Epsilon Archive for Student Projects

Abstract

Handling of animals during anaesthesia is an important field in the profession as a veterinary nurse and in which intubation is an essential part. Hence, adequate knowledge is necessary for the welfare of the animal.

The objective of this literature study was to make it useful and trustworthy for veterinary nurses. It is intended to describe and summarize existing scientificity with its benefits and disadvantages within the different areas of intubation techniques and alternative methods of inhalation anaesthetic supplementation for general anaesthesia in rabbits.

Endotracheal intubation in rabbits can be complicated and technically demanding due to the anatomy of the oropharynx including the narrowness of this structure, a relatively large tongue, large incisors and a limited mobility of the temperomandibular joint. The obstructed visualization of larynx and the rabbit’s tendency to develop laryngospasm contributes to the difficulty of intubation.
Rabbits are susceptible to tracheal injury and multiple intubation attempts can cause tracheal lesions due to repeated damage to the tracheal mucous membrane, although damage can occur after a single intubation attempt as well.

An ETT (endotracheal tube) with or without a cuff can be used during orotracheal intubation in rabbits. Different sizes of ETT have been used to intubate rabbits and appropriate size can be selected based on the animals’ weight and then adjusted depending on ease of placement.
Orotracheal intubation may be performed with the use of an endoscope or laryngoscope for visualization of structures during intubation and they can be used without causing any severe complications such as laryngospasm or orotracheal trauma.

Nasotracheal intubation implies passage of an ETT through the nares, ventral nasal meatus, choana and nasofarynx before entering the trachea and has the advantage, compared to orotracheal intubation, of not claiming any space in the oral cavity. It may be performed without causing any clinical signs of respiratory disease, which suggests that the concern of pathogens introduced from the nasal cavity into the lungs not necessarily is justifiable.
A facemask can be used as an alternative to endotracheal intubation for induction and/or maintenance of anaesthesia but may lead to dyspnea or apnea during the induction.
Another alternative is the laryngeal mask, which can be described as a compound of a mask and an ETT that covers larynx without entering larynx or trachea.
Use of an anaesthetic chamber for supplementation of inhalation anaesthetics during induction is another option but it requires a larger volume of anaesthetic gas compared to a face mask and can lead to apnea.

Due to the low number of studies in these areas, more research about mainly nasotracheal intubation and the use of a laryngeal mask is required before any conclusions about these methods suitability are made. The laryngeal mask, for example, states to be easy to place, but the opinions differ whether they cause leakage of anaesthetic gas or not. Further research in this area could possibly clear this vagueness.