Thinking of adding exotic mammals to your case load? Equipment needs (Proceedings)

For the dog and cat veterinarian, making the transition to include exotic companion mammals in the practice caseload is not difficult. The extent of special equipment needed varies with the degree to which the veterinarian plans to pursue this field of interest. Minor changes in physical plant that provide an ICU, special cages or an exotics ward, and extra storage for foods appropriate to the species the veterinarian plans on examining is a great start. Converting an exam room to reflect your interest exotic mammals is an option that improves upon equipment utilization and efficiency and demonstrates this special interest to your clients. An initial investment in syringes, catheters, surgical and dental instruments, and anesthetic equipment all designed for these small patients will be necessary. More sophisticated equipment can be added as the interest in exotic mammals grows and finances allow. Please see the attached equipment list (Table 1) for more information on equipment discussed in this paper

Exotic mammal equipment list

Examination

Every veterinary visit with an exotic mammal begins in the exam room. A general discussion on husbandry, behavior and nutrition is part of every initial exam and being organized helps this discussion go more smoothly and efficiently. The author prepares in-house information packets full of client education handouts addressing various topics on the species being seen. These handouts are also required reading for all staff members so that they are able to initiate husbandry discussions. Having an educated and well-trained staff capable of helping with client education, patient restraint and diagnostic sample collection is a real time saver. Check lists are provided to remind staff members on topics of importance and also serve to notify the veterinarian in charge of what has already been discussed with the client.

Inappropriate feeding practices are a common problem in many exotic mammals and part of every new patient office visit should be devoted to this topic. Many veterinarians stock a variety of exotic mammal diets in order to allow the client the opportunity to start making immediate dietary changes. Showing the client a bag of food that meets the nutritional needs of their pet gives a more memorable impression than just discussing these products alone. Oxbow Animal Health (www.oxbowanimalhealth.com) supplies the veterinary market with a variety of legume and grass hays for herbivores and pelleted diets for herbivores and rodents. Zupreem (www.zupreem.com) makes reliable ferret, rabbit and guinea pig diets and Mazuri (www.mazuri.com) offers pelleted diets for ferrets, guinea pigs, rabbits, rodents and insectivores such as hedgehogs and sugar gliders. Keeping fresh, leafy greens on hand is not only a great way to show clients appropriate produce to provide herbivores but also serves as an aid in testing patient inappetence in suspect ileus cases.

For precise pharmacological dosing and for monitoring body condition, accurate body weights are important. Two portable scales are ideal: for example, a Mars MS-6 for smaller exotic mammals that measures patients in grams up to 6.6 kg, and a Shoreline feline digital scale used to weigh larger exotic mammals in kilograms.

Each exam room is stocked with towels in a variety of sizes to aid in patient restraint and to help ensure footing and prevent heat loss on stainless steel exam tables. Some practitioners prefer to use a rubber bath mat with suction cups on the exam table. The rubber provides traction and increased security for anxious rabbits and guinea pigs during exams and the mats are easily washed and disinfected. FerreTone, a palatable oily supplement designed for ferrets, serves as a nice distraction device that when offered in a syringe keeps busy ferrets occupied so that they may be more readily examined. Feline /avian nail trimmers are provided for all staff members to encourage patient nail trims. A wire mesh aquarium top can be used as an aid when trimming nails on hedgehogs or sugar gliders as they cling to the wire mesh. For initial dental exams on rabbits, chinchillas and guinea pigs a small animal otoscope or an illuminated Welch Allyn bivalve speculum can be used. We have a separate set of cones set aside for this purpose, as the pets gnawing action during oral examination will damage the plastic leaving rough edges. Magnification loupes such as the Optivisor can be a great aid in the general examination of mice, hamsters and gerbils as well as an aid in viewing close-ups of skin and other lesions. For auscultation of the heart and lungs a pediatric or infant stethoscope helps with clarity and function.

Diagnostics

Upon completion of the history and physical exam the exotic mammal practitioner may choose to initiate a diagnostic workup which benefits from the availability of diagnostic equipment well suited to the species being treated. The size of many exotic mammal patients limits the volume of blood draws, therefore working with equipment that yields the greatest amount of information from small volumes of blood and that is calibrated for exotic mammals is ideal. Abaxis Veterinary Diagnostics makes the VetScan VS2 Chemistry Analyzer with the capability of using 100μl whole blood or serum/plasma to provide a chemistry panel calibrated for a variety of exotic mammals. The Abaxis VetScan HMT 2 Hematology Analyzer can be calibrated to provide CBC information on ferrets, guinea pigs and rabbits.

For in-house chemistry analyzers or outside laboratories requiring serum or palsma the StatSpin MV Centrifuge is designed to efficiently centrifuge small volumes of blood (up to 2ml) and allows for maximum yields. It can also be used on small volumes of urine to obtain sediment samples for cytological review. For blood cultures, Septi-chek BBL 20 ml (pediatric) collection vials from Becton Dickinson Microsystems are designed for 1-3ml blood draws. Monoject has available 0.5cc tuberculin syringes with permanently attached 28-gauge (0.36mm) needles that allow for easier collection from cephalic or lateral saphenous veins on exotic mammals. These can be used to obtain samples for quick in-house packed cell volume, total solids determination (PCV/TS), blood smears for estimated white blood cell counts and differentials and blood glucose levels. In this way the practitioner can obtain baseline diagnostic information in patients as small as 100 grams. Alternatively, 3 cc syringes with 22-ga x ¾ inch (0.72 x 19mm) needles can be used for larger blood draws from the vena cava of ferrets, guinea pigs and hedgehogs and 1 ml tuberculin syringes with 25-ga x 5/8 inch (0.5 x 16mm) syringes work well for rabbit lateral saphenous venipuncture.

A variety of glucometers are on the market that use one drop of whole blood to determine blood glucose levels. The Accu-Chek Advantage from Roche Diagnostics is one such glucometer that provides a convenient means of assessing patients for hypo- or hyperglycemia and for monitoring insulinoma therapy in ferrets.

Medical therapy

When hospitalizing an exotic mammal for medical or surgical therapy the availability of supplies and equipment appropriate for the species being treated will simplify and improve patient treatment. Venous access is important for fluid therapy and administration of certain medications. 24 gauge x .75in (0.56 x 19 mm) or 26-gauge x .75in (0.46 x 19 mm IV catheters can be placed in the cephalic vein of ferrets, rabbits, prairie dogs and guinea pigs with little difficulty. Rabbit and guinea pig cephalic catheters can be taped in place using 2.5cm 3M Micropore surgical tape. Due to its hypoallergic properties this tape is less irritating to the fine skin of these pets. An IV fluid pump is essential when administering intravenous fluids to these small patients. The model 2.2 Heska Vet IV fluid pump is one such infusion pump that ensures accurate administration of small volumes of fluid (2-10cc) per hour. If unsuccessful at passing an IV catheter or if the peripheral veins have collapsed as a result of patient condition (severe dehydration, shock), then consider placing an intraosseus cannula or needle as an alternative to central venous access. A 22 gauge (0.72mm X 3.81 cm) or 25 gauge (0.5mm x 25mm) spinal needle can be readily placed in the femur of ferrets and guinea pigs (introduced through the trochanteric fossa) or the humerus of rabbits (introduced through the greater tubercle). Most drugs administered intravenously can be given via this route and circulation is maintained even in circulatory failure. The intraosseus needles can be anchored by applying a butterfly tape wing attached to the needle hub and suturing to the skin with 4-0 suture material. With any IV setup a 30 inch extension set can be used with a 78 inch Primary IV Set to allow for more patient mobility while hospitalized.

For very sick patients an ICU cage can be set up for close monitoring in the hospital treatment area. The Petiatric Digital Nursing Hospital 3A and the Snyder Avian Treatment Cage are two units that provide for temperature and humidity control and allow for optional oxygen and nebulization therapy. Both units are small and mobile enough to conveniently fit into a treatment room setting.

For more routine hospitalization a ward area modified to meet the special needs of exotic mammals should be set up. Keep in mind that rabbits, guinea pigs and chinchillas may be stressed by being housed with dogs, cats and ferrets. Ward design should allow for the visual, olfactory and auditory separation of these species in order to decrease stress level. Plexiglass cage doors covered with towels can help insulate prey species from carnivorous patients when limitation in space prevents complete separation. Other considerations in cage design include temperature control and being escape proof. Laminate cages with built in conductive warming units and clear acrylic doors are available from Snyder Manufacturing. Heat supplementation is important in debilitated hypothermic patients and those recovering from anesthesia. Keep in mind that rabbits and ferrets are both cold adapted species and may not need heat supplementation unless directed by a disease process. Regardless, cage floors should be covered with easily disinfected bedding (towels work well to aid in hypothermia prevention and to provide a place to hide under). Hide boxes can also be provided to offer some seclusion.

For cages with solid acrylic doors appropriate sized holes can be drilled into a top corner to allow for IV line or electrical cord access. These holes can be made small enough to prevent escape of most exotic mammals. Smaller rodents may need to be placed into container cages within an exotic or dog/cat cage to prevent escape. Some veterinarians may choose to adapt existing dog and cat cages for use with exotics by covering the cage front with a sturdy piece of plexiglass. Cages with narrow spacing between the grates are ideal For exotic mammals that are hypothermic secondary to illness the Bair Hugger forced air warming system uses warmed forced air heat blankets to quickly warm the patient. For severely depressed, hypothermic emergency patients the author uses the Bair Hugger to warm the patient along with subcutaneous fluids and oral 50% dextrose as an initial treatment stabilization protocol while discussing diagnostic options with the owner.

An ultrasonic nebulizer such as the Mabis Mist II, is another equipment purchase that is a worthwhile investment to aid in the therapy of chronic respiratory disease in rabbits and rodents. Most rabbits tolerate the nebulizer face mask for 10 to 15 minute nebulization sessions of saline, antibiotics and mucolytics to ease respiratory infection and congestion. Rats with dyspnea secondary to rodent respiratory disease complex can be placed in an anesthetic induction chamber for minimal-stress nebulization therapy several times a day.

For ferrets with urethral blockage secondary to urethral calculi or prostatomegaly as a result of adrenal disease, the Slippery Sam Silicone Urinary Catheter 3.0 or 3.5 Fr. is the most ideal catheter for urethral flushing and relief of blockage. Flushing the urethral opening with a 20 gauge (0.9mm) needle and saline can help dilate the opening and aid in initial passage of the urinary catheter. The catheter can be sutured in place and protected with a body wrap until surgical or medical correction of the underlying problem. For urethral calculi in male guinea pigs and rabbits, or flushing bladder sludge (severe calcium deposits in the urine) in male rabbits a 3½ Fr 14 cm Tom Cat catheter can be used for urethral catheterization.

Facial dermatitis as a result of chronic epiphora secondary to dacryocystitis and/or elongated incisor tooth roots and blockage of the nasolacrimal system is not uncommon in the rabbit. In the anesthetized patient a 23 ga (0.64mm) lacrimal canula, or small plastic irrigating cannula can be used to cannulate the punctum lacrimale in the medial canthus for gentle flushing with saline. This will help remove purulent debris and possibly relieve any blockage.

Certain drugs and diseases are best administered or treated by Constant Rate Infusion (CRI) therapy. Baxter Healthcare Corporation has available a Mini-Infuser™ pump that allows attachment of various size syringes for infusion of small volumes over 40 minutes.

For nutritional support of anorexic rabbits, guinea pigs, prairie dogs and chinchillas Oxbow Critical Care for Herbivores is an excellent source of fiber and nutrition. For supplemental nutrition of ferrets, Oxbow Carnivore Care provides a high protein, nutritionally complete assist feeding formula for convalescing carnivores. Both products come in a powder form to be re-constituted with water and force fed from a 35 or 60cc oral feeding syringe. For severely debilitated ferrets an esophagostomy tube can be placed for long-term nutritional support using a 10 French Sovereign red rubber feeding tube. A five or six French nasogastric feeding tube available through Global Veterinary Products can be placed in rabbits but the small diameter precludes feeding of fiber and makes long-term nutritional support via a feeding tube difficult in this species.

Imaging

Radiology of the exotic mammals is useful in determining the size, shape and position of organs within the body relative to each other. Radiography of the exotic mammal generally involves patients less than 10cm thick and less than 10 kg body weight and as a general rule positioning is similar to the dog and cat for most procedures. Exposure settings, cassette and film types must take into account the small patient size. A radiographic unit with a capability of high mA settings (minimum 300 mA), and a short exposure time of 0.008 seconds or less is recommended for enhanced detail radiographs. High-detail, rare-earth intensifying screens with compatible film are essential in obtaining diagnostic radiographs in the smaller exotic mammals weighing less than one kilogram. High-detail, fast-speed film cassettes work for larger rabbits and ferrets. Mammography file may be used to enhance soft tissue detail. Dental films may be used to highlight distinct anatomical areas. Digital radiography is replacing conventional radiography due to its computer-generated images that demonstrate superior detail and allow for adjustments in tissue density and contrast at the touch of a keypad. are common in exotic herbivores and dental radiograph units are much easier to manipulate than bulky conventional machines. They allow for multiple views (lateral, dorsoventral and rostro-caudal are most informative) at different angles without needing to repeatedly move the patient. Dental films are non-screen and provide the fine detail required to diagnose dental pathology. Reasonably priced digital dental radiography units are now available and include a new hand held unit from iM3, Inc.

Ultrasonography differentiates between fluid and soft tissues while imaging a small area of the body. Ultrasonography is a dynamic modality and using the Doppler unit is especially useful in assessing cardiac contractility and blood flow. Ultrasound waves are blocked by gas and this fact along with the large size of the herbivore cecum makes abdominal ultrasonography difficult in rabbits, guinea pigs and chinchillas. It is vital that the ultrasonographer be familiar with both the practice of ultrasonography as well as the normal anatomy of the species under examination. For the most common exotic mammals a high-frequency transducer with a footprint of less than 2 cm is required. Due to the large body size differential of exotic mammals a full complement of linear, sector and curvilinear probes from 3.5-20 MHz are required. The GE LOGIQ Book XP (GE Healthcare, United Kingdom) is a portable ultrasonography unit that is fairly economical and produces great images.

Dental equipment

There are a number of distributors that carry dental instruments designed for use in the rabbit and rodent. These include, iM3 Inc. (www.im3vet.com) Dr Shipp's Laboratories (www.drshipp.com), Jorgensen Laboratories (www.jorvet.com), Sontec Surgical Instruments (www.sontecinstruments.com), Universal Surgical Instruments (www.universalsurgical.com) and Veterinary Instrumentation (www.veterinary-instrumentation.co.uk). The author describes dental instruments and equipment used in his veterinary practice and most of which can be purchased from any of the above distributors.

Conventional small animal dental equipment including an ultrasonic dental scaler and 2.0-5mm dental elevators can be used for ferret prophylactic cleanings and extractions. The USI Nazzy Ferret Mouth Gag has been designed to aid in oral visualization of the anesthetized ferret. For the oral visualization and dental care of rabbits and herbivorous rodents such as chinchillas and guinea pigs, a variety of specialized equipment has been designed. Examination of the oral cavity is difficult in these species due to the limited opening of the mouth, the buccal skin folds, the long narrow oral cavity and caudally positioned cheek teeth, and the long incisors and fleshy tongue. All of these anatomical features may obstruct visualization making thorough examination of the oral cavity nearly impossible in the awake patient. When history, external observation and palpation suggest a dental problem, general anesthesia for a more thorough oral exam is indicated. It should be kept in mind that not all patients show obvious signs of oral problems and that general loss of condition, decreased appetite, digestive disturbances and ocular discharge may all be signs associated with dental disease in these species. Dental radiographs are also much easier to take on the anesthetized patient. As these species are obligate nasal breathers the oral examination can take place while maintaining general gas anesthesia with a modified face mask placed over the nostrils or with the use of an aerosol tube inserted 2 cm into one of the nostrils and held in place manually. A number of instruments have been designed to aid in performing a comprehensive oral exam in the anesthetized patient. An oral dental speculum is inserted between the incisors and opens the mouth from top to bottom. Cheek dilators have spatulated wings that are inserted in the mouth and open it from side to side with a spring action. These tools used in combination with a cotton-tipped applicator or stainless steel spatula to move oral soft tissues allow for visual assessment of the premolars and molars. As well, the stainless steel spatula is used to protect the oral mucosa while filing or burring teeth can be used to move the tongue and buccal mucosa for better observation. Many veterinarians prefer to use a specially designed dental platform, the rodent table retractor restrainer, that allows for elevation of the head and opening of the incisors, which aids in visualization of the oral cavity while allowing the doctor to work in a more ergonomically friendly position.

The oral exam can also be enhanced with the use of an otoendoscope that intensifies illumination and magnification of the cheek teeth. A plastic otoscope cone can be modified to cover and protect the otoendoscope from inadvertent damage in the light patient that begins to chew.

The same physical factors that make oral observation difficult contribute to need for specialized equipment to safely and efficiently bur dental points, reduce elongated crowns and extract molars and premolars. A high speed dental drill (iM3 Pty Ltd, Lane Cove, NSW Australia) is the preferred method of trimming or filing of overgrown incisors, in order to properly shape and contour teeth with minimal damage to the reserve crown located below the gum line. Alternatively a low speed dental drill with an LED light source (iM3 Pty Ltd, Lane Cove, NSW Australia) that significantly aids in visualization, is preferred for gently burring overgrown molars or severe molar points without over heating or damaging the reserve crown. For minor dental points a diamond coated rasp is an effective tool in manually smoothing these sharp edges.

Extraction of the incisor teeth is an accepted method of treating persistent malocclusion problems in rabbits and rodents. Curved rabbit incisor luxators have been especially designed for insertion into the periodontal space of the strongly curved incisor teeth where they cut the periodontal ligament and aid in the medial and lateral movements necessary to loosen and extract the incisor teeth. Dental elevators, 1.5 – 5mm straight dental luxators and 2-5mm and rodent molar extractors have all been similarly designed to aid in the extraction of molars and premolars with the least amount of patient trauma.

Anesthesia and anesthetic monitoring

Small animal anesthetic machines utilizing isoflurane or sevoflurane vaporizers are suitable for use in exotic companion mammals. Anesthetic induction using a facemask can be easily accomplished in most exotic mammals. Alternatively, an induction chamber can be used in fractious or hyper-excitable patients. Most ferrets can be readily intubated using a 2.0 – 3.5 mm uncuffed endotracheal tube. Some veterinarians prefer to use a laryngoscope with a #0 Miller Laryngoscope Blade to aid visualization while intubating ferrets but the author has found them cumbersome in spite of their small size (53mm) and prefers to use a cotton tipped applicator to hold the tongue out of the way while intubating. Even with a laryngoscope the rabbit tracheal opening is difficult to visualize due to the limiting oropharyngeal anatomy. The thick tongue, small mouth opening, and laryngeal spasm all add to the difficulty of intubation and some practitioners prefer using a rigid endoscope as a visual aid in placing the endotracheal tube. Alternatively, many rabbits can be intubated using a 2.0-3.0 mm uncuffed Cole endotracheal tube and a "blind" approach. Swabbing the epiglottis with lidocaine gel (Xylocaine 2% jelly) helps reduce laryngospasm and aids intubation. Small animal facemasks are available in varying sizes and are used routinely in guinea pigs and rodents to maintain anesthesia due to the extreme degree of difficulty in intubating and in rabbits where intubation attempts fail. A 12 cc syringe case with the end cut open for an anesthetic attachment makes a good small rodent facemask. A non-rebreathing system such as the Ayres T piece is used for delivery of anesthetic gases. The human pediatric versions are inexpensive and can be re-used numerous times.

A good veterinary technician is essential in managing the perioperative support and anesthetic depth of these small patients as physiologic status can change rapidly. Anesthetic depth depends on drug dosage, anesthetics/pre-anesthetics used, species, physiologic status and presence or absence of disease. Tools to aid the veterinary technician in monitoring the patient's response to anesthesia include electrocardiography, Doppler flow detection, blood pressure measurement, capnography and pulse oximetry. ECG standard lead positions described for dogs and cats are used for small exotic mammals. In general the ECG tracings of small exotic mammals resemble those of dogs and cats in general form. Doppler ultrasonic flow-detection monitors (Parks Medical Electronics) are used for measuring indirect blood pressure as well as for audible monitoring of blood flow, use a probe placed as close as possible to the blood flow in an artery or the heart. The Doppler is used wherever major arteries are close to the skin and in small exotic mammals have been used at the ventral aspect of the tail base, the carotid or femoral arteries, the radial artery (in ferrets and rabbits), the auricular artery (in rabbits) or directly over the heart. The author uses a Cardell 9405 multi-parameter monitor (Sharn Veterinary Inc.) that allows for measurement of patient indirect blood pressure, ECG, heart and respiratory rates, oxygen saturation (SpO2) and end tidal CO2 (EtCO2). Potential sites for placement of transmission pulse oximeter sensors include the ear, tongue, paw and tail.

Exotic mammal surgery

For equipment needs associated with exotic mammal surgery see notes on perioperative care.

Summary

Many tools used in the small animal practice can be adapted for use with exotic mammals. For those veterinarians with a strong interest in exotic mammals specific equipment and supply needs need to be taken under consideration. The initial investment need not be great and as the practice develops more specialized equipment can be added. Starting with equipment that aids in patient husbandry, diagnostic sampling and routine hospital medical and surgical care is very helpful in creating confidence and expertise with these species. As the practice caseload grows more sophisticated equipment can be added allowing for better diagnostic workups, medical treatment and surgical care. The right equipment for the right job makes for a more rewarding and efficient exotic mammal practice.

The author describes equipment and products he routinely uses in his private practice and has provided a list of available sources. Readers should keep in mind that this list is not all-inclusive and that in many instances products discussed can be found from multiple veterinary distributors or vendors. The author does not promote or recommend one supplier or manufacturer over another.

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