Veterinary anaesthesia and analgesia最新文献

A 14-year-old, male castrated, Domestic Short Hair cat was presented for thoracic duct ligation via thoracoscopy. To optimise surgical visualisation, the surgeons requested one-lung ventilation. Because adequately sized bronchial blockers or fibreoptic bronchoscopes were not available, a modified single-lumen endotracheal tube guided by a novel method was used. The distance between the incisors, the carina and the mainstem bronchi was premeasured on a computed tomography scan. Once under general anaesthesia, one-lung ventilation was achieved by introducing a guidewire through a modified, previously extended endotracheal tube, confirming its advancement towards the left main bronchus with fluoroscopy, and subsequently advancing the endotracheal tube over the guidewire. Confirmation of one-lung ventilation was initially obtained by observation of unilateral thoracic excursions and later confirmed by thoracoscopic visualisation of right lung atelectasis. The manoeuvre was successfully completed in 8 minutes and no clinically significant complications occurred. Adequate ventilation was achieved using pressure control mode and positive end-expiratory pressure, and allowing permissive hypercapnia. After thoracic duct ligation, bilateral lung ventilation was resumed by slight withdrawal of the endotracheal tube. The cat was allowed to recover from anaesthesia and transferred to the intensive care unit. This report describes a novel method to achieve one-lung ventilation in a cat that may constitute a valid alternative when adequately sized bronchial blockers or fibreoptic bronchoscopes are not available.

Objective: To characterize the pharmacokinetics of combinations of dexmedetomidine, vatinoxan and ketamine in cats.

Study design: Partially randomized, crossover, experimental study.

Animals: A group of six healthy male neutered cats, aged 1-2 years, weighing 5.4 ± 0.3 kg.

Methods: Each cat was administered six treatments: dexmedetomidine (25 μg kg^-1; D) + vatinoxan (600 μg kg^-1; V) + ketamine (2.5 mg kg^-1; K2.5) intramuscularly (IM) (DVK2.5IM); D + V + ketamine (5 mg kg^-1; K5) IM (DVK5IM); D + V + ketamine (10 mg kg^-1; K10) IM (DVK10IM); D + K5 IM (DK5IM); D + V + K5 subcutaneously (SC) (DVK5SC); or D + V + K5 intravenously (IV) (DVK5IV). Venous blood samples were collected before treatment injection, and at various times up to 6 hours thereafter. Plasma dexmedetomidine, vatinoxan and ketamine concentrations were measured using liquid chromatography/tandem mass spectrometry. Compartment models were fitted to the time-plasma dexmedetomidine, vatinoxan and ketamine data using nonlinear mixed effect modeling, including covariates for the effects of vatinoxan and the dose of ketamine where appropriate.

Results: Two-compartment models best fitted the time-plasma dexmedetomidine, vatinoxan and ketamine concentrations. The models predicted that vatinoxan increases the clearance of dexmedetomidine and decreases the bioavailability of IM ketamine and that increasing doses of ketamine increase the volume of the central compartment for dexmedetomidine and the bioavailability of IM ketamine. The volume of distribution at steady state (mL kg^-1) and metabolic clearance (mL minute^-1 kg^-1) were 1012-2429 and 12.5-15.4 for dexmedetomidine, 666 and 3.7 for vatinoxan and 2260 and 23.8 for ketamine, respectively. Bioavailability (%) for IM and SC dexmedetomidine, vatinoxan and ketamine was 83 and 95, 99 and 95 and 60-100 and 100, respectively.

Conclusions and clinical relevance: The pharmacokinetics of dexmedetomidine and the bioavailability of ketamine were affected by vatinoxan and the dose of ketamine.

Objective: To determine the influence of xylazine infusion on survival to discharge and describe the associated intraoperative requirement for isoflurane, use of positive inotropes and vasopressors, and recovery time in horses undergoing exploratory laparotomy.

Study design: Retrospective cohort study.

Animals: A total of 352 horses.

Methods: Medical records of horses undergoing anesthesia for exploratory laparotomy from January 2018 to December 2023 were reviewed. Data collected included survival to discharge, results of diagnostic tests, end tidal isoflurane concentration (FE'Iso), use of vasopressors/inotropes, and duration of recovery in horses with (WX) or without (WOX) intraoperative xylazine infusion. For survival to discharge, univariable and multivariable logistic regression was performed adjusting for the effects of other infusions. For all other variables, descriptive statistics were performed.

Results: Survival to discharge was 80.6% and 78.5% for WX and WOX, respectively (p = 0.431). Mean ± standard deviation FE'Iso was 0.82 ± 0.21% and 0.94 ± 0.21% for WX and WOX, respectively. Dobutamine was given to 159/166 (95.8%) and 176/186 (94.6%) horses at a rate of 1 (0.1-3.0) μg kg^-1 minute^-1 and 1 (0.25-3.0) μg kg^-1 minute^-1 in WX and WOX, respectively. Norepinephrine infusion was given to 15/166 (9%) and 27/186 (15%) horses at a rate of 0.2 (0.025-0.4) μg kg^-1 minute^-1 and 0.2 (0.05-0.7) μg kg^-1 minute^-1 in WX and WOX, respectively. Median (range) recovery times were 70 (15-310) minutes and 75 (20-313) minutes for WX and WOX, respectively.

Conclusions: The use of xylazine as a part of a balanced anesthesia protocol in horses undergoing exploratory laparotomy did not negatively affect survival to discharge.

Clinical relevance: Xylazine infusion as part of a balanced anesthesia protocol appears promising based on this single-center study. Further research is required to fully explore the risks and benefits of xylazine infusions in this context.

Burn-related neuropathic pain (BRNP) can arise following burn-induced nerve damage, affects approximately 6% of burned human patients and can result in chronic pain. Although widely studied in humans, data on BRNP or its treatment in animals is lacking. A 4-year-old domestic shorthair cat was presented with an infected, non-healing wound suspected to be a caustic burn. Initial treatments included surgical debridement, antimicrobials, and corticosteroids, but the cat developed persistent pruritus leading to self-inflicted trauma. Despite various interventions, including prednisone, chloramphenicol and cyclosporine, clinical signs persisted, leading to a referral for suspected BRNP. Additional support for neuropathic pain was provided through thermal sensitivity testing and applying a modified Neuropathic Pain Symptoms Inventory. Treatment with gabapentin, amantadine, and acupuncture yielded little improvement, prompting an increasing escalation in gabapentin dosage. The cat was then treated with gabapentin compounded with compound 194, a small molecule that is a potent and selective inhibitor of voltage-gated sodium channel 1.7 (Na_V1.7). The cat exhibited significant pain relief and improvements in overall condition. After gabapentin was tapered, compound 194 effectively maintained pain control. The cat's clinical condition stabilized with no adverse effects. Hematology and serum biochemistry results remained within reference intervals throughout the treatment period. This case highlights the potential of Na_V1.7 inhibitors in multimodal management of neuropathic pain in animals.

Objective: To investigate whether infiltrating bupivacaine with ketamine into the epaxial muscles improves quality and duration of analgesia perioperatively compared with bupivacaine alone or ketamine intramuscularly.

Study design: Prospective blinded randomized clinical study.

Animals: A group of 66 dogs randomized into three groups (n = 22).

Methods: Before surgery, bupivacaine 0.5% 2 mg kg^-1 alone (group B) or combined with ketamine 2 mg kg^-1 (group BK) was infiltrated peri-incisionally into the epaxial muscles. Group K received ketamine 2 mg kg^-1 injected intramuscularly into a cervical muscle without infiltration. Meloxicam 0.2 mg kg^-1 was given intravenously (IV) before moving to theatre. Cardiovascular variables: heart rate and systolic, mean and diastolic blood pressure were recorded. Intraoperative fentanyl 5 μg kg^-1 IV was administered if these variables increased by 20% from baseline. Fentanyl continuous infusion (5 μg kg^-1 hour^-1) was started if more than three boluses were required. The Glasgow Composite Pain Scale-Short Form was used pre- and postoperatively for acute pain assessment at different time intervals; methadone 0.2 mg kg^-1 IV was administered if scores were greater 5/20. Analgesia requirements, time to first administration, pain scores, total opioids interventions, need for sedation, first food intake and adverse effects were recorded. Continuous, normally distributed and non-normally distributed variables were analysed using ANOVA or Kruskal Wallis test, respectively.

Results: No significant difference was found for cardiovascular variables between groups over time, intra- or postoperative analgesia requirements, time to administration, pain scores total opioids, time to first food intake, sedation and occurrence of adverse effects.

Conclusions and clinical relevance: No difference in perioperative rescue analgesia was found between groups.

Objective: To determine the effects of rapid (1 minute) and slow (10 minutes) intravenous (IV) injection of sodium penicillin on arterial blood pressure in anesthetized horses.

Study design: Prospective randomized clinical trial.

Animals: A group of 29 client-owned horses of various breeds, 1-20 years old, with body masses of 360-710 kg.

Methods: General anesthesia was induced with a variety of anesthetic protocols and maintained with isoflurane under mechanical ventilation, with hourly doses of IV lidocaine and an infusion of dexmedetomidine. Horses were administered IV intraoperative penicillin every 2 hours after the preoperative dose, reconstituted with 50 mL of saline (group small dilution, SD) and administered over 1 minute, or with 250 mL of saline (group large dilution, LD) administered over 10 minutes. Systolic, diastolic and mean arterial blood pressures (SAP, DAP, MAP), heart rate, end-tidal isoflurane and carbon dioxide, dobutamine rate and arterial electrolytes were recorded before and for 20 minutes after penicillin. Comparisons between and within groups were with two-way anova.

Results: Dose and time to penicillin delivery during anesthesia were similar between groups. SAP decreased significantly by 4.8-9.6% (p < 0.0001-0.038), DAP by 12.7-25.4% (p = 0.0009-0.016) and MAP by 6.6-18.4% (p = 0.0009-0.028) from injection and for 15-20 minutes in group SD. In group LD, significant decreases in DAP (13.8-18.5%; p < 0.0001-0.005) and MAP (10.1-13.9%; p < 0.0001-0.003) occurred at 3-15 minutes, and DAP (p = 0.013 and 0.008) and MAP (p = 0.016 and 0.007) were higher than for group SD at 1 and 3 minutes. Dobutamine rate and other variables were similar between groups.

Conclusions and clinical relevance: Arterial blood pressure decreased with both SD and LD in anesthetized horses, but to a lesser extent in the slower, more diluted LD group.

This report describes the case of a brown-black coloured mountain goat (Caprinae), aged 13 months and weighing 46 kg, which was presented for anaesthesia to facilitate surgical repair of a femoral head fracture in the left pelvic limb. Clinical evaluation was unremarkable except for marked lameness (5/5). After sedation, general anaesthesia was induced for open reduction and internal fixation of the fracture using pins. After aseptic preparation, a 'GIN & TONIC' block, comprising the combination of an ultrasound-guided greater ischiatic notch (GIN) plane block (bupivacaine 0.25%; 0.25 mL kg^-1) and a caudal quadratus lumborum block (C-QLB, bupivacaine 0.25%; 0.3 mL kg^-1), was performed. No significant changes in monitored physiologic variables were observed during the fracture repair except for a slight heart rate increase (21% above 77 beats minute^-1 at baseline) during fracture reduction, which was treated with a single dose of intravenous ketamine (0.2 mg kg^-1). Regurgitation of ruminal contents occurred just before ketamine injection. At extubation, the interior of the endotracheal tube was clear and no signs of aspiration were observed postoperatively. The goat readily accepted food 3 hours after surgery, and no pain response was elicited on palpation of the surgical site immediately after recovery or during the next 12 hours. This case suggests that the ultrasound-guided GIN plane block combined with the C-QLB (GIN & TONIC block) offers effective and reliable analgesia for surgeries at the hip joint in goats. Future studies are warranted to further validate the efficacy and safety of this technique in goats and explore its potential benefits in other ruminants undergoing orthopaedic procedures.