Dexmedetomidine Prolongs the Duration of Ropivacaine Corneal Anesthesia After Subconjunctival Injection in Healthy Horses.

Dexmedetomidine prolongs ropivacaine corneal anesthesia in horses but delays onset.

This randomized, blinded, crossover study evaluated whether dexmedetomidine extends corneal anesthesia duration when combined with subconjunctival ropivacaine in horses. Ten horses received either ropivacaine alone (R) or dexmedetomidine-ropivacaine combination (DR) in one eye, with saline control in the contralateral eye, with a minimum 4-week washout between treatments. Corneal touch thresholds were measured serially until return to baseline. Results demonstrated that DR significantly prolonged total anesthesia time (196±121 minutes vs. 103±47 minutes, p=0.02) compared to R alone. However, DR delayed onset to minimum anesthesia, requiring 32±12 minutes versus 16±10 minutes for R (p<0.001). No significant differences were observed in minimum corneal touch threshold values, duration at minimum threshold, maximal corneal pressure tolerance, or subconjunctival hemorrhage scores between treatments. All hemorrhage resolved within 7 days. The authors concluded that dexmedetomidine effectively prolongs corneal anesthesia duration from subconjunctival ropivacaine in healthy horses, though the delayed onset warrants consideration in clinical practice.

This summary was distilled by AI and may occasionally misinterpret data. Confirm critical details with the primary literature before clinical application.