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.
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.
Created by veterinary technician specialist, Katrina Lafferty, this anesthesia monitoring record is available for download as as both a Word document and PDF.
Download this anesthetic record, available as a PDF, and recommended by veterinary technician specialist, Katrina Lafferty.
Download this anesthesia & recovery record, suggested by veterinary technician specialist, Katrina Lafferty. This anesthetic record was created by the Association of Veterinary Anaesthetists and is from a collection of online resources recommended by the Royal College of Veterinary Surgeons Practice Standards Scheme.
Download this anesthesia monitoring sheet, available as a PDF, and recommended by veterinary technician specialist, Katrina Lafferty.
Rabbit intubation can be accomplished using either an orotracheal or nasotracheal technique. Both intubation methods can be challenging in rabbit patients and require patience and practice. Nasotracheal intubation may be the preferred approach in situations where maximum access and maneuverability is required in the oral cavity. Nasotracheal intubation is also preferred where an extended recovery is expected.
Katrina Lafferty received her degree in Veterinary Technology in 2005. She earned her veterinary technician specialty (VTS) in Anesthesia in 2009 and is one of less than 200 technicians worldwide to have that designation. Katrina is a Senior Technician in the Anesthesia and Pain Management Department at the University of Wisconsin-Madison School of Veterinary Medicine. She is also the Director of the Veterinary Technician Student Internship Program at UW-Madison. Katrina is involved in the education of all members of the veterinary community and she has written numerous articles and textbook chapters.