An observational clinical study in cats and rabbits of an anatomically designed supraglottic airway device for use in companion animal veterinary anaesthesia

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.

Evaluation of supraglottic airway device use during inhalation anesthesia in healthy African pygmy hedgehogs (Atelerix albiventris)

OBJECTIVE

To evaluate a supraglottic airway device (SGAD) designed for rabbits in African pygmy hedgehogs (Atelerix albiventris) during inhalation anesthesia.

STUDY DESIGN

Prospective, randomized, blinded experimental study.

ANIMALS

A total of 12 adult African pygmy hedgehogs (seven male, five female).

METHODS

Hedgehogs were placed in a chamber and anesthesia was induced using isoflurane in oxygen. Oropharyngeal endoscopy was performed and video recorded. The SGAD (v-gel R1) was inserted and connected to a Mapleson D circuit. Capnography, pulse oximetry and physiologic variables were measured during anesthesia, and lung inflation was tested at 10 and 20 cmH₂O. With the SGAD temporarily disconnected, anesthetized hedgehogs were randomly positioned into right and left lateral, dorsal and sternal recumbency to evaluate the effect of a change in body position on SGAD placement. Oropharyngeal endoscopy was repeated at the end of anesthesia, and recovery time was recorded. Pre- and post-SGAD placement endoscopy videos were retrospectively reviewed and scored for gross trauma.

RESULTS

The median [interquartile range (IQR)] time to successful SGAD placement was 38 (16-68) seconds. The time to SGAD placement decreased as the study progressed. SGAD required repositioning in six hedgehogs, median 2.5 (IQR, 1-3.5) adjustments each, to successfully perform lung inflation or maintain capnography readings. Lung inflation at 10 cmH₂O was successfully performed without leakage in nine animals, and in the other three animals after adjusting the SGAD at 1-2 time points. Inflation at 20 cmH₂O was rarely achieved without an air leak. Changes in heart and respiratory rates during anesthesia were not clinically relevant. Median endoscopic scores were 0 (no lesions) for both pre-and postplacement.

CONCLUSIONS AND CLINICAL RELEVANCE

The SGAD was relatively quickly and easily placed, permitted lung inflation and caused no significant oropharyngeal damage. The SGAD is a practical option for airway management in African pygmy hedgehogs.

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.

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.

The Association of Shelter Veterinarians' 2016 Veterinary Medical Care Guidelines for Spay-Neuter Programs

As community efforts to reduce the overpopulation and euthanasia of unwanted and unowned cats and dogs have increased, many veterinarians have increasingly focused their clinical efforts on the provision of spay-neuter services. Because of the wide range of geographic and demographic needs, a wide variety of spay-neuter programs have been developed to increase delivery of services to targeted populations of animals, including stationary and mobile clinics, MASH-style operations, shelter services, community cat programs, and services provided through private practitioners. In an effort to promote consistent, high-quality care across the broad range of these programs, the Association of Shelter Veterinarians convened a task force of veterinarians to develop veterinary medical care guidelines for spay-neuter programs. These guidelines consist of recommendations for general patient care and clinical procedures, preoperative care, anesthetic management, surgical procedures, postoperative care, and operations management. They were based on current principles of anesthesiology, critical care medicine, infection control, and surgical practice, as determined from published evidence and expert opinion. They represent acceptable practices that are attainable in spay-neuter programs regardless of location, facility, or type of program. The Association of Shelter Veterinarians envisions that these guidelines will be used by the profession to maintain consistent veterinary medical care in all settings where spay-neuter services are provided and to promote these services as a means of reducing sheltering and euthanasia of cats and dogs.