anti-inflammatory drug (NSAID) diclofenac. Carcasses of domesticated ungulates are the main food source for Asia's vultures and birds die from kidney failure after consuming diclofenac-contaminated tissues. Here, we report on the safety testing of the NSAID ketoprofen, which was not reported to cause mortality in clinical treatment of scavenging birds and is rapidly eliminated from livestock tissues. Safety testing was undertaken using captive non-releasable Cape griffon vultures (Gyps coprotheres) and wild-caught African white-backed vultures (G. africanus), both previously identified as susceptible to diclofenac and suitable surrogates. Ketoprofen doses ranged from 0.5 to 5 mg kg(-1) vulture body weight, based upon recommended veterinary guidelines and maximum levels of exposure for wild vultures (estimated as 1.54 mg kg(-1)). Doses were administered by oral gavage or through feeding tissues from cattle dosed with ketoprofen at 6 mg kg(-1) cattle body weight, before slaughter. Mortalities occurred at dose levels of 1.5 and 5 mg kg(-1) vulture body weight (within the range recommended for clinical treatment) with the same clinical signs as observed for diclofenac. Surveys of livestock carcasses in India indicate that toxic levels of residual ketoprofen are already present in vulture food supplies. Consequently, we strongly recommend that ketoprofen is not used for veterinary treatment of livestock in Asia and in other regions of the world where vultures access livestock carcasses. The only alternative to diclofenac that should be promoted as safe for vultures is the NSAID meloxicam.

Analysis of nine NSAIDs in ungulate tissues available to critically endangered vultures in India

In 2006, India, Pakistan, and Nepal banned the manufacture of veterinary formulations of the nonsteroidal anti-inflammatory drug (NSAID) diclofenac. This action was taken to halt the unprecedented decline of three Gyps vulture species that were being poisoned by diclofenac residues commonly present in carcasses of domestic livestock upon which they scavenged. To assess the affect of this ban and evaluate residue prevelances of other NSAIDs, we present a method to detect diclofenac and eight more NSAIDs by liquid chromatography-mass spectrometry and apply this to 1488 liver samples from carcasses of livestock taken across seven Indian states. Diclofenac was present in 11.1% of samples taken between April and December 2006, and meloxicam (4%), ibuprofen (0.6%), and ketoprofen (0.5%) were also detected. Although meloxicam is safe for a range of avian scavengers, including Gypsvultures, data regarding the safety of other NSAIDs is currently limited. If wild Gyps on the Indian subcontinent are to survive, diclofenac bans must be completely effective, and NSAIDs that replace it within the veterinary drug market must be of low toxicity toward Gyps and other scavenging birds.

NSAIDs and scavenging birds: potential impacts beyond Asia's critically endangered vultures

Veterinary treatment of livestock with diclofenac, a non-steroidal anti-inflammatory drug (NSAID), has caused catastrophic declines of Gyps vultures in Asia. This has highlighted a lack of knowledge on the potential impacts of NSAIDs on scavenging birds. Surveys of veterinarians and zoos document the outcomes of the treatment of over 870 scavenging birds from 79 species. As well as diclofenac, carprofen and flunixin were associated with mortality, with deaths observed in 13 and 30% of cases, respectively. Mortality was also found following treatment with ibuprofen and phenylbutazone. NSAID toxicity was reported for raptors, storks, cranes and owls, suggesting that the potential conservation impact of NSAIDs may extend beyond Gyps vultures and could be significant for New World vultures. In contrast, there were no reported mortalities for the NSAID meloxicam, which was administered to over 700 birds from 60 species. The relative safety of meloxicam supports other studies indicating the suitability of this NSAID to replace diclofenac in Asia.