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

BACKGROUND: Ensuring patient safety during small animal anaesthesia is crucial. This study aimed to assess anaesthetic-related deaths in dogs globally, identify risks and protective factors and inform clinical practice. METHODS: This prospective cohort multicentric study involved 55,022 dogs from 405 veterinary centres across various countries. Data on anaesthesia-related deaths from premedication to 48 hours post-extubation were collected. Logistic regression was used to analyse patient demographics, American Society of Anesthesiologists (ASA) classification, procedure type and anaesthetic drugs used. RESULTS: Anaesthetic-related mortality was 0.69%. Most deaths occurred postoperatively (81%). Age, obesity and a higher ASA classification score were associated with increased mortality. Urgent procedures, non-urgent but unscheduled anaesthesias and short procedures also had higher mortality. Some sedatives, systemic analgesics, hypnotics and the use of locoregional anaesthesia were linked to a decrease in mortality. LIMITATIONS: The limitations of the study include the non-randomised sample, potential selection bias, lack of response rate quantification, variable data quality control, subjectivity in classifying causes of death and limited analysis of variables. CONCLUSION: Careful patient evaluation, drug selection and monitoring can be associated with reduced mortality. These findings can be used to develop guidelines and strategies to improve patient safety and outcomes. Further research is needed to refine protocols, enhance data quality systems and explore additional risk mitigation measures.

Haemodynamic Effects of Pimobendan during General Anaesthesia in Healthy Senior Dogs: A Prospective, Randomised, Triple-Blinded, Placebo-Controlled Clinical Study.

Pimobendan is an inotropic and vasodilator drug with no sympathomimetic effects. This study aimed to evaluate the haemodynamic effects of pimobendan during anaesthesia in healthy senior dogs. A prospective, randomised, triple-blinded, placebo-controlled clinical study was conducted. Thirty-three dogs (median [range]: 9 [7, 12] years) were anaesthetised for surgical procedures. The dogs were randomly allocated into two groups: eighteen dogs received intravenous pimobendan at a dose of 0.15 mg/kg (PIMOBENDAN), and fifteen dogs received intravenous saline solutions at a dose of 0.2 mL/kg (PLACEBO). Data were recorded before, 1 min, 10 min, and 20 min after injection. Velocity-time integral (VTI), peak-velocity (PV), and mean-acceleration (MA) were measured using an oesophageal Doppler monitor (ODM). Heart rate and mean arterial pressure were also registered. The data were analysed using a two-way ANOVA for trimmed means. Statistical differences were considered if p < 0.05. Twenty minutes after injection, the VTI (13.0 cm [10.4, 22.3]), PV (95.0 [83.0, 160] m/s), and MA (12.6 [9.40, 17.0] m/s2) were significantly higher in the PIMOBENDAN group compared to the PLACEBO group (VTI: 10.5 [6.50, 17.4] cm, PV: 80.0 [62.0, 103] m/s and MA: 10.2 [7.00, 16.0] ms2). No significant differences were observed in the rest of the variables. Using pimobendan during anaesthesia increases VTI, PV, and MA, as measured by an ODM.

Data Collection for the Fourth Multicentre Confidential Enquiry into Perioperative Equine Fatalities (CEPEF4) Study: New Technology and Preliminary Results.

It is almost 20 years since the largest observational, multicentre study evaluating the risks of mortality associated with general anaesthesia in horses. We proposed an internet-based method to collect data (cleaned and analysed with R) in a multicentre, cohort, observational, analytical, longitudinal and prospective study to evaluate peri-operative equine mortality. The objective was to report the usefulness of the method, illustrated with the preliminary data, including outcomes for horses seven days after undergoing general anaesthesia and certain procedures using standing sedation. Within six months, data from 6701 procedures under general anaesthesia and 1955 standing sedations from 69 centres were collected. The results showed (i) the utility of the method; also, that (ii) the overall mortality rate for general anaesthesia within the seven-day outcome period was 1.0%. In horses undergoing procedures other than exploratory laparotomy for colic ("noncolics"), the rate was lower, 0.6%, and in "colics" it was higher, at 3.4%. For standing sedations, the overall mortality rate was 0.2%. Finally, (iii) we present some descriptive data that demonstrate new developments since the previous CEPEF2. In conclusion, horses clearly still die unexpectedly when undergoing procedures under general anaesthesia or standing sedation. Our method is suitable for case collection for future studies.

Validation of a bioabsorbable device that seals perforations after Tuohy needle dural puncture in an ovine model.

BACKGROUND: We designed a device to close accidental dural puncture via the offending puncturing epidural needle directly after diagnosis of the puncture and before removing the needle. The aim of this study was to quantify this device's ability to seal cerebrospinal fluid leakage. METHODS: Forty-six anesthetized adult sheep were studied in a single-blind randomized controlled fashion in two equal groups.An intentional dural puncture was performed with an 18-gage Tuohy needle on all the sheep between L6 and S1 levels. Contrast medium was injected through the needle. Twenty-three animals receive treatment with the sealing device. Two minutes after device placement, or dural puncture in the control group, a CT scan was performed on the animals to estimate contrast material leakage. A region of interest (ROI) was defined as the region that enclosed the subarachnoid space, epidural space, and neuroforaminal canal (the vertebral body above and half of its equivalent height in sacrum below the puncture site). In this region, the total contrast volume and the volumes in the epidural space (EPIDURAL) were measured. The primary outcome measure was the EPIDURAL/ROI ratio to ascertain the proportion of intrathecally injected fluid that passed into the epidural space in both groups. The secondary outcomes were the total amount of contrast in the ROI and the EPIDURAL. RESULTS: The device was deployed successfully in all but two instances, where it suffered from manufacturing defects.Leakage was less in the study group (1.0 vs 1.4 mL, p=0.008). The median EPIDURAL/ROI ratio was likewise less in the study group (29 vs 46; p=0.013; 95% CI (-27 to -3.5)). CONCLUSION: This novel dural puncture-sealing device, also envisaged to be used in other comparable iatrogenic leakage scenarios to be identified in the future, was able to reduce the volume of cerebrospinal fluid that leaked into the epidural space after dural puncture. The device is possibly a valuable way of preventing fluid leakage immediately after the recognition of membrane puncture.

Audit of Anesthetic Equipment in Veterinary Clinics in Spain and Portugal.

The objective of this retrospective study was to review the results of a 4-year audit performed on anesthetic machines and vaporizers used in veterinary clinics in Spain and Portugal. Data was collected between July 2016 and April 2020. Inspections were carried out by a team of seven veterinarians, using a human-modified system of checks that was adapted to a veterinary practice. The evaluation of each item was noted as "correct" or "incorrect". The vaporizers' performance was evaluated using a self-calibrating gas analyzer. The vaporizer was classified as "correct" or "incorrect" when the vaporization error was less than or equal to, or more than 20%, respectively. The anesthetic machine was classified as "conforming" if all its components were noted as "correct" and no leaks were detected, or as "non-conforming" if any of the components was noted as "incorrect" or if a leak was detected. If the inspector was able to repair on-site the item malfunctions detected and the machine was fit for use, they issued a final report as "conforming." On the contrary, if such malfunctions persisted, the final report was "non-conforming," and a recommendation to remove the machine from service until its final repair was provided. To perform statistical analysis, each inspected item was used as predictor, classification and regression trees were built, and a random forest analysis was performed. A total of 2,001 anesthetic machines and 2,309 vaporizers were studied. After inspection, 42.7 and 26.4% of the machines were non-conforming and conforming, respectively, whereas 30.9% could be repaired in situ. A total of 27.1% of the isoflurane vaporizers and 35.9% of the sevoflurane vaporizers were incorrect. Machine learning techniques showed that the most important variables in the classification of the anesthetic machines as conforming or non-conforming were mostly the scavenger system and the canister, followed some way behind by the APL valve, source of oxygen, reservoir bag, vaporizer, and connections.

The effect of user experience and inflation technique on endotracheal tube cuff pressure using a feline airway simulator.

OBJECTIVE: The effect of user experience and inflation technique on endotracheal tube cuff pressure using a feline airway simulator. STUDY DESIGN: Prospective, experimental clinical study. METHODS: Participants included veterinary students at the beginning (group S1) and end (group S2) of their 2-week anaesthesia rotation and veterinary anaesthetists (group A). The feline airway simulator was designed to simulate an average size feline trachea, intubated with a 4.5 mm low-pressure, high-volume cuffed endotracheal tube, connected to a Bain breathing system with oxygen flow of 2 L minute-1. Participants inflated the on-endotracheal tube cuff by pilot balloon palpation and by instilling the minimum occlusive volume (MOV) required for loss of airway leaks during manual ventilation. Intracuff pressures were measured by manometers obscured to participants and ideally were 20-30 cm H2O. Student t, Fisher exact, and Chi-squared tests were used where appropriate to analyse data (p < 0.05). RESULTS: Participants were 12 students and eight anaesthetists. Measured intracuff pressures for palpation and MOV, respectively, were 19 ± 12 and 29 ± 19 cm H2O for group S1, 10 ± 5 and 20 ± 11 cm H2O for group S2 and 13 ± 6 and 29 ± 18 cm H2O for group A. All groups performed poorly at achieving intracuff pressures within the ideal range. There was no significant difference in intracuff pressures between techniques. Students administered lower (p = 0.02) intracuff pressures using palpation after their training. CONCLUSIONS AND CLINICAL RELEVANCE: When using palpation and MOV for cuff inflation operators rarely achieved optimal intracuff pressures. Experience had no effect on this skill and, as such, a cuff manometer is recommended.

Comparison of the hanging-drop technique and running-drip method for identifying the epidural space in dogs.

OBJECTIVE: To compare the running-drip and hanging-drop techniques for locating the epidural space in dogs. STUDY DESIGN: Prospective, randomized, clinical trial. ANIMALS: Forty-five healthy dogs requiring epidural anaesthesia. METHODS: Dogs were randomized into four groups and administered epidural anaesthesia in sternal (S) or lateral (L) recumbency. All blocks were performed by the same person using Tuohy needles with either a fluid-prefilled hub (HDo) or connected to a drip set attached to a fluid bag elevated 60 cm (RDi). The number of attempts, 'pop' sensation, clear drop aspiration or fluid dripping, time to locate the epidural space (TTLES) and presence of cerebrospinal fluid (CSF) were recorded. A morphine-bupivacaine combination was injected after positive identification. The success of the block was assessed by experienced observers based on perioperative usage of rescue analgesia. Data were checked for normality. Binomial variables were analysed with the chi-squared or Fisher's exact test as appropriate. Non-parametric data were analysed using Kruskal-Wallis and Mann-Whitney tests. Normal data were studied with an anova followed by a Tukey's means comparison for groups of the same size. A p-value of < 0.05 was considered to indicate statistical significance. RESULTS: Lateral recumbency HDo required more attempts (six of 11 dogs required more than one attempt) than SRDi (none of 11 dogs) (p = 0.0062). Drop aspiration was observed more often in SHDo (nine of 11 dogs) than in LHDo (two of 11 dogs) (p = 0.045). Mean (range) TTLES was longer in LHDo [47 (18-82) seconds] than in SHDo [20 (14-79) seconds] (p = 0.006) and SRDi [(34 (17-53) seconds] (p = 0.038). There were no differences in 'pop' sensation, presence of CSF, rescue analgesia or pain scores between the groups. CONCLUSION AND CLINICAL RELEVANCE: The running-drip method is a useful and fast alternative technique for identifying the epidural space in dogs. The hanging-drop technique in lateral recumbency was more difficult to perform than the other methods, requiring more time and attempts.

Canine anaesthetic death in Spain: a multicentre prospective cohort study of 2012 cases.

OBJECTIVE: To study current perianaesthetic mortality in dogs in Spain and to identify the main risk factors predisposing to perianaesthetic mortality in our country. STUDY DESIGN: A multicentre prospective cohort study. ANIMAL POPULATION: Dogs anaesthetised for different surgical and diagnostic procedures at 39 Spanish veterinary clinics between February 2007 and March 2008. METHODS: Data of patients, procedures and anaesthetic management were recorded. Anaesthetic death was defined as perioperative death within 24 hours of the procedure end. A multivariate study evaluated perinanaesthetic death using logistic binary regression models with the Wald technique. RESULTS: 2012 animals were included in the analyses. Twenty-six dogs died. The global mortality rate was 1.29% (95% Confidence interval (95% CI): 0.88-1.89%). ASA I-II was 0.33% (95 CI: 0.14-0.78%); ASA III-V was 4.06% (95% CI: 2.67-6.13%). Most deaths occurred during the post-operative period (20 dogs, 77%). The multivariate analysis revealed that high ASA grade was associated with an increased risk of mortality. The use of opioids plus NSAIDs during anaesthesia was related with a decrease of the risk. CONCLUSIONS: Perianaesthetic mortality in dogs in Spain was 1.29% (95% CI: 0.88-1.89%). ASA grade was the main prognostic factor of likelihood of death. The use of some analgesics (opioids and NSAIDs) in the perioperative period was associated with reduced odds of death and may be protective. CLINICAL RELEVANCE: Evaluation and stabilisation of patients before interventions may help lower risk of death during the anaesthesia. In addition to their use for welfare purposes, analgesics may be beneficial in reducing anaesthetic-related deaths.

Effects of intravenous administration of dexmedetomidine on intraocular pressure and pupil size in clinically normal dogs.

OBJECTIVE: To evaluate the effects of the intravenous administration of dexmedetomidine on the intraocular pressure (IOP) and pupil size (PS) in normal dogs. ANIMALS STUDIED: Forty-two animals with no ocular abnormalities were included in this study. PROCEDURE: Following initial readings (T(0)) of IOP and PS, the dogs received an intravenous injection of dexmedetomidine (5 µg/kg). Both measurements were repeated 10 min (T(10) ) and 20 min (T(20)) later. RESULTS: There were no significant differences in IOP measurements between T(0) and T(10), although a significant decrease was observed at T(20). A significant miosis was found in the first 10 min after sedation. At T(20), the PS slightly increased, resulting in no statistical differences with T(0) and T(10). CONCLUSION: Dexmedetomidine is an excellent option for surgery or diagnostic ocular procedures in dogs when a specific control of IOP is required. However, it must be used in combination with mydriatics in ophthalmic surgical or diagnostic procedures, which require complete dilation of the pupil.

Cardiorespiratory effects of desflurane in dogs given romifidine or medetomidine before induction of anesthesia with propofol.

The objective of this study was to evaluate the use of desflurane after induction of anesthesia with propofol in dogs sedated with romifidine or medetomidine. Each of 8 healthy dogs received intravenously, in random order, 3 preanesthetic protocols: romifidine, 40 microg/kg of body weight (BW) (R40); romifidine, 80 microg/kg BW (R80); and medetomidine, 10 microg/kg BW (MED). Cardiovascular and respiratory variables were recorded during the procedure. Time to extubation, time to sternal recumbency, and time to standing were also recorded. Heart rate and respiratory rate decreased significantly during sedation from baseline values, but there were no differences between the means for the 3 preanesthetic protocols. Mean values for heart rate, mean arterial blood pressure, systolic arterial pressure, diastolic arterial pressure, respiratory rate, tidal volume, arterial oxygen saturation, end-tidal CO2 level, pH, and arterial blood gas values during anesthesia were similar for the 3 protocols. The mean end-tidal desflurane concentration was significantly lower with the R80 protocol than with the R40 protocol. The mean time to extubation was significantly shorter with the R40 protocol than with the R80 and MED protocols.

Experimental use of polyamide bands in combination with intramedullary pinning for repair of oblique femoral fractures in rabbits.

OBJECTIVE: To evaluate the use of polyamide bands, manufactured for securing electrical cables, for repair of oblique femoral fractures in rabbits. STUDY DESIGN: Experimental study. ANIMALS: Twelve nulliparous, 21-25-week-old, California female rabbits. METHODS: Rabbits were divided into 3 groups (n=4) and studied for 14, 28, or 56 days. A Z-shaped mid-diaphyseal femoral osteotomy was repaired with a 2.5 mm intramedullary pin and a polyamide 6.6 cerclage band. Healing was evaluated at intervals by physical examination, limb use, femoral radiographs, and callus histology. RESULTS: Rabbits had early limb use with good wound healing. From the 1st day, movement of the hip and stifle joints was satisfactory. Radiographically, fractures were healed at 28 days. Histologically, there was no foreign body reaction and bone healing was normal. CONCLUSION: Nylon cerclage band application was accomplished easily, maintained reduction, and resulted in good healing and limb use. CLINICAL RELEVANCE: Sterilized nylon bands, manufactured for electrical use, can be used for cerclage in rabbits.