Plus-Hex CLINICAL
The toad was placed in an airtight bag inflated with 100 % oxygen with 8 % sevoflurane gas to induce anaesthesia ( Figure 1 ).
The use of bags for ‘ chamber ’ inductions can be helpful , as amphibians often go through an excitation phase during anaesthesia , and the slight ‘ give ’ in plastic bags can help to prevent skin damage [ 24 ] .
Monitoring anaesthesia
As shown in Figure 1a , anaesthetic monitoring began during induction , by placing a Doppler probe under the thoracic girdle to assess the heart rate and rhythm . Respiration was monitored by the gular pumping reflex and abdominal breathing movements , although it should be noted that this can become delayed or absent depending on the anaesthetic depth . Unlike mammals , amphibians can perform cutaneous respiration through their highly complex , vascularised integument . Maintaining moisture and preventing damage to the skin is important , as damage , dryness or injury can impede the effectiveness of cutaneous respiration [ 26 , 28 ] .
Assessment of anaesthetic depth
Anaesthetic depth can be assessed by monitoring the ‘ escape reflex ’, loss of righting reflex , superficial and deep pain responses and palpebral reflexes . Mitchell [ 28 ] emphasises the importance of characterising the patient ' s responses to these stimuli prior to anaesthesia as they may vary between individuals . In this case , the toad showed a delayed palpebral reflex prior to anaesthesia , so this was not relied on to assess depth .
Surgical preparation
Figure 1a . A Doppler probe was placed under the toad ' s thorax , outside the bag , to monitor its heart rate and quality on induction .
Surgery and hospitalisation were performed in the predicted optimum environmental temperature range for the species ( 14 – 18 ° C ), and the temperature was controlled to prevent overheating [ 9 , 11 , 12 ] . An incontinence pad was moistened with purified water and placed under the patient to keep its skin moist , and the wound was flushed with 0.9 % sterile saline and prepared with a dilute iodine solution ( 1:10 ) and gauze swabs . Chai [ 8 ] recommends cleaning with sterile cotton tips soaked in povidone-iodine solution diluted 1:10 with sterile saline . Alternatively , a dilute povidone-iodine-soaked gauze swab can be placed over / around the area for 10 – 15 seconds as an effective method of surgical site preparation . Chlorhexidine was avoided due to reports of toxicity ; however , it may be used in dilute ( 0.05 %) form for flushing and cleaning wounds [ 10 ] .
Recovery considerations
The wound was debrided and sutured closed . The patient ' s enclosure was kept as sterile as possible , with no loose substrate and the use of moistened paper towels ( Figure 2 , page 56 ). Unfortunately , the wound began to break down 7 days postoperatively and bone was seen to protrude from it .
Figure 1b . Induction in a sealed bag , using 100 % oxygen with 8 % sevoflurane .
Healing by second intention was an option , but it was decided to intervene surgically in an attempt to reduce the recovery time . The stress and burrowing behaviour of the toad in sterile , substrate-free conditions caused the toad to sustain superficial abrasion wounds to the
Volume 39 ( 4 ) • August 2024
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