Hello VETAHEADERS!

It’s that time again for our monthly newsletter. This month, we’re diving into some fascinating research on our feathered patients, specifically chickens! Let’s explore two recent studies that provide valuable insights into chicken’s anesthesia.

First up, we have a 2023 study on the effects of two continuous infusion doses of lidocaine on isoflurane minimum alveolar concentration (MAC) in chickens. The objective was to assess how different doses of lidocaine impact the amount of isoflurane needed to maintain anesthesia. Six adult female chickens were used in this study, which followed a blinded, prospective, randomized, experimental crossover design.

Here’s the breakdown: Chickens were anesthetized with isoflurane, and their MAC was determined using an electrical noxious stimulus. After the initial MAC determination, they received either a low dose (3 mg/kg/h) or high dose (6 mg/kg/h) of lidocaine intravenously. The MAC was re-evaluated at 1.5 and 3 hours after lidocaine administration. Surprisingly, neither the low nor high doses of lidocaine significantly reduced the isoflurane MAC in chickens.

And look at that: Plasma concentrations of lidocaine remained consistent, and no serious adverse events were observed. The study suggests that while lidocaine is commonly used in mammals to reduce anesthetic requirements, it doesn’t seem to have the same effect in chickens under the conditions tested.

Take home: Lidocaine does not significantly change the isoflurane MAC in chickens, at the doses studied, but it is well-tolerated without causing significant cardiovascular depression. For those interested in avian anesthesia, this is a noteworthy finding!

Next, we have a comparison study on the cardiopulmonary effects of propofol, ketamine–propofol, and isoflurane anesthesia in domestic chickens (Gallus gallus domesticus). The aim was to compare the effects of these anesthetics on heart and respiratory functions at similar anesthetic depths.

In this prospective, randomized, crossover trial, ten male Leghorn chickens were assigned to one of three anesthetic protocols: intravenous propofol, intravenous ketamine–propofol, or isoflurane. Anesthesia was induced and maintained with propofol (10 mg/kg initially, then 1.1 mg/kg/min), ketamine–propofol (a combination of 5 mg/mL ketamine and 5 mg/mL propofol, 10 mg/kg initially, then 1.1 mg/kg/min), or isoflurane (5% initially, then an end-tidal concentration of 2%) for 65 minutes. Heart rate, respiratory rate, noninvasive arterial blood pressure, and arterial blood gases were measured.

The findings showed that cardiopulmonary variables remained within clinically acceptable ranges for all treatments. However, ketamine–propofol was associated with a significantly higher heart rate and lower respiratory rate compared to propofol or isoflurane alone. Importantly, coadministration of ketamine with propofol significantly reduced the induction and maintenance dose of propofol needed.

Take home: All three anesthetic protocols maintained cardiovascular and respiratory variables within normal ranges, but ketamine–propofol reduced the required doses of propofol, suggesting it may be a more efficient option for maintaining anesthesia in chickens.

These studies highlight the importance of tailored anesthetic protocols for avian patients to ensure safety and effectiveness.

I hope these insights are useful! Let us know which one was your favorite!

And don’t forget, VETAHEAD is launching a new course on chicken medicine and anesthesia!

This comprehensive course will cover everything from husbandry and breed basics, egg quality, anatomy and physical examination, preventative medicine, to sedation, anesthesia, analgesia, and much more.

Whether you’re a seasoned vet or just starting out, this course will provide you with the knowledge and skills to excel in chicken care.

As always, see you next month.

Reference:

Escobar, A., Dzikiti, B. T., Thorogood, J. C., Bailey, S., & Maney, J. K. (2023). Effects of two continuous infusion doses of lidocaine on isoflurane minimum anesthetic concentration in chickens. Veterinary Anaesthesia and Analgesia, 50(1), 91-97.

Zendeboudi, M., & Vesal, N. (2024). Comparison of cardiopulmonary effects of propofol, ketamine-propofol and isoflurane anesthesia in the domestic chicken (Gallus gallus domesticus). Veterinary Anaesthesia and Analgesia.