Veterinary Anaesthesia Research Articles

Choose your own adventure: using Twine for gamified interactive learning in veterinary anaesthesia

Choose your own adventure: using Twine for gamified interactive learning in veterinary anaesthesia

Second victim in veterinary anaesthesia: support structures – Part 2

Second victim in veterinary anaesthesia: support structures – Part 2

“Whisper down the lane” can lead to morbidity and mortality in veterinary anaesthesia. A fatal outcome after multiple intra-anaesthetic, non-standardized handovers of a high-risk patient

“Whisper down the lane” can lead to morbidity and mortality in veterinary anaesthesia. A fatal outcome after multiple intra-anaesthetic, non-standardized handovers of a high-risk patient

Second victim in veterinary anaesthesia: psychological impact – Part 1

Second victim in veterinary anaesthesia: psychological impact – Part 1

Comparison of two formulas for estimating number of staff for a veterinary anesthesia service

Comparison of two formulas for estimating number of staff for a veterinary anesthesia service

A systematic review of perioperative use of artificial intelligence since 2010 in anaesthesia and it’s critical application to veterinary anaesthesia

A systematic review of perioperative use of artificial intelligence since 2010 in anaesthesia and it’s critical application to veterinary anaesthesia

Risk of burnout among veterinary anaesthesia specialists: a call for action

Risk of burnout among veterinary anaesthesia specialists: a call for action

Effects of a synergic interaction between magnesium sulphate and ketamine on the perioperative nociception in dogs undergoing tibial plateau leveling osteotomy: a pilot study

IntroductionMagnesium Sulphate (MgSO4) is commonly used in human medicine for the management of perioperative pain in different types of procedures. However, in veterinary medicine, the use of MgSO4 has not been evaluated for its analgesic efficacy in dogs, which has generated conflicts of opinion in this area of veterinary anesthesiology. The aim of this study was to evaluate the perioperative analgesic efficacy of MgSO4 in combination with Ketamine in dogs undergoing Tibial Plateau Leveling Osteotomy (TPLO). Our hypothesis is that MgSO4 plus ketamine have a synergistic action in the management of intra-and postoperative pain.MethodsTwenty adult mixed breed dogs with average age 5.9 ± 2.6 years and weight 27.8 ± 9.2 kg were included in this prospective, clinical, randomized study. Dogs were randomly assigned to two groups. The MK group received ketamine (0.5 mg/kg as starting bolus followed by continuous infusion rate at 1 mg/kg/h). At the end of the ketamine bolus, MgSO4 (50 mg/kg over 15 min) was administered by the same route, followed by a constant rate infusion (CRI) at 15 mg/kg/h, IV. K group received a bolus of ketamine followed by a CRI at the same dosage described in MK group. Main cardiorespiratory parameters were recorded 10 min before the start of surgery (BASE), after the ketamine bolus (T1) and the MgSO4 bolus (T2), during the skin incision (SKIN), the osteotomy (OSTEOTOMY) and skin suturing (SUTURE). In the postoperative period, the short form of Glasgow Composite Pain scale (SF-CMPS) was used to assess pain at 30, 60, 120, and 180 min after extubation (Post30, Post60, Post120, and Post180, respectively). The main blood electrolytes (Mg2+, Ca2+, Na+, K+) were analyzed at BASE, T2, OSTEOTOMY, SUTURE and T3 (one hour after stopping MgSO4 infusion). Number of rescue analgesia and administration times were recorded both in the intra-and postoperative period.ResultsIn K group 7 out of 10 dogs required intraoperatory rescue analgesia compared to MK group (3/10). Furthermore, mean arterial pressure (MAP) and heart rate (HR) were significantly higher at OSTEOTOMY compared to BASE time in both groups. In the postoperative period, at T120, ICMPS-SF score was higher in K group than MK group.ConclusionThe administration of MgSO4 could guarantee better analgesia in the perioperative period in dogs undergoing TPLO, performing a synergistic action with ketamine.

Mitochondria are absent from microglial processes performing surveillance, chemotaxis, and phagocytic engulfment.

Microglia continually surveil the brain allowing for rapid detection of tissue damage or infection. Microglial metabolism is linked to tissue homeostasis, yet how mitochondria are subcellularly partitioned in microglia and dynamically reorganize during surveillance, injury responses, and phagocytic engulfment in the intact brain are not known. Here, we performed intravital imaging of microglia mitochondria, revealing that microglial processes diverge, with some containing multiple mitochondria while others are completely void. Microglial processes that engage in minute-to-minute surveillance typically do not have mitochondria. Moreover, unlike process surveillance, mitochondrial motility does not change with animal anesthesia. Likewise, the processes that acutely chemoattract to a lesion site or initially engage with a neuron undergoing programmed cell death do not contain mitochondria. Rather, microglia mitochondria have a delayed arrival into the responding cell processes. Thus, there is subcellular heterogeneity of mitochondrial partitioning and asymmetry between mitochondrial localization and cell process motility or acute damage responses.

Electrocardiogram assessment in long-eared hedgehogs (Hemiechinus auritus) following administration of anesthetics

Anesthesia in animals is a crucial requirement for conducting surgery, diagnostic imaging, and other procedures when the animal cannot be safely managed in a conscious state. The present study aimed to compare the impact of different anesthetic techniques on the electrocardiogram of hedgehogs. The animals were given three different anesthetic combinations: ketamine + xylazine, ketamine + diazepam, and ketamine + midazolam. The study measured the heart rate, duration, and amplitude of the P wave, QRS complex, and T wave through bipolar II derivations. Normal sinus rhythm was observed following induction by all anaesthetic combinations; however, the combination of ketamine and xylazine resulted in a significant decrease in heart rate. The P wave was positive with different combinations of anesthetics. The mean amplitude of the P wave in hedgehogs anesthetized using ketamine+xylazine was significantly lower than when using ketamine+diazepam and ketamine+midazolam. The QRS polarity was positive in leads I, II, and aVF after anesthesia induced by all combinations. The duration and amplitude of the QRS complexes did not differ significantly between all combinations. Hedgehogs anesthetized with ketamine+midazolam revealed the highest amplitude of the QRS (0.23 mv), while in the ketamine+diazepam anesthetized group, lowest amplitude (0.18 mv) was observed. The T wave was positive in all leads except leads III and aVR. Animals anesthetized with ketamine + xylazine had the lowest amplitude (0.117 mv) and the longest duration (0.08 s) of the T waves. The findings suggest that ketamine+midazolam is the choice combination based on ECG evaluation in hedgehogs.

The impact of human factors on veterinary anaesthesia

Human factors are an evidence-based science that consider how external factors and personal circumstances influence work behaviours and the reasons why events happen. It has been frequently studied in professions where mistakes can have disastrous consequences, such as aviation and human medicine, and is now becoming more considered in veterinary medicine. Understanding how human factors influence the safe delivery of anaesthesia means more safety measures can be put in place for both the wellbeing of patients and veterinary staff. These measures include surgical safety checklists, open communication between colleagues and the use of adverse event reporting platforms.

A survey study on the availability of anaesthetic breathing systems and their use in dogs weighing 5–10 kg

ObjectiveTo investigate which breathing systems are available and why they are selected in dogs weighing 5–10 kg. Study designAnonymous online voluntary open survey. MethodsAn online survey, designed following CHERRIES guidelines, was advertised through the American College of Veterinary Anesthesiologists - List, Association of Veterinary Anaesthesia and European College of Veterinary Anaesthesia and Analgesia (February–March 2022). A convenience sample was taken. ResultsOf the 256 responses received, 138 were completed. This included (n responses received) veterinarians (107) and veterinary nurses or technicians (29) actively involved in the anaesthesia of dogs.The most prevalent breathing systems available to respondents were circle (99%), coaxial Bain (79%) and modified Ayre’s T-piece (with adjustable pressure limiting valve; 72%). When recommending a dog weight range suitable for the use with these systems, respondents advised a median (interquartile range) from 5 (3–10) to 100 (100–100), 3 (0–8) to 20 (10–33) and 0 (0–0) to 10 (7–10) kg, respectively. Respondents agreed or strongly agreed that important factors in selecting a breathing system were the fresh gas flow requirement (92%), dog weight (91%), resistance (83%) and environmental pollution (79%). In clinical scenarios based on 5–10 kg dogs, the circle system was chosen by 58% for a thin and 77% for a keel-chested versus 44% for an obese and 66% for a barrel-chested dog, respectively. Conclusions and clinical relevanceThe circle system is the most commonly available breathing system. The minimum weight limit used for the circle system is less than that reported by previous surveys. Several factors influence the choice of breathing system other than dog weight.

A survey on the use of total intravenous anaesthesia in small animals by veterinary anaesthesiologists

ObjectiveTo describe the use of total intravenous anaesthesia (TIVA) in dogs and cats by veterinary anaesthesiologists. Study designA cross-sectional online, voluntary, anonymous survey. PopulationData from 153 answered questionnaires. MethodsAn anonymous questionnaire was sent via e-mail to diplomates, residents and residency-trained individuals from the American and European Colleges of Veterinary An(a)esthesia and Analgesia, to gather information on the use, perceived advantages, reasons for the use or not of TIVA and attitudes towards this technique in dogs and cats. Descriptive statistics and logistic regression analysis to detect significant associations were performed. The effect size was estimated using the odds ratio (OR) and 95% confidence interval (CI). A significance level of p < 0.05 was used. ResultsWe obtained 153/703 responses (66% diplomates, 34% residents; overall response rate of 21.7%). Although 99% and 94% of respondents used TIVA in dogs and cats, respectively, only 14% used it frequently (several times a week) in dogs, and < 1% in cats. Most respondents used propofol (97%, dogs) and alfaxalone (85%, cats), mostly combined with opioids. Reasons for not using TIVA more frequently included prolonged recovery (49%, dogs; 61%, cats), higher cost (46%, dogs) and concerns about drug accumulation (44%, cats). Frequent TIVA use was driven by clinical indications (100%) and greater haemodynamic stability (87%). A higher proportion of respondents using TIVA frequently reported the high stability of the anaesthetic plane (20%; OR = 5.0; 95% CI: 1.4–17.8; p = 0.013) and disagreed with using TIVA only when a specific clinical indication existed (OR = 3.3; 95% CI: 1.4–10.0; p = 0.013). Conclusions and clinical relevanceAlthough occasional, TIVA use is reported among veterinary anaesthesiologists. Clinical indications for TIVA are the most likely reason for its use, whereas factors such as a prolonged recovery or higher cost might limit its use.

The impact of isoflurane anesthesia on brain metabolism in mice: An MRI and electroencephalography study.

Isoflurane is one of the most widely used anesthetic agents in rodent imaging studies. However, the impact of isoflurane on brain metabolism has not been fully characterized to date, primarily due to a scarcity of noninvasive technologies to quantitatively measure the brain's metabolic rate in vivo. In this study, using noncontrast MRI techniques, we dynamically measured cerebral metabolic rate of oxygen (CMRO2) under varying doses of isoflurane anesthesia in mice. Concurrently, systemic parameters of heart and respiration rates were recorded alongside CMRO2. Additionally, electroencephalogram (EEG) recording was used to identify changes in neuronal activities under the same anesthetic regimen employed in the MRI experiments. We found suppression of the CMRO2 by isoflurane in a dose-dependent manner, concomitant with a diminished high-frequency EEG activity. The degree of metabolic suppression by isoflurane was strongly correlated with the respiration rate, which offers a potential approach to calibrate CMRO2 measurements. Furthermore, the metabolic level associated with neural responses of the somatosensory and motor cortices in mice was estimated as 308.2μmol/100 g/min. These findings may facilitate the integration of metabolic parameters into future studies involving animal disease models and anesthesia usage.

Metal-organic frameworks and polymer nanoplatform: Biocompatible and photothermal responsive tribromoethanol anesthetic for mice

Effective anesthesia is crucial for ensuring the validity and reliability of animal experiments. In recent years, tribromoethanol has been widely used for small animal anesthesia. However, direct injection poses risks of overdose, anesthesia instability, and organ damage, affecting experimental reliability and animal welfare. Therefore, developing a safer and more stable delivery system for tribromoethanol is essential. In this study, we first synthesized two complexes using a solvothermal method. Then, we modified the traditional biopolymer PEG to synthesize an amphiphilic block copolymer, Cyanine 7-PEG-DDAT, which was used to coat CP1 and load tribromoethanol (TBE) for structural characterization. We then conducted biological tests on Cyanine 7-PEG-DDAT-CP1@TBE and compared its anesthetic effects in C57BL/6 mice with those of direct tribromoethanol injection. The results provide a reference for the application of tribromoethanol in mouse models and surgeries.

Case study: chemical contaimnent in parrots (Amazona SP - Lesson, 1830) from de Quinzinho de Barros Zoological Park, municipality of Sorocaba, São Paulo

The containment and anesthesia of wild animals is extremely important for veterinarians who intend to or already practice in this field. However, before administering anesthesia, it is essential to understand the pharmacology of anesthetics and the biological aspects related to the anatomical, physiological, and behavioral peculiarities of the species to be restrained. The aim of this research was to evaluate parameters such as heart rate (HR), respiratory rate (RR), temperature (T°), muscle relaxation, reflexes (palpebral, ocular, and pedal), and respiratory pattern in four anesthetic protocols: ketamine 5% at a dose of 30mg/kg combined with xylazine 2%-2mg/kg; ketamine 5% at doses of 15mg/kg and 20mg/kg with diazepam 1% at a dose of 1mg/kg; diazepam 0.5% at a dose of 5mg/kg 15 minutes before isoflurane administration; and the use of isoflurane alone in parrots (Amazona sp) kept at the Quinzinho de Barros Municipal Park, Sorocaba, São Paulo. Eleven animals were used: three with the ketamine combined with xylazine protocol, three with ketamine plus diazepam, three with diazepam before isoflurane, and two with the isolated use of isoflurane. The results of this research showed that with the use of ketamine combined with xylazine at this dosage, only superficial sedation was achieved. With the supplementary dose of ketamine and xylazine, the animal reached a moderate anesthetic plane, but respiratory depression occurred. The use of diazepam combined with ketamine 5% at a dose of 15mg/kg is only recommended for minor procedures. Recovery was slightly less prolonged and with less cardiorespiratory depression compared to the use of ketamine combined with xylazine. Diazepam 0.5%-5mg/kg before isoflurane did not allow for the intubation of the animal; it served to reduce the stress of restraint, requiring a lower concentration of isoflurane for induction. Apnea was observed with the increase of isoflurane concentration, even with the use of diazepam before isoflurane. With the isolated use of isoflurane, the animal reached a moderate to deep anesthetic plane, which would allow for more invasive procedures.

Xylazine Exacerbates Fentanyl-Induced Respiratory Depression and Bradycardia.

Fatal opioid overdoses in the United States have nearly tripled during the past decade, with greater than 92% involving a synthetic opioid like fentanyl. Fentanyl potently activates the μ-opioid receptor to induce both analgesia and respiratory depression. The danger of illicit fentanyl has recently been exacerbated by adulteration with xylazine, an α2-adrenergic receptor agonist typically used as a veterinary anesthetic. In 2023, over a 1,000% increase in xylazine-positive overdoses was reported in some regions of the U.S. Xylazine has been shown to potentiate the lethality of fentanyl in mice, yet a mechanistic underpinning for this effect has not been defined. Herein, we evaluate fentanyl, xylazine, and their combination in whole-body plethysmography (to measure respiration) and pulse oximetry (to measure blood oxygen saturation and heart rate) in male and female CD-1 mice. We show that xylazine decreases breathing rate more than fentanyl by increasing the expiration time. In contrast, fentanyl primarily reduces breathing by inhibiting inspiration, and xylazine exacerbates these effects. Fentanyl but not xylazine decreased blood oxygen saturation, and when combined, xylazine did not change the maximum level of fentanyl-induced hypoxia. Xylazine also reduced heart rate more than fentanyl. Finally, loss in blood oxygen saturation correlated with the frequency of fentanyl-induced apneas, but not breathing rate. Together, these findings provide insight into how the addition of xylazine to illicit fentanyl may increase the risk of overdose.

Agreement of Pain Assessment Using the Short Form of the Canine Glasgow Composite Measure Pain Scale between Veterinary Students, Veterinary Nurses, Veterinary Surgeons, and ECVAA-Diplomates.

Several pain scoring systems have been validated to measure pain in dogs. However, pain may not be adequately assessed since these tools are associated with high-level inter-observer variation. The aim of this study is to evaluate the agreement of pain assessment using the CMPS-SF between veterinary students, veterinary nurses, veterinary surgeons, and European College of Veterinary Anaesthesia and Analgesia (ECVAA) diplomates. Forty-five client-owned dogs presented to a teaching hospital were enrolled in this prospective, observational study. All dogs were pain-scored in vivo, while a video of the assessment was recorded and subsequently evaluated by twenty assessors, with five per group. Mean scores between groups were compared, and agreement within groups and agreement of the average scores between groups were assessed by calculating the intraclass correlation coefficient (ICC). The intervention point at which dogs were deemed to require additional analgesia was also evaluated. Overall agreement of pain assessment was poor (ICC = 0.494). Nurses had the best inter-observer agreement (ICC = 0.656), followed by ECVAA diplomates (ICC = 0.540), veterinary surgeons (ICC = 0.478), and veterinary students (ICC = 0.432). The best inter-group agreement was between veterinary surgeons and nurses (ICC = 0.951) and between ECVAA diplomates and nurses (ICC = 0.951). Students were more likely to determine that additional analgesia was required compared to other groups. Pain assessment is key for animal welfare, and training in this area should be reinforced to improve consistency.

Inhalational anaesthetic agent consumption within a multidisciplinary veterinary teaching hospital: an environmental audit

Inhalational anaesthetic agents are routinely used in veterinary anaesthesia practices, yet their consumption contributes significantly to greenhouse gas emissions and environmental impact. We conducted a 55-day observational study at a veterinary teaching hospital in Switzerland, monitoring isoflurane and sevoflurane consumption across small, equine and farm animal clinics and analysed the resulting environmental impact. Results revealed that in total, 9.36 L of isoflurane and 1.27 L of sevoflurane were used to anaesthetise 409 animals across 1,489 h. Consumption rates varied among species, with small and farm animals ranging between 8.7 and 13 mL/h, while equine anaesthesia exhibited a higher rate, 41.2 mL/h. Corresponding to 7.36 tonnes of carbon dioxide equivalent in total environmental emissions or between 2.4 and 31.3 kg of carbon dioxide equivalent per hour. Comparison to human anaesthesia settings showed comparable consumption rates to small animals, suggesting shared environmental implications, albeit on a smaller scale. This research highlights the importance of continued evaluation of veterinary anaesthesia practices to balance patient safety with environmental stewardship; potential mitigation strategies are explored and discussed.

Anaesthetic mortality in cats: A worldwide analysis and risk assessment.

Patient safety is essential in small animal anaesthesia. This study aimed to assess anaesthesia-related deaths in cats worldwide, identify risk and protective factors and provide insights for clinical practice. A prospective multicentre cohort study of 14,962 cats from 198 veterinary centres across different countries was conducted. Data on anaesthesia-related deaths, from premedication up to 48 hours postextubation, were collected. Logistic regression was used to analyse patient demographics, American Society of Anesthesiologists (ASA) classification, procedure type and anaesthetic drugs. The anaesthesia-related mortality was 0.63%, with 74.5% of deaths occurring postoperatively. Cats with cachexia, a higher ASA status or who underwent abdominal, orthopaedic/neurosurgical or thoracic procedures exhibited elevated mortality. Mechanical ventilation use was associated with increased mortality. Mortality odds were reduced by the use of alpha2-agonist sedatives, pure opioids in premedication and locoregional techniques. Limitations include non-randomised sampling, potential biases, unquantified response rates, subjective death cause classification and limited variable analysis. Anaesthetic mortality in cats is significant, predominantly postoperative. Risk factors include cachexia, higher ASA status, specific procedures and mechanical ventilation. Protective factors include alpha2-agonist sedatives, pure opioids and locoregional techniques. These findings can help improve anaesthesia safety and outcomes. However, further research is required to improve protocols, enhance data quality and minimise risks.