Moderately more challenging techniques include the use of an electrical nerve stimulator ( to identify the location of a nerve ) and ultrasound-guided nerve blocks . Examples of these are transversus abdominis plane ( TAP ), femoral – sciatic or brachial plexus blocks . The use of these blocks in small mammals is discussed by DiGeronimo and da Cunha [ 35 ] . However , the authors could not find any literature on these blocks specifically related to ferrets .
Figure 13 . A different infraorbital block approach . Photo permission from Cathy Johnson-Delaney .
Voltage-gated ion channels are conserved across the vertebrate taxa , so local anaesthetics are likely to be effective even in species in which they have not been studied [ 35 ] . The toxic doses and effects are similar to those described in cats and dogs [ 22 ] . Therefore , it appears that the only barrier to the use of local anaesthesia in exotic animals may be the lack of research into the technical aspects or the application of the more difficult nerve blocks in different exotic species ; however , this is often also a barrier to effective local analgesia in cats and dogs .
Simple techniques – such as local infiltration , splash block or any simple nerve block where the nerve anatomy is straightforward to access and the practitioner feels comfortable doing so – are all easily achievable . Training veterinary nurses to perform local blocks has been suggested [ 24 ] .
Appropriate anaesthesia
Figure 14 . Local infiltration around a tooth to be removed . Photo permission from Cathy Johnson-Delaney .
Figure 15 . Administration of a block into the pulp cavity . Photo permission from Cathy Johnson-Delaney .
Further information is provided by Cooper [ 33 ] , who provides a comprehensive review of ferret dentistry and dental nerve blocks .
Porter-Blackwell et al . [ 34 ] describe an inferior alveolar block for a partial hemimandibulectomy at the level of teeth 408 / 409 in a ferret .
The profession has moved away from ‘ gassing down ’ cats and dogs , and inhalational induction of exotic species may also fall out of favour . Some sources state that the sole use of inhalant agents is no longer acceptable in exotic species [ 36 ] . As with cats and dogs , the use of smaller doses of multimodal injectable sedation or anaesthesia is safer for the exotic patient and veterinary staff [ 36 ] , and some injectable agents have the benefit of being reversible if an anaesthetic complication arises .
Mask or chamber inductions cause central excitation and cardiopulmonary depression during induction , and are associated with longer times to achieve endotracheal intubation and also environmental contamination [ 6 ] . The use of sole-agent anaesthesia requires higher doses to induce unconsciousness . Inhalant agents can cause life-threatening hypotension due to cardiopulmonary and respiratory depression , especially in sick or compromised animals , and the stress of induction can cause increases in circulating catecholamines , which can cause cardiac arrhythmias [ 36 ] . In cats , chamber or mask inductions are described as a ‘ last resort ’ and the ‘ least desirable ’ method for fractious or agitated patients [ 37 ] . In dogs , mask induction has been shown to cause a greater proportion of anaesthetic-related deaths in sick patients [ 38 ] .
If an inhalant agent is to be used as an induction agent , appropriate premedication is advised [ 7 ] to reduce stress and anxiety , address pain , and lower the overall dose of the inhalant .
20 Veterinary Nursing Journal