The Effects of Prophylactic Dexmedetomidine Administration on General Anesthesia Recovery Quality in Healthy Dogs Anesthetized With Sevoflurane and a Fentanyl Constant Rate Infusion Undergoing Elective Orthopedic Procedures

Abstract

To determine the effects of a dexmedetomidine slow bolus, administered prior to extubation, on recovery from sevoflurane-anesthesia and a fentanyl continuous rate infusion (CRI) in dogs undergoing orthopedic surgical procedures. Sixty-two client-owned, healthy dogs weighing 27.4 ± 11 kg undergoing elective orthopedic procedures were premedicated with: 0.1 mg/kg hydromorphone intramuscular, 0.05 mg/kg hydromorphone intravenously (IV) or 5 mcg/kg fentanyl IV. Following premedication, dogs were induced with propofol, administered locoregional anesthesia and maintained with sevoflurane and a fentanyl CRI (5–10 mcg/kg/hr). Dogs were randomly assigned to one of two treatment groups: 0.5 mcg/kg dexmedetomidine (DEX) or 0.5 ml/kg saline (SAL). Following surgery, patients were discontinued from the fentanyl CRI and administered DEX or SAL IV over 10 min. Following treatment, dogs were discontinued from sevoflurane and allowed to recover without interference. Recoveries were video recorded for 5 min following extubation and assessed by two blinded anesthesiologists using a visual analog scale (VAS; 0–10 cm) and a numerical rating scale (NRS; 1–10). Mean arterial pressure (MAP), heart rate (HR), pulse oximetry (SpO2), temperature, respiratory rate (RR), and end-tidal sevoflurane (EtSevo) and carbon dioxide (EtCO2) concentrations were recorded at specific time-points from induction to 5 min post-bolus administration and analyzed using linear mixed models. Fentanyl, propofol, and hydromorphone dose and the time to extubation were compared using an unpaired t-test. Differences in recovery scores between groups were evaluated with a Mann-Whitney test. Data reported as mean ± SD or median [interquartile range] when appropriate. A p < 0.05 was significant. There were no significant differences between groups in fentanyl, propofol, and hydromorphone dose, duration of anesthesia, intraoperative MAP, HR, RR, SpO2, temperature, EtCO2, EtSevo or anesthetic protocol. MAP was higher in DEX compared to SAL at 10 (104 ± 27 and 83 ± 23, respectively) and 15 (108 ± 28 and 86 ± 22, respectively) min after treatment. DEX had significantly lower VAS [0.88 (1.13)] and NRS [2.0 (1.5)] scores when compared to SAL [VAS = 1.56 (2.59); NRS = 2.5 (3.5)]. Time to extubation (min) was longer for DEX (19.7 ± 11) when compared to SAL (13.4 ± 10). Prophylactic dexmedetomidine improves recovery quality during the extubation period, but prolongs its duration, in sevoflurane-anesthetized healthy dogs administered fentanyl.

Randomized clinical trial comparing outcomes after fentanyl or ketamine‐dexmedetomidine analgesia in thoracolumbar spinal surgery in dogs

“…Although specific postsurgical analgesic protocols vary among veterinary hospitals, opioids are the most effective drug class for managing acute pain, 1 and currently form the cornerstone of postoperative pain management 2 . Despite these advantages, adverse effects associated with opioid analgesics in dogs include bradycardia, 3‐5 hypoventilation, 3,5 gastroesophageal reflux, 6 and dysphoria, 7 as well as a single report of myoclonus and urinary retention following subarachnoid administration 8 . Postoperatively, the most prominent adverse effects include dysphoria, nausea, vomiting, ileus and panting 6,9‐11 …”

A retrospective observational cohort study on the postoperative respiratory complications and their risk factors in brachycephalic dogs undergoing BOAS surgery: 199 cases (2019‐2021)

“…et al, 2020). In healthy dogs undergoing orthopaedic procedures, dexmedetomidine administered before tracheal extubation prolonged recovery time but improved recovery quality by reducing dysphoric-like behaviours, a feature that is desirable during recovery from BOAS surgeries (Jarosinski et al, 2021).…”

Treatment of Y-T Humeral Fractures with Polyaxial Locking Plate System (PAX) in 14 Dogs

“…In both cases, after the lateral implant removal, the dogs, at FU 120, did not show any need for medial implant removal. In both subjects, delayed bone healing and mild osteoarthritis development [ 20 ] was observed. Both dogs presented mild limb function with severe reduction in elbow flexion.…”

“…Additional clinical and radiographic examination 30 days later (FU 60) or 60 days later (FU 90) were recommended to the patients with no evidence of bone union based on the callus stage. At FU 120, all subjects, except for one patient who died previously (case 13), were evaluated, and each patient underwent sedation [ 20 ] and radiographic study was performed to assess implant position, necessity of implant removal and osteoarthritis development. OA was graded: absent or minimal evidence of OA with no radiographic signs; mild with osteophytes smaller than 2 mm, moderate with osteophytes between 2 and 3 mm and severe osteoarthritic changes with osteophytes larger than 5 mm [ 21 , 22 ].…”

“…Fentanyl was used as intraoperative pain therapy with the initial dose of 5 mcg/kg/hr, and adjustments were determined based on fluctuations in physiological parameters (e.g., ±20% change in heart rate and blood pressure) and anesthetic depth. After induction of general anesthesia [ 20 ], each patient was positioned in dorso-lateral recumbency with the affected limb free to be approached both medially and laterally and the contralateral limb extended caudally. All dogs received antibiotic treatment with cefazolin 20 mg/kg administered IV at the time of induction of general anesthesia and then every 90 min until the end of the procedure.…”