Recent advances in inhalation anesthesia.

The research article describes the advantages of desflurane and sevoflurane over other inhalation anesthetics for horses, key in which are improved control over delivery and possible faster rates of recovery. Nevertheless, these new agents also present some challenges such as higher expense, necessity of new equipment and, in sevoflurane’s case, potential for renal damage.

Advantages of Desflurane and Sevoflurane

• Both desflurane and sevoflurane have lower solubility compared to older inhalation anesthetics. This promotes better control over the administration of the anesthetic and offsets the influence of the large breathing circuit often used in anesthetizing horses.
• Due to their lower solubility, these anesthetics are thought to provide faster recovery rates.
• The pharmacodynamic effects of both desflurane and sevoflurane are largely similar to isoflurane, a commonly used anesthesia. They exhibit low tendencies for causing irregular heart rhythms. However, desflurane might have less impact on cardiovascular function especially during regulated ventilation.

Challenges with Desflurane and Sevoflurane

• Respiratory depression with both new agents is either similar to or worse than isoflurane. This suggests that mechanical ventilation might be required, particularly for prolonged periods of anesthesia.
• Both new anesthetics come at a high cost. In addition, they necessitate the acquisition of new vaporizers. Specifically for desflurane, due to its high boiling point and steep vapor-pressure curve, the use of innovative technology was needed
• Its high expense is further compounded by the cost of these new equipment. Additionally, electricity is necessary for the functioning of the new desflurane vaporizer, contributing to its cost, limiting its portability and adding more practical considerations for its clinical application.
• Despite desflurane’s resistance to degradation both in vitro and in vivo, sevoflurane might degrade in vitro by CO2 absorbents, potentially causing kidney damage, especially with low fresh-gas inflow rates and in prolonged anesthesia, more common in university based practices.
• The less potent anesthetic effect of these new agents compared to isoflurane not only impacts the cost of anesthesia but also sets a limit on the inspired oxygen concentration, a concern particularly with desflurane.