Bupivacaine 0.25% and methylene blue spread with epidural anesthesia in dog

An Update on Drugs Used for Lumbosacral Epidural Anesthesia and Analgesia in Dogs

“…This property of “differential” or “selective” blockade may be attributed to the larger diameter and more profound myelination of Aα motor nerve fibers when compared with Aδ and C fibers (39). However, this is not always the case and motor function may be blocked even when low concentrations are administered (40). …”

“…In the authors’ routine, injectate volume is commonly administered over approximately 1 min. Peak cephalad migration of the injectate to the level of the cervical vertebra within the spinal canal is typically reached at doses of 0.4 mL kg −1 in dogs (40). Patients with high body mass index may have a smaller volume of epidural space due to accumulation of adipose tissue in the spinal canal (34, 44).…”

“…Although volumes of local anesthetic exceeding 0.2–0.25 mL kg −1 may desensitize areas up to the thoracic and cervical vertebrae (31, 40), the use of greater volumes is not recommended because long-term blockade of sympathetic fibers may lead to severe cardiovascular depression, characterized by peripheral vasodilation, hypotension and bradycardia (47), and respiratory compromise as a result of blockade of the phrenic nerve (48). Hypovolemia should be treated before epidural anesthesia and cardiorespiratory monitoring is strongly recommended during injection otherwise serious complications may occur.…”

“…Other factors such as season, housing, diet, or care of the coat may contribute to delayed hair growth following lumbosacral epidurals in dogs (14). The epidural administration of 0.2 mL kg −1 or 0.22 mL kg −1 of 0.25% or 0.75% bupivacaine results in analgesia to the level of the third or fourth lumbar vertebra, respectively (40, 58). A larger volume (0.31 mL kg −1 ) is required to anesthetize up to the eleventh thoracic vertebra (59) but this volume may not be recommended for clinical use because sympathetic blockade followed by hypotension may result especially during the combine used of epidural anesthesia with inhalational anesthetics.…”

Comparative Evaluation of the Epidural Dexmedetomidine, Ketamine or Fentanyl in Combination With Bupivacaine in Dogs

“…All the assigned groups received bupivacaine 0.25% 1.5 mg kg −1 (0.6 mL kg −1 ) (Bucaine 0.5%, vial Weimar, German) (Freire et al, 2010) in combination with adjuvants according to randomization; Bupivacine Group (BG): 1 mL placebo; Ketamine Group (BKG): Ketamine HCL 2 mg kg −1 (Hamilton et al, 2005); Fentanyl Group (BFG): Fentanyl HCL 2 µg kg −1 (Almeida et al, 2007); Dexmedetomidine Group (BDG): Dexmedetomidine HCL 1.13 µg kg −1 (Sabbe et al, 1994).…”