Anaesthesia in two species of large Australian skink

Efficacy and safety of xylazine-ketamine combination for immobilisation of captive African rock pythons (Python sebae)

The African rock python is a cosmopolitan snake in Nigeria widely kept as a zoo animal and also in recreational facilities. There is need for chemical immobilisation of this animal species for managemental, diagnostic and therapeutic procedures. A mixture of xylazine and ketamine (XK) was compared with the administration of a mixture of xylazine and normal saline solution (XS) in six captive African rock pythons in 2 trials with reference to onset and duration of anaesthesia. Changes in the heart rate (HR), respiratory rate (RR) and rectal temperature (RT) as well as selected biochemical parameters were recorded. Although there were no statistically significant (P>0.05) differences in HR and RR values between XK and XS treatments, significant (P<0.05) differences were recorded for RT. Nonetheless, the significant differences were of no clinical importance. It was therefore recommended to safely immobilise an African rock python using XK for a procedure lasting over 1 hour with minimal cardiopulmonary and plasma enzymatic effect. To the knowledge of the authors, this is the first study assessing the anaesthetic efficacy and safety in African Rock pythons.

Sedation and Anesthesia of Lizards

The field of lizard sedation, anesthesia, and locoregional anesthesia is advancing with new drug protocols being evaluated, and new locoregional techniques being developed and evaluated. Inducing and maintaining effective and safe chemical restraint in lizards can be challenging, particularly in systemically diseased individuals. Understanding the anatomic and physiologic adaptations of lizards, using reversible or partially reversible injectable protocols, and using locoregional anesthesia may increase the quality of chemical restraint, facilitate faster recoveries, and limit anesthesia-related morbidity and mortality.

SPINAL ANESTHESIA IN GREEN SEA TURTLES (CHELONIA MYDAS) UNDERGOING SURGICAL REMOVAL OF CUTANEOUS FIBROPAPILLOMAS

Techniques for anesthesia of green sea turtles (Chelonia mydas) are required for medical treatment. The use of spinal anesthesia has been reported in a few species of turtles for different purposes. The objective of this study was to evaluate the use of 2% lidocaine for spinal anesthesia of green sea turtles undergoing surgical removal of cutaneous fibropapillomas. Ten free-ranging green turtles presenting with cutaneous fibropapillomas were included in the study. Animals were accidentally captured or rescued by local fishermen and brought to the Ubatuba Research Base (Sao Paulo, Brazil) of the Brazilian Sea Turtle Conservation Program for rehabilitation. Animals were administered 2% lidocaine (0.2 ml/10 cm of carapace) in the epidural/subarachnoid space of the tail and monitored throughout surgery. The technique was effective for all animals, with fast onset of motor and sensory blockade (3 ± 1.76 min) and relatively fast recovery time (83.9 ± 16.2 min). Fibropapillomas were removed from all animals with no signs of pain (i.e., no behavioral response during surgical procedure, such as head and forelimb movement, showing discomfort) and they were all rehabilitated and successfully returned to their natural habitat. The technique was considered effective, safe, and affordable for use on green turtles undergoing surgical removal of cutaneous fibropapillomas.

INTRAMUSCULAR ADMINISTRATION OF KETAMINE-MEDETOMIDINE ASSURES STABLE ANAESTHESIA NEEDED FOR LONG-TERM SURGERY IN THE ARGENTINE TEGU SALVATOR MERIANAE

  To define a protocol of anesthesia for long-duration invasive surgery in a lizard, eight young adult Argentine tegus ( Salvator merianae) of mean body weight 3.0 kg (interquartile range [IQR] 3.40-2.65) were anesthetized with a mixture of ketamine (K) and medetomidine (M) at 19°C, injected intramuscularly and equally distributed in the four limbs. As the experimental surgery procedure required a prolonged deep anesthesia with a good myorelaxation (between 16 and 21 hr), reinjections were required and reflexes were checked during surgery. Times for anesthetic induction, anesthetic reinjection, and recovery periods were recorded for five different combinations of ketamine-medetomidine: 1) 66 mg/kg K + 100 μg/kg M; 2) 80 mg/kg K + 100 μg/kg M; 3) 100 mg/kg K + 130 μg/kg M; 4) 125 mg/kg K + 200 μg/kg M; and 5) 150 mg/kg K + 200 μg/kg M. The effect on the recovery speed of the postoperative atipamezole injection was also evaluated. The median induction time was 30 (IQR 35-27.5) min with no statistical difference between all the concentrations tested. The first reinjection of half a dose was administered after a mean of 5 hr (5.64 hr, IQR 5.95-4.84) as were the subsequent reinjections of a quarter dose (3.99 hr, IQR 5.98-3.23). Intramuscular administration of the ketamine-medetomidine combination is a simple, rapid, and efficient anesthesia for long-term surgery (>12 hr). A mix of 100 mg/kg ketamine and 200 μg/kg medetomidine, with reinjections every 4 hr of half a dose of the previous injection can maintain a good quality of anesthesia for at least 16 hr. The injection of atipamezole after the surgery reverses the effects of medetomidine and permits a reduction of the recovery period.

Pain and nociception in reptiles

The ability of reptiles to "feel" pain and the significance of pain or nociception on physiologic homeostasis is an exceedingly complex question requiring integration of both physiologic and behavioral evidence. Until further information is available, it would seem most ethical for veterinarians to assume that reptiles are capable of feeling pain, and to treat or manage pain when there is reasonable evidence that pain is present. With increased information available regarding analgesic use in reptiles and with the heightened awareness of the importance of analgesia for zoologic companion animals, it is likely that more veterinarians will provide pain relief to their reptile patients.

Evaluation of the use of anesthesia and analgesia in reptiles

OBJECTIVE

To determine anesthetic techniques and the drugs used to provide anesthesia and analgesia to reptiles.

DESIGN

Mail-out questionnaire.

SAMPLE POPULATION

367 members of the Association of Reptile and Amphibian Veterinarians.

PROCEDURE

1,091 members listed in the 2002 directory of the Association of Reptile and Amphibian Veterinarians were asked to complete a questionnaire regarding anesthesia and analgesia.

RESULTS

367 of 1,091 (33.6%) individuals completed the questionnaire; 88.8% used inhalants (particularly isoflurane) for anesthesia, and ketamine, propofol, and butorphanol were the most commonly used injectable agents. Intubation, fluids, and having a dedicated anesthetist were most commonly used for patient support, and pulse oximetry and Doppler ultrasonography were most commonly used for monitoring. Respiratory depression, difficulty monitoring anesthetic depth, prolonged recovery, and hypothermia were the most frequent complications. Nearly all respondents believed that reptiles feel pain, but analgesics were used infrequently for many reasons.

CONCLUSIONS AND CLINICAL RELEVANCE

Providing anesthesia in reptiles is difficult, especially regarding anesthetic depth and vital parameters, and methods of support are used less frequently than in domestic species. Provision of analgesia is uncommon. Research regarding pain and its assessment, response to analgesics, and drug pharmacokinetics is needed. Dissemination of this information to practitioners needs to be improved for enhancement of the standard of care for reptiles.

Reptile anesthesia

Successful reptile anesthesia requires patience, planning, and understanding of normal anatomy and physiology in health and disease. Reptiles make good anesthetic patients because of their physiologic resilience. New drugs that are not only safe and efficacious, but also result in relatively short recovery times, have greatly enhanced the design of anesthetic regimens. Further studies are required to quantitatively evaluate the physiologic effects of drugs used and validate available monitoring modalities for use in a wide variety of reptiles.