Clinical techniques in veterinary dermatology Regional anaesthesia of the canine and feline nose.

Local anaesthesia techniques are now essential parts of the multimodal analgesic approach applied in the care of small animals. The sensory innervation of the nose is provided by the maxillary division of the trigeminal nerve, so nasal pain can be prevented or alleviated by blocking branches of this nerve. Maxillary or infraorbital nerve block can be used if invasive procedures are performed on the nose of the canine and feline patients. Clear anatomical landmarks facilitate the placements of these blocks, which impose relatively low risk to the patients. These blocks do not require any advanced equipment and all necessary material is widely available in small animal veterinary practices. The total dose of the local anaesthetic agents should be calculated precisely to avoid toxicity.

Les techniques d'anesthésie locale sont aujourd'hui une part essentielle de l'approche analgésique multimodale appliquée aux soins des petits animaux. L'innervation sensorielle du nez est assurée par la division maxillaire du nerf trijumeau, de sorte que la douleur nasale peut être prévenue ou soulagée en bloquant les branches de ce nerf. Un bloc nerveux maxillaire ou sous-orbitaire peut être utilisé si des procédures invasives sont effectuées sur le nez des patients canins et félins. Des repères anatomiques clairs facilitent la mise en place de ces blocs, qui présentent un risque relativement faible pour les patients. Ces blocs ne nécessitent aucun équipement de pointe et tout le matériel nécessaire est largement disponible dans les cabinets vétérinaires pour petits animaux. La dose totale des agents anesthésiques locaux doit être calculée avec précision pour éviter toute toxicité.

Las técnicas de anestesia local son ahora partes esenciales en la estrategia analgésica multimodal aplicado para el cuidado de animales pequeños. La inervación sensorial de la nariz la proporciona la división maxilar del nervio trigémino, por lo que el dolor nasal se puede prevenir o aliviar bloqueando las ramas de este nervio. El bloqueo del nervio maxilar o infraorbitario se puede utilizar si se realizan procedimientos invasivos en la nariz de los pacientes caninos y felinos. Los puntos de referencia anatómicos claros facilitan la colocación de estos bloqueos, que suponen un riesgo relativamente bajo para los pacientes. Estos bloqueos no requieren ningún equipo avanzado y todo el material necesario está ampliamente disponible en las prácticas veterinarias de pequeños animales. La dosis total de los agentes anestésicos locales debe calcularse con precisión para evitar la toxicidad.

As técnicas de anestesia local são partes essenciais da abordagem anestésica multimodal aplicada na assistência de pequenos animais. A inervação sensorial do nariz é fornecida pela a divisão maxilar do nervo trigêmeo, assim, a dor nasal por ser prevenida ou aliviada pelo bloqueio dos ramos deste nervo. O bloqueio do nervo maxilar ou infraorbital pode ser utilizado em procedimentos invasivos realizados no nariz de cães e gatos. Marcadores anatômicos claros facilitam o posicionamento desses bloqueios, submetendo os pacientes a um risco relativamente baixo. Esses bloqueios não necessitam de nenhum equipamento avançado e todo o material necessário é amplamente disponível em clínicas e hospitais veterinários. A dose total dos anestésicos locais deve ser calculada com precisão para evitar toxicidade.

Optimising endotracheal length in adult cats: a retrospective CT study.

OBJECTIVES: The aim of this study was to determine the maximal endotracheal insertion length by measuring the larynx to carina (L-C) distance by means of CT. An additional objective was to establish certain anatomical landmarks to optimise the process of endotracheal intubation (ETI). METHODS: Head, neck and thoracic CT images from adult cats at a single referral hospital between 2013 and 2020 were retrospectively evaluated. After standardising and identifying key markers (larynx, carina and first rib) the L-C, larynx to first rib (L-1R) and first rib to carina (1R-C) distances were measured. RESULTS: Forty-five adult cats were enrolled in the study, from which a total of nine different breeds were identified. The L-C distance was 14.3 ± 1.1 cm. This was longer in male (14.7 ± 1.1 cm) than in female cats (13.5 ± 0.7 cm). The first rib (1R) was 8.8 ± 0.7 cm from the larynx and the mean 1R-C distance was 5.4 ± 0.7 cm. The carina was found within the fifth intercostal space in 93.3% (n = 42) of the cats. CONCLUSIONS AND RELEVANCE: The process of ETI in adult cats may be guided by using the L-C and L-1R distance for a maximal and optimal endotracheal tube introduction, respectively. In addition, the maximal insertion length may be guided by estimating the position of the carina parallel to the fifth intercostal space.

Evaluation of corneal anaesthesia after the application of topical 0.5% bupivacaine, 2% lidocaine and 0.4% oxybuprocaine in normal horses.

OBJECTIVE: To compare the corneal anaesthetic effect of 0.5% bupivacaine, 2% lidocaine and 0.4% oxybuprocaine on normal equine eyes. STUDY DESIGN: Prospective, blinded crossover study. ANIMALS: A group of 10 clinically healthy horses. METHODS: Corneal sensitivity was determined in each eye by measuring corneal touch threshold (CTT). The study had three phases. Each subject was randomly given one of the three treatments followed by a 72 hour washout period. Every horse received all treatments. Baseline CTT was recorded prior to anaesthetic instillation (T0) then CTT was measured 5 and 10 minutes after (T1 and T2, respectively), then 20 to 90 minutes (T3 to T10) at 10 minute intervals. CTT data were compared among treatments at each time point using the Friedman test p < 0.05. RESULTS: Median (range) baseline CTT was 51.3 (25.0-60.0) mm for bupivacaine, 50.0 (40.0-55.0) mm for oxybuprocaine and 55.0 (30.0-60.0) mm for lidocaine. All treatments caused a significant decrease in CTT at T1. The lowest CTT was observed at T3 with bupivacaine and oxybuprocaine treatments. Median CTTs at this time point were 18.7 (5.0-25.0) mm and 28.7 (25.0-40.0) mm, respectively. The lowest CTT with lidocaine treatment was 28.7 (20.0-50.0) mm at T6 (50 minutes). At T3, CTT was significantly lower with the bupivacaine treatment compared with oxybuprocaine and lidocaine treatments (p < 0.0074). There was no significant difference in CTT values between T1 and T6 for bupivacaine, between T1 and T7 for lidocaine, and between T1 and T8 for oxybuprocaine. Duration of the maximum effect was 45 minutes for the bupivacaine, 55 minutes for the lidocaine and 65 minutes for the oxybuprocaine treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of a 0.5% injectable solution of bupivacaine or a 2% lidocaine had similar anaesthetic effect to the commonly used oxybuprocaine. Therefore, they might be used as alternatives for corneal anaesthesia.

Effects of Intravenous Flunixin Meglumine, Phenylbutazone, and Acupuncture on Ocular Pain Scores in the Horse: A Pilot Study.

In this controlled, blinded, randomized block pilot study, the main objective was to evaluate the effectiveness of intravenous flunixin meglumine, phenylbutazone, and acupuncture on ocular pain relief using a multifactorial pain scale in the horse. Four experimental horses underwent corneal epithelial debridement in four sessions, when a randomly selected treatment or a control was used. All horses were pain scored before corneal wounding, then at 18 time points, when 11 parameters were allocated. Differences in the area under the curve of pain scores between the treatment groups were analyzed using a paired t-test. Corneal pain was significantly reduced by the third postoperative day (P = .03) when all 11 parameters were considered. Five ocular signs showed significant differences between treatments and proved to be good indicators of ocular pain. The other parameters (heart rate, corneal touch threshold, respond to palpation, and three behavioral parameters) were determined to be irrelevant when evaluating the degree of pain. When considering the five ocular signs, the lowest pain score was attributed to the flunixin meglumine group (1114), followed by the electroacupuncture group (1356), the phenylbutazone group (1397), and the control group (1580). There were significantly lower pain scores (P = .01) in the flunixin meglumine group when compared with those recorded in the control group during the first 46 hours. Flunixin meglumine was the most effective treatment at reducing ocular pain in the horse. In the future, a reduction in the number of pain score parameters and more precisely defined image evaluation criteria could be used.

Quantitative sensory testing of the equine face.

BACKGROUND: Quantitative sensory testing methods are now standard in the evaluation of sensory function in man, while few normal equine values have been reported. OBJECTIVES: The aim of this experimental study was (a) to define the tactile sensory, mechanical nociceptive and thermal nociceptive thresholds of the equine face; (b) to assess the effect of age, sex, stimulation site and shaving; (c) to evaluate the reliability of the methods and (d) to provide reference facial quantitative sensory testing values. STUDY DESIGN: Method description. METHODS: Thirty-four healthy Warmblood horses were used in the study. Six (tactile sensory threshold) and five (mechanical nociceptive and thermal nociceptive thresholds) areas of the left side of the face with clear anatomical landmarks were evaluated. Ten horses had two (mechanical nociceptive threshold) or three (tactile sensory and thermal nociceptive thresholds) of these areas shaved for another study. A linear Mixed model was used for data analysis. RESULTS: All thresholds increased with age (tactile sensory threshold: by 0.90 g/y (CI = [0.12 g; 0.36 g]) P = .001; mechanical nociceptive threshold: by 0.25 N/y (CI = [0.13-0.36 N]) P = .000; thermal nociceptive threshold: by 0.2°C/y (CI = [0.055-0.361]) P = .008). Sex had no effect on thresholds (tactile sensory threshold: P = .1; mechanical nociceptive threshold: P = .09; thermal nociceptive threshold: P = .2). Stimulation site affected tactile sensory and mechanical nociceptive thresholds (P = .001 and P = .008), but not thermal nociceptive threshold (P = .9). Shaving had no significant effect on any of the thresholds (tactile sensory threshold: P = .06; mechanical nociceptive threshold: P = .08; thermal nociceptive threshold: P = .09). MAIN LIMITATIONS: Only the left side was investigated and measurements were obtained on a single occasion. CONCLUSIONS: Handheld quantitative sensory testing does not require shaving or clipping to provide reliable measurements. Stimulation over the nostril (tactile sensory threshold), temporomandibular joint (mechanical nociceptive threshold) and supraorbital foramen (thermal nociceptive threshold) resulted in the most consistent thresholds.

Analysis of teaching methods in anaesthesia in the undergraduate curriculum of four veterinary universities.

OBJECTIVE: To design a holistic audit tool to assess the effectiveness of anaesthesia teaching strategies, and thereby to study veterinary undergraduate teaching methods in different geographical areas. STUDY DESIGN: Qualitative study using interviews of university staff and students to identify common themes and differences in teaching veterinary anaesthesia. METHODS: An audit was performed using an audit tool in four veterinary universities (École Nationale Vétérinaire d'Alfort, France; Royal Veterinary College, UK; University of Buenos Aires, Argentina; and Alma mater studiorum - Università di Bologna, Italy). First, an open-question interview of anaesthesia head of service (60-90 minutes) identified the pedagogical strategies in order to conceive a subsequent semi-directive interview formulated as a SWOT analysis (Strength/Weaknesses/Opportunity/Threats). Second, the SWOT reflection was conducted by a second staff member and focussed on: 1) general organization; 2) topics for pre-rotation teaching; 3) teaching methods for clinical rotation; and 4) assessment methods. Qualitative analysis of the interview responses was performed with semi-structured interviews. Finally, the students evaluated their teaching through a students' questionnaire generated from the output of both interviews. RESULTS: A group of nine lecturers and 106 students participated in the study at four different sites. Preclinical teaching ranged from 13 to 24 hours (median 15 hours). Clinical teaching ranged from 4 to 80 hours (median 60 hours). Overall, all faculties perceived time as a limitation and attempted to design strategies to achieve the curriculum expectations and optimize teaching using more time-efficient exercises. Large animal anaesthesia teaching was found to be a common area of weakness. Internal feedback was delivered to each university, whereas generalized results were shared globally. CONCLUSIONS: This preliminary study proved the generalizability of the protocol used. Recruiting a larger pool of universities would help to identify and promote efficient teaching strategies and innovations for training competent new graduates in an ever-expanding curriculum.

Anaesthetic management and complications of canine adrenalectomies: 41 cases (2007-2017).

Little information is available about the management of adrenalectomies in veterinary anaesthesia. The aim of this study was to describe the anaesthetic techniques, the complication rate and outcome of these cases. Data were collected retrospectively from patients' records. Descriptive statistics were performed with Student's t-tests and Chi-square tests where appropriate. Forty-one cases were included. The mean age was 124.7 ± 29.4 months and the median body weight was 23.1 kg (5.3-69 kg). Carcinoma was the most common diagnosis (34.1%). Premedication was most commonly achieved with methadone alone (70.7%) IV. Propofol was the most common induction agent (39%). An infusion of opioids (80.4%) and an epidural injection of morphine (70.7%) were the most common analgesic techniques. Hypotension was the most common complication observed (51.2%). The mortality rate was 14.6%. The lowest recorded oesophageal temperature was statistically associated with the incidence of haemorrhage (P = 0.025). The invasion of the vena cava (P = 0.001) was significantly associated with haemorrhagic complications. The survival rate was better when patients received hydrocortisone intra-operatively (P = 0.026). This study highlights some possible association between the anaesthetic management and the outcome of the procedure.

A comparison of the effect of propofol and alfaxalone on laryngeal motion in nonbrachycephalic and brachycephalic dogs.

OBJECTIVE: To compare the effect of propofol and alfaxalone on laryngeal motion under a light plane of anaesthesia in nonbrachycephalic and brachycephalic dogs anaesthetized for nonemergency procedures. STUDY DESIGN: Prospective, randomized clinical trial. ANIMALS: A total of 48 client-owned dogs (24 nonbrachycephalic and 24 brachycephalic). METHODS: A standardized premedication of methadone (0.2 mg kg-1) and acepromazine (0.01 mg kg-1) was administered intramuscularly. Dogs were randomly assigned to be induced with increments of propofol (1-4 mg kg-1) or alfaxalone (0.5-2 mg kg-1). Laryngeal assessment was performed under a light plane of anaesthesia by a surgeon (GTH) who was unaware of the induction protocol. Laryngeal movement was assessed as either being present when abduction of the laryngeal cartilages upon inspiration was identified, or absent when abduction was not recognized. Simultaneously, a 60-second video was recorded. The same surgeon (GTH) and an additional surgeon (NK) re-evaluated the videos 1 month later. Categorical comparisons were studied using Chi square and Fisher's exact test where appropriate. Pairwise evaluation of agreement between scorers was undertaken with the kappa statistic (κ). RESULTS: There were no significant differences (p > 0.05) identified between the presence or absence of laryngeal motion between dogs administered propofol or alfaxalone, as well as when analysing nonbrachycephalic and brachycephalic dogs separately. The majority of dogs (>75%) maintained some degree of laryngeal motion with both protocols. Agreement between assessors was excellent (κ = 0.822). CONCLUSIONS: Alfaxalone maintained laryngeal motion similarly to propofol in nonbrachycephalic and brachycephalic dogs. CLINICAL RELEVANCE: Both agents would appear appropriate for allowing assessment of laryngeal motion in nonbrachycephalic and brachycephalic dogs. The assessment technique of subjective evaluation of laryngeal motion via peroral laryngoscopy under a light plane of anaesthesia produced consistent results amongst assessors, regardless of the induction agent used.

A pilot study of the effects of acupuncture treatment on objective and subjective gait parameters in horses.

OBJECTIVES: To investigate whether acupuncture can alter gait in horses as assessed by objective and subjective parameters. STUDY DESIGN: Prospective, randomized, singleblinded, crossover study. ANIMALS: Eight adult horses. METHODS: Horses were randomly assigned to a treatment (three acupuncture treatments in 8 days) or control group. Subjective and objective gait analyses were performed before and after each treatment and at 1, 3 and 7 days after the last treatment (time-points 1-9, respectively). Horses were assessed at the trot in a straight line on a hard surface and on the lunge on the left and right reins on a soft surface (conditions 1-3, respectively). After 12 weeks, groups were reversed. Objective gait analysis was performed using inertial sensors and subjective analysis by two board- certified surgeons who reviewed video-recordings. Each limb was assessed for lameness before and after treatment. Lameness and global scores were assigned using 4-point scales. Assessors were blinded to treatment status. The effects of treatment (yes/no), time (1-9) and horse under conditions 1 -3 were compared using a linear mixed-effects model and a generalized estimating equation. RESULTS: Treatment decreased hip hike difference under all conditions [condition 1: control, 6.3 ± 6.4 mm versus treatment, -0.2 ± 6.4 mm (p = 0.007); condition 2: control, 9.7 ± 7.8 mm versus treatment, 2.8 ± 7.8 mm (p = 0.032); condition 3: control, 7.3 ± 6.3 mm versus treatment, -2.7 ± 6.4 mm (p = 0.003)]. Other parameters also improved significantly under conditions 1 and 3. Based on subjective gait analysis, treatment decreased lameness [odds ratio (OR) 0.51, 95% confidence interval (CI) 0.34-0.78; p = 0.002] but not global (OR 0.53, 95% CI 0.24-1.10; p = 0.12) scores. CONCLUSIONS AND CLINICAL RELEVANCE: Acupuncture can change horses' gaits to a degree appreciable by objective and subjective analyses.

Pancuronium dose refinement in experimental pigs used in cardiovascular research.

OBJECTIVE: To quantify the dose of pancuronium required to obtain moderate neuromuscular blockade as monitored by acceleromyography (NMB(mod) : train-of-four count of ≤2) as a part of a balanced anaesthetic protocol in pigs used in cardiovascular research. STUDY DESIGN: Prospective cross-sectional study. ANIMALS: Five pigs (median body weight: 60 (range 60-63) kg). METHODS: Anaesthesia was induced with xylazine, ketamine, atropine and midazolam and maintained with isoflurane in O(2) :air and fentanyl. Pigs received 0.1 mg kg(-1) pancuronium initial bolus to reach NMB(mod) followed by 0.1 mg kg(-1) hour(-1) constant rate infusion (CRI). During anaesthesia a twitch count of 3 or measureable T4/T1 ratio indicated unsatisfactory NMB. In this case additional 0.4 mg boluses of pancuronium were administered IV to effect in addition to the CRI. Descriptive statistical analysis was performed to express the median and range of the bolus and CRI dose of pancuronium in pigs. Cardiovascular parameters were analyzed at selected time points with Friedman Repeated Measures Analysis on Ranks. Spearman Rank test was used to evaluate correlation between parameters. RESULTS: Acceleromyographic monitoring of NMB is feasible in anaesthetized pigs. The median initial dose and rate of pancuronium required to achieve NMB(mod) were 0.10 (range 0.10-0.13) mg kg(-1) and 0.11 (range 0.10-0.21) mg kg(-1) hour(-1) , respectively. The administration rate showed considerable individual variation. CONCLUSIONS AND CLINICAL RELEVANCE: These pancuronium doses can be used as a guideline to achieve NMB(mod) in pigs as part of a balanced anaesthetic protocol. Instrumental NMB monitoring is essential because of individual kinetic variations and compliance to monitoring guidelines.