Abstract

One hundred fourteen frogs (weight 283.1±72.4 grams) were anaesthetized at Jersey Zoo for intracoelomic radio transmitter placement; a standardized anaesthetic protocols was used in order to establish the efficacy and safety of isoflurane anaesthesia in combination with endotracheal intubation in this species.

Each frog was placed in a plastic bag filled with 5% isoflurane and oxygen. Reflexes were monitored every 60 seconds and heart rate was monitored throughout the procedure at five-minute intervals (Table 1). Righting reflex was lost at 3.4±2.3 minutes, 2–3 minutes later the frogs were removed from the bag for intubation.

Intubation was carried out at 7.6±2.2 minutes, using a cuffed endotracheal tube (2.5 mm to 3.5 mm), specially modified due to the upper airway anatomy in this species. Manual intermittent positive pressure ventilation (IPPV) every 15 seconds was initiated and maintained through the anaesthesia; isoflurane concentration was reduced and maintained at 2%.

Gular movement was lost at 7.6±2.7 minutes, followed by withdrawal reflex (10.6±4.8 minutes) and response to painful stimuli (11.1±2.9 minutes).

Surgical procedure from incision to last suture took 8.2±2.3 minutes. Isoflurane was discontinued as the last skin suture was placed. Total anaesthesia time since the animal was placed in the bag until the isoflurane was discontinued was 21±6.4 minutes.

IPPV, using room air, was continued until the animals recovered the righting reflex, which occurred at 40.4±10.1 minutes. Specimens were kept in a tray containing amphibian’s ringers throughout the procedure.

Isoflurane and endotracheal intubation proved to be a safe and effective anaesthesia method in this species.

Table 1

Basal heart rate prior to anesthesia obtained under physical restraint and during anesthesia obtained at five minute intervals. Number in brackets indicate sample size [n].
HR: heart rate, beats per minute.