Minimum alveolar concentration of desflurane in llamas and alpacas.

OBJECTIVE

To determine the minimum alveolar concentration (MAC) of desflurane in llamas and alpacas.

DESIGN

Prospective study. Animals Six healthy adult llamas and six healthy adult alpacas.

PROCEDURE

Anesthesia was induced with desflurane delivered with oxygen through a mask. An endotracheal tube was inserted, and a port for continuous measurement of end-tidal and inspired desflurane concentrations was placed between the endotracheal tube and the breathing circuit. After equilibration at an end-tidal-to-inspired desflurane concentration ratio >0.90 for 15 minutes, a 50-Hz, 80-mA electrical stimulus was applied to the antebrachium until a response was obtained (i.e. gross purposeful movement) or for up to 1 minute. The vaporizer setting was increased or decreased to effect a 10-20% change in end-tidal desflurane concentration, and equilibration and stimulus were repeated. The MAC was defined as the average of the lowest end-tidal desflurane concentration that prevented a positive response and the highest concentration that allowed a positive response.

RESULTS

Mean +/- SD MAC of desflurane was 7.99 +/- 0.58% in llamas and 7.83 +/- 0.51% in alpacas.

CONCLUSIONS AND CLINICAL RELEVANCE

The MAC of desflurane in llamas and alpacas was in the range of that reported for other species.