Master of Science (MS)
Biomedical and Veterinary Medical Sciences - Veterinary Clinical Sciences
Lidocaine, an amide local anesthetic agent, is commonly used in mammals, including humans. There is a general assumption that birds are more sensitive to lidocaine than mammals. Relatively low doses of lidocaine have been suggested to cause toxic effects in birds. While this information appears to be anecdotal, it has been perpetuated in the literature. The overall objective of this thesis research was to determine the tolerance and safety of intravenous lidocaine in broiler chickens. To assess the cardiovascular effects of lidocaine, relative changes on heart rate and mean blood pressure were calculated. Clinically significant cardiovascular effects were defined as relative decrease of heart rate and/or mean blood pressure equal to or greater than 30%. On the first study, doses below the reported toxic dose were assessed. The effects of 2.5, 3.0, 3.5 mg/kg intravenous lidocaine were compared with a control (saline) group. Each dose was used in 2 randomly selected animals. No significant cardiovascular effects were detected; therefore, higher doses were investigated. On a 2nd study, using an up-and-down study design, a total of 11 subjects were evaluated. The up-and-down method is a sequential design with binary response variables within a certain population which allows the determination of an effective dose to 50% of the population (ED50). The ED50 was defined as the dose that would cause clinically insignificant cardiovascular depression to 50% of the population. Using two statistical methods, the ED50 of cardiovascular function was 6.3 mg/kg and 6.22 mg/kg (95% confidence interval, 5.3 – 7.13 mg/kg). The safety of this dose was then tested in a new group of broiler chickens. The dose of 6 mg/kg was administered to 6 animals. No clinically significant cardiovascular effects were detected in any animal. In conclusion, the 3 studies performed for this thesis indicates that the reported toxic dose of lidocaine appears to be erroneous. Furthermore, this thesis determined the highest tolerable dose and its safety in a specific group of broiler chickens. Further studies assessing analgesia and anesthetic effects of lidocaine are necessary, both in chickens and other avian species.
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Lemos Brandao, Joao Manuel, "Cardiovascular tolerance and safety of intravenous lidocaine in the broiler chicken (Gallus gallus domesticus)" (2014). LSU Master's Theses. 690.