Intra- and postoperative opioid-sparing analgesia in a cat undergoing pelvic limb amputation.

Case summary: A combination of preoperative epidurally administered morphine, peripheral nerve blocks and postoperative wound irrigation with ropivacaine is described as an opioid-sparing analgesic protocol for a feline immunodeficiency virus-positive cat with hypertrophic cardiomyopathy undergoing hindlimb amputation. The reported strategy resulted in a lack of intraoperative sympathetic response, haemodynamic stability and adequate postoperative analgesia. No rescue analgesia was needed at any point. Relevance and novel information: This report represents an example of how several locoregional techniques can be effectively combined to minimise the perioperative use of systemic opioids and their potential side effects in selected cases.

A Modified Approach for the Ultrasound-Guided Quadratus Lumborum Block in Dogs: A Cadaveric Study.

Ultrasound-guided quadratus lumborum block (QLB) is a locoregional technique described in canine cadavers. The aim of this study was to assess a modified approach to QLB to minimise potential complications such as abdominal organ puncture. Nine canine cadavers were included and were positioned in lateral recumbency. An ultrasound-guided QLB was performed on each side. The probe was placed in the transverse position over the lumbar muscles just caudal to the last rib, and a needle was advanced in-plane from a dorso-lateral to a ventro-medial. A volume of 0.2 mL kg-1 of a mixture of iomeprol and methylene blue was injected. Computed tomography (CT) and dissection were performed to evaluate the spreading. Success was defined as staining of the nerve with a length of more than 0.6 cm. Potential complications such as intra-abdominal, epidural, or intravascular spreading of the mixture were also assessed. The CT images showed a T13 to L7 vertebra distribution, with a median of 5 (3-6). Dissection showed staining of the nerves from T13 to L4, with a median of 3 (2-5). No complications were found. This modified approach to QLB is safe and shows similar results to the previous studies in canine carcass.

Perioperative pharmacokinetics and pharmacodynamics of meloxicam in emus (Dromaius novaehollandiae) of different age groups using nonlinear mixed effect modelling.

Meloxicam is a widely used nonsteroidal anti-inflammatory drug in avian species. However, variability in pharmacokinetic (PK) and pharmacodynamic (PD) parameters in birds warrants species-specific studies for dose and dosing interval optimization. We performed a perioperative PK study of meloxicam (0.5 mg/kg, intravenously) on emus of three different age groups: 3 chicks (5 weeks old, 3.5 kg), 4 juveniles (26 weeks old, 18.8 kg) and 6 adults (66 weeks old, 38.8 kg). A two-compartment population PK model including weight as a significant covariate on clearance and central volume of distribution (V1) best fitted the data. The typical values (20 kg bird) for clearance and V1 were 0.54 L/kg/h and 0.095 L/kg. Both parameters significantly decreased with increasing weight/age. Meloxicam potency and selectivity for COX-1 and COX-2 were measured in whole blood assays (TxB2 production endpoint). Meloxicam was partially selective in emus (IC50 COX-1:COX-2 = 9.1:1). At the current empirical dose (0.5 mg/kg/24 hr), plasma meloxicam concentration is above IC50 of COX-2 for only 2 hr. PK/PD predicted dose required for 80% COX-2 inhibition over 24 hr were 3.4, 1.4 and 0.95 L/kg/day in chicks, juveniles and adult emus, respectively. The safety, therapeutic efficacy and practicality of modifying the daily dose or dose interval should be considered for dose recommendations in emus.

Description and evaluation of four ultrasound-guided approaches to aid spinal canal puncture in dogs.

OBJECTIVE: To describe four ultrasound-guided approaches to the lumbar and thoracic spine to aid spinal canal puncture in the dog and to evaluate the feasibility of the technique. STUDY DESIGN: Prospective experimental study. ANIMAL POPULATION: Two canine cadavers. METHODS: In the first part of the study, the ultrasonographic appearance of the interlaminar space in the lumbosacral, lumbar and thoracic regions was described. In the second part of the study, four operators attempted a real-time, ultrasound-guided approach to the vertebral canal. Each operator performed the technique 20 times in total: five times at the lumbosacral junction, five in the thoracic region, five in the lumbar region with an in-plane approach, and five in the lumbar region with an out-of-plane approach. Computed tomography (CT) was used to confirm the position of the needle. The procedure was considered successful when the tip of the needle was observed within the vertebral canal. The success rate was calculated for each approach and operator. Fisher's exact test was used to compare differences between approaches and operators. RESULTS: In all cases, visualization of a ventral, parallel and straight hyperechoic line (floor of the vertebral canal) was considered a necessary prerequisite for successful positioning of the needle within the vertebral canal. A straight hyperechoic line (ligamentum flavum or dura mater) closer to the ultrasound probe was visualized in both the median lumbosacral approach and the transverse lumbar approach. The success rate overall was 81%; for the lumbosacral approach, 100%; for the thoracic approach, 80%; for the in-plane lumbar approach 95%; and for the out-of-plane lumbar approach, 45%. These differences were statistically significant (p < 0.001). CONCLUSIONS AND CLINICAL RELEVANCE: The sonographic description of these approaches was considered adequate for performing spinal canal puncture. In-plane techniques achieved a higher success rate than out-of-plane ones. Further studies are needed to evaluate them in a clinical setting.