To compare the duration of regional anesthesia of the pelvic limb using bupivacaine with- versus without a temperature-responsive hydrogel (TRH) in dogs.
Methods: Under anesthesia, using intravenous medetomidine (10 µg kg-1), alfaxalone (2 mg kg-1), and isoflurane, seven beagles (8.8 ± 1.3 kg) received four injections of 0.5% bupivacaine (each 1 mg kg-1 with 5 µg mL-1 epinephrine) to block the femoral and sciatic nerves bilaterally via ultrasound with nerve stimulation guidance. Bupivacaine alone was used on one pelvic limb (Bup treatment) and bupivacaine with TRH was used on the contralateral limb (Bup-TRH treatment). Four injections were completed within 20 minutes, and then the vaporizer was turned off, with intravenous atipamezole given (50 µg kg-1). Pinch test (on the digital pads and mid-tibial skin of both pelvic limbs using mosquito forceps), proprioception, and locomotion were tested before (baseline) and at each hour after the block until sensory and motor functions returned to baseline. The effect of TRH was analyzed using a linear mixed model.
