Cardiovascular and sedation reversal effects of intramuscular administration of atipamezole in dogs treated with medetomidine hydrochloride with or without the peripheral α2-adrenoceptor antagonist vatinoxan hydrochloride.

OBJECTIVE: To investigate the cardiovascular and sedation reversal effects of IM administration of atipamezole (AA) in dogs treated with medetomidine hydrochloride (MED) or MED and vatinoxan (MK-467). ANIMALS: 8 purpose-bred, 2-year-old Beagles. PROCEDURES: A randomized, blinded, crossover study was performed in which each dog received 2 IM treatments at a ≥ 2-week interval as follows: injection of MED (20 µg/kg) or MED mixed with 400 µg of vatinoxan/kg (MEDVAT) 30 minutes before AA (100 µg/kg). Sedation score, heart rate, mean arterial and central venous blood pressures, and cardiac output were recorded before and at various time points (up to 90 minutes) after AA. Cardiac and systemic vascular resistance indices were calculated. Venous blood samples were collected at intervals until 210 minutes after AA for drug concentration analysis. RESULTS: Heart rate following MED administration was lower, compared with findings after MEDVAT administration, prior to and at ≥ 10 minutes after AA. Mean arterial blood pressure was lower with MEDVAT than with MED at 5 minutes after AA, when its nadir was detected. Overall, cardiac index was higher and systemic vascular resistance index lower, indicating better cardiovascular function, in MEDVAT-atipamezole-treated dogs. Plasma dexmedetomidine concentrations were lower and recoveries from sedation were faster and more complete after MEDVAT treatment with AA than after MED treatment with AA. CONCLUSIONS AND CLINICAL RELEVANCE: Atipamezole failed to restore heart rate and cardiac index in medetomidine-sedated dogs, and relapses into sedation were observed. Coadministration of vatinoxan with MED helped to maintain hemodynamic function and hastened the recovery from sedation after AA in dogs.

Behavioural alterations in piglets after surgical castration: Effects of analgesia and anaesthesia.

The present study aimed to use behavioural measures to assess pain induced by surgical castration of piglets, and evaluate the efficacy of pain-relief medications. In total, 143 male piglets from 29 sows were used. The treatments included: 1) non-castration (NC; n = 28), 2) castration without medication (SC; n = 29), 3) castration with meloxicam injection 0.4 mg/kg i.m. (ME; n = 28), 4) castration with 0.5 ml of 2% lidocaine in each testicle (LA; n = 29), and 5) castration with general inhalation anaesthesia using isoflurane (1.5%) and meloxicam injection (GA; n = 29). Behaviour was monitored continuously for a ten minute period one hour prior to castration (-1 h), as well as immediately (0 h), one hour (1 h), and two hours (2 h) after castration. Behaviour was also monitored twice (08:00 and 20:00) during the following day. Compared to -1 h, castration induced changes in several behavioural measures in SC piglets at 0 h, suggesting that castration was painful. Furthermore, inactive standing or sitting, tail wagging and aggressive behaviour differed between SC and NC piglets at 0 h. ME and LA piglets spent less time standing or sitting inactively, and LA and GA piglets showed more tail wagging than SC piglets at 0 h (P < 0.05 for all). No other behavioural measures differed among the various groups of castrated piglets. In conclusion, the results indicate that surgical castration is indeed painful. However, the efficacy of various pain-relief protocols in piglets shortly after castration was not verified.

Vertebral Subluxation Repair in a Pet Goat.

OBJECTIVES: To describe the perioperative management, including surgery, anesthesia, metabolic derangements, and physiotherapy, in a goat referred for paraparesis secondary to a road traffic accident. STUDY DESIGN: Case report. ANIMALS: 2-year-old mixed breed dwarf 44 kg female pet goat. METHODS: Clinical examination showed symptoms of early compensatory stages of shock, paraparesis with hyperextension of the thoracic limbs, pain on palpation of the thoracolumbar spine, increased patellar reflexes of both pelvic limbs without superficial sensitivity, but preserved deep pain sensation. These signs suggested a spinal cord injury with upper motor neuron syndrome and an anatomic localization between the third thoracic and third lumbar vertebrae. Radiographic examination revealed a thoracolumbar vertebral subluxation. Vertebral stabilization was achieved with the application of pins in the vertebral bodies stabilized by an interconnecting bridge of polymethylmethacrylate, a technique commonly adopted in companion animals. RESULTS: Surgery and recovery from anesthesia were uneventful, but 3 days later ruminal atony and subsequent bloating occurred. This was associated with metabolic derangements (metabolic alkalosis), decreased mentation, and marked tachypnea that responded to medical treatment. From day 3 post-surgery, the goat underwent physiotherapy with manual and active exercises during the rehabilitation period of 21 days duration. CONCLUSION: The injury in this goat was successfully managed using vertebral stabilization similar to that used in dogs and cats. Extensive postoperative physiotherapeutic support contributed to the complete recovery of the animal.