Endoscopic intubation of exotic companion mammals

Cadaveric Study on Comparison of Neck Extension Angles for Endotracheal Intubation in Rabbits Using a Rigid and Flexible Endoscope

Endotracheal intubation in rabbits is always challenging due to the unique anatomical conformation. To improve endotracheal intubation success, this study determined the relationship between head placement angles guided by endoscope-assisted visualization techniques and the endotracheal intubation success rate. Thirty-two rabbit cadavers were used in the study. Six veterinary practitioners who had no experience with rabbit endotracheal intubation were randomly assigned to intubate rabbit cadavers using the guidance of either a rigid endoscope (RE) or flexible endoscope (FE), with the head placement angles with an ascending neck at 90, 100, 110, 120 and 130 degrees. The endotracheal intubation completed in 90 s was determined to be a success. The success rates using RE and FE were 97.2% and 95.9%, respectively. The means and standard error of means (SEM) of endotracheal intubation times guided by RE and FE were 53.7 ± 4.68 and 55.2 ± 4.24 s, respectively. Results from survival time analysis show that the five veterinarians successfully intubated the rabbit within 90 s, regardless of the different types of endoscopes. Angle was the only significant factor that affected the endotracheal intubation success. The head placement angle at 110 and 120 degrees had the highest success rate of endotracheal intubation compared to 90 degrees (p ≤ 0.05). In conclusion, for inexperienced veterinarians, the success of endotracheal intubation in rabbits, guided by endoscope-assisted visualized techniques regardless of rigid endoscope or flexible endoscope guidance, is improved when the head extension is 110 and 120 degrees.

Retrospective comparison of the effects of laryngeal mask and endotracheal tube on some cardio-respiratory variables in pet rabbits undergoing anaesthesia for elective gonadectomy

BACKGROUND

Endotracheal intubation in rabbits is challenging and supraglottic airway devices, such as laryngeal masks (LMA), represent an alternative as they are easy to insert, and do not stimulate the larynx requiring therefore a lighter plane of anaesthesia for their insertion and positioning than the endotracheal tubes. We investigated whether, compared to an endotracheal tube, the LMA can reduce the negative effects of general anaesthetics on some cardiovascular and respiratory parameters routinely monitored in rabbits anaesthetized for elective gonadectomy. The records of 21 adult mixed breed pet rabbits were collected retrospectively. Rabbits were divided in two groups based on the type of airway device used. A laryngeal mask secured the airway in group LMA (n = 11), and in group ETT (n = 10) an endotracheal tube was used. The amount of propofol used before successful insertion of the airway device was recorded. A pitot-based spirometer was connected and ventilatory variables were measured immediately after insertion. Pulse rate, non-invasive arterial blood pressure, haemoglobin oxygen saturation, respiratory rate, end-tidal carbon dioxide and volatile anaesthetic consumption were also monitored during the surgical procedure; extubation time was noted as well.

RESULTS

The use of LMA required significantly less propofol (0.8 to 4 mg/kg) for insertion than the ETT (1.2 to 5.6 mg/kg), and the difference was statistically significant (P < 0.01). No differences were observed in ventilatory variables measured immediately after airway positioning. Intraoperatively, there were no differences between groups for respiratory and cardiovascular variables, and amount of isoflurane administered. In all rabbits mean and diastolic blood pressure progressively decreased during surgery. Mean extubation time was shorter in group LMA (6 ± 2 min) than group ETT (8 ± 3 min, P < 0.01).

CONCLUSION

The airway device did not clinically affect the cardiovascular and respiratory variables during anaesthesia. Intraoperative hypoventilation was observed in most rabbits regardless of the device being used; therefore ventilatory support may be required. Rabbits with the laryngeal masks were extubated earlier.

AN ENDOSCOPY-GUIDED TECHNIQUE FOR THE COLLECTION OF MICROBIOLOGY SAMPLES FROM THE TRACHEA OF COMMON WOMBATS (VOMBATUS URSINUS)

Respiratory infections are common in young wombats and determining the causative agent is critical to establish an appropriate treatment. A group of 12 young, wild common wombats (Vombatus ursinus) ranging from 6 to 10 kg developed a range of respiratory signs after being in care following the severe bushfires in Australia in early 2020. The oral anatomy of wombats makes collection of tracheal samples difficult. An endoscopy-guided technique was established to collect microbiology samples aseptically from the anesthetized patients. A guarded, sterile swab was introduced in the mouth and inserted into the trachea of two wombats, visualizing the procedure with the endoscope. A similar technique is described for endotracheal intubation of small mammals. This approach allowed for a safe and aseptic sampling collection. A pure growth of Escherichia coli was cultured from the samples, and appropriate antibiotic treatment was established according to the antimicrobial sensitivity test.

The Spritztube: A New Device for the Extraglottic Intubation of Rabbits

The Spritztube (ST) is an extraglottic airway device developed for humans. The aim of the study was to design an ST for rabbits and to evaluate its feasibility. The study was divided into two phases. Phase I: anatomical study on 12 rabbit cadavers to design 2 STs (8 and 10 Ch, external diameter) for rabbits. Phase II: fourteen privately owned rabbits were anaesthetised, and intubation was attempted using a ST. Tube size, the method for confirming the correct positioning, the number of attempts, the time needed for the correct positioning of the ST and complications were recorded. The ST placement was feasible in all rabbits. The positioning of the ST was completed in 2.1 ± 1 attempts in 43 ± 21.4 s. A correct placement was confirmed by the visualisation of the proximal cuff at visual inspection of the oral cavity (14/14), by the detection of the airflow (9/14 rabbits) and by the visualisation of a capnographic wave (14/14 rabbits). Only one rabbit developed respiratory distress after the ST placement. The results of the present study allowed designing a ST specific for rabbits which was used a supraglottic airway device for the maintenance of isoflurane anaesthesia in spontaneously breathing rabbits.

Rabbit Sedation and Anesthesia

With the increasing frequency of rabbits as veterinary patients, the expectation for high-quality, intensive veterinary care, and resultantly an understanding of anesthesia has been increasing. Sedation and general anesthesia are commonly required for many routine and emergency procedures in rabbits, and this results in the need for a strong awareness of anesthetic principles, knowledge of limitations of anesthesia, and maintenance of high standards of anesthesia.

African Pygmy Hedgehog (Atelerix albiventris) and Sugar Glider (Petaurus breviceps) Sedation and Anesthesia

African pygmy hedgehogs and sugar gliders are common zoologic companion animals frequently presented to veterinarians for routine preventive care and illness. Given their small size, intravascular access, intubation, and monitoring can be challenging, and hypothermia is a common problem during chemical immobilization. Studied injectable sedation options are limited, but can provide an alternative to general anesthesia for minor procedures. Anesthetic induction and maintenance are most commonly performed with inhalant anesthetics, such as isoflurane or sevoflurane. Preparation of all necessary equipment and emergency drugs before chemical immobilization increases the chance of a successful procedure.

Sedation and Anesthesia in Rodents

Sedation and anesthesia in rodent species are complex due to their wide species variation, small size, and metabolism. This review article covers recent advances in sedation and anesthesia as well as an updated drug formulary for sedation protocols. Setup, equipment, monitoring, maintenance, and recovery are reviewed as well as species-specific anatomy.

Respiratory Diseases in Guinea Pigs, Chinchillas and Degus

The diagnosis and treatment of respiratory disease in pet guinea pigs, chinchillas, and degus still face profoundly serious challenges owing to their relatively small size, conspicuous clinical signs, difficulty for sampling, and insufficient scientific evidence to correlate signs and particular pathologies. This article is intended to summarize the available information on the relevant anatomy, physiology, and respiratory pathology in these species.

Comparison of blind intubation and a smartphone-based endoscope-assisted intubation in rabbits

OBJECTIVE

To compare between blind and smartphone-based endoscope-assisted techniques for endotracheal intubation in rabbits.

STUDY DESIGN

Prospective clinical study.

ANIMALS

A total of 34 rabbits.

METHODS

Rabbits were assigned to four groups: intubation by a veterinary anesthesiologist (VA) or an exotic pet medicine specialist (EPS) using blind or endoscope-assisted techniques. Propofol dose, number of attempts until successful intubation, total time for intubation, duration of the successful attempt and occurrence of lingual cyanosis/laryngeal lesions were recorded. Data were analyzed by t test, Wilcoxon-Mann-Whitney U test or chi-square test. Pearson correlation for body weight was performed.

RESULTS

The success rate of blind intubation was 88.9% and 77.8% for VA and EPS, respectively. Propofol dose, total and median number of attempts, total time for intubation and duration of the successful attempt were 3.1 (0-6.2) mg kg^-1, 19, 2 (1-5), 79 ± 65 and 30 ± 20 seconds for VA and 1.5 (0-4.5) mg kg^-1, 24, 3 (1-5), 136 ± 92 and 38 ± 16 seconds for EPS. The success rate of endoscope-assisted intubation was 87.5% for both operators. Propofol dose, total and median number of attempts, total time for intubation and duration of the successful attempt were 2.5 (1.3-7.4) mg kg^-1, 22, 3 (1-5), 170 (65-368) and 46 (22-150) seconds for VA and 3.2 (0-6) mg kg^-1, 11, 1 (1-4), 56 (27-432) and 55 (26-79) seconds for EPS. VA performed blind intubation more quickly, propofol dose was lower and cyanosis was less frequent than in the endoscope-assisted group.

CONCLUSIONS AND CLINICAL RELEVANCE

Both techniques were reliable for rabbit endotracheal intubation. Best results were achieved when the operator was experienced in the technique. The smartphone-based endoscope is a useful aid for rabbit intubation.

Flexible fibreoptic intubation in swine - improvement for resident training and animal safety alike

Background

Efficient airway management to facilitate tracheal intubation encompasses essential skills in anaesthesiologic and intensive care. The application of flexible fibreoptic intubation in patients with difficult airways has been identified as the recommended method in various international guidelines. However, providing the opportunity to adequately train residents can be challenging. Using large animals for practice during ongoing studies could help to improve this situation, but there is no recent data on fibreoptic intubation in swine available.

Methods

Thirty male German landrace pigs were anesthetized, instrumented and randomized into two groups. The animals were either intubated conventionally using direct laryngoscopy or a single-use flexible video-endoscope. The intervention was carried out by providers with 3 months experience in conventional intubation of pigs and a brief introduction into endoscopy. Intubation attempts were supervised and aborted, when SpO2 dropped below 93%. After three failed attempts, an experienced supervisor intervened and performed the intubation. Intubation times and attempts were recorded and analysed.

Results

Flexible fibreoptic intubation showed a significantly higher success rate in first attempt endotracheal tube placement (75% vs. 47%) with less attempts overall (1.3 ± 0.6 vs. 2.1 ± 1.3, P = 0.043). Conventional intubation was faster (42 s ± 6 s vs. 67 s ± 10s, P < 0.001), but showed a higher complication rate and more desaturation episodes during the trial.

Conclusions

Flexible fibreoptic intubation in swine is feasible and appears to be a safer and more accessible method for inexperienced users to learn. This could not only improve resident training options in hospitals with animal research facilities but might also prevent airway complications and needless animal suffering.

Comparison of endoscopic endotracheal intubation and the v-gel supraglottic airway device for spontaneously ventilating New Zealand white rabbits undergoing ovariohysterectomy

BACKGROUND

Due to the technical difficulties with endotracheal intubation of rabbits, a prospective, randomised, controlled study was performed to compare a rabbit-specific supraglottic airway device (SGAD), the v-gel, with endoscopic endotracheal intubation (EEI) in spontaneously breathing rabbits undergoing ovariohysterectomy.

METHODS

Fourteen adult female New Zealand white rabbits were randomly allocated to one of two groups based on the method of airway establishment: EEI or v-gel SGAD. Anaesthesia was induced with ketamine and xylazine and maintained using isoflurane in 100 per cent oxygen. Comparisons were made between groups based on placement time of endotracheal tube/SGAD, number of attempts and adjustments, the necessity to increase isoflurane concentrations to maintain a surgical plane of anaesthesia, arterial blood gas values, gross laryngeal evaluation, and laryngotracheal histopathology.

RESULTS

Both techniques resulted in elevated arterial pCO₂ levels, but the v-gel was associated with more elevated pCO₂ in comparison with EEI (P=0.045). Airway trauma was histologically present but clinically negligible in both groups, with no statistically significant differences observed between techniques (P>0.05). Placement time of the v-gel was significantly faster (P=0.003) and required less technical skill than EEI, but was more easily displaced when changing the animal's position (P=0.004).

CONCLUSION

The v-gel is a practical alternative to EEI for securing the airway of healthy spontaneously ventilating rabbits, provided a capnograph is utilised to ensure continuous placement. Both airway techniques appear safe and effective with few complications, as long as intermittent positive pressure ventilation can be employed to correct hypercapnia.

Geriatric Hedgehogs

African hedgehogs are susceptible to aging changes like those of other small exotic mammals. Common conditions of the geriatric hedgehog include heart disease, chronic renal disease, and dental/periodontal disease. Hedgehogs are unique in that they have an unusually short life span and a propensity for neoplasia. These 2 factors make it especially common for exotic animal practitioners to encounter geriatric hedgehogs affected by one of the many conditions outlined in this article.

Technological Advances in Exotic Pet Anesthesia and Analgesia

Even when performed by skilled operators, locating the nerves can be challenging in small exotic pets; in such cases, the use of an electrical nerve stimulator may be useful to confirm the correct identification of the target nerve. Exotic animal anesthesia and analgesia have dramatically progressed over the past decade and continue to do so as more research and technologies develop. Technological advancements such as airway devices, endoscopic intubation techniques, positive intermittent pressure ventilators, and invasive and noninvasive blood pressure monitors have played a significant role in improving patient safety and the anesthetic outcomes of exotic animals.

Capnography-guided Endotracheal Intubation as an Alternative to Existing Intubation Methods in Rabbits

Rabbits provide a unique challenge for routine endotracheal intubation in clinical practice because of various distinctive anatomic and physiologic features. Many previously proposed methods for endotracheal intubation in rabbits are limited by several factors, including the needs for expensive equipment and high levels of technical expertise. We evaluated capnography for its effectiveness in assisting endotracheal intubation in rabbits. New Zealand white rabbits were divided into 3 groups of 5 animals. In the first 2 groups, mainstream (nondiverting) or sidestream (diverting) capnography (MC and SC groups, re- spectively) was used; in the third group (LS group), a laryngoscope with a size 00 Miller blade was used to guide endotracheal tube placement. Anesthesia was induced through intramuscular administration of ketamine (10 mg/kg), medetomidine (0.1 mg/kg), and midazolam (1 mg/kg) mixed in the same syringe prior to administration. Intubation time was defined from the point of opening the jaws to the completion of the first capnogram after intubation. Intubation was accomplished successfully in all animals in both capnography groups, but 2 rabbits in the laryngoscopy group could not be intubated. Intubation time was compared among groups was compared by using one-way ANOVA, and posthoc Bonferroni testing was applied to isolate significant differences between groups. The intubation time (mean ± 1 SD) was 46.4 ± 12.6 s in the MC group, 147.2 ± 44.2 s in the SC group, and 385.0 ± 114.1 in the LS group, with intubation time significantly differing among all groups. In conclusion, both mainstream and sidestream capnography-guided endotracheal intubation techniques were more effective and efficient than conventional laryngoscope-guided endotracheal intubation in rabbits. Furthermore, mainstream capnography was preferred over sidestream capnography because mainstream capnography resulted in significantly shorter intubation times.

Endotracheal Intubation of Rabbits Using a Polypropylene Guide Catheter

Endotracheal intubation in rabbits can be challenging due to their unusual anatomy. Achieving a patent airway during anesthesia is critical for the avoidance of airway obstruction, prevention of gastric tympany, and to allow ventilatory support. Due to the difficulty of intubation, alternative methods such as the use of laryngeal mask airways or laryngeal tubes have been explored. However, these methods do not result in direct access to the trachea and thus may present a risk for development of complications. In addition, lack of direct intubation of the trachea can result in personnel exposure to waste anesthetic gases. Numerous methods for endotracheal intubation have been described, including blind placement, use of a fiberoptic laryngoscope or endoscope, and cricoid placement. Despite these numerous publications, many still struggle to achieve success. Here we provide a detailed description of an intubation technique that can be taught with minimal training with a short time to proficiency. Briefly, after administration of injectable anesthesia and proper positioning of the rabbit, a polypropylene catheter is placed into the trachea by direct visualization using a laryngoscope. The catheter is then used as a guide to direct the endotracheal tube into the trachea. This method allows for intubation without the need for expensive equipment and can be performed by a single individual without the need for an assistant. In conclusion, this technique can be easily taught and performed at very little cost in any clinical or research setting.

Comparison of a Supraglottic Airway Device (v-gel®) with Blind Orotracheal Intubation in Rabbits

INTRODUCTION

Achieving a secure airway in rabbits is generally considered more difficult than in cats or dogs. Their relatively large tongue, small oropharyngeal cavity and glottis limit direct visualization. A rabbit-specific supraglottic airway device (SGAD) may offer benefits over blind orotracheal intubation.

ANIMALS AND METHODS

Fifteen adult New Zealand white rabbits were randomized to SGAD or orotracheal intubation (ETT). All animals were sedated with dexmedetomidine (0.1 mg kg^-1 IM) and midazolam (0.5 mg kg^-1 IM), followed by induction with alfaxalone (0.3 mg kg^-1 IV). Two CT scans of the head and neck were performed, following sedation and SGAD/ETT placement. The following were recorded: time to successful device insertion, smallest cross-sectional airway area, airway sealing pressure, and histological score of tracheal tissue. Data were analyzed with a Mann-Whitney test.

RESULTS

Two rabbits were excluded following failed ETT. Body masses were similar [ETT; n = 6, 2.6 (2.3-4.5) kg, SGAD; n = 7, 2.7 (2.4-5.0) kg]. SGAD placement was significantly faster [33 (14-38) s] than ETT [59 (29-171) s]. Cross-sectional area (CSA) was significantly reduced from baseline [12.2 (6.9-3.4) mm²] but similar between groups [SGAD; 2.7 (2.0-12.3) mm², ETT; 3.8 (2.3-6.6) mm²]. In the SGAD group, the device tip migrated into the laryngeal vestibule in 6/7 rabbits, reducing the CSA. ETT airway seals were higher [15 (10-20) cmH₂O], but not significant [SGAD; 5 (5-20) cmH₂O, p = 0.06]. ETT resulted in significantly more mucosal damage [histological score 3.3 (1.0-5.0)], SGAD; 0.67 (0.33-3.67).

CONCLUSION

The SGAD studied was faster to place and caused less damage than orotracheal intubation, but resulted in a similar CSA.

Common Emergencies in Small Rodents, Hedgehogs, and Sugar Gliders

Small exotic mammal pets such as rats, mice, hamsters, gerbils, degus, hedgehogs, and sugar gliders are becoming more popular. Because these animals are prone to a variety of health problems, and require specialized husbandry care to remain healthy, they may present to emergency hospitals in critical condition. This article provides a basic overview of common emergency presentations of these species.

Animal facility videoendoscopic intubation station: tips and tricks from mice to rabbits

Endotracheal intubation of laboratory animals is a common procedure shared by several research fields for different purposes, such as mechanical ventilation of anaesthetized animals, instillation of cytotoxic nanoparticles, infectious agents or tumour cells for induction of disease models, and even for diagnostic and therapeutic purposes. These different research purposes, achieved in different animal models, require technical expertise and equipment that suits every research need from animal facilities. In this short report we propose a videoendoscopic intubation station that could be shared among the most common laboratory animals, namely the mouse, rat, guinea pig and rabbit, from neonates to adult animals. This report aims to contribute to the reduction of animals excluded from experiments due to false paths during direct and blind intubations and to the refinement of procedures by replacing surgical approaches such as tracheotomy.

Rabbit Soft Tissue Surgery

This article summarizes the available information on different soft tissue surgical procedures in rabbits, based on the literature and the authors' experiences, emphasizing the differences between rabbits and the more familiar dogs and cats. The major surgical principles in rabbits are discussed, and common surgical procedures, such as abdominal exploration, gastrotomy, enterotomy, liver lobectomy, nephrectomy, cystotomy, cystectomy, ovariohysterectomy, ovariectomy, orchidectomy, are described.

Anesthesia in swine : optimizing a laboratory model to optimize translational research

In order to extrapolate novel therapies from the bench to the bedside (translational research), animal experiments are scientifically necessary. Swine are popular laboratory animals as their cardiorespiratory physiology is very similar to humans. Every study has to be approved by the local and/or national animal ethical committees. As swine are extremely sensitive to stress the primary goal is therefore to provide a calm, stress-free environment in both housing and experimental facilities. Swine should be properly sedated for transport and normothermia needs to be ensured. It is recommended to commence anesthesia by injecting ketamine and propofol followed by endotracheal intubation during spontaneous breathing. After intubation, anesthesia maintenance is performed with morphine or piritramide, propofol and rocuronium and routine monitoring is applied analogue to a clinical operating theater for humans. Normothermia (38.5 °C) needs to be ensured. While surgical procedures can be readily extrapolated from a human operating theater to swine, non-anesthesiologist scientists may lose the animal rapidly due to airway management problems. Vascular access can be secured by cut-downs or ultrasound-guided techniques in the inguinal and the neck region. For humane euthanasia of pigs, morphine, followed by propofol, rocuronium and potassium chloride are recommended. As radical animal right groups may threaten scientists, it is prudent that animal laboratories have unmarked entrance doors, are located in buildings that are not accessible to the public and strictly controlled access of laboratory staff is enforced. In conclusion, swine are an excellent laboratory animal for bench to bedside research and can be managed properly when basic knowledge and adequate skills on careful handling, anesthesia and surgical considerations are present.

Desflurane but not sevoflurane augments laryngeal C-fiber inputs to nucleus tractus solitarii neurons by activating transient receptor potential-A1

AIMS

Volatile anesthetics have distinct odors and some are irritating to the upper airway and may cause cough and laryngospasm, which may result, in part, from stimulation of C-fiber reflex. Local exposure of such anesthetics increases the sensitivity of capsaicin-sensitive laryngeal C-fiber endings compatible with airway irritability presumably by activation of transient receptor potential (TRP) ion channels, but the physiological relevance of this sensitization transmitted to the higher-order neurons in the central reflex pathway and output is unknown.

MAIN METHODS

In anesthetized young guinea pigs, baseline and left atrial capsaicin evoked changes in the extracellular unit activity of laryngeal C-fiber-activated neurons in the nucleus tractus solitarii (NTS) and phrenic nerve activity were compared between irritant (desflurane) and non-irritant (sevoflurane) anesthetic gas exposure to the isolated larynx.

KEY FINDINGS

Desflurane significantly augmented the peak and duration (p<0.01) of the NTS neuronal responses and the prolongation of expiratory time (p=0.017). The effect was enhanced by iontophoretic application of the TRPA1 agonist allyl-isothiocyanate (p<0.05), inhibited by TRPA1 antagonist HC-030031 (p<0.01), but not by TRPV1 antagonist BCTC. Sevoflurane did not affect the central pathway.

SIGNIFICANCE

Thus, the sensitization of the laryngeal C-fiber endings by irritant volatile anesthetics is transmitted to the NTS via activation of the TRPA1 and is associated with a prolonged reflexively evoked expiratory apnea. The findings may help to explain local deleterious effects of irritant volatile general anesthetics on the airways during inhaled induction or bronchodilator therapy for status asthmatics.

Technique of blind tracheal intubation in rabbits (Oryctolagus cuniculi) supported by previous maneuver of esophageal cannulization

PURPOSE: To describe and evaluate a modified technique of blind orotraqueal intubation in rabbits, by supporting of previous cannulization of the esophagus. METHODS: Twelve New Zealand rabbits, weighing between 2,780 a 4,140 kg were anesthetized with xilazine (3mg/Kg) and ketamine (20mg/Kg). The animals were positioned in ventral decubitus with the head hyperextend. With one of the hands the anesthetist with the index and thumb fingers positioned in the labial fissures carry on the opening of animal oral cavity. The esophagus was previously cannulized with a tube # 3.5 (3.5mm ID), obstructing its lumen. The trachea lumen was intubated with a probe # 2.5 (2.5mm ID). The positioning of the probe was confirmed through the oscillatory movement of a gauze filament put at outside extremity of tube, resulting from the inspiratory and expiratory flow. RESULTS: The success index was of 100%. CONCLUSIONS: This technique is of easy execution, high success index, sparing the use of several devices for visualization of the larynx and glottis. No complications were observed. It also serves for short period training of human resources.

Hedgehogs and sugar gliders: respiratory anatomy, physiology, and disease

This article discusses the respiratory anatomy, physiology, and disease of African pygmy hedgehogs (Atelerix albiventris) and sugar gliders (Petaurus breviceps), two species commonly seen in exotic animal practice. Where appropriate, information from closely related species is mentioned because cross-susceptibility is likely and because these additional species may also be encountered in practice. Other body systems and processes are discussed insofar as they relate to or affect respiratory function. Although some topics, such as special senses, hibernation, or vocalization, may seem out of place, in each case the information relates back to respiration in some important way.

Diagnostic imaging of the respiratory system in exotic companion mammals

The level of care for smaller companion mammals has increased significantly during the past few years. Today, exotic companion mammals are acknowledged as a specific area of zoologic medicine. Owner demands for a higher level of care is increasing dramatically. Because most of these patients are small (less than 2 kg), this represents a great challenge, in particular for the field of diagnostic imaging. This article reviews the 5 main diagnostic imaging modalities currently available for investigation of the respiratory system of exotic companion mammals: radiography, ultrasonography, endoscopy, computed tomography, and magnetic resonance.