Cardiopulmonary effects and induction and recovery characteristics of isoflurane and sevoflurane in foals.

This research article investigates the effects of two anesthetics, isoflurane and sevoflurane, on foals. The study found no significant differences in the induction or recovery characteristics and cardiopulmonary effects between the two anesthetics, endorsing both for usage and suggesting their equivalence in performance.

Study Design

• The study was designed as a prospective crossover study, involving 6 healthy foals who were each anesthetized twice, once at 1 month of age and then at 3 months of age.
• This design allowed for the application of both anesthetics in each foal across different time points, enabling a direct comparison of the effects of each anesthetic.

Procedure

• For the anesthesia procedure, the chosen agent was administered in oxygen through a nasotracheal tube.
• During the maintenance of anesthesia, the foals were positioned in dorsal recumbency, a posture that involves lying on the back with the ventral side up, and intermittent positive-pressure ventilation was performed. This strategy helps in maintaining airflow and respiratory function during the period of anesthesia.
• Assessment of the properties of induction and recovery were recorded. This typically includes the time it takes for anesthesia to set in and for the subject to regain consciousness and normal functions.
• Cardiopulmonary variables were recorded 10 minutes after anesthetic induction and then 15, 30, 45, and 60 minutes later. These measures monitor the immediate effects of the anesthetics on heart and lung function.

Results

• All foals were successfully anesthetized with both isoflurane and sevoflurane.
• No significant differences were found in the characteristics of induction or recovery for the two drugs. Induction and recovery were generally smooth and unproblematic.
• There were no significant differences in measured cardiopulmonary variables between the two drugs, though both caused initial hypotension that resolved with time. The drop in blood pressure following anesthetic administration, also referred to as hypotension, while expected, highlights the importance of continuous monitoring during these procedures.

Conclusions

• The absence of notable differences between the effects of sevoflurane and isoflurane suggests their interchangeability for general anesthesia in foals aged 1 to 3 months.
• The research provides affirmation of the efficacy of both anesthetics in the controlled setting and shows them to be equal in terms of the quality of anesthesia provided.