PICO: Rabbit Anesthesia
PICO series:
This is the first installment in a series I hope to do, where I have a question and develop a PICO to address it. All steps, from asking the question to comparing the evidence are all challenges for the early practitioner of EBVM. The following is just my effort to identify the question, find the evidence, and apply it to a clinical environment within a reasonable amount of time. As I continue, I hope these improve.
The following is the first PICO study to address my anesthetic needs for rabbit anesthesia. It is important to remember that just because intubating a rabbit may be a better standard of anesthesia, it was not realistic to time requirements or experience.
PICO form :
Patient Information ( signalment , species and disease ):
species : Rabbit
age : 3yo and 9mo
breed : NZW
Primary complaint
OHE
differential diagnosis
diagnosis
Intervention ( treatment options )
diagnostic
drug
Pre - med : Buprenorphine v. Buprenorphine/Midazolam v. Buprenorphine/Midazolam/Ketamine v. Buprenorphine/Acepromazine/Ketamine
Comparison ( examination of new treatment v . best practice alternative treatment or no treatment )
what options will we explore :
Buprenorphine/Ketamine/Midazolam
what is the gold standard : Buprenorphine
Outcome :
What do we hope to achieve with this intervention :
Iso-sparing effect
ease of delivery
What is the Evidence ?:
3 non-systematic overviews and 3 randomized control trials were used to evaluate ketamine-midazolam as a pre-medication.
When compared to using an Alpha-2 agonist, anesthesia and analgesia is not as effective, but additional negative side effects are not as readily witnessed with Ketamine and Midazolam pre-medication/sedation 1,2. I treated the gold standard as an opioid alone with isoflurane inhalant. However, the gold standard appears to be dissociative/benzodiazepine combination1-6.
Overall premedication protocol recommended(with facility equipment):
Iso induction - pulse ox, ECG, and Doppler monitoring 3,4,6
if catheter is placed: provide 4% glucose was administered 5 ml/kg during anesthesia2.
Recovery: wait until rabbit is bright and alert and sternal.
The Final Outcome:
We did not have Vitamin C to inject, so the night before and prior to anesthesia, I had our staff provide food with high Vitamin C content. The premedication was given IM and took about five minutes to have effect for the older rabbit which was then placed under maintenance isoflurane by mask. The rabbit was prepped and taken to surgery with monitoring including: ECG, doppler, and pulse oximetry (one of the review articles mentioned you can measure systolic by using a sphygmomanometer and waiting for the pulse ox signal to return for a MAP value). Monitoring was easy to establish and run. An IV catheter was not placed, so the rabbit did not receive IV fluids with glucose. Patient was maintained on about 2% isoflurane. When the surgery ended, I stayed with the rabbit until it righted itself from lateral. The patient was righting itself within a half-hour, at which point, I did give Karo syrup to the patient to help compensate for anesthetic metabolic requirements.
The second rabbit, I used a 3/4 dose, this rabbit was younger and it took longer to see some sedation. Masked induction with isoflurane did take a little longer. Surgery went well and the patient was maintained at 2.5% isoflurane. The patient spent less time in recovery, and righted itself in about 15 minutes. Karo syrup was also applied to the mucosa of the 2nd rabbit.
Post-operatively, the rabbits received two doses of buprenorphine and were placed on Meloxicam for 5 days.
In retrospect, due to less iso-sparing effect with the second rabbit, I would maintain the same dose. The pre-medication with isoflurane masked maintenance allowed for a quick procedure with minimal complication. Alpha-2 agonists would be nice to work with, but at this time, due to the limited clinical environment, they were unavailable.
This is the first installment in a series I hope to do, where I have a question and develop a PICO to address it. All steps, from asking the question to comparing the evidence are all challenges for the early practitioner of EBVM. The following is just my effort to identify the question, find the evidence, and apply it to a clinical environment within a reasonable amount of time. As I continue, I hope these improve.
The following is the first PICO study to address my anesthetic needs for rabbit anesthesia. It is important to remember that just because intubating a rabbit may be a better standard of anesthesia, it was not realistic to time requirements or experience.
PICO form :
Patient Information ( signalment , species and disease ):
species : Rabbit
age : 3yo and 9mo
breed : NZW
Primary complaint
OHE
differential diagnosis
diagnosis
Intervention ( treatment options )
diagnostic
drug
Pre - med : Buprenorphine v. Buprenorphine/Midazolam v. Buprenorphine/Midazolam/Ketamine v. Buprenorphine/Acepromazine/Ketamine
sx
treatmentComparison ( examination of new treatment v . best practice alternative treatment or no treatment )
what options will we explore :
Buprenorphine/Ketamine/Midazolam
what is the gold standard : Buprenorphine
Outcome :
What do we hope to achieve with this intervention :
Smoother induction and recovery
Better analgesiaIso-sparing effect
ease of delivery
What is the Evidence ?:
3 non-systematic overviews and 3 randomized control trials were used to evaluate ketamine-midazolam as a pre-medication.
When compared to using an Alpha-2 agonist, anesthesia and analgesia is not as effective, but additional negative side effects are not as readily witnessed with Ketamine and Midazolam pre-medication/sedation 1,2. I treated the gold standard as an opioid alone with isoflurane inhalant. However, the gold standard appears to be dissociative/benzodiazepine combination1-6.
Overall premedication protocol recommended(with facility equipment):
- Vitamin C 30 - 240 mg/kg before the pre-med IM as little as 5 minutes prior to dissociative premedication5
- Buprenorphine 0.03 mg/kg IM
- Midazolam 0.5 mg/kg IM
- Ketamine 10 mg/kg IM4
Iso induction - pulse ox, ECG, and Doppler monitoring 3,4,6
if catheter is placed: provide 4% glucose was administered 5 ml/kg during anesthesia2.
Recovery: wait until rabbit is bright and alert and sternal.
- provide q 6-8 hours buprenorphine 0.01- 0.03 mg/kg SC3
- NSAID Meloxicam 0.2-0.5 mg/kg SC q 12-24hrs6.
References:
1.
Dupras J, Vachon P, Cuvelliez S, Blais D. SCIENTIFIC - ARTICLES -
anesthesie du lapin de nouvelle-zelande utilisant les combinaisons
tiletamine-zolazepam et ketamine-midazolam avec ou sans xylazine. The Canadian veterinary journal = La revue vétérinaire canadienne. 2001;42(6):455.
2.
Grint NJ, Murison PJ. RESEARCH PAPER: A comparison of
ketamine-midazolam and ketamine-medetomidine combinations for induction
of anaesthesia in rabbits. Veterinary Anaesthesia and Analgesia. 2008;35(2):113-121.
3. Borkowski R, Karas AZ. Sedation and anesthesia of pet rabbits. Clin Tech Small Anim Pract. 1999;14(1):44-9.
4. Cantwell SL. Ferret, rabbit, and rodent anesthesia. The veterinary clinics of North America.Exotic animal practice. 2001;4(1):169-91.
5. Elsa A, Ubandawaki S. Ketamine anaesthesia following premedication of rabbits with vitamin C. Journal of veterinary science. 2005;6(3):239-41.
6. Inglis S., Strunk A. Rabbit anesthesia. Lab Anim.Lab Animal. 2009;38(3):84-85.
The Final Outcome:
We did not have Vitamin C to inject, so the night before and prior to anesthesia, I had our staff provide food with high Vitamin C content. The premedication was given IM and took about five minutes to have effect for the older rabbit which was then placed under maintenance isoflurane by mask. The rabbit was prepped and taken to surgery with monitoring including: ECG, doppler, and pulse oximetry (one of the review articles mentioned you can measure systolic by using a sphygmomanometer and waiting for the pulse ox signal to return for a MAP value). Monitoring was easy to establish and run. An IV catheter was not placed, so the rabbit did not receive IV fluids with glucose. Patient was maintained on about 2% isoflurane. When the surgery ended, I stayed with the rabbit until it righted itself from lateral. The patient was righting itself within a half-hour, at which point, I did give Karo syrup to the patient to help compensate for anesthetic metabolic requirements.
The second rabbit, I used a 3/4 dose, this rabbit was younger and it took longer to see some sedation. Masked induction with isoflurane did take a little longer. Surgery went well and the patient was maintained at 2.5% isoflurane. The patient spent less time in recovery, and righted itself in about 15 minutes. Karo syrup was also applied to the mucosa of the 2nd rabbit.
Post-operatively, the rabbits received two doses of buprenorphine and were placed on Meloxicam for 5 days.
In retrospect, due to less iso-sparing effect with the second rabbit, I would maintain the same dose. The pre-medication with isoflurane masked maintenance allowed for a quick procedure with minimal complication. Alpha-2 agonists would be nice to work with, but at this time, due to the limited clinical environment, they were unavailable.
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