Anwendbarkeit, Wiederholbarkeit und Zuverlässigkeit der deutschen Version der Glasgow Composite Measured Pain Scale - feline während der Einführungsphase in eine KleintierklinikApplicability, reproducibility, and reliability of the German version of the Glasgow composite measured pain scale - feline during implementation into a small animal clinic. / Anwendbarkeit, Wiederholbarkeit und Zuverlässigkeit der deutschen Version der Glasgow Composite Measured Pain Scale ­ feline während der Einführungsphase in eine KleintierklinikApplicability, reproducibility, and reliability of the German version of the Glasgow composite measured pain scale ­ feline during implementation into a small animal clinic.

OBJECTIVE: The aim of the study was to evaluate reproducibility and practicality of the German version of the Glasgow composite measured pain scale - feline, during its implementation into a German veterinary hospital. MATERIAL AND METHODS: The study comprised of 2 parts. Participation of veterinary professionals was voluntary. During part 1, 15 staff members (all rater=AR) with variable clinical experience (nurses, interns, junior clinician, senior clinicians), from 4 disciplines (anesthesia, internal medicine, surgery, neurology), and one main investigator (AC), pain scored 45 diseased cats and 10 healthy cats. Part 2 was an online survey, evaluating the practical experience of participants during part 1 and asking for suggestions to improve the scale and process of pain assessment. For part 1 normal distribution of data was tested by Shapiro-Wilk-Test and histograms. Intrarater and interrater reliability were evaluated by calculating the intraclass-correlation. Statistical analysis of part 2 used descriptive methods. RESULTS: The interrater reliability was moderate (ICC AR : 0.59) and the intrarater reliability was good (ICC AC : 0.88). The pain scores of cats with medical (AR: 3.06±2.33, AC 3.52±2.34) and surgical disease (AR: 3.78±2.38, AC: 4.02±2.72) showed no significant difference. All healthy cats were classified as "not painful" (AR: 0.77±0.67, AC: 1.09±0.83). Clinical experience of the rater did not significantly influence pain scores. The GCMPS-F was judged as easy to use and as helpful tool for cats with unclear pain conditions. CONCLUSION: The GCMPS-F had a good acceptance and moderate interrater reliability. CLINICAL RELEVANCE: Using the German version of the GCMPS-F, veterinary professionals from different disciplines and with different grades of specialisation can reliably assess pain levels in cats without prior extensive training.

Cold stimulation is feasible and has limited aversiveness in healthy, pain-free dogs.

OBJECTIVE: The study aimed to evaluate the applicability and repeatability of cold stimulation in dogs. ANIMALS: 10 healthy Beagle dogs were used in a blinded cross-over experiment. METHODS: Measurements were performed in triplicate at 4 skin locations. The probe was manually placed, and temperature decreased (32 to 10 °C) at different cooling rates (0.5, 1, and 5 °C second-1) and latency was measured (11 °C for 60 seconds). Stimulations were discontinued when avoidance reactions were detected. Thermal threshold or time-to-reaction were recorded. Experiments were performed 3 times per animal in weeks 1 (Exp1), 2 (Exp2), and 5 (Exp3). Feasibility of cold stimulation was scored (0-5). Data were analyzed with mixed logistic regression. RESULTS: No significant differences in number of avoidance reactions between cooling-rates were detected. Significantly more reactions (P < .001) were observed during Exp1 compared to Exp2 and Exp3. Thermal thresholds were 13 ± 2.6 °C, 17.7 ± 4 °C and 16.3 ± 4.6 °C for 5, 0.5 and 1 °C second-1, respectively. Latency to the reaction was determinable in 37% of measurements. The mean time-to-reaction was 13 ± 11 seconds. In 85% of measurements, a feasibility score of 0 (best feasibility) was assigned. CLINICAL RELEVANCE: The method is easily applicable and well tolerated, but habituation could not be excluded. Overall, the aversiveness of cold stimulation in healthy dogs is limited and it is not possible to recommend a specific protocol. In future studies, it needs to be determined if the aversiveness of cold stimulation is increased in diseased dogs.

Explainable automated pain recognition in cats.

Manual tools for pain assessment from facial expressions have been suggested and validated for several animal species. However, facial expression analysis performed by humans is prone to subjectivity and bias, and in many cases also requires special expertise and training. This has led to an increasing body of work on automated pain recognition, which has been addressed for several species, including cats. Even for experts, cats are a notoriously challenging species for pain assessment. A previous study compared two approaches to automated 'pain'/'no pain' classification from cat facial images: a deep learning approach, and an approach based on manually annotated geometric landmarks, reaching comparable accuracy results. However, the study included a very homogeneous dataset of cats and thus further research to study generalizability of pain recognition to more realistic settings is required. This study addresses the question of whether AI models can classify 'pain'/'no pain' in cats in a more realistic (multi-breed, multi-sex) setting using a more heterogeneous and thus potentially 'noisy' dataset of 84 client-owned cats. Cats were a convenience sample presented to the Department of Small Animal Medicine and Surgery of the University of Veterinary Medicine Hannover and included individuals of different breeds, ages, sex, and with varying medical conditions/medical histories. Cats were scored by veterinary experts using the Glasgow composite measure pain scale in combination with the well-documented and comprehensive clinical history of those patients; the scoring was then used for training AI models using two different approaches. We show that in this context the landmark-based approach performs better, reaching accuracy above 77% in pain detection as opposed to only above 65% reached by the deep learning approach. Furthermore, we investigated the explainability of such machine recognition in terms of identifying facial features that are important for the machine, revealing that the region of nose and mouth seems more important for machine pain classification, while the region of ears is less important, with these findings being consistent across the models and techniques studied here.

Meningioma and associated cerebral infarction in three dogs.

BACKGROUND: In dogs, meningiomas mostly cause chronic progressive clinical signs due to slow tumor growth. CASE PRESENTATION: In contrast, three dogs were presented with the history of chronic generalized tonic-clonic seizures and peracute deterioration with sudden onset of neurological deficits in accordance with an extensive unilateral forebrain lesion. Magnetic resonance imaging examinations of the dogs revealed a well-delineated extraaxial T2W hyperintense mass in the rostral forebrain with homogeneous contrast enhancement. Additionally, an intraaxial, well-demarcated, unilateral lesion was apparent in the parenchyma supplied by the middle cerebral artery. In two cases, necropsy revealed meningothelial meningioma in the rostral fossa and marked eosinophilic neuronal necrosis, a sign of ischemia, focal malacia, edema and gliosis in the temporal lobe and hippocampus because of a focal thrombosis of the middle cerebral artery. In the third case symptomatic treatment resulted in improvement of clinical signs enabling a good quality of life for the patient. CONCLUSIONS: In dogs with structural epilepsy caused by meningioma, acute deterioration of clinical signs can be associated with ischemic infarctions as a potential complication.

Intervertebral disc herniation in two coatis (Nasua nasua) and postoperative laminectomy membrane formation.

Magnetic resonance imaging revealed spinal cord compression due to intervertebral disc herniation of Hansen type I and II in the thoracolumbar vertebral column in two middle-aged coatis (Nasua nasua) with chronic progressive paraparesis. Surgical treatment included hemilaminectomy and partial corpectomy in one and dorsal laminectomy in the other coati. Both coatis recovered well after surgery. One showed unremarkable gait 6 and 15 months post surgery, while the other one suffered from recurrence of paraparesis leading to euthanasia because of deterioration of neurological signs 20 months after the first surgery. Necropsy revealed formation of a laminectomy membrane compressing the spinal cord. Histopathological signs of spinal cord injury and findings of degenerative processes in the intervertebral disc were comparable to those described in dogs. In conclusion, this case report shows for the first time that surgical intervention seems to be a useful and safe treatment in chronic intervertebral disc herniation in coatis, but relapses are possible.

Influence of tramadol on acute thermal and mechanical cutaneous nociception in dogs.

OBJECTIVE: The aim of the study was to evaluate the influence of tramadol on acute nociception in dogs. STUDY DESIGN: Experimental, blinded, randomized, crossover study. ANIMALS: Six healthy laboratory Beagle dogs. METHODS: Dogs received three treatments intravenously (IV): isotonic saline placebo (P), tramadol 1 mg kg-1 (T1) and tramadol 4 mg kg-1 (T4). Thermal thresholds were determined by ramped contact heat stimulation (0.6 °C second-1) at the lateral thoracic wall. Mechanical thresholds (MT) were measured using a probe containing three blunted pins which were constantly advanced over the radial bone, using a rate of force increase of 0.8 N second-1. Stimulation end points were defined responses (e.g. skin twitch, head turn, repositioning, vocalization) or pre-set cut-out values (55 °C, 20 N). Thresholds were determined before treatment and at predetermined time points up to 24 hours after treatment. At each measurement point, blood was collected for determination of O-desmethyltramadol concentrations. The degree of sedation and behavioural side effects were recorded. Data were analysed by one-way anova and two-way anova for repeated measurements. RESULTS: Thermal nociception was not influenced by drug treatment. Mechanical nociception was significantly increased between P and T1 at 120 and 240 minutes, and between P and T4 at 30, 60, 240 and 420 minutes. T1 and T4 did not differ. O-desmethyltramadol (M1) maximum plasma concentrations (Cmax) were 4.2±0.8 ng mL-1 and 14.3±2.8 ng mL-1 for T1 and T4, respectively. Times to reach maximum plasma concentrations (Tmax) were 27.6±6.3 minutes for T1 and 32.1±7.8 minutes for T4. No sedation occurred. There were signs of nausea and mild to moderate salivation in both groups. CONCLUSION AND CLINICAL RELEVANCE: Tramadol was metabolized marginally to O-desmethyltramadol and failed to produce clinically relevant acute antinociception. Therefore, the use of tramadol for acute nociceptive pain is questionable in dogs.

[Comparison of ultrasound guided femoral and sciatic nerve block versus epidural anaesthesia for orthopaedic surgery in dogs]. / Ultraschallgesteuerte Nervenblockade des Nervus femoralis und ischiadicus im Vergleich zur Epiduralanästhesie bei orthopädischen Eingriffen am Hund.

OBJECTIVE: Comparison of ultrasound-guided femoral and sciatic nerve block versus epidural anaesthesia with bupivacaine and morphine for orthopaedic surgery of the pelvic limb in dogs with respect to analgesic effectiveness, clinical utility and side effects. MATERIAL AND METHODS: The study included 22 dogs (American Society of Anesthesiologists, ASA grades I and II) undergoing orthopaedic surgery distal to the mid-femoral bone. The study was designed as a randomized, prospective, blinded clinical trial. All dogs were randomly assigned to receive 0.5 mg/kg bupivacaine (0.5%) and 0.1 mg/kg morphine sulphate (1%) either as epidural anaesthesia (group EPI) or by ultrasound-guided femoral and sciatic nerve block (group LA). During surgery, the heart rate, respiratory rate, mean arterial pressure (MAP), end-tidal isoflurane concentrations and dose of rescue analgesia (fentanyl boluses of 5 µg/kg i. v.) were measured. Pain severity was scored (short form of the Glasgow Composite Measure Pain Scale, GCMPS) before surgery and postoperatively at 2, 4, 6, 12 and 24 hours after extubation. Post-operative rescue analgesia consisted of methadone (0.2 mg/kg i. v.), and was applied when the GCMPS > 6. For statistical analysis, the Chi-square, Fisher, and Wilcoxon tests and one- and two-way ANOVA were applied. Differences were considered statistically significant at p < 0.05. RESULTS: Only the MAP was significantly different between the two treatment groups. Intra- and postoperative MAP of group LA (111.2 ± 11.2 mmHg and 119.3 ± 18.2 mmHg, respectively) was higher than in group EPI (86.6 ± 8.7 mmHg and 95.2 ± 13.1 mmHg, respectively). None of the dogs developed urinary retention or ambulatory deficits when completely recovered from anaesthesia. No other side effects were noted. CLINICAL RELEVANCE: In conclusion, femoral and sciatic nerve blocks and epidural anaesthesia ensure comparable analgesic effects in canine patients undergoing orthopaedic surgery of the pelvic limb. The lower mean arterial blood pressure of group EPI was not of clinical relevance.

Influence of metamizole on 1) minimal alveolar concentration of sevoflurane in dogs and 2) on thermal and mechanical nociception in conscious dogs.

OBJECTIVE: To determine the acute anti-nociceptive and the minimal alveolar concentration (MAC) sparing effects of metamizole sodiummonohydrate (dipyrone) in dogs for possible perioperative analgesia. STUDY DESIGN: Two groups of seven adult dogs were used in two separate randomised, blinded, controlled, cross-over studies. In each study, each dog received metamizole 50 mg kg(-1) intravenously (IV) and placebo (saline 0.9%) IV. METHODS: Sevoflurane MAC was determined using the bracketing technique and electrical stimulation (50 V, 50 Hz, 10 milliseconds) at a thoracic limb, before treatment and 1 and 4 hours post treatment. In conscious dogs, thermal thresholds were determined by ramped contact heat at the thoracic wall. Mechanical thresholds (MTs) were measured by constantly rising force pressing against the radial bone. Thresholds were determined pre and 45, 75, 105, 135, 165, 195, 225, 255, 285, 315, 345, 375, 435, 495, 555, 615, 675, 735 minutes and 24 hours post treatment. Parametric data were analyzed by analysis of variance for repeated measurements and paired t-tests. Friedman test was used for nonparametric data. Level of significance was set to <5%. RESULTS: Metamizole did not change MAC of sevoflurane significantly compared to baseline values [mean ± SD Vol%; 2.7 ± 0.5 (BL); 2.8 ± 0.6 (1 hour); 2.8 ± 0.4 (4 hours)] and placebo [2.8 ± 0.5 (BL); 2.9 ± 0.5 (1 hour); 2.9 ± 0.4 (4 hour)]. Metamizole caused a significant rise in % TE up to 105 minutes (66.5 ± 12.1%) and in MT up to 75 minutes (12.7 ± 5.0 N) compared to baseline (55 ± 10%; 7.9 ± 1.8 N). There were no significant differences between treatments. CONCLUSION AND CLINICAL RELEVANCE: Metamizole did not induce an anaesthetic sparing effect. In awake dogs metamizole induced only mild and short cutaneous anti-nociception. Metamizole as the sole analgesic drug in the perioperative periode is not recommended.