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

Risk factors associated with increased mortality within 14 days of general anesthesia in specialty veterinary dentistry and oral surgery practices

OBJECTIVE

To investigate the overall mortality rate and risk factors associated with mortality in dogs within 2 weeks of general anesthesia in a specialty veterinary dentistry and oral surgery practice.

STUDY DESIGN

Retrospective cohort study.

ANIMALS

A total of 3210 dogs were anesthetized for advanced imaging and/or oral surgery.

METHODS

Electronic medical records of four clinics were examined for dogs that had undergone advanced imaging and/or oral surgery requiring general anesthesia over a 2 year period (2021-2023). Data were collected on patient demographics, procedural and anesthetic details, and mortality status 2 weeks after anesthesia. Univariate analyses and multivariable logistic regression were used to identify risk factors associated with anesthetic death.

RESULTS

The mortality rate of the study population of dogs was 0.37%. Median age at death was statistically higher than that of dogs alive 2 weeks after anesthesia following univariate analysis (12 and 7 years, respectively). Median anesthetic duration was statistically longer in dogs that died than those that were alive following univariate analysis (177.5 minutes and 141 minutes, respectively). Following multivariate analysis, however, only older age remained a significant risk factor (odds ratio 1.364). Weight, sex, and American Society of Anesthesiologists physical status classification were not statistically significant risk factors for anesthetic death.

CONCLUSIONS AND CLINICAL RELEVANCE

Data from this study may facilitate risk discussions with clients, especially owners of older dogs undergoing anesthesia in veterinary dental practices.

Inter-observer agreement in classifying anesthetic deaths in cats and dogs

Determining the cause of death in studies assessing mortality during small animal anesthesia poses challenges due to varying definitions of anesthetic death, limited information, and differences in evaluators' interpretations. This study aims to establish the interobserver agreement in classifying the cause of death in anesthetized animals. The observational, retrospective, multicenter study analyzed 432 deaths (83 cats and 349 dogs). Data were collected from a database of 55,022 anesthetized dogs and 14,962 anesthetized cats, created to investigate anesthetic-related mortality in these species. Three highly qualified veterinary anesthesiologists independently assessed whether the deaths were related to anesthesia, using their professional judgment. Data were collected from questionnaires that included the animal's signalment, reason for anesthesia, ASA status, drugs, anesthetic procedures, and comments from the submitting veterinarian. Light's Kappa and the intraclass correlation coefficient (ICC) measured interrater agreement among the three evaluators, while Cohen's Kappa assessed interrater reliability between pairs of observers (p < 0.05). Evaluators A, B, and C classified 296/432 (68.5%), 264/432 (61.1%), and 54/432 (12.5%) of the cases as anesthesia-related deaths, respectively. Agreement among the three evaluators was 128/432 (29.6%) [Light's Kappa: 0.17, p = 0.00026; ICC: 0.06, p-value = 0.0167]. The three evaluators agreed on classifying a death as anesthetic-related in 14.1% of cases (50 out of 354 cases where at least one evaluator classified the death as anesthetic-related). Similarly, for non-anesthetic-related deaths, the three evaluators reached an agreement in 20.4% of cases (78 out of 382 cases where at least one evaluator classified the death as non-anesthetic-related). Overall, agreement between two out of three evaluators was 304/432 (70.4%). Evaluators A and B had a 65.7% agreement [Cohen's Kappa: 0.25, p < 0.00001], A and C had a 46.6% agreement [Cohen's Kappa: 0.10, p < 0.00001], and B and C had a 50.9% agreement [Cohen's Kappa: 0.16, p < 0.00001]. In conclusion, the evaluators' agreement was weak, highlighting the need for a consensus on defining anesthetic mortality in dogs and cats.

Error management in large data sets: A critical component of data collection in veterinary medicine

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.

Anaesthetic practices and attitudes to patient safety in a sample of Australian veterinary practices

OBJECTIVE

To survey anaesthetic practices and attitudes towards veterinary patient safety in Australia.

STUDY DESIGN

This was a cross-sectional sample population from Australian veterinary practices, including first opinion small animal, mixed animal and referral small animal practices. The survey included practices' anaesthetic management, monitoring equipment and topics regarding patient safety.

RESULTS

Responses were obtained from 310/1700 (18%) veterinary practices, with 208 respondents from small animal practices (67%), 71 mixed animal practices (23%) and 31 referral small animal centres (10%). Overall, 61% of respondents reported always having a dedicated staff member monitoring the anaesthetic, who was most commonly a certified veterinary nurse (89%). In 22% of the practices, some of the staff monitoring an anaesthetic did not have any qualification. Completion of anaesthetic plans for each animal prior to an anaesthetic was reported by 24.5% of respondents and labelling of syringes was completed in 80% of practices. Pulse oximetry (98%) and temperature (88%) were the most common clinical variables monitored. The use of capnography (46%) or an electrocardiogram (48%) was also reported by the respondents. Emergency drugs, airway and ventilation equipment are available in 96%, 88% and 59% of practices, respectively. A defibrillator was available in 11% of practices with only 54% respondents being confident in using it. Of the respondents 60% were aware of anaesthesia safety interventions and clinical guidelines regarding patient safety during anaesthesia.

CONCLUSIONS AND CLINICAL RELEVANCE

Despite practices showing a relative improvement over the years in the standard of anaesthesia care, most of them are still not meeting international guidelines. Areas where changes could lead to improved safety practices could include: a trained person dedicated to monitor anaesthesia, pain scoring evaluation in patients recovering from anaesthesia, an increased use of standardised handover checklists, record keeping and an increase in open discussion of adverse events by the veterinary team.

Anaesthetic mortality in cats: A worldwide analysis and risk assessment

BACKGROUND

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.

METHODS

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.

RESULTS

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

Limitations include non-randomised sampling, potential biases, unquantified response rates, subjective death cause classification and limited variable analysis.

CONCLUSIONS

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.

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.

A Retrospective Study on Canine and Feline Mortality during Anaesthesia at a University Clinic in Greece

This retrospective cohort study investigated the mortality rate during anaesthesia and possible contributing factors in canine and feline population in an academic institution in Greece. Data on 1187 dogs and 250 cats which underwent general anaesthesia from 1 January 2018 to 31 December 2019 at the Veterinary Faculty of the Aristotle University of Thessaloniki were analysed regarding cardiac arrest and mortality. In dogs, the rate of cardiac arrest was 1.1% and the rate of death was 0.6%. In cats, these rates were 2.8% and 0.8%, respectively. The mortality rate in healthy/mild disease (ASA I-II) dogs was 0.1% and in cats was 0.5%. Sick (ASA III-V) dogs exhibited a death rate of 2.6%, while sick cats had a rate of 2.2%. In dogs, ASA status had a positive association with cardiac arrest and mortality, with sick dogs being 23 times more likely to suffer cardiac arrest and 24.5 times more likely to die than healthy/mild disease ones. Other factors associated with cardiac arrest and mortality were the anaesthetic protocol and the use of inotropes. In cats, premedication and inotropic support were related to cardiac arrest and death. Feline anaesthesia involves higher risk, and requires greater vigilance in peri-anaesthetic management than dogs.

Use of ketamine and xylazine anesthesia in dogs: A retrospective cohort study of 3,413 cases

The information regarding the risk of anesthesia-related death in veterinary medicine is scarce, and little is known about the mortality risk of specific anesthetics. The study conducted during 2019 at University of Sarajevo, Veterinary faculty, aimed to estimate the mortality risk of intermittent injectable ketamine-xylazine anesthesia in dogs and to investigate the potential relationship between mortality rate and anesthesiologists’ experience. Anesthetic records, where ketamine and xylazine combination was used for anesthesia induction and maintenance, were reviewed and divided into two groups: inexperienced (AN1) and experienced anesthesiologists (AN2). Inexperienced anesthesiologists were constantly supervised by experienced ones, whose corrective interventions were recorded. Overall detected mortality rate was 0.15%, with 0.18% and 0.11% in the AN1 and AN2 groups, respectively. A statistically significant difference was not found. Records of the AN1 group revealed interventions of experienced anesthesiologist in 92% of cases. Detected mortality rate was within the values previously established for inhalant anesthesia indicating high safety in usage of investigated protocol, if performed by experienced anesthesiologists. The high percentage of interventions of a senior anesthesiologist suggests that supervised upskilling of inexperienced anesthesiologists before their independent work could result in a better outcome.

[A multifactorial risk index for evaluation of anesthetic risk in dogs: the LeiV-Risk-Index]

OBJECTIVE

The Leipzig Veterinary Risk-Index - "LeiV-Risk-Index" is a multifactorial risk index developed to enable an improved objective assessment of the anesthetic risk in dogs. The scoring system is based on 10 risk factors affecting perioperative mortality. The aim of this study was to evaluate the applicability of the LeiV-Risk-Index and its risk factors as well as to perform a direct comparison with the ASA-classification.

MATERIAL AND METHODS

An online survey was conducted among veterinarians working in small animal medicine throughout Germany. Participants received a questionnaire containing information on 15 selected patients. They were asked to classify the patients according to the LeiV-Risk-Index and ASA-classification and to answer several questions concerning their professional background. The results were statistically analyzed considering the consistency among veterinarians of rating the different patients by using Fleiss'-Kappa. The correlation of LeiV-Risk-Index and ASA-classification was calculated.

RESULTS

The consistency of all assigned LeiV-risk classes between participants was moderate (κ = 0.55) and higher than classification by ASA (κ = 0.33). On average, 3 different LeiV-risk classes and 4 different ASA-classes were assigned for one patient. There was a positive correlation between LeiV-risk class and increasing ASA-class. No effect of gender or clinical experience of the veterinarian could be demonstrated on ranking patients. There was also no effect of how confident veterinarians felt in applying the LeiV-Risk-Index.

CONCLUSION UND CLINICAL RELEVANCE

The LeiV-Risk-Index is the first index available in veterinary medicine for assessing anesthetic risk that is based on objective risk criteria and whose objectivity exceeds that of the ASA classification. Anesthetic patients can thus be evaluated more consistently in veterinary medicine as well. Utility and practicability were positively received by 95 % of the participants. Further revision of individual risk criteria needs to be reconsidered.

Assessment of changes in blood pancreatic lipase activities using FDC-v-LIP in dogs that underwent various surgical procedures

OBJECTIVE

To describe the perioperative changes in blood pancreatic lipase activity and explore the contributing clinical factors associated with these changes.

DESIGN

Prospective observational study.

SETTING

University teaching hospital.

ANIMALS

One hundred and four dogs underwent various surgical procedures under general anesthesia.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Blood pancreatic lipase activities, which were measured using FUJI DRI-CHEM v-Lip-P (FDC-v-Lip), significantly increased postoperatively compared to preoperative measurements (premedian 58.5 U/L [range, 23-157] vs. postmedian 80 U/L [range, 22-1000], P < 0.0001). The patient with a postoperative increase in FDC-v-Lip over the normal range (35 dogs [33.6%]) had significantly higher preoperative FDC-v-Lip values.

CONCLUSIONS

In this study, dogs had significantly increased pancreas-specific lipase activities after surgical procedures under general anesthesia. Direct contributors to the increase and its relevance to clinical and histological pancreatitis should be determined in the future.

Perianesthetic mortality in English Bulldogs: a retrospective analysis in 2010 - 2017

Background

Many veterinarians consider English Bulldogs to have a greater perianesthetic mortality risk. The aims of this study were to 1) determine total and anesthesia-related, perianesthetic mortality (PAM) rates in English Bulldogs (EB), 2) identify potential risk factors associated with mortality in EB, and 3) determine the difference in the perianesthetic mortality rates between EB, other-brachycephalic breeds (OB), and non-brachycephalic breeds (NB).

Records from EB that were anesthetized between 2010 and 2017, were investigated. OB and NB were enrolled to match with each EB based on a procedure and age from the study period. Data collected in EB included: age, ASA status, weight, procedure types, anesthetic and analgesic management, anesthetic duration, anesthetic recovery location, and cause of death. Age and cause of death were determined from OB and NB. Fisher’s exact test was used to compare PAM rate and age in EB, OB, and NB. Mann–Whitney U test was used to compare EB survivor and EB non-survivor. Logistic regression models were used to identify factors and odds ratio (OR) associated with PAM in EB.

Result

Two hundred twenty nine EB, 218 OB, and 229 NB were identified. The total and anesthesia-related PAM rates in EB were 6.6 and 3.9%, respectively. EB had a greater total PAM rate compared with OB (p = 0.007). ASA status was different between survivors and non-survivors in EB (p < 0.01). Risk factors identified regardless of the cause of death were premedication with full μ opioids (OR = 0.333, p = 0.114), continuous infusion of ketamine post-operatively (OR = 13.775, p = 0.013), and acepromazine administration post-operatively (OR = 7.274, p = 0.004). The most common cause of death in EB was postoperative respiratory dysfunction (87.5%).

Conclusion

Total and anesthesia-related mortality in EB is considerable. Most deaths in EB occurred during the postoperative period secondary to respiratory complications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03301-9.

Avian anaesthesia related mortality and the associated risk factors in a UK zoological collection

OBJECTIVE

To analyse avian anaesthesia-related mortality in a UK zoological collection over a 5-year period and identify risk factors for mortality.

STUDY DESIGN

Retrospective cohort study.

ANIMALS

A total of 135 individual birds across 37 species, anaesthetized during 206 events in a UK zoological collection between 1 January 2014 and 30 June 2019 (inclusive).

METHODS

Anaesthesia records were reviewed and variables such as age, body condition, weight, sex, duration of anaesthesia and health status were collated. Anaesthesia-related mortality was defined as those deaths occurring during anaesthesia and up to 7 days postanaesthesia. Outcome was analysed using multivariable conditional logistic regression. Overall mortality was defined and included birds euthanised during anaesthesia for non-anaesthesia related reasons. Data were summarised as median (range). A value of p < 0.05 was considered significant. Relative risks and 95% confidence intervals (95% CI) were calculated for the association between risk factors and anaesthetic death where a statistically significant difference was found.

RESULTS

The overall mortality rate was 10.19% (95% CI = 6.06-14.3%), while anaesthesia-related mortality was 3.88% (95% CI = 1.69-7.51%). Birds with an abnormal health status had a 15.53-fold (95% CI = 1.95-123.63) increased risk of death compared with those with a normal health status. The duration of anaesthesia was also a statistically significant risk factor (p = 0.021) in the univariable analysis, but not when combined with health status. No other variables were associated with anaesthesia-related mortality.

CONCLUSIONS AND CLINICAL RELEVANCE

Abnormal health status and longer anaesthetic procedures were associated with a significantly increased risk of anaesthesia-related death in this population of birds. It is recommended that anaesthetic duration is minimized, and pre-existing diseases are diagnosed where possible prior to general anaesthesia of birds. Anaesthetizing healthy birds was associated with a low risk of mortality.

Preanaesthetic blood tests in cats and dogs older than 8 years: anaesthetists' prediction and peri-anaesthetic changes

OBJECTIVE

To evaluate the anaesthetist's ability to predict abnormalities in preanaesthetic blood test results obtained from cats and dogs older than 8 years and to describe the impact of these preanaesthetic blood test results on the American Society Anesthesiologists (ASA) physical status classification, anaesthetic protocol and procedures.

STUDY DESIGN

Observational, prospective, clinical multi-centre study.

ANIMALS

A total of 333 cats and dogs.

METHODS

After a clinical examination and review of the animal´s clinical history the anaesthetist completed the first part of a set of questions including ASA status and anticipated abnormalities in blood tests. After this, blood results were presented, and the anaesthetist completed the second part of the set of questions, including changes in ASA status or anaesthetic protocol, and procedure delay or cancellation. Preanaesthetic blood tests included: haematocrit, total proteins, electrolytes, glucose, lactate, urea and creatinine. Examiners were classified as senior clinicians, clinicians, anaesthesia residents or nurses, and interns. For statistical analysis, the chi-square test was used. A p value < 0.05 was considered significant.

RESULTS

The ASA status increased in three dogs and one cat (1.2%); in two of them abnormalities were not expected by the examiner. The anaesthetic protocol changed in seven animals (2.1%); the most common change related to fluid therapy. Anaesthesia was delayed in two dogs (0.6%) to administer intravenous fluid therapy. No cases were cancelled. Abnormalities were more commonly found [37 out of 58 assessments (approximately 64%)] when the anaesthetist predicted them compared to when they were unexpected [49 of 275 assessments (approximately 18%); p < 0.001].

CONCLUSIONS AND CLINICAL RELEVANCE

Routine non-targeted blood tests in cats and dogs older than 8 years led to few changes in the anaesthetic management, and anaesthetists correctly predicted blood test results in most cases.

Pre-anaesthetic clinical examination influences anaesthetic protocol in dogs undergoing general anaesthesia and sedation

OBJECTIVES

Identify whether pre-anaesthetic clinical examination influences anaesthetic and analgesic agents and techniques protocol in dogs presented for general anaesthesia and sedation at a large referral hospital.

MATERIALS AND METHODS

In this prospective clinical audit, 554 dogs, undergoing general anaesthesia or sedation for surgical, diagnostic or imaging procedures were included. Multiple attending anaesthetists completed a questionnaire divided into four sections (American Society of Anesthesiologists physical status classification, anaesthetic and analgesic agents and techniques protocol, pre-anaesthetic clinical examination findings and changes made to the anaesthetic protocol). The attending anaesthetist was able to review the patient's history before planning the anaesthetic and analgesic agents and techniques protocol. The patients were examined and changes in American Society of Anesthesiologists physical status classification or anaesthetic protocol were recorded.

RESULTS

The initial anaesthetic and analgesic agents and techniques protocol was altered in 23.3% (n=129/554) of cases following a pre-anaesthetic clinical examination, but American Society of Anesthesiologists physical status reclassification occurred in only 8.0% (n=37/464) of cases. Multivariable logistic regression analysis showed that pre-anaesthetic clinical examination performed by European College of Veterinary Anaesthesia and Analgesia diplomates (odds ratio 5.8, 95% confidence interval 2.0 to 17.2), compared to anaesthesia interns, and the presence of an audible heart murmur (odds ratio 2.4, 95% confidence interval 1.4 to 4.4) were factors linked to changes in anaesthetic and analgesic agents and techniques protocol, whereas for each one kilogram increase in patient's weight, the odds of a change in anaesthetic and analgesic agents and techniques protocol to occur decreased by 1.7% (odds ratio 0.98, 95% confidence interval 0.97 to 1.0).

CLINICAL SIGNIFICANCE

Pre-anaesthetic clinical examination has impact on American Society of Anesthesiologists physical status classification, therefore estimation of patient's anaesthetic risk, and influences anaesthetic and analgesic agents and techniques protocol choice.

Impact of intra-operative hypotension on mortality rates and post-operative complications in dogs undergoing cholecystectomy

OBJECTIVES

To report the mortality rate within a cohort of dogs undergoing cholecystectomy and investigate the impact of intra-operative hypotension on mortality.

MATERIALS AND METHODS

Clinical records at five UK referral centres were reviewed for dogs undergoing cholecystectomy. Data collected included presenting signs, pre-operative blood test results, intra-operative data including frequency and duration of hypotension and the incidence and type of post-operative complications.

RESULTS

Data from 119 dogs were included. Sixteen dogs (13%) died before discharge and by 28 days after surgery the total mortality was 19 dogs (17%). Hypotension lasting over 10 minutes during general anaesthesia occurred in 65 dogs (54.6%), with a mean ± sd duration of 36.1 ± 30.0 minutes. Intra-operative hypotension or the number of hypotensive episodes did not appear to be associated with in-hospital or 28-day mortality. American Society of Anaesthesiologists grade (of fitness for surgery) was significantly associated with both in-hospital and 28-day mortality on univariable analysis, as were post-operative hypoproteinaemia, ileus and pancreatitis. However on multivariable analysis, only ileus and pancreatitis were found to significantly impact mortality.

CLINICAL SIGNIFICANCE

Dogs presenting with a higher American Society of Anaesthesiologists grade appear to have a higher risk of mortality, although intra-operative hypotension did not appear to be part of this risk.

Investigation of associations between preoperative acepromazine or dexmedetomidine administration and development of arterial hypotension or bradycardia in dogs undergoing ovariohysterectomy

OBJECTIVE To evaluate potential associations between preanesthetic administration of acepromazine or dexmedetomidine and development of arterial hypotension or bradycardia in isoflurane-anesthetized dogs undergoing ovariohysterectomy. ANIMALS 341 dogs. PROCEDURES Medical records were searched to identify dogs that underwent ovariohysterectomy between January 2009 and December 2010 and received hydromorphone with acepromazine or dexmedetomidine as preanesthetic agents. Demographic data, sedative and anesthetic drugs, duration of anesthesia, average vaporizer setting, positive pressure ventilation, occurrence of hypotension (mean arterial pressure < 60 mm Hg) or bradycardia (> 50% reduction in heart rate, compared with the preanesthetic value), time to first occurrence and duration of hypotension, and treatment with dopamine or anticholinergic agents were recorded. Data were compared between dogs that received acepromazine and dexmedetomidine. Logistic regression was used to investigate associations between the treatments of interest (and other putative risk factors) and development of hypotension or bradycardia. RESULTS For dogs that received acepromazine, the odds of developing hypotension were 2.61 times those for dogs that received dexmedetomidine. Hypotension occurred earlier and lasted longer in dogs that received acepromazine, and this group was treated with dopamine more frequently than the group that received dexmedetomidine. Lower body weight was associated with increased odds of hypotension. Odds of developing bradycardia were greater for dogs sedated with dexmedetomidine (vs acepromazine) and for dogs that underwent anesthetic induction with propofol or a ketamine-benzodiazepine combination (vs thiopental). CONCLUSIONS AND CLINICAL RELEVANCE Anesthetic complications differed between isoflurane-anesthetized dogs undergoing ovariohysterectomy after premedication with acepromazine or dexmedetomidine in this study; future prospective investigations are warranted to investigate these effects in other, less homogenous populations of dogs.

Management of veterinary anaesthesia in small animals: A survey of current practice in Quebec

OBJECTIVE

To describe how small animal anaesthesia is performed in French-speaking Eastern Canada, and the variations between practices, in particular based on practice type, veterinarian gender and experience.

DESIGN

Observational study, survey.

SAMPLE

156 respondents.

PROCEDURE

A questionnaire was designed to assess current small animal anaesthesia practices in French-speaking Eastern Canada, mainly in the province of Quebec. The questionnaire was available through SurveyMonkey, and consisted of four parts: demographic information about the veterinarians surveyed, evaluation and management of anaesthetic risk, anaesthesia procedure, monitoring and safety. Gender, year of graduation, and type of practice were tested as potential risk factors. Chi-square exact test was used to study relations between each risk factor, and the effect of the selected risk factor on each response of the survey. For ordinal data, the Cochran-Mantel-Haenszel test was used to maximize power.

RESULTS

Response rate over a period of 3 months was 20.85% (156 respondents). Overall, the way anaesthesia is performed by most respondents does not meet international guidelines, such as patient preparation and evaluation prior to anaesthesia, not using individualised protocols (for 41%), not obtaining intravenous access (12.4% use it for all their anaesthesia in cats, and 30.6% in dogs), lack of patient monitoring at certain intervals for 55% of the responses, and client prompted optional analgesia (for 29% of respondents). Some practices are more compliant than others. Among them, referral centres generally offer better care than general practices.

CONCLUSIONS AND CLINICAL RELEVANCE

The level of care in anaesthesia and analgesia in practices in French-speaking Eastern Canada is concerning, highlighting the need for more sustained continuing education.

The ASA Physical Status Classification: What Is the Evidence for Recommending Its Use in Veterinary Anesthesia?-A Systematic Review

Background: The effectiveness of the American Society of Anesthesiologists (ASA) Physical Status (PS) classification to identify the animals at a greater risk of anesthesia-related death and complications is controversial. In this systematic review, we aimed to analyze studies associating the ASA PS scores with the outcome of anesthesia and to verify whether there was any evidence for recommending the use of the ASA PS in veterinary patients.

Methods: Research articles found through a systematic literature search were assessed for eligibility, and data were extracted and analyzed using random-effects analysis.

Results: A total of 15 observational prospective and retrospective studies including 258,298 dogs, cats, rabbits, and pigs were included. The analysis found consistency between the studies showing that dogs, cats and rabbits with an ASA-PS ≥III had 3.26 times (95% CI = 3.04–3.49), 4.83 times (95% CI = 3.10–7.53), and 11.31 times (95% CI = 2.70–47.39), respectively, the risk of anesthesia-related death within 24 h (dogs) and 72 h (cats and rabbits) after anesthesia compared with those with an ASA PS <III. In addition, the analysis showed that dogs and cats with ASA PS ≥III had 2.34 times the risk of developing severe hypothermia during anesthesia (95% CI = 1.82–3.01).

Conclusions: The simple and practical ASA PS was shown to be a valuable prognostic tool and can be recommended to identify an increased risk of anesthetic mortality until 24–72 h after anesthesia, and a greater risk of development severe intraoperative hypothermia.

The Association of Shelter Veterinarians' 2016 Veterinary Medical Care Guidelines for Spay-Neuter Programs

As community efforts to reduce the overpopulation and euthanasia of unwanted and unowned cats and dogs have increased, many veterinarians have increasingly focused their clinical efforts on the provision of spay-neuter services. Because of the wide range of geographic and demographic needs, a wide variety of spay-neuter programs have been developed to increase delivery of services to targeted populations of animals, including stationary and mobile clinics, MASH-style operations, shelter services, community cat programs, and services provided through private practitioners. In an effort to promote consistent, high-quality care across the broad range of these programs, the Association of Shelter Veterinarians convened a task force of veterinarians to develop veterinary medical care guidelines for spay-neuter programs. These guidelines consist of recommendations for general patient care and clinical procedures, preoperative care, anesthetic management, surgical procedures, postoperative care, and operations management. They were based on current principles of anesthesiology, critical care medicine, infection control, and surgical practice, as determined from published evidence and expert opinion. They represent acceptable practices that are attainable in spay-neuter programs regardless of location, facility, or type of program. The Association of Shelter Veterinarians envisions that these guidelines will be used by the profession to maintain consistent veterinary medical care in all settings where spay-neuter services are provided and to promote these services as a means of reducing sheltering and euthanasia of cats and dogs.

Perianesthetic Mortality in Domestic Animals

Autopsy of animals that die in the perianesthetic period allows identification of anesthetic and surgical complications as well as preexisting disease conditions that may have contributed to mortality. In most studies to date investigating perianesthetic mortality in animals, inclusion of autopsy data is very limited. This retrospective study evaluated autopsy findings in 221 cases of perianesthetic death submitted to a veterinary diagnostic laboratory from primary care and referral hospitals. Canine ( n = 105; 48%) and feline ( n = 90; 41%) cases predominated in the study, involving elective (71%) and emergency (19%) procedures. The clinical history provided to the pathologist was considered incomplete in 42 of 221 cases (19%), but this history was considered essential for evaluating the circumstances of perianesthetic death. Disease had been recognized clinically in 69 of 221 animals (31%). Death occurred in the premedication or sedation ( n = 19; 9%), induction ( n = 22; 11%), or maintenance ( n = 73; 35%) phases or in the 24 hours postanesthesia ( n = 93 animals; 45%). Lesions indicative of significant natural disease were present in 130 of 221 animals (59%), mainly involving the heart, upper respiratory tract, or lungs. Surgical or anesthesia-associated complications were identified in 10 of 221 cases (5%). No lesions were evident in 80 of 221 animals (36%), the majority of which were young, healthy, and undergoing elective surgical procedures. Lesions resulting from cardiopulmonary resuscitation were identified in 75 of 221 animals (34%). Investigation of perianesthetic death cases should be done with knowledge of prior clinical findings and antemortem surgical and medical procedures; the autopsy should particularly focus on the cardiovascular and respiratory system, including techniques to identify pneumothorax and venous air embolism.

An evidence-based medicine approach to small animal anaesthetic mortality in a referral practice: the influence of initiating three recommendations on subsequent anaesthetic deaths

OBJECTIVE

To evaluate anaesthetic death after implementation of recommendations and its risk factors in a small animal practice.

STUDY DESIGN

Observational cohort study.

ANIMALS

All cats and dogs anaesthetized at the Centre Hospitalier Vétérinaire des Cordeliers during two periods, from April 15th, 2008 to April 15th, 2010 (period 1) and from June 15th, 2010 to August 24th, 2011 (period 2).

METHODS

Death occurring during or before full recovery from anaesthesia was recorded. At the end of period 1, a logistic regression model was generated to describe anaesthetic death and identify risk factors. Potential risk factors in our practice setting were identified, and three recommendations, relating to improving physical status and anaesthetic/analgesic regimen implemented for period 2. The relationship between anaesthetic death and recorded variables were analyzed, and where relevant, compared between periods.

RESULTS

Six thousand two hundred and thirty-one animals underwent general anaesthesia. The overall death rate during period 1 was 1.35% (48 in 3546, 95% CI [1.0-1.7%]) and during period 2 was 0.8% (21 in 2685, 95% CI [0.6-1.2%]). For sick animals (ASA status 3 and over), the overall death rate was 4.8% (45 of 944 95% [CI 3.5-6.4%]) during period 1 and 2.2% (18 of 834 95% CI [1.3-3.5%]) during period 2; this represented a significant decrease in death rate in period 2 (p = 0.002). In period 2, the main factors associated with an increased odds ratio of anaesthetic death were poor health status (ASA physical status classification) and old age. Species, gender, anaesthetic regimen, the nature and urgency of the procedure were not associated with risk.

CONCLUSION AND CLINICAL RELEVANCE

Following evidence based recommendations, the death rate related to anaesthesia was significantly decreased during period 2 compared to period 1. Application of evidence-based medicine may contribute to an effective approach to decrease death rates. Other factors, not monitored in this study, may also have had an impact.

Predictors of outcome in dogs undergoing thoracic surgery (2002-2011)

OBJECTIVE

To evaluate mortality in a canine population undergoing thoracic surgery and identify factors which may be associated with outcome.

STUDY DESIGN

Retrospective cohort study.

ANIMALS

286 dogs anaesthetized for thoracic surgery at the Royal Veterinary College between June 2002 - June 2011.

METHODS

Variables examined included: signalment; ASA status; nature of disease; presence of co-morbidities; pre-anaesthetic oxygen requirement; surgical approach; anaesthesia management [anaesthetic agents; requirement for thoracocentesis; central venous pressure measurement; duration of surgery and anaesthesia; use of colloids, blood products, inotropes or neuromuscular blocking agents (NMBA)]. Outcome was defined as either non-survival to 24 hours after surgery or (having survived to 24 hours) to discharge. Univariate and multivariable logistic regressions were performed to identify risk factors associated with non-survival.

RESULTS

Overall non-survival (excluding those euthanased) to discharge was 5.9%. Non-survival was 2.2% at 24 hours and 3.6% at time of discharge. Non-survival to 24 hours was associated with pre-anaesthetic oxygen requirement (odds ratio (OR) 12.2 [95% CI 1.8-84.5]) and NMBA use (OR 9.6 [95% CI 1.6-57.9]). Non-survival to discharge was associated with surgical duration, with surgeries >180 minutes having OR 16.9 [95% CI 2.0-144.0] compared to surgeries ≤90 minutes and blood product use (OR 4.6 [95% CI 1.3-14.6]). No association was found between ASA category and non-survival at 24 hours (OR 1.4 [95% CI 0.2-11.7]) or discharge (OR 4.4 [95% CI 0.6-34.3]). Significant associations were found between NMBA use and ASA category (p = 0.046), surgical duration (p = 0.002), use of colloids (p = 0.011), blood products (p = 0.001) and inotropes and/or vasopressors (p < 0.001).

CONCLUSIONS AND CLINICAL RELEVANCE

Variables significantly associated with non-survival from canine thoracic surgery at 24 hours include NMBA use and pre-anaesthetic oxygen requirement. Blood product use and increasing surgical duration were associated with non-survival to hospital discharge. The associations may relate to the need for such products in the most complicated cases.