Urodynamic parameters and anesthetic depth vary depending on anesthetic agent (alfaxalone, dexmedetomidine, propofol) at doses necessary to facilitate preclinical testing

Objectives: To compare the effects of select agents (dexmedetomidine, alfaxalone, propofol, isoflurane, and α-chloralose) on anesthetic and urodynamic parameters in felines. Materials and Methods: Adult male cats (n=5) were sedated at least three times per agent with dexmedetomidine (reversed with atipamezole), alfaxalone, and propofol on separate days, and anesthetized one time with isoflurane, then transitioned to α-chloralose during a terminal procedure. At least two cystometrograms (CMGs) were conducted in each sedated session. Urodynamic parameters (Δpressure, bladder capacity, bladder compliance, non-voiding contractions, bladder pressure slopes) and anesthetic parameters (change in heart rate [ΔHR], average heart rate [HR], reflexes, induction/recovery times) were evaluated. Results: Δpressure was greatest with propofol (117 ± 10 cm H20), bladder capacity was highest with α-chloralose (60 ± 9 ml), non-voiding contractions (NVCs) were greatest with α-chloralose (0.03 ± 0.01 NVCs/s). Propofol and dexmedetomidine had the highest bladder pressure slopes during the initial and final portions of the CMGs respectively. Cats progressed to a deeper plane of anesthesia (lower HR, smaller ΔHR, decreased reflexes) under dexmedetomidine (HR 117 ± 6; ΔHR 19 ± 21 bpm), compared to propofol (HR 174 ± 6 bpm; ΔHR 85 ± 22 bpm) and alfaxalone (HR 211 ± 6 bpm; ΔHR 77 ± 21 bpm). Time to induction was shortest with propofol, and time to recovery was shortest with dexmedetomidine. Conclusion: These agent-specific differences in urodynamic and anesthetic parameters in cats will facilitate appropriate study-specific anesthetic choice.