Veterinary anaesthesia and analgesia最新文献

Objective: To develop an ultrasound-guided technique for intercostal nerve blocks in rabbit cadavers and to compare the success rate and potential complications of this technique to blind injection.

Study design: Prospective, randomized, blinded, descriptive experimental cadaveric study.

Animals: A group of nine adult domestic rabbit cadavers (body mass 1.8-2.4 kg).

Methods: Anatomic landmarks were identified by dissection of one cadaver and used to develop the ultrasound-guided technique. Eight cadavers were administered blind injections on one hemithorax and ultrasound-guided injections on the opposite hemithorax. The side used for each treatment was randomly assigned. For both techniques, the third to ninth intercostal nerves were targeted and 0.1 mL of yellow dye solution was injected per site. Medial displacement of the parietal pleura was assessed during ultrasound-guided injections. Rabbits were dissected following injection, and injections were considered successful if the circumference of the intercostal nerve was stained with dye. Additionally, the internal aspect of the parietal pleura was assessed for the presence of free dye to determine whether perforation of the parietal pleura had occurred. The number of stained nerves and incidence of pleural perforations were compared between injection techniques using Fisher's exact test. Data were considered statistically different if p < 0.05.

Results: A total of 56 blind and 56 ultrasound-guided intercostal injections were performed. Success rates of the blind and ultrasound-guided techniques were 35.7 % and 66.0 %, respectively (p = 0.002). The internal aspect of the pleura was stained in 23.2 % of blind and 21.4 % of ultrasound-guided injections, with no significant difference between groups (p > 0.999).

Conclusions and clinical relevance: Ultrasound guidance improves the accuracy of intercostal nerve injections when compared with a blind technique; however, pleural puncture is a common complication when performing intercostal injections with both techniques studied.

Objective: To model pharmacokinetics of three benzodiazepines and their metabolites in sheep.

Study design: A nonblinded, prospective, experimental study.

Animals: A group of six adult Hampshire-Suffolk cross-bred sheep (three females, three castrated males), 73 ± 3 kg (mean ± standard deviation).

Methods: Remimazolam, midazolam and diazepam were coadministered as an intravenous (IV) bolus to each sheep, and blood was sampled at 18 time points over 10 hours. HPLC-MS/MS was used to simultaneously measure plasma concentrations of the parent benzodiazepines (metabolites) for remimazolam (CNS 7054), midazolam (α-hydroxymidazolam) and diazepam (nordiazepam, temazepam, oxazepam). Concentrations over time for each compound were fit to noncompartmental models using commercial software. Calculated pharmacokinetic parameters were compared using either repeated-measures anova if normally distributed or Wilcoxon signed-rank tests if not. Differences between agents were significant when p < 0.05 after adjustments for multiple comparisons.

Results: Remimazolam was undetectable in the plasma of all sheep by 3 hours, whereas midazolam and diazepam concentrations were still quantifiable 10 hours after injection. Median (range) clearance rate from plasma was 103 (61-256), 22 (9.6-37) and 38 (20-46) mL kg^-1 minute^-1 for remimazolam, midazolam and diazepam, respectively. Median (range) terminal elimination half-time was 9.8 (4.6-15), 113 (90-271) and 246 (170-624) minutes for remimazolam, midazolam and diazepam, respectively. Except for temazepam, terminal elimination half-times were generally longer for metabolites than for their parent drug.

Conclusions and clinical relevance: Remimazolam elimination is significantly faster than either midazolam or diazepam. The rapid pharmacokinetics of remimazolam may be particularly useful to facilitate fast recovery from sedation and minimize drug residue exposures in food-producing animals.

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

Study design: Randomized crossover experimental study.

Animals: A group of seven healthy male neutered cats, with body mass 5.2 ± 0.4 kg and aged 1-2 years.

Methods: Cats were implanted with a telemetric transmitter for remote recording of mean arterial pressure and heart rate before beginning the study. Each cat received a total of six treatments, coadministered in a single syringe, each at least 2 weeks apart: 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). Select physiologic variables and time to recumbency, immobilization, first movement, head lift, return to sternal recumbency and walking were recorded. Quality of sedation/anesthesia was assessed using a visual analog score. Response to noxious electrical stimulation was assessed at 10 minute intervals.

Results: Heart rate (beats minute^-1) was significantly greater in DVK5IM (overall mean ± standard deviation 142 ± 19) than in DK5IM (115 ± 16). No treatment consistently prevented movement in response to noxious stimulation. Time to first movement was significantly shorter in DVK2.5IM (45 ± 10 minutes) than in DVK10IM (93 ± 25 minutes), and in DVK5IM (53 ± 12 minutes) than in DK5IM (95 ± 39 minutes).

Conclusions and clinical relevance: Dexmedetomidine-vatinoxan-ketamine combinations, at the doses studied, may be useful to produce sedation, but do not appear to consistently produce anesthesia as characterized by immobility in response to noxious stimulation.

Objective: To document the anesthesia curricula in colleges of veterinary medicine and compare it with student clinical supervision and expectations of new graduates by anesthesia staff.

Study design: Cross-sectional open survey study.

Population: American Veterinary Medical Association-accredited colleges of veterinary medicine (41 out of 49) and members of the American College of Veterinary Anesthesia-L (ACVA-L) listserv (88 of 128 responses).

Methods: We created two separate surveys: one distributed to colleges and one distributed to individuals. Anesthesia faculty members of each college were encouraged to complete the survey together; only one survey was submitted for each accredited veterinary college. The college survey asked about current practices of teaching veterinary anesthesia. The individual survey was distributed to the ACVA-L listserv and asked members about tasks they permit students to perform on clinic rotations, knowledge, and skills they believe are Day One Competencies.

Results: Communicating with clients about anesthesia was a Day One Competency for 95% of respondents, but not taught in almost 50% of colleges. Students are not allowed to perform this duty on their clinical rotation by almost 60% of instructors. Cardiac arrest and resuscitation, euthanasia, patient safety/systems thinking, and professionalism were cited as Day One Competencies by 97% of participants but were not taught in the anesthesia core course in at least 25% of colleges. Use of simulations for education was mentioned as important but was rare as an instructional tool.

Conclusions and clinical relevance: Veterinary anesthesia curricula generally agree with each other and the content generally aligns with what are expected Day One Competencies, as judged by anesthetists. Some topics are taught in the core anesthesia course although they were rarely considered Day One Competencies. Removal of these topics may allow room in the curriculum for the content cited more commonly as Day One Competencies.

Objective: To describe an ultrasound-guided technique for anaesthesia of the pudendal nerve with evaluation of the anatomical spread of a bupivacaine-methylene blue solution in sheep.

Study design: Prospective, experimental study.

Animals: A total of seven adult experimental sheep and one sheep cadaver.

Methods: The study had two phases. First, the anatomy and ultrasound imaging of the gluteal region, caudal to the region of tuber coxae was reviewed in one sheep cadaver. Second, in seven healthy sedated sheep, a linear transducer (8-13 MHz) was positioned on the lateral area of the hip to identify pudendal vessels at the level of the ischial spine ventral to the sacrotuberous ligament. The right and left pudendal nerves area were injected with 0.1 mL kg^-1 of a 1:1 solution of bupivacaine-methylene blue. The ultrasound image quality was considered as excellent, good, or poor. Following euthanasia, both pudendal areas were dissected and the staining of the nerves assessed, expressed as the percentage of success (%) and compared with the chi-square test.

Results: The relevant ultrasound landmarks were visualized in both areas of all sheep, with an excellent visualization of the landmarks before and during injection in most cases (13/14). On dissection, methylene blue dispersion was observed surrounding the pudendal nerve, with at least 1 cm length in 13/14 cases (93%; the remainder partially stained). No evidence of dye was found around the sciatic nerve in any case nor was there any evidence of haematoma or faecal contamination within the punctured area.

Conclusions and clinical relevance: Ultrasound-guided injection with 0.1 mL kg^-1 in close proximity to the pudendal nerve at the ischial spine level resulted in a high success rate of nerve staining. This procedure may be a suitable technique for pudendal nerve blockade providing analgesia for common reproductive or perineal surgical procedures in sheep.

Objective: To describe recent evidence-based and peer-reviewed literature on the topic of pain assessment and pain management in guinea pigs in a systematic review. To consider impacts of current practice on guinea pig welfare and to identify areas in need of further research.

Databases used: ScienceDirect, PubMed and CAB abstracts along with relevant information from books and ebooks were searched. Terms used were guinea pigs, cavies, Cavia porcellus, pain, surgery, surgical procedures, grimace, dental, bloat, analgesia, non-steroidal anti-inflammatories and opiates.

Conclusions: There are few studies available in the areas of pain assessment and pain management in guinea pigs. Grimace scales and in-clinic pain assessment scales are available for other species but have not been developed for guinea pigs. Doses of analgesic drugs are extrapolated from other species or used from anecdotal evidence in the absence of validated values. The specified dose for the only UK licenced analgesic drug for guinea pigs (meloxicam) is significantly lower than doses suggested in the reviewed literature which may have a negative impact on the welfare of this species. To improve the welfare of guinea pigs, further research into the pharmacokinetic (PK) and pharmacodynamic (PD) properties of analgesic drugs specific to this species are required. Further research into the development and validation of pain assessment methods is also indicated to promote better welfare of this species.

Objective: To assess the effect of two different doses of intramuscular atipamezole on head height (HH) in horses after sedation with detomidine.

Study design: Randomized, blinded, triple crossover study.

Animals: Eight healthy adult horses.

Methods: Baseline HH was measured before detomidine (40 μg kg^-1) was injected intravenously. HH was measured at 10 and 20 minutes after injection. Then, saline, atipamezole 60 μg kg^-1 (AT60) or 120 μg kg^-1 (AT120) was injected intramuscularly. HH measurements were repeated at 10 minutes intervals for 100 minutes. HH data were analyzed with a linear mixed model. Significance was set at p < 0.05. Data are reported as mean ± standard deviation.

Results: Baseline HH (cm) was 118 ± 14 for saline, 120 ± 10 for AT60, and 115 ± 14 for AT120 and was not significantly different among groups (p > 0.05). AT60 HH was greater than saline at 80 (33 ± 11 versus 28 ± 11), 90 (45 ± 15 versus 26 ± 13), and 110 (57 ± 24 versus 32 ± 11) minutes (all p < 0.002). AT120 HH was greater than saline at 50 (33 ± 16 versus 22 ± 8), 80 (44 ± 11 versus 28 ± 11), 90 (45 ± 11 versus 26 ± 13), 100 (52 ± 18 versus 30 ± 16) and 110 (64 ± 23 versus 32 ± 11) minutes (all p < 0.002). HH was not significantly different at any time between AT60 and AT120 (all p > 0.05).

Conclusions and clinical relevance: Horses administered atipamezole showed signs of reversal of sedation, as evaluated by HH compared with saline. Horses administered the higher dose of atipamezole had HH greater than saline sooner than horses administered the lower dose. Intramuscular atipamezole may be useful for reversal of detomidine sedation in horses.

Objective: To review and systematically analyse the literature describing the effects of anaesthesia drugs on puppy vitality scores or survival in dogs undergoing caesarean section.

Animals: Overall 13 randomized controlled trials (RCTs) involving 1978 puppies were included.

Methods: A comprehensive search using PubMed, Embase and Scopus databases was performed from 1970 until September 2024 to obtain nonrandomized and RCTs examining the effects of anaesthetics on puppy survival rates or vitality scores after caesarean section in dogs. Only studies in English were screened. Search terms included: 'c-section' or 'caesarean section' and 'anaesthesia' and 'dog'. Two authors independently searched, classified and extracted the data. Studies were included if they evaluated the effects of anaesthesia drugs in dogs undergoing general anaesthesia and puppy survival or vitality scores. The level of evidence was scored according to the Oxford Centre for Evidence-based Medicine criteria, and a modified criterion score was used to assess the risk of bias based on the SYRCLE risk of bias tool and the SIGN checklists.

Results: Methodological characteristics varied considerably between studies, including drug doses, titration of anaesthetics, anaesthesia monitoring and puppy outcome scores. Ten studies assessed puppy vitality by using a modified Apgar score (AS). A high risk of bias was identified in six studies, whereas three had a low risk of bias. The scarcity of methodologically consistent studies and the quality of data limit identification of an optimal anaesthetic regimen to improve puppy survival. Low doses of morphine, methadone, dexmedetomidine or meloxicam preoperatively did not produce a significant impact on puppy vitality. Ketamine-midazolam, etomidate or thiopental appear to worsen immediate neonatal outcomes. No difference in neonatal survival was found between alfaxalone and propofol, but AS were higher with alfaxalone than with propofol immediately after birth.

Conclusions: The use of injectable anaesthetics for maintenance of anaesthesia led to lower puppy vitality.

Objective: To assess the usefulness of a webpage incorporating a real-time error management system for the Confidential Enquiry into Perioperative Equine Fatalities 4 (CEPEF4).

Study design: An observational, descriptive, retrospective, longitudinal study.

Animals: Data sets from 48,075 general anaesthetics and 12,453 standing sedations.

Methods: Comparison of three consecutive phases of data collection [phase I: personal document file (PDF) by e-mail, manual revision; phase II: PDF by e-mail, automatic revision; phase III: web system, automatic correction] objectively (number of e-mails sent and received by the data managers related to data correction; number of detected errors by phase) and subjectively (16 questions in Likert format; one open-ended question).

Results: Objectively, the average number of e-mails sent per day was reduced from phase I (3.6) and II (3.9) to 1.7 in phase III. The ratio of e-mails per 100 cases received was reduced from phase I (5.8) and II (4.0) to 2.4 in phase III. Errors remained below 2,000 during phase I, reaching a peak of 5,430 in phase 2 owing to a strengthened error detection strategy. During phase III, errors were reduced from 3,200 to 423 within 94 days. Subjectively, questions evaluating the PDF system indicated that users overall agree/strongly agree (54-84%) with its comfort level versus the (89-99%) of the web system. When compared, users found the web system more comfortable than the PDF system (86-95%).

Conclusions and clinical relevance: The transition to a real-time error management system in phase III led to considerably fewer e-mails sent and received plus fewer errors. Users also found the website preferable to the PDF system. Our findings highlight the importance of implementing an error management system to minimize data inaccuracies and to improve the overall efficiency and ease of use of large data set collection in veterinary medicine.