Sublingual microcirculation in isoflurane-anesthetized horses receiving dexmedetomidine and lidocaine constant rate infusion.

The research study evaluates the effect of dexmedetomidine and lidocaine constant rate infusion on the sublingual microcirculation in isoflurane-anesthetized horses undergoing arthroscopy. It concludes that the combination of these drugs maintains stable hemodynamic conditions without affecting sublingual microcirculation or recovery.

Research Design and Methodology

• The study was conducted on 16 horses randomized into two groups, which were blinded and unassigned.
• The first group received dexmedetomidine (DEX) and lidocaine (LID) at a constant rate infusion.
• The second group received only lidocaine (LID) at the same dose.
• Various hemodynamic variables were measured, such as mean, systolic, and diastolic blood pressure; heart rate; capnography; blood gas analysis; and blood lactate.
• In addition, orthogonal polarization spectral imaging was used to assess sublingual microcirculation.
• These measurements were taken before and at 15-minute intervals up to 60 minutes after the start of the infusion.

Key Findings

• There was no significant difference observed in microcirculation variables between the two groups.
• Notably, the total vessel density, the microvascular flow index, and the De Backer score, which are measures of capillary density and blood flow, were similar in both groups at the 60-minute mark.
• However, it was observed that five out of eight horses in the LID group required ephedrine for the management of hypotension (low blood pressure), while none in the DEX-LID group did.

Conclusion and Implications

• The combination of DEX and LID during isoflurane anesthesia provided stable hemodynamic conditions during arthroscopic surgery in horses without adversely affecting sublingual microcirculation or the recovery process.
• These findings suggest that the combination of DEX and LID can be used to maintain hemodynamic stability during surgery without compromising microcirculation function.