A dedicated anesthetist should be assigned to monitor every patient during the perianesthetic period. The anesthetist is fundamental to patient safety because she assures the patient is not aware, not moving, and not in pain, all while maintaining stable anesthetic depth. A deep plane of anesthesia can lead to hypoventilation and hypoxemia, reduced cardiac output, hypotension, inadequate tissue perfusion, central nervous system (CNS) depression, and prolonged recovery. This review article first explores the stages of anesthesia and then discusses assessment of anesthetic depth in exotic companion mammals, birds, and reptiles.
Jody Nugent-Deal is a registered veterinary technician and a veterinary technician specialist in anesthesia/analgesia and clinical practice – exotic companion animal. Jody has worked for the University of California at Davis Veterinary Medical Teaching Hospital since 1999, working in the Companion Exotics Department for 10 years and currently the Small Animal Anesthesia Department, where she is the supervisor. Ms. Nugent-Deal is a founding member of the Academy of Veterinary Technicians in Clinical Practice and is the executive secretary for the group as well as the appeals committee chair. Jody is an active member with the Academy of Veterinary Technicians in Anesthesia and Analgesia having served on the nominations, credentials and appeals committees.
Capnometry measures the maximum value of carbon dioxide (CO2) obtained at the end of expiration or end-tidal carbon dioxide (ETCO2). There is good correlation between ETCO2 and arterial CO2 in birds and mammals and capnography can be used as a reliable tool to evaluate the adequacy of ventilation in these species. Capnography can only be used to identify trends in reptiles because of cardiac shunting of blood past the reptilian lungs.
Even the most steadfast and seasoned veterinary anesthetist can find themselves intimidated by exotic animal patients. Standard veterinary anesthesia monitors are not designed to read the extremely high (or extremely low) heart rates and respiratory rates of some exotic animal patients. Despite these challenges, valuable information can be gathered from monitoring tools as well as hands-on techniques. Essential vital signs, such as heart rate and rhythm, respiratory rate and depth, body temperature, and mucous membrane color should all be evaluated.
Arterial blood pressure is a function of heart rate, blood volume, stroke volume, and arterial compliance. Indirect arterial blood pressure is most commonly measured by Doppler ultrasound or non-invasive oscillometric monitors. What are the limitations of indirect blood pressure measurements in exotic animal patients? How is this technique unique in exotic companion mammals when compared to dogs and cats? How is this technique performed in birds and can this procedure be used in reptiles?
Electrocardiography can be used to detect and diagnose arrhythmias and conduction abnormalities, particularly during long-term anesthesia. How are leads attached to exotic animal patients? And what is the normal appearance of normal electrocardiogram tracings in birds or reptiles?
Heart rate and oxygenation should ideally be monitored during every anesthetic event. Patient size can limit the accuracy of pulse oximetry readings in exotic companion mammals and this technique has not been validated in birds or reptiles, however trends during the course of anesthesia can still provide useful clues to patient clinical status.
Quality Exotic Small Mammal Anesthesia was reviewed and approved by the American Association of Veterinary State Boards (AAVSB) Registry of Approved Continuing Education (R.A.C.E.) program for 1 hour of continuing education, in jurisdictions which recognize AAVSB R.A.C.E. approval….
Exotic small mammals can be challenging to safely induce, maintain and recover from general anesthesia. View the recording of this RACE-approved webinar, which explores clinical anesthesia in exotic companion mammals from patient assessment and anesthetic induction to monitoring and recovery. The use of common premedications, induction agents, maintenance drugs, and post-operative analgesics will be compared and contrasted in exotic companion mammals. Multimodal anesthetic techniques, such as epidural anesthesia and constant rate infusions, will also be discussed.
Blood collection is challenging in sugar gliders. Heavy sedation or general anesthesia, using isoflurane or sevoflurane, is almost always required in clinical practice. The most common sites for blood collection in the glider are the jugular vein and the…
Blood collection is challenging in rats and mice, and heavy sedation or general anesthesia is almost always required in clinical practice. Increasing patient body temperature to promote vasodilation can also be helpful. Gently warm the rodent by placing its cage on a heating pad set on low or by placing the cage in an incubator set at 39°C (102°F) for 5 to 10 minutes. Monitor the patient carefully…
Intravenous catheters are commonly placed in rabbits to administer fluids, medications, induce anesthesia, and for delivery of analgesic drugs during the perioperative and postoperative periods. Catheterization techniques used in dogs and cats can also be used for rabbits. To reduce the time in handling and reduce stress, supplies needed for catheterization should be set out and ready to go, prior to removing the patient from the cage.
The rabbit has a relatively short prothrombin time and whole blood quickly clots at room temperature. To minimize the risk of clot formation, it can be helpful to pre-heparinize the needle and syringe by drawing heparin into the needle and expelling the excess from the hub. The total volume of blood that can be safely collected typically ranges from 0.5% to 1.0% body weight. Collect smaller volumes from geriatric patients or those suspected to have anemia or hypoproteinemia.
Use this video clip or article with still images to review equipment needed, and potential venipuncture sites including the jugular vein, lateral saphenous vein, and ear vessels.
Hematological and serum chemistry tests are considered part of the minimum database, yet collecting blood samples from small mammals can be extremely challenging. This review article reviews the recommended venipuncture site in popular exotic companion mammals including many rodents, rabbits, ferrets, hedgehogs, and sugar gliders. Sample collection from peripheral vessels including the cephalic, saphenous, tail, jugular, ear, and submandibular vein is discussed.
Blind venipuncture sites such as the cranial vena cava and femoral vessels are also described. Veterinary health professionals are also acquainted with the potential risks associated with blood collection from these small species, especially those presenting in advanced diseased states. Tips for clinical success are also shared.
Physical examination in exotic small mammals is performed similarly to examinations in dogs and cats, however many small mammals can easily become stressed. Approach these patients calmly, gently, and quietly. Gather all items that may be needed during the physical exam beforehand since it is essential to keep time to a minimum. Ideally schedule examination of nocturnal species such as sugar gliders, rats, and mice during the evening hours. It can also be helpful to dim the lights while examining these species.