Pharmacokinetics of hydrorphone hydrochloride after intravenous and subcutaneous administration in ferrets (Mustela putorius furo).

OBJECTIVE: To determine the pharmacokinetic profile of hydromorphone 0.2 mg kg-1 administered by the intravenous (IV) and subcutaneous (SC) route in ferrets. STUDY DESIGN: Randomized, crossover study. ANIMALS: A group of eight adult ferrets weighting (mean ± standard deviation) 1.02 ± 0.22 kg. METHODS: Hydromorphone hydrochloride 0.2 mg kg-1 was administered IV or SC with a washout period of 7 days. Blood samples were collected from a jugular catheter before administration of hydromorphone and at 5, 10, 15, 20, 30, 45, 60, 90, 120, 240, 360, 480 and 720 minutes after hydromorphone administration. Plasma hydromorphone concentrations were determined by liquid chromatography/tandem mass spectrometry. Data were analyzed using a non-linear mixed effects model. RESULTS: The hydromorphone effective half-life was (t1/2) 45 min-1. Systemic clearance (Cls) and the volume of distribution (Vdss) following IV administration were 84.8 mL kg-1 min-1 and 5.59 L kg-1, respectively. The maximum observed plasma concentration was 59.53 ± 14.02 ng mL-1 within 10 minutes following SC administration. The SC bioavailability was 102.0%. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of IV and SC hydromorphone (0.2 mg kg-1) was characterized by a high clearance, short terminal half-life and large volume of distribution. Hydromorphone plasma concentrations remained greater than 2 ng mL-1 for 2 hours in most ferrets, a threshold reported to provide antinociceptive effects in other species. Hydromorphone was well absorbed following SC injection, providing an alternative administration route for clinical use in ferrets.

Subcutaneous administration of hydromorphone (0.2 mg/kg) provides antinociception in ferrets (Mustela putorius furo).

OBJECTIVE: To evaluate antinociceptive efficacy of SC administration of hydromorphone hydrochloride and buprenorphine hydrochloride in ferrets (Mustela putorius furo). ANIMALS: 14 healthy adult ferrets (6 neutered males, 8 spayed females). METHODS: In a randomized, blind, controlled, complete crossover design, all 14 ferrets received a single, SC injection of hydromorphone low dose (0.1 mg/kg), hydromorphone high dose (0.2 mg/kg), buprenorphine low dose (0.02 mg/kg), buprenorphine high dose (0.04 mg/kg), or saline solution (0.2 mL/kg). Sedation and forelimb withdrawal latency from a noxious thermal stimulation were evaluated, and behavior was recorded for a total of 8 hours postinjection. RESULTS: Compared to saline, administration of hydromorphone at 0.2 mg/kg resulted in an estimated increase of withdrawal latencies of 7.4 seconds (95% CI, 3.2 to 11.6) at 60 minutes, of 6.6 seconds (2.4 to 10.8) at 90 minutes, of 6.0 seconds (1.8 to 10.2) at 120 minutes, of 7.0 seconds (2.9 to 11.1) at 180 minutes, and of 4.5 seconds (0.5 to 8.6) at 240 minutes. These differences were statistically significant. Hydromorphone administered at a lower dose and buprenorphine at either dose did not increase withdrawal latencies compared to saline. Based on the sedation score used in this study, signs of sedation increased over time in a similar fashion with all treatments, including saline. Erratic dysphoric-like behaviors occurred in all groups except for saline. CLINICAL RELEVANCE: SC administration of hydromorphone at a dose of 0.2 mg/kg provided antinociception from 1 to 4 hours postinjection. Further validation of sedation scores in ferrets is warranted.

Remibrutinib inhibits hives effector cells stimulated by serum from chronic urticaria patients independently of FcεR1 expression level and omalizumab clinical response.

BACKGROUND: Despite advances in the treatment of chronic urticaria, in a significant percentage of the patients symptoms are not fully controlled with conventional approaches. New strategies under development include blocking intracellular mediators of mast cell and basophil activation. OBJECTIVE: We aim to investigate the effects of the Bruton's tyrosine kinase (BTK) inhibitor remibrutinib on human blood basophils and CD34+ -derived mast cells activation induced by serum obtained from chronic urticaria patients. METHODS: Twenty-two patients with chronic spontaneous urticaria (mean age 52 years, 27% women) and 22 patients with chronic inducible urticaria (46 years, 27% women) were included in the study together with a sex-matched control group. Patients were classified as responders or non-responders to anti-IgE therapy on the basis of their clinical data, FcεR1a expression on blood basophils and total IgE levels. Changes on CD63 expression-as an activation marker-, were used to evaluate in vitro the response of basophils and mast cells to serum exposure and the inhibitory effects of remibrutinib. RESULTS: Remibrutinib inhibits degranulation induced by IgE cross-linking in mast cells and basophils and also the activation triggered by factors present in the sera of spontaneous and inducible chronic urticaria patients. Patient's serum induces a greater degranulation of effector cells than controls. Activation of mast cells and basophils by patient sera and remibrutinib effects were not related to omalizumab responsiveness. CONCLUSION: Remibrutinib inhibits activation of human basophils and mast cells induced in vitro by exposure to the serum of chronic urticaria patients independently of their response to omalizumab.

Comparison of the effect of sedation and general anesthesia on pattern and flash visual evoked potentials in normal dogs.

BACKGROUND: Visual evoked potentials (VEPs) can provide objective functional assessment of the post-retinal visual pathway. This study compared the effects of sedation (butorphanol and dexmedetomidine) and general anesthesia (propofol and sevoflurane) on pattern and flash VEPs. Dogs (n = 13) underwent sedation or anesthesia and VEPs were obtained from 3 subcutaneous recording electrodes placed on the head (O1, Oz, O2). RESULTS: Pattern VEPs could only be recorded under sedation and a maximum of 3 peaks were identified (N75, P100, N135). Flash VEPs could be recorded under both sedation and anesthesia and a maximum of 5 peaks were identified (N1, P1, N2, P2, N3). The latency of the N1 peak and the baseline-N1 amplitude were significantly longer under general anesthesia. CONCLUSION: Visual evoked potentials should be preferentially recorded in dogs sedated with dexmedetomidine and butorphanol, regardless of the stimulus.

Comparison of Sedative Effects of Alfaxalone-Ketamine and Alfaxalone-Midazolam Administered Intramuscularly in Chickens.

The objective of this study was to compare the sedative effects of intramuscular alfaxalone combined with either ketamine or midazolam in chickens (Gallus gallus domesticus). A prospective, randomized blinded crossover study design with a 7-day washout period was used. Nine adult layer hens received alfaxalone 15 mg/kg with ketamine 5 mg/kg IM (treatment AK) or alfaxalone 15 mg/kg with midazolam 1 mg/kg IM (treatment AM). Time to lateral recumbency, time to loss of righting reflex, induction quality, duration of loss of righting reflex, time to sternal recumbency or vigorous response to stimulation, and time to standing were recorded. Muscle tone, response to noxious stimulation, heart rate, respiratory rate, and oxygen saturation were monitored once the righting reflex was absent. Induction and recovery times were not different between treatments. Lateral recumbency was induced in 8 of 9 birds receiving AK compared to 6 of 9 birds receiving AM. Righting reflex was absent in 7 of 9 and 5 of 9 chickens administered AK and AM, respectively. Median time to loss of righting reflex for AK and AM were 5.5 (4.3-9.3) minutes and 9.1 (4.8-15.0) minutes, respectively (P = .88). Median duration of loss of righting reflex was 21.6 (16.0-36.9) minutes for AK and 21.1 (11.9-26.4) minutes for AM (P = .38). Alfaxalone-ketamine resulted in moderate excitation during induction. Further investigations are warranted to investigate the effects of alfaxalone and midazolam or ketamine at different doses.

A performance comparison of the most commonly used minimally invasive monitors of cardiac output.

BACKGROUND: Shock is common in critically ill and injured patients. Survival during shock is highly dependent on rapid restoration of tissue oxygenation with therapeutic goals based on cardiac output (CO) optimization. Despite the clinical availability of numerous minimally invasive monitors of CO, limited supporting performance data are available. METHODS: Following approval of the University of Saskatchewan Animal Research Ethics Board, we assessed the performance and trending ability of PiCCOplus™, FloTrac™, and CardioQ-ODM™ across a range of CO states in pigs. In addition, we assessed the ability of invasive mean arterial blood pressure (iMAP) to follow changes in CO using a periaortic transit-time flow probe as the reference method. Statistical analysis was performed with function-fail, bias and precision, percent error, and linear regression at all flow, low-flow (> 1 standard deviation [SD] below the mean), and high-flow (> 1 SD above the mean) CO conditions. RESULTS: We made a total of 116,957 paired CO measurements. The non-invasive CO monitors often failed to provide a CO value (CardioQ-ODM: 40.6% failed measurements; 99% confidence interval [CI], 38.5 to 42.6; FloTrac: 9.6% failed measurements; 99% CI, 8.7 to 10.5; PiCCOplus: 4.7% failed measurements; 99% CI, 4.5 to 4.9; all comparisons, P < 0.001). The invasive mean arterial pressure provided zero failures, failing less often than any of the tested CO monitors (all comparisons, P < 0.001). The PiCCOplus was most interchangeable with the flow probe at all flow states: PiCCOplus (20% error; 99% CI, 19 to 22), CardioQ-ODM (25% error; 99% CI, 23 to 27), FloTrac (34% error; 99% CI, 32 to 38) (all comparisons, P < 0.001). At low-flow states, CardioQ-ODM (43% error; 99% CI, 32 to 63) and Flotrac (45% error; 99% CI, 33 to 70) had similar interchangeability (P = 0.07), both superior to PiCCOplus (48% error; 99% CI, 42 to 60) (P < 0.001). Regarding CO trending, the CardioQ-ODM (correlation coefficient, 0.82; 99% CI, 0.81 to 0.83) was statistically superior to other monitors including iMAP, but at low flows iMAP (correlation coefficient, 0.58; 99% CI, 0.58 to 0.60) was superior to all minimally invasive CO monitors (all comparisons P < 0.001). CONCLUSIONS: None of the minimally invasive monitors of CO performed well at all tested flows. Invasive mean arterial blood pressure most closely tracked CO change at critical flow states.

RéSUMé: CONTEXTE: L'état de choc est fréquent chez les patients blessés et en urgence absolue. La survie pendant le choc dépend fortement de la restauration rapide de l'oxygénation tissulaire avec des objectifs thérapeutiques basés sur l'optimisation du débit cardiaque (DC). Malgré la disponibilité clinique de nombreux moniteurs minimalement invasifs du DC, il n'existe que des données limitées sur leur performance pour appuyer leur utilisation. MéTHODE: À la suite de l'approbation du comité d'éthique de la recherche animale de l'Université de la Saskatchewan, nous avons évalué la performance et la capacité de suivi des tendances des appareils PiCCOplus™, FloTrac™ et CardioQ-ODM™ sur une vaste gamme d'état de DC chez des cochons. Nous avons également évalué la capacité de la tension artérielle moyenne invasive (iMAP) à suivre les changements de DC en utilisant une sonde périaortique de débit basée sur le temps de transit comme méthode de référence. L'analyse statistique a été réalisée avec fonction-échec, biais et précision, pourcentage d'erreur et régression linéaire à des conditions de DC de tous les débits, de faible débit (> 1 écart-type [ET] au-dessous de la moyenne) et de débit élevé (> 1 ET au-dessus de la moyenne). RéSULTATS: Nous avons effectué un total de 116 957 mesures de DC appariées. Les moniteurs non invasifs de la DC n'ont souvent pas réussi à fournir une valeur de DC (CardioQ-ODM : 40,6% de mesures échouées; intervalle de confiance [IC] de 99 %, 38,5 à 42,6; FloTrac : 9,6 % de mesures échouées; IC 99 %, 8,7 à 10,5; PiCCOplus : 4,7 % de mesures échouées; IC 99 %, 4,5 à 4,9; toutes les comparaisons, P < 0,001). La tension artérielle moyenne invasive n'a fourni aucun échec plus souvent que n'importe lequel des moniteurs de DC testés (toutes les comparaisons, P < 0,001). Le PiCCOplus était le plus interchangeable avec la sonde de débit à tous les états de débit : PiCCOplus (erreur de 20 %; IC 99 %, 19 à 22), CardioQ-ODM (erreur de 25 %; IC 99 %, 23 à 27), FloTrac (erreur de 34 %; IC 99 %, 32 à 38) (toutes les comparaisons, P < 0,001). Aux états de débit faible, les moniteurs CardioQ-ODM (erreur de 43 %; IC 99 %, 32 à 63) et FloTrac (erreur de 45 %; IC 99 %, 33 à 70) présentaient une interchangeabilité similaire (P = 0,07), tous deux supérieurs au PiCCOplus (erreur de 48 %; IC 99 %, 42 à 60) (P < 0,001). En ce qui concerne le suivi des tendances de DC, le CardioQ-ODM (coefficient de corrélation, 0,82; IC 99 %, 0,81 à 0,83) était statistiquement supérieur aux autres moniteurs, y compris au iMAP, mais à faibles débits, l'iMAP (coefficient de corrélation, 0,58; IC 99 %, 0,58 à 0,60) était supérieure à tous les moniteurs de DC minimalement invasifs (toutes les comparaisons, P < 0,001). CONCLUSION: Aucun des moniteurs de DC minimalement invasif n'a donné de bons résultats à tous les débits testés. La tension artérielle moyenne invasive était le moniteur qui a suivi de plus près les changements de DC dans des états critiques de débit.

Effect of preoxygenation before isoflurane induction and rocuronium-induced apnea on time until hemoglobin desaturation in domestic chickens (Gallus gallus domesticus).

OBJECTIVE: To evaluate the time to hemoglobin oxygen desaturation in chickens (Gallus gallus domesticus) with and without preoxygenation before isoflurane induction of anesthesia and rocuronium-induced apnea. STUDY DESIGN: Prospective, randomized crossover study. ANIMALS: A total of 10 healthy adult Lohmann Brown-Lite hens. METHODS: Hens were anesthetized with isoflurane for intravenous (IV) and intraarterial catheter placement and allowed to fully recover from anesthesia. Hens in the preoxygenation treatment were administered oxygen (2 L minute-1) via a facemask for 3 minutes prior to induction of anesthesia with 3% isoflurane in oxygen. In the alternative treatment, hens were not preoxygenated prior to induction of anesthesia with isoflurane in oxygen. Apnea was then induced with rocuronium bromide (1.0 mg kg-1) administered IV, and anesthesia was maintained with IV propofol infusion. A cloacal pulse oximeter measured hemoglobin oxygen saturation (SpO2). Time was recorded from the start of apnea until SpO2 was 90% (desaturation). The trachea was intubated, and anesthesia was maintained with isoflurane in oxygen with manual ventilation until spontaneous breathing returned and SpO2 ≥ 99%. PaO2 was measured before each treatment, after preoxygenation, postinduction and at desaturation. Data were analyzed between treatments using Wilcoxon matched-pairs signed rank tests with Holm-Sidák multiple comparison test, and within treatments using Friedman test with Dunn's multiple comparison test (p < 0.05). Data are reported as median (range). RESULTS: Time from start of apnea until hemoglobin desaturation was not significantly different between preoxygenated and nonpreoxygenated hens [26.5 (16-50) seconds and 24.0 (5-57) seconds, respectively; p = 0.25]. No differences in PaO2 between treatments were observed at any time point. CONCLUSIONS AND CLINICAL RELEVANCE: Preoxygenation for 3 minutes before isoflurane mask induction of anesthesia and apnea does not significantly increase time until desaturation in hens.

Pharmacokinetics of hydromorphone hydrochloride after intravenous and intramuscular administration in guinea pigs (Cavia porcellus).

OBJECTIVE: To determine the pharmacokinetics of hydromorphone hydrochloride after IV and IM administration in guinea pigs (Cavia porcellus). ANIMALS: 8 healthy adult guinea pigs (4 sexually intact females and 4 sexually intact males). PROCEDURES: In a crossover study, hydromorphone (0.3 mg/kg) was administered once IM (epaxial musculature) or IV (cephalic catheter) to each guinea pig at a 1-week interval (2 treatments/guinea pig). Blood samples were collected before and at predetermined intervals after drug administration via a vascular access port. Plasma hydromorphone concentrations were determined by liquid chromatography-tandem mass spectrometry. Noncompartmental analysis of data was used to calculate pharmacokinetic parameters. RESULTS: Mean ± SD clearance and volume of distribution for hydromorphone administered IV were 52.8 ± 13.5 mL/min/kg and 2.39 ± 0.479 L/kg, respectively. Mean residence time determined for the IV and IM administration routes was 0.77 ± 0.14 hours and 0.99 ± 0.34 hours, respectively. The maximum observed plasma concentration following IM administration of hydromorphone was 171.9 ± 29.4 ng/mL. No sedative effects were observed after drug administration by either route. CONCLUSIONS AND CLINICAL RELEVANCE: Pharmacokinetic data indicated that hydromorphone at a dose of 0.3 mg/kg may be administered IV every 2 to 3 hours or IM every 4 to 5 hours to maintain a target plasma concentration between 2 and 4 ng/mL in guinea pigs. Hydromorphone had high bioavailability after IM administration. Further research is necessary to evaluate the effects of other doses and administration routes and the analgesic effects of hydromorphone in guinea pigs.

Effect of Instructional Format on Veterinary Students' Task Performance and Emotional State during a Simulation-Based Canine Endotracheal Intubation Laboratory: Handout versus Video.

Video- versus handout-based instructions may influence student outcomes during simulation training and competency-based assessments. Forty-five third-year veterinary students voluntarily participated in a simulation module on canine endotracheal intubation. A prospective, randomized, double-blinded study investigated the impact of video (n = 23) versus handout (n = 22) instructions on student confidence, anxiety, and task performance. Students self-scored their confidence and anxiety before and after the simulation. During the simulation laboratory, three raters independently evaluated student performance using a 20-item formal assessment tool with a 5-point global rating scale. No significant between- or within-group differences (p > .05) were found for both confidence and anxiety scores. Video-based instructions were associated with significantly higher (p < .05) total formal assessment scores compared with handout-based instructions. The video group had significantly higher scores than the handout group on 3 of the 20 individual skills (items) assessed: placement of tie to the adaptor-endotracheal tube complex (p < .05), using the anesthetic machine (p < .01), and pop-off valve management (p < .001). Inter-rater reliability as assessed by Cronbach's α (.92), and Kendall's W (.89) was excellent and almost perfect, respectively. A two-faceted crossed-design generalizability analysis yielded G coefficients for both the handout (Ep2 = .68) and the video (Ep2 = .72) groups. Video instructions may be associated with higher performance scores than handout instructions during endotracheal intubation simulation training. Further research into skill retention and learning styles is warranted.

Total intravenous anesthesia with alfaxalone, dexmedetomidine and remifentanil in healthy foals undergoing abdominal surgery.

OBJECTIVE: To evaluate effects of anesthesia induced with alfaxalone and maintained with alfaxalone, dexmedetomidine and remifentanil infusions in foals. STUDY DESIGN: Prospective, experimental study. ANIMALS: A group of six healthy foals [median (range) 11 (8-33) days] undergoing abdominal surgery. METHODS: Intravenous (IV) dexmedetomidine (3-7µgkg-1) provided sedation for insertion of a pulmonary artery catheter. IV anesthesia was induced with alfaxalone (2mgkg-1) and maintained with alfaxalone (6mgkg-1hour-1), dexmedetomidine (1µgkg-1hour-1) and remifentanil (3µgkg-1hour-1). Foals were endotracheally intubated and lungs were mechanically ventilated with oxygen. Cardiac output (thermodilution), heart rate and systemic arterial pressure were measured. Arterial and mixed venous blood was analyzed for PO2 and PCO2, and glucose, lactate and electrolyte concentrations. Anesthetic depth was subjectively assessed. Systemic vascular resistance (SVR), oxygen utilization and intrapulmonary shunt were calculated. Preinduction (PB) or 10 minutes postinduction (+10B) data were used as baselines with one-way analysis of variance for repeated measures. Data are mean ± standard deviation; significance was p ≤ 0.05. RESULTS: Duration of anesthesia was 129 ± 22minutes. One foal was administered additional alfaxalone (0.5mgkg-1) following induction. Cardiac index decreased to 107 ± 31 and 87 ± 21mLkg-1minute-1 at 60 and 80minutes, respectively, compared with PB (157 ± 33mLkg-1minute-1). SVR increased to 1223 ± 166dynessecond-1cm-5 at 80minutes compared with +10B (704 ± 247dynessecond-1cm-5). Mean arterial pressures were 63-128mmHg. Time from stopping infusions to standing was 46-106minutes. All foals were hypothermic (<36°C) and three foals were administered atipamezole (0.05mgkg-1) intramuscularly during recovery. CONCLUSION: and clinical relevance Combined alfaxalone-dexmedetomidine-remifentanil provided suitable anesthesia to permit laparotomy in foals. At the doses evaluated, prolonged recovery may occur.

Effects of two fentanyl constant rate infusions on thermal thresholds and plasma fentanyl concentrations in awake cats.

OBJECTIVE: To determine the pharmacokinetics and effects on thermal thresholds (TT) of two fentanyl constant rate infusions in awake cats. STUDY DESIGN: A blinded, randomized crossover study. ANIMALS: A group of six healthy female cats, aged 3 ± 1 years, weighing 4.1 ± 0.7 kg. METHODS: Skin temperature (TSKIN) and TT were evaluated using a wireless TT device. TSKIN, TT, sedation score (SS) and blood samples were collected before an intravenous loading dose (LD; over 5 seconds) and at specific time points during (360 minutes) and after infusion. Each cat was administered two treatments: fentanyl (LD 3 µg kg-1, infusion 3 µg kg-1 hour-1; treatment F3) or fentanyl (LD 5 µg kg-1, infusion 5 µg kg-1 hour-1; treatment F5). SS between treatments was analyzed using a Kruskal-Wallis test. Statistical analysis of TT and TSKIN was performed using analysis of variance with appropriate post hoc test (p < 0.05). RESULTS: TSKIN did not vary over time for each treatment. SS did not differ between treatments. TTs were significantly higher than baseline at 15 minutes after LD for F3 and F5. TT was significantly increased at 30, 90, 120, 180 and 300 minutes in treatment F5 but not in F3. Plasma fentanyl concentrations decreased rapidly in both treatments over the first 30 minutes after infusion. The terminal half-life was 3.31 (2.93-4.41) hours for F3 and 3.67 (3.39-4.32) hours for F5 (median, range). Systemic clearance for treatments F3 and F5 was 1.95 (1.46-2.44) and 2.25 (1.98-2.47) L hour-1 kg-1 (median, range), respectively. Plasma concentrations <1.84 ng mL-1 were not associated with a significant increase in TT. CONCLUSIONS: and clinical relevance A fentanyl infusion rate of 5 µg kg-1 hour-1 increased TT during the infusion period. Effects on TT were lost rapidly with cessation of the infusion.

Effects of alfaxalone, thiopental, or propofol and diazepam on laryngeal motion in healthy dogs.

Laryngeal function is assessed by direct visualization of the larynx under a light plane of anesthesia. This study compared the effects of 3 anesthetic protocols on arytenoid motion in healthy dogs. Eight dogs were randomly assigned to receive alfaxalone, propofol and diazepam, or thiopental. Videolaryngoscopy was performed and still images at maximum inspiration and expiration were used to measure the area and height of the glottal gap. The normalized glottal gap area (NGGA = area in pixels/height2) was calculated. The NGAA change was defined as the difference between NGAA during inspiration and exhalation. Data were analyzed using Mann-Whitney and Kruskal-Wallis tests, P-values < 0.05 were considered statistically significant. No significant difference among induction protocols was found when comparing NGGA change after induction or before recovery. Alfaxalone and propofol/diazepam are useful for evaluation of laryngeal function when administered to effect and a light plane of anesthesia is maintained.

Effets de l'alfaxalone, du thiopental ou du propofol et du diazépam sur le mouvement du larynx chez des chiens en santé. La fonction du larynx est évaluée par visualisation directe du larynx sous une légère anesthésie. Cette étude a comparé les effets de trois protocoles anesthésiques sur le mouvement aryténoïde chez des chiens en santé. Huit chiens ont été assignés au hasard pour recevoir de l'alfaxalone, du propofol et du diazépam ou du thiopental. Une vidéo-laryngoscopie a été réalisée et des images fixes à l'inspiration et à l'expiration maximales ont été utilisées pour mesurer la région et la hauteur de l'écart glottal. La région normalisée de l'écart glottal (RNEG = région en pixels/hauteur2) a été calculée. Le changement RNEG a été défini comme la différence entre le RNEG durant l'inspiration et l'expiration. Les données ont été analysées en utilisant les tests de Mann-Whitney et Kruskal-Wallis, les valeurs-P < 0,05 étaient considérées comme étant significatives sur le plan statistique. Aucune différence significative n'a été trouvée parmi les protocoles d'induction lors de la comparaison du changement RNEG après l'induction ou le réveil. L'alfaxalone et le propofol/diazépam sont utiles pour l'évaluation de la fonction du larynx lorsqu'ils sont administrés jusqu'à l'effet et qu'une légère anesthésie est maintenue.(Traduit par Isabelle Vallières).

Desaturation times between dogs preoxygenated via face mask or flow-by technique before induction of anesthesia.

OBJECTIVE: To compare time to desaturation after induction of anesthesia following administration of oxygen via face mask or flow-by for 3 minutes. STUDY DESIGN: Randomized crossover study. ANIMALS: A group of six healthy adult dogs weighing 15.0 ± 3.4 kg. METHODS: Dogs were anesthetized twice separated by 14 days. Intramuscular administration of dexmedetomidine (4 µg kg-1), acepromazine (0.01 mg kg-1) and butorphanol (0.2 mg kg-1) provided sedation for percutaneous insertion of a catheter into the tracheal lumen. The tip was advanced to the thoracic inlet and position confirmed using fluoroscopy. Using a sample aspiration rate 200 mL minute-1, inspired (FIO2) and end-tidal oxygen (Fe'O2) were measured. Oxygen (100 mL kg-1 minute-1) was delivered into a circle delivery system and administered to the dog for 3 minutes via face mask or flow-by from the circle Y-piece 2.5 cm from the nares. Then, propofol was administered to induce anesthesia and apnea. A pulse oximeter (lingual probe) measured hemoglobin saturation (SpO2). At SpO2 90% (desaturation point), an endotracheal tube was inserted to allow administration of oxygen and artificial ventilation. Arterial blood and data were collected at baseline (before oxygen administration), 5 seconds after induction of anesthesia, and every 30 seconds until the desaturation point was reached. Data were analyzed using an unpaired and paired t test with (p < 0.05). RESULTS: FIO2, Fe'O2 and PaO2 (mean ± standard deviation) were significantly higher after mask preoxygenation [89.7 ± 5.5%, 83.0 ± 7.6% and 394 ± 112 mmHg (52.4 ± 14.9 kPa)] compared with flow-by [30.0 ± 5.4%, 22.7 ± 3.8% and 133 ± 22 mmHg (17.7 ± 2.9 kPa)], respectively. Time to desaturation was significantly longer after mask treatment compared with flow-by (187 ± 67 versus 66 ± 17 seconds). CONCLUSIONS AND CLINICAL RELEVANCE: Mask preoxygenation provided longer time to desaturation compared with the flow-by technique tested.

The effect of anesthetic drug choice on accuracy of high-definition oscillometry in laterally recumbent horses.

OBJECTIVE: To determine the accuracy of high-definition oscillometry (HDO) for arterial pressure measurement during injectable or inhalation anesthesia in horses. STUDY DESIGN: Prospective, clinical study. ANIMALS: Twenty-four horses anesthetized for procedures requiring lateral recumbency. METHODS: Horses were premedicated with xylazine, and anesthesia induced with diazepam-ketamine. Anesthesia was maintained with xylazine-ketamine-guaifenesin combination [TripleDrip (TD; n = 12) or isoflurane (ISO; n = 12)]. HDO was used to obtain systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures, and heart rate (HR) using an 8-cm-wide cuff around the proximal tail. Invasive blood pressure (IBP), SAP, MAP, DAP and HR were recorded during HDO cycling. Bland-Altman analysis for repeated measures was used to compare HDO and IBP for all measurements. The generalized additive model was used to determine if means in the differences between HDO and IBP were similar between anesthetic protocols for all measurements. RESULTS: There were >110 paired samples for each variable. There was no effect of anesthetic choice on HDO performance, but more variability was present in TD compared with ISO. Skewed data required log-transformation for statistical comparison. Using raw data and standard Bland-Altman analysis, HDO overestimated SAP (TD, 3.8 ± 28.3 mmHg; ISO, 3.5 ± 13.6 mmHg), MAP (TD, 4.0 ± 23.3 mmHg; ISO, 6.3 ± 10.0 mmHg) and DAP (TD, 4.0 ± 21.2 mmHg; ISO, 7.8 ± 13.6 mmHg). In TD, 26-40% HDO measurements were within 10 mmHg of IBP, compared with 60-74% in ISO. Differences between HDO and IBP for all measurements were similar between anesthetic protocols. The numerical difference between IBP and HDO measurements for SAP, MAP and DAP significantly decreased as cuff width:tail girth ratio increased toward 40%. CONCLUSION AND CLINICAL RELEVANCE: More variability in HDO occurred during TD. The cuff width:tail girth ratio is important for accuracy of HDO.

Comparison of intraoperative and postoperative pain during canine ovariohysterectomy and ovariectomy.

This study compared physiologic parameters indicating nociception during surgery and pain scores after surgery among dogs undergoing ovariohysterectomy (OHE) and ovariectomy (OVE). Twenty healthy adult female dogs were randomly assigned to either the OHE or the OVE group. Physiologic data collected during surgery included heart rate, respiratory rate, temperature, blood pressure, hemoglobin oxygen saturation, end-tidal CO2 and isoflurane, and vaporizer settings. Postoperative pain was measured using the short form Glasgow Composite Pain Scale, an interactive visual analog scale, and algometry. There were no clinically relevant differences in intraoperative nociception indices between groups. Duration of surgery for OVE was significantly shorter than for OHE (OVE 15.4 minutes, OHE 17.5 minutes, P = 0.04). There was no significant difference between groups in the use of rescue analgesia after surgery, in the average interactive visual analog scale score over the 24-hour postoperative period (P = 0.12), and in algometer readings (P = 0.34).

Comparaison de la douleur peropératoire et postopératoire durant l'ovariohystérectomie et l'ovariectomie canines. Cette étude a comparé les paramètres physiologiques indiquant la nociception durant la chirurgie et la cotation des douleurs après la chirurgie parmi les chiennes subissant une ovariohystérectomie (OHE) et une ovariectomie (OVE). Vingt chiennes adultes en santé ont été réparties au hasard soit au groupe OHE ou au groupe OVE. Les données physiologiques recueillies durant la chirurgie incluaient la fréquence cardiaque, la fréquence respiratoire, la température, la tension artérielle, la saturation en oxygène de l'hémoglobine le PCO2 et l'isoflurane de fin d'expiration ainsi que les réglages du nébuliseur. La douleur postopératoire a été mesurée à l'aide de la forme abrégée de l'échelle de douleur composée de Glasgow, d'une échelle analogue visuelle interactive et de l'algométrie. Il n'y avait pas de différences pertinentes sur le plan clinique dans les indices de nociception peropératoire entre les groupes. La durée de la chirurgie d'OVE était significativement plus courte que celle d'OHE (OVE 15,4 minutes, OHE 17,5 minutes, P = 0,04). Il n'y avait aucune différence significative entre les groupes pour le recours à un analgésique de secours après la chirurgie, dans la note d'échelle visuelle interactive moyenne pendant la période postopératoire de 24 heures (P = 0,12) et dans les lectures de l'algésimètre (P = 0,34).(Traduit par Isabelle Vallières).

The effects of intravenous alfaxalone with and without premedication on intraocular pressure in healthy dogs.

The objective of this study was to investigate the effects of intravenous alfaxalone with and without premedication on intraocular pressure (IOP) in healthy dogs. Thirty-three dogs were randomized to receive 1 of 3 treatments: acepromazine [0.03 mg/kg body weight (BW)] with butorphanol (0.2 mg/kg BW) intramuscularly (IM), followed by intravenous (IV) alfaxalone (1.5 mg/kg BW); dexmedetomidine (0.002 mg/kg BW) with hydromorphone (0.1 mg/kg BW) IM, followed by alfaxalone (1 mg/kg BW) IV; and saline 0.9% (0.02 mL/kg BW) IM, followed by alfaxalone (3 mg/kg BW) IV. Intraocular pressure (IOP) was measured at baseline, 15 min, and 30 min after premedication, after pre-oxygenation, after administration of alfaxalone, and after intubation. After induction and after intubation, the IOP was significantly increased in all groups compared to baseline. While premedication with acepromazine/butorphanol or dexmedetomidine/hydromorphone did not cause a significant increase in IOP, the risk of vomiting and the associated peak in IOP after dexmedetomidine/hydromorphone should be considered when selecting an anesthetic protocol for dogs with poor tolerance for transient increases in IOP.

L'objectif de la présente étude était d'examiner les effets de l'administration intraveineuse (IV) d'alfaxalone avec et sans prémédication sur la pression intraoculaire (PIO) chez des chiens en santé. Trente-trois chiens ont été randomisés pour recevoir un des trois traitements: acépromazine [0,03 mg/kg de poids corporel (PC)] avec du butorphanol (0,2 mg PC) par voie intramusculaire (IM), suivi d'alfaxalone (1,5 mg/kg PC) IV; dexmedetomidine (0,002 mg/kg PC) avec de l'hydromorphone (0,1 mg/kg PC) IM, suivi d'alfaxalone (1 mg/kg PC) IV; et saline 0,9 % (0,02 mL/kg PC) IM, suivi d'alfaxalone (3 mg/kg PC) IV. La PIO a été mesurée au départ, 15 min et 30 min après la prémédication, après pré-oxygénation, après administration d'alfaxalone, et après intubation. Suite à l'induction et après intubation, la PIO était augmentée de manière significative dans tous les groupes comparativement à la valeur de base. Bien que la prémédication avec les combinaisons acépromazine/butorphanol ou dexmedetomidine/hydromorphone n'a pas causée d'augmentation significative de la PIO, le risque de vomissements et le pic associé de la PIO suite à l'administration de dexmedetomidine/hydropmorphone devraient être pris en considération lors de la sélection d'un protocole d'anesthésie pour des chiens avec une faible tolérance à une augmentation transitoire de la PIO.(Traduit par Docteur Serge Messier).