Normal Values and Incidence of Cardiorespiratory Complications in Dogs During General Anaesthesia. A Review of 1281 Cases

Physiological variables for the objective detection of nerve block failure in dogs

OBJECTIVE

To identify physiological variables for objectively detecting nociception indicative of intraoperative peripheral nerve block failure.

STUDY DESIGN

A double-blinded randomized clinical study.

ANIMALS

A sample of 14 male (40.8 ± 12 kg; mean ± standard deviation) and 16 female (34.3 ± 11.4 kg) client-owned dogs.

METHODS

Dogs were randomly assigned to one of three groups for psoas compartment and proximal sciatic nerve blocks (0.2 mL kg-1 per site): guided bupivacaine (GBB), or saline (GSB) block or a blind bupivacaine block (BBB). Guided blocks were performed using an ultrasound-peripheral nerve locator combination. Premedication consisted of medetomidine 0.01 mg kg-1 and morphine 0.3 mg kg-1. General anaesthesia was induced with propofol and maintained with isoflurane in oxygen. Receiver operator characteristic curve analysis was used to compare actual values and change in values of physiological variables between GSB and GBB. The Youden index and associated criterion for each physiological variable were used to determine an objective measure for nociception. Fisher's exact t test, McNemar's test and Cohen's kappa statistical analysis were used to determine association, differences and inter-score reliability between the objective and subjective scoring for BBB.

RESULTS

Cardiovascular variables had good discriminating ability to identify a nociceptive response (p < 0.01). The Youden indices for mean (MAP) and diastolic (DAP) arterial pressure were most reliable in detecting nociception. The highest sensitivity was that of ΔMAP (100%) with good agreement between the subjective and objective scores of Δheart rate or systolic arterial pressure (SAP). The use of ΔMAP, ΔSAP, ΔDAP had the best ability in indicating peripheral nerve block failure (p < 0.001).

CONCLUSIONS AND CLINICAL RELEVANCE

Blood pressure values can detect a response to surgical stimulus in adequately anaesthetized dogs. The use of ΔMAP, ΔSAP or ΔDAP may be considered as objective measures to detect nerve block failure.

Retrospective comparison between low-volume high-concentration and high-volume low-concentration levobupivacaine for bilateral erector spinae plane block in dogs undergoing hemilaminectomy

OBJECTIVE

To compare the analgesic effect of a bilateral ultrasound-guided erector spinae plane block (ESPB) in dogs undergoing hemilaminectomy using either a low-volume high-concentration (LV-HC) or a high-volume low-concentration (HV-LC) local anaesthetic solution.

STUDY DESIGN

Retrospective observational equivalence trial.

ANIMALS

A total of 391 client-owned dogs undergoing hemilaminectomy.

METHODS

Dogs were assigned to group LV-HC or HV-LC depending on whether 0.2-0.25% levobupivacaine (0.4-0.5 mL kg-1) or 0.125-0.15% levobupivacaine (0.8-1 mL kg-1) was used to perform the ESPB, respectively. The number of dogs in which intraoperative rescue fentanyl boluses were administered, the total dose of fentanyl administered, the overall methadone consumption during the first 24 hours postoperatively and anaesthetic complications were recorded. Univariate and multivariate statistical analyses were performed considering p < 0.05 significant.

RESULTS

A total of 248 and 143 dogs were assigned to groups LV-HC and HV-LC, respectively. In group HV-LC, the number of dogs requiring fentanyl intraoperatively (64.3%) was higher (p = 0.0001) than that in group LV-HC (43.5%). The overall intraoperative fentanyl consumption was higher in group HV-LC between the first skin incision and the end of the lamina drilling (p = 0.028). According to the regression analysis, the group allocation was the best variable to predict the intraoperative fentanyl consumption (p < 0.001). Antimuscarinic drugs were administered more frequently in group LV-HC (p < 0.02). However, the prevalence of hypotension and other pharmacological cardiovascular interventions did not differ between groups. No differences in methadone consumption during the first 24 hours postoperatively were found between the groups.

CONCLUSIONSAND CLINICAL RELEVANCE

When performing a bilateral ESPB in dogs undergoing hemilaminectomy, compared with HV-LC, the use of LV-HC local anaesthetic solution reduces the intraoperative fentanyl consumption without affecting the postoperative methadone requirement.

Computer-controlled closed-loop norepinephrine infusion system for automated control of mean arterial pressure in dogs under isoflurane-induced hypotension: a feasibility study

Introduction

Intra-operative hypotension is a common complication of surgery under general anesthesia in dogs and humans. Computer-controlled closed-loop infusion systems of norepinephrine (NE) have been developed and clinically applied for automated optimization of arterial pressure (AP) and prevention of intra-operative hypotension in humans. This study aimed to develop a simple computer-controlled closed-loop infusion system of NE for the automated control of the mean arterial pressure (MAP) in dogs with isoflurane-induced hypotension and to validate the control of MAP by the developed system.

Methods

NE was administered via the cephalic vein, whereas MAP was measured invasively by placing a catheter in the dorsal pedal artery. The proportional-integral-derivative (PID) controller in the negative feedback loop of the developed system titrated the infusion rate of NE to maintain the MAP at the target value of 60 mmHg. The titration was updated every 2 s. The performance of the developed system was evaluated in six laboratory Beagle dogs under general anesthesia with isoflurane.

Results

In the six dogs, when the concentration [median (interquartile range)] of inhaled isoflurane was increased from 1.5 (1.5-1.5)% to 4 (4-4)% without activating the system, the MAP was lowered from 95 (91-99) to 41 (37-42) mmHg. In contrast, when the concentration was increased from 1.5 (1.0-1.5)% to 4 (4-4.8)% for a 30-min period and the system was simultaneously activated, the MAP was temporarily lowered from 92 (89-95) to 47 (43-49) mmHg but recovered to 58 (57-58) mmHg owing to the system-controlled infusion of NE. If the acceptable target range for MAP was defined as target MAP ±5 mmHg (55 ≤ MAP ≤65 mmHg), the percentage of time wherein the MAP was maintained within the acceptable range was 96 (89-100)% in the six dogs during the second half of the 30-min period (from 15 to 30 min after system activation). The median performance error, median absolute performance error, wobble, and divergence were - 2.9 (-4.7 to 1.9)%, 2.9 (2.0-4.7)%, 1.3 (0.8-1.8)%, and - 0.24 (-0.34 to -0.11)%·min-1, respectively. No adverse events were observed during the study period, and all dogs were extubated uneventfully.

Conclusion

This system was able to titrate the NE infusion rates in an accurate and stable manner to maintain the MAP within the predetermined target range in dogs with isoflurane-induced hypotension. This system can be a potential tool in daily clinical practice for the care of companion dogs.

Risk assessment in equine anesthesia: a first evaluation of the usability, utility and predictivity of the two-part CHARIOT

Introduction

An accurate risk score that can predict peri-anesthetic morbidity and mortality in equine patients could improve peri-operative management, outcome and client communication.

Materials and methods

Three hunded horses underwent pre-anesthetic risk assessment using the American Society of Anesthesiologists-Physical Status augmented with equine-specific diseases (ASA-PS-Equine), a multifactorial 10-part rubric risk scale (10-RS), and a combination of both, the Combined horse anesthetic risk identification and optimization tool (CHARIOT). Intra-and post-anesthetic complications, the recovery phase and mortality were recorded over a period of 7 days following general anesthesia. To compare the utility and predictive power of the 3 scores, data were analyzed using binominal logistic regression (p ≤ 0.05) and receiver operating characteristic curve analysis. In addition, inter-observer reliability, speed, safety, ease of use and face validity of the ASA-PS-Equine and the 10-RS were analyzed based on five hypothetical patients.

Results

All scores showed statistically significant associations with various intra-anesthetic complications and parameters of the recovery phase. The discriminant ability of the scores related to the occurrence of intra-anesthetic (AUC = 0.6093-0.6701) and post-anesthetic (AUC = 0.5373-0.6194) complications was only low. The highest diagnostic accuracy for all scores was observed for overall mortality (AUC = 0.7526-0.7970), with the ASA-PS-Equine differentiating most precisely (AUC = 0.7970; 95% CI 0.7199-0.8741). Inter-observer reliability was fair for the 10-RS (κ = 0.39) and moderate for the ASA-PS-Equine (κ = 0.52). Patient assignment to the CHARIOT was predominantly rated as rather easy and quick or very quick.

Limitations and conclusion

The main limitations of the study are the monocentric study design and failure to obtain the full range of points. In conclusion, all 3 scores provide useful information for predicting the mortality risk of equine patients undergoing general anesthesia, whereas intra-and postoperative complications cannot be predicted with these scores.

Association between body mass and hypotension in dogs under general anaesthesia

OBJECTIVES

To investigate the association between body mass and hypotension during general anaesthesia in dogs undergoing surgical and diagnostic procedures within a referral hospital.

MATERIALS AND METHODS

Retrospective evaluation of the anaesthetic records of 1789 dogs was performed. Data on signalment, anaesthetic protocol and physiological variables, including mean arterial pressure, were collected. A multivariable generalised linear model was used to identify associations between explanatory variables, including body mass, and hypotension.

RESULTS

In the population studied, increasing body mass (per 10 kg) was significantly associated with decreasing odds of hypotension (odds ratio 0.68; 95% confidence interval: 0.60 to 0.77). Additional variables associated with a decreased odds of hypotension were pre-anaesthetic medication with alpha-2 agonists (odds ratio 0.63; 95% confidence interval 0.48 to 0.82) and increased body temperature (per 1°C) during general anaesthesia (odds ratio 0.77; 95% confidence interval 0.67 to 0.88). Brachycephaly (odds ratio 1.72; 95% confidence interval 1.25 to 2.38), ASA physical status classification >3 (odds ratio 2.03; 95% confidence interval 1.16 to 3.56), undergoing a surgical procedure (versus diagnostic) (odds ratio 1.57; 95% confidence interval 1.10 to 2.23) and bradycardia (odds ratio 1.37; 95% confidence interval 1.05 to 1.80) were independently associated with increased odds of hypotension.

CLINICAL SIGNIFICANCE

Dogs of lower body mass and brachycephalic breeds may be at higher risk of hypotension during general anaesthesia or alternatively represent subpopulations in which accurate blood pressure measurement presents a greater challenge. Monitoring blood pressure accurately in these groups requires particular attention and provisions for treating hypotension should be readily accessible.

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.

Two Amnion-Derived Mesenchymal Stem-Cells Injections to Osteoarthritic Elbows in Dogs-Pilot Study

The aim of the study was to investigate the potential of cell-based regenerative therapy for elbow joints affected by osteoarthritis. Interest was focused on two intra-articular applications of amnion-derived mesenchymal stem cells (A-MSCs) to a group of different breeds of dogs with elbow osteoarthritis (13 joints). Two injections were performed 14 days apart. We evaluated synovial fluid biomarkers, such as IFN-γ, IL-6, IL-15, IL-10, MCP-1, TNF-α, and GM-CSF, by multiplex fluorescent micro-bead immunoassay in the treated group of elbows (n = 13) (day 0, day 14, and day 28) and in the control group of elbows (n = 9). Kinematic gait analysis determined the joint range of motion (ROM) before and after each A-MSCs application. Kinematic gait analysis was performed on day 0, day 14, and day 28. Kinematic gait analysis pointed out improvement in the average range of motion of elbow joints from day 0 (38.45 ± 5.74°), day 14 (41.7 ± 6.04°), and day 28 (44.78 ± 4.69°) with statistical significance (p < 0.05) in nine elbows. Correlation analyses proved statistical significance (p < 0.05) in associations between ROM (day 0, day 14, and day 28) and IFN-γ, IL-6, IL-15, MCP-1, TNF-α, and GM-CSF concentrations (day 0, day 14, and day 28). IFN-γ, IL-6, IL-15, MCP-1, GM-CSF, and TNF- α showed negative correlation with ROM at day 0, day 14, and day 28, while IL-10 demonstrated positive correlation with ROM. As a consequence of A-MSC application to the elbow joint, we detected a statistically significant (p < 0.05) decrease in concentration levels between day 0 and day 28 for IFN-γ, IL-6, and TNF-α and statistically significant increase for IL-10. Statistical significance (p < 0.05) was detected in TNF-α, IFN-γ, and GM-CSF concentrations between day 14 and the control group as well as at day 28 and the control group. IL-6 concentrations showed statistical significance (p < 0.05) between day 14 and the control group.

Clinical presentation, diagnosis, treatment, and outcome in 8 dogs and 2 cats with global hypoxic-ischemic brain injury (2010-2022)

BACKGROUND

Global hypoxic-ischemic brain injury (GHIBI) results in variable degrees of neurological dysfunction. Limited data exists to guide prognostication on likelihood of functional recovery.

HYPOTHESIS

Prolonged duration of hypoxic-ischemic insult and absence of neurological improvement in the first 72 hours are negative prognostic indicators.

ANIMALS

Ten clinical cases with GHIBI.

METHODS

Retrospective case series describing 8 dogs and 2 cats with GHIBI, including clinical signs, treatment, and outcome.

RESULTS

Six dogs and 2 cats experienced cardiopulmonary arrest or anesthetic complication in a veterinary hospital and were promptly resuscitated. Seven showed progressive neurological improvement within 72 hours of the hypoxic-ischemic insult. Four fully recovered and 3 had residual neurological deficits. One dog presented comatose after resuscitation at the primary care practice. Magnetic resonance imaging confirmed diffuse cerebral cortical swelling and severe brainstem compression and the dog was euthanized. Two dogs suffered out-of-hospital cardiopulmonary arrest, secondary to a road traffic accident in 1 and laryngeal obstruction in the other. The first dog was euthanized after MRI that identified diffuse cerebral cortical swelling with severe brainstem compression. In the other dog, spontaneous circulation was recovered after 22 minutes of cardiopulmonary resuscitation. However, the dog remained blind, disorientated, and ambulatory tetraparetic with vestibular ataxia and was euthanized 58 days after presentation. Histopathological examination of the brain confirmed severe diffuse cerebral and cerebellar cortical necrosis.

CONCLUSIONS AND CLINICAL IMPORTANCE

Duration of hypoxic-ischemic insult, diffuse brainstem involvement, MRI features, and rate of neurological recovery could provide indications of the likelihood of functional recovery after GHIBI.

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.

The impact of stress and anesthesia on animal models of infectious disease

Stress and general anesthesia have an impact on the functional response of the organism due to the detrimental effects on cardiovascular, immunological, and metabolic function, which could limit the organism's response to an infectious event. Animal studies have formed an essential step in understanding and mitigating infectious diseases, as the complexities of physiology and immunity cannot yet be replicated in vivo. Using animals in research continues to come under increasing societal scrutiny, and it is therefore crucial that the welfare of animals used in disease research is optimized to meet both societal expectations and improve scientific outcomes. Everyday management and procedures in animal studies are known to cause stress, which can not only cause poorer welfare outcomes, but also introduces variables in disease studies. Whilst general anesthesia is necessary at times to reduce stress and enhance animal welfare in disease research, evidence of physiological and immunological disruption caused by general anesthesia is increasing. To better understand and quantify the effects of stress and anesthesia on disease study and welfare outcomes, utilizing the most appropriate animal monitoring strategies is imperative. This article aims to analyze recent scientific evidence about the impact of stress and anesthesia as uncontrolled variables, as well as reviewing monitoring strategies and technologies in animal models during infectious diseases.

Development and comparison of an esophageal Doppler monitoring-based treatment algorithm with a heart rate and blood pressure-based treatment algorithm for goal-directed fluid therapy in anesthetized dogs: A pilot study

The objective of this pilot study was to determine the feasibility of a study comparing the efficacy of an esophageal Doppler monitor (EDM)-based fluid therapy algorithm with a heart rate (HR)- and mean arterial blood pressure (MAP)-based algorithm in reducing hypotension and fluid load in anesthetized dogs. Client-owned dogs undergoing general anesthesia for surgical procedures were randomized to two groups. An EDM probe for monitoring blood flow in the descending aorta was placed in each dog before receiving a crystalloid bolus (5 mL/kg) over 5 min. Fluids were repeated in case of fluid responsiveness defined by increasing Velocity Time Integral (VTI) ≥ 10% in group EDM and by decreasing HR ≥ 5 beats/min and/or increasing MAP ≥ 3 mmHg in group standard. The feasibility outcomes included the proportion of dogs completing the study and the clinical applicability of the algorithms. The clinical outcomes were the total administered fluid volume and the duration of hypotension defined as MAP < 60 mmHg. Data was compared between groups with Mann-Whitney U-test. p < 0.05 were deemed significant. Of 25 dogs screened, 14 completed the study (56%). There were no differences in the proportion of recorded time spent in hypotension in group standard [2 (0–39)% (median (range))] and EDM [0 (0–63) %, p = 1], or the total volume of fluids [standard 8 (5–14) mL/kg/h, EDM 11 (4–20) mL/kg/h, p = 0.3]. This study declined the feasibility of a study comparing the impact of two newly developed fluid therapy algorithms on hypotension and fluid load in their current form. Clinical outcome analyses were underpowered and no differences in treatment efficacy between the groups could be determined. The conclusions drawn from this pilot study provide important information for future study designs.

Advances in the pharmaceutical treatment options for canine osteoarthritis

Canine osteoarthritis is a significant cause of pain in many dogs and can therefore compromise animal welfare. As the understanding of the biology and pain mechanisms underpinning osteoarthritis grows, so do the number of treatments available to manage it. Over the last decade, there have been a number of advances in the pharmaceutical treatment options available for dogs with osteoarthritis, as well as an increasing number of clinical trials investigating the efficacy of pre-existing treatments. This review aims to examine the current evidence behind pharmaceutical treatment options for canine osteoarthritis, including non-steroidal anti-inflammatory drugs, piprants, monoclonal antibodies, adjunctive analgesics, structure modifying osteoarthritis drugs and regenerative therapies.

Ultrasound-guided bilateral erector spinae plane block in dogs undergoing sternotomies anaesthetised with propofol-dexmedetomidine continuous infusion

BACKGROUND

To describe the use of a bilateral thoracic (T5 - T9) ultrasound-guided erector spinae plane block (UG-ESPB) in dogs undergoing sternotomy anaesthetised with propofol and dexmedetomidine continuous infusions.

METHODS

Demographic information, perioperative anaesthetic and analgesic drugs, the prevalence of hypotension and nociceptive events, and their treatment, were recorded and analysed. Local anaesthetic injection point, volume and concentration were reported for each dog. In attempt to differentiate somatic nociception from visceral nociception, the surgery was divided into three timeframes: from the skin incision to the thoracic cavity opening; from the latter to the beginning of its closure; from thoracic cavity closure to the end of surgery.

RESULTS

Overall, 10 dogs were included and four experienced nociception: somatic nociception was recorded in one dog, whereas visceral nociception was recorded in four dogs. The overall fentanyl consumption to control nociception was 0.3 µg/kg/h. No adverse events associated with the UG-ESPB were reported.

CONCLUSION

The bilateral UG-ESPB could be used as a part of a multimodal analgesic technique in dogs undergoing sternotomies. However, more clinical studies are warranted to assess its safety and effects.

Clinical Assessment of Introducing Locoregional Anaesthesia Techniques as Part as the Intraoperative Analgesia Management for Canine Ovariohysterectomy in a Veterinary Teaching Hospital

This study compared four methods to provide intraoperative analgesia during canine ovariohysterectomy in a veterinary teaching hospital. A retrospective study was designed to assess the nociceptive response, cardiorespiratory stability, quality of recovery and complications of four analgesic protocols: epidural analgesia (EPIDURAL group), Quadratus Lumborum block (QLB group), Transversus Abdominis Plane block (TAP group), and just systemic analgesia (GENERAL group). Undergraduate students carried out all the loco-regional techniques under the direct supervision of a qualified anaesthetist. A total of 120 cases met the inclusion criteria and were included in the study and were distributed as follows: 22, 27, 32 and 39 cases with EPIDURAL, GENERAL, QLB and TAP groups, respectively. Data were analysed with statistical software R using different statistical methods. Significant differences among groups were defined as p < 0.05. Based on our results, all the groups needed the same number of rescue analgesia during the intra-operative period. The use of loco-regional techniques anticipated a better quality of recovery compared with the general group. The EPIDURAL group showed a statistically lower expired fraction of sevoflurane. No differences were found regarding complications. In conclusion, these four analgesic methods are suitable and safe to be performed for canine ovariohysterectomy, although loco-regional techniques might have some advantages.

Comparison of Mean Arterial Blood Pressure and Heart Rate Changes in Response to Three Different Randomized Isotonic Crystalloid Boluses in Hypotensive Anesthetized Dogs

The aim of this prospective, randomized, nonblinded, controlled clinical trial was to compare mean arterial blood pressure (MAP) and heart rate (HR) during an intravenous bolus of three different balanced isotonic crystalloid solutions in euvolemic, anesthetized dogs with hypotension. Thirty healthy dogs (American Society of Anesthesiologists Physical Status I–II) weighing at least 15 kg that presented for elective orthopedic or dental surgical procedures at the Ryan Veterinary Hospital for Small Animals of the University of Pennsylvania were included in this study. Anesthetized hypotensive patients (defined as a MAP ≤ 65 mmHg), were administered an infusion of Lactated Ringer’s solution (LRS), Plasma-Lyte (PLYTE) or Canadian Plasma-Lyte (PLYTECA), selected at random. The infusion was administered over 15 min via a volumetric fluid pump. Differences in oscillometric MAP and HR between time points and across treatments were evaluated by mANOVA. Intravenous isotonic crystalloid infusions over 15 min did not significantly change MAP or HR in hypotensive dogs under general anesthesia. Neither LRS, PLYTE nor PLYTECA exacerbated hypotension or caused tachycardia.

Use of adrenaline continuous infusion to treat hypotension during general anaesthesia in a cow and a calf

Background

Hypotension is one of the most common complications observed during inhalation anaesthesia in veterinary patients. Treatment of hypotension in cattle is more challenging than in other species, owing to the limited number of drugs licensed in food producing animals. The use of adrenaline as an infusion to support blood pressure has not been described previously in bovines.

Case presentation

A cow and a calf presented to University College Dublin Veterinary Hospital for bilateral mandibular fracture repair and bladder rupture repair respectively, developed severe anaesthetic related hypotension unresponsive to conventional treatments. In both cases an adrenaline infusion was started and slowly increased to effect, with infusion rates ranging from 0.01 to 0.25 μg/kg/min. Blood pressure increased as the adrenaline infusion rate increased, but clinically significant improvements in blood pressure were only observed with infusion rates exceeding 0.05 μg/kg/min. The side effect observed with adrenaline infusion was an increase in plasma lactate levels in both cases. Both animals were euthanised due to non-anaesthetic related complications.

Conclusions

Maintenance of normotension is important during bovine anaesthesia to prevent the development of post-anaesthetic complications. In the cases described here, adrenaline was effective as an additional treatment of anaesthetic related hypotension. Further research is required to establish the recommended infusion rates, cardiovascular effects and possible side effects of adrenaline infusion administration as a treatment for hypotension in bovines.

Anaesthetic management and complications of transvascular patent ductus arteriosus occlusion in dogs

OBJECTIVE

To retrospectively analyse the anaesthetic management, complications and haemodynamic changes in a cohort of dogs undergoing transvascular patent ductus arteriosus (PDA) occlusion in a tertiary referral centre (from January 2017 to August 2018).

STUDY DESIGN

Retrospective study.

ANIMALS

A total of 49 client-owned dogs.

METHODS

Anaesthetic records of dogs with PDA that underwent transvascular occlusion of the ductus were reviewed. Anaesthetic complications evaluated included tachycardia [heart rate (HR) > 160 beats minute^-1], bradycardia (HR < 50 beats minute^-1), hypertension [systolic arterial pressure (SAP) > 150 mmHg], hypotension [mean arterial pressure (MAP) < 60 mmHg], hypothermia (<37 °C) and the presence of arrhythmias. Cardiovascular variables [HR and invasive SAP, MAP and diastolic arterial pressure (DAP)] at the time of occlusion device deployment (time 0) were compared with variables at 5 and 10 minutes after deployment. Descriptive statistics, Shapiro-Wilk test and repeated measures analysis of variance followed by a Dunnett's post hoc test were used to analyse the data (p < 0.05).

RESULTS

Crossbreed dogs were the most commonly represented followed by the Cavalier King Charles Spaniel. The median age was 8 (2-108) months, and female dogs were over-represented (65.3%). The most common American Society of Anesthesiologists score was III. Mean duration of anaesthesia was 96 ± 26 minutes and mean surgery time was 58 ± 21 minutes. Acepromazine with methadone was the most commonly used premedication combination (77.6%). Propofol was the most common induction agent (73.5%). General anaesthesia was maintained with isoflurane in oxygen in all dogs. Complications included hypotension (63%), hypothermia (34%), bradycardia (28%), arrhythmias (16%), hypertension (16%) and haemorrhage (2%). MAP and DAP increased significantly 10 minutes after device deployment compared with time 0.

CONCLUSIONS

and clinical relevance: Hypotension was the most common complication reported in dogs undergoing transvascular PDA occlusion. No major adverse events were documented.

The effect of intravenous maropitant on blood pressure in healthy awake and anesthetized dogs

OBJECTIVE

To evaluate the effects of intravenous maropitant on arterial blood pressure in healthy dogs while awake and under general anesthesia.

DESIGN

Experimental crossover study.

ANIMALS

Eight healthy adult Beagle dogs.

PROCEDURE

All dogs received maropitant (1 mg kg-1) intravenously under the following conditions: 1) awake with non-invasive blood pressure monitoring (AwNIBP), 2) awake with invasive blood pressure monitoring (AwIBP), 3) premedication with acepromazine (0.005 mg kg-1) and butorphanol (0.2 mg kg-1) intramuscularly followed by propofol induction and isoflurane anesthesia (GaAB), and 4) premedication with dexmedetomidine (0.005 mg kg-1) and butorphanol (0.2 mg kg-1) intramuscularly followed by propofol induction and isoflurane anesthesia (GaDB). Heart rate (HR), systolic (SAP), diastolic (DAP), and mean blood pressures (MAP) were recorded before injection of maropitant (baseline), during the first 60 seconds of injection, during the second 60 seconds of injection, at the completion of injection and every 2 minutes post injection for 18 minutes. The data were compared over time using a Generalized Linear Model with mixed effects and then with simple effect comparison with Bonferroni adjustments (p <0.05).

RESULTS

There were significant decreases from baseline in SAP in the GaAB group (p < 0.01) and in MAP and DAP in the AwIBP and GaAB (p < 0.001) groups during injection. A significant decrease in SAP (p < 0.05), DAP (p < 0.05), and MAP (p < 0.05) occurred at 16 minutes post injection in GaDB group. There was also a significant increase in HR in the AwIBP group (p < 0.01) during injection. Clinically significant hypotension occurred in the GaAB group with a mean MAP at 54 ± 6 mmHg during injection.

CONCLUSION

Intravenous maropitant administration significantly decreases arterial blood pressure during inhalant anesthesia. Patients premedicated with acepromazine prior to isoflurane anesthesia may develop clinically significant hypotension.

Brachycephalic airway syndrome: management of post-operative respiratory complications in 248 dogs

OBJECTIVE

As ownership of brachycephalic dog breeds rises, the surgical correction of components of brachycephalic airway syndrome (BAS) is increasingly recommended by veterinarians. This study's objective was to describe the incidence of, and strategies for the management of post-operative respiratory complications in brachycephalic dogs undergoing surgical correction of one or more components of BAS.

METHODS

Medical records of 248 brachycephalic dogs treated surgically for BAS were retrospectively reviewed for demographic information, procedures performed, post-operative complications and treatment implemented, hospitalisation time, and necessity for further surgery.

RESULTS

Pugs, Cavalier King Charles Spaniels and British Bulldogs were the most commonly encountered breeds. Dogs which experienced a complication were significantly older (mean was 5.5 years, compared with 4.1 years [P < 0.01]). Fifty-eight dogs (23.4%) had complications which included: dyspnoea managed with supplemental oxygen alone (7.3%, n = 18), dyspnoea requiring anaesthesia and re-intubation (8.9%, n = 22), dyspnoea necessitating treatment with a temporary tracheostomy (8.9%, n = 22), aspiration pneumonia (4%, n = 10), and respiratory or cardiac arrest (2.4%, n = 6). Five of the 22 dogs requiring anaesthesia and re-intubation deteriorated 12 or more hours after post-surgical anaesthetic recovery. The overall mortality rate in this study was 2.4% (n = 6). Age, concurrent airway pathology, and emergency presentation significantly predicted post-operative complications.

CONCLUSION

Our data show the importance of close monitoring for a minimum of 24 h following surgery by an experienced veterinarian or veterinary technician. Surgical intervention for BAS symptomatic dogs should be considered at an earlier age as an elective procedure, to reduce the risk of post-operative complications.

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.

Conventional and functional magnetic resonance imaging features of late subacute cortical laminar necrosis in a dog

Cerebral cortical laminar necrosis (CLN) is a consequence of severe hypoxic, ischemic, or hypoglycemic events. In humans, these cortical lesions show characteristic linear T1‐weighted (T1W) hyperintensity in the late subacute stage. Limited information reporting magnetic resonance imaging (MRI) findings in dogs affected by CLN is available. A 3‐year‐old Belgian Shepherd dog was referred 8 days after sudden onset of blindness after general anesthesia. Neurological examination showed central blindness and mild ataxia. Three‐Tesla MRI examination of the brain revealed bilateral asymmetrical areas of T2‐weighted hyperintensity within the occipital, parietal, temporal, and frontal cortex, involving gray and white matter. Furthermore, linear T1W‐hyperintense lesions were found in the cerebral cortex of the same areas and showed heterogeneous contrast enhancement. Perfusion‐weighted images revealed hyperperfusion in the affected regions. Lesions were compatible with subacute CLN with corresponding edema suspected to be secondary to anesthesia‐related brain hypoxia. Three‐Tesla MRI enabled identification of the laminar pattern of the cortical lesions.

Ropivacaína isolada ou associada à metadona ou à morfina, pela via epidural, em cadelas submetidas à ovário-histerectomia

RESUMO Objetivou-se avaliar os efeitos fisiológicos, sedativos e analgésicos da administração peridural de ropivacaína isolada ou associada à morfina ou à metadona. Para tal, 24 cadelas submetidas à ovário-histerectomia receberam acepromazina, e a anestesia foi induzida e mantida com propofol e isoflurano (FiO2 = 1,0), respectivamente. De acordo com o protocolo peridural, formaram-se três grupos de igual número: GR (ropivacaína - 2,0mg/kg); GRMETA (ropivacaína - 2,0mg/kg e metadona - 0,3mg/kg) e GRMORF (ropivacaína - 2,0mg/kg e morfina - 0,1mg/kg). Registraram-se os parâmetros fisiológicos intraoperatórios e os graus de sedação e analgesia pós-operatórios. No GR constataram-se maiores médias de pressões arteriais 30 minutos após a anestesia epidural em relação ao GRMETA (sistólica e média) e ao final do procedimento cirúrgico comparativamente ao GRMORF (sistólica, diastólica e média). Não foram observadas diferenças significativas entre os grupos relativamente à analgesia e ao grau de sedação pós-operatórios. A administração epidural de ropivacaína é segura e eficaz e proporciona boa analgesia, independentemente da sua associação com morfina ou metadona.

Clinical comparison of two techniques of brachial plexus block for forelimb surgery in dogs

The objective of this study was to compare two different local anaesthesia techniques for intraoperative analgesia in dogs undergoing surgical procedures distal to the mid humeral diaphysis. Thirty-two dogs were divided into two groups: the US group received an ultrasound-guided brachial plexus block at the level of the first rib and the N group received a neurostimulation-guided paravertebral brachial plexus block. Ropivacaine 0.75% at 1.5mg/kg was injected in each case. Dogs were monitored during the surgical procedure, and rescue analgesia was administered whenever the heart rate, respiratory rate or blood pressure increased more than 20% from the basal values. Success rate was defined as no need for rescue analgesia during surgery and complete blockade of the operated leg evaluated just after anaesthesia recovery. Complications were also recorded. Data was analysed using Fisher exact and Mann/Whitney tests. Success rate was observed in 14/16 (87%) dogs and in 12/16 (75%) dogs in the US and N groups, respectively (P=0.65). Complications recorded were hypotension in three cases (US group, n=1; N group, n=2) and Horner's syndrome in three cases (US group, n=1; N group, n=2; P=0.65). Both techniques were found to provide good level of analgesia that allowed performing the orthopaedic procedures from the mid humeral diaphysis and distal in the limb, without the need for further analgesia.

Clinical Findings in Dogs Trained for Awake-MRI

Training dogs for awake-MRI began in 2012 for the study of canine cognition. Although originally envisioned as a research technique to understand the neural mechanisms of canine cognitive function, its potential as a new diagnostic clinical tool has become apparent. A high-quality structural scan of the brain can be acquired without sedation or anesthesia in as little as 30 s in a well-trained dog. This has opened the possibility of longitudinal imaging of CNS disease with MRI both as a means of monitoring treatment and potentially as a surveillance tool for inflammatory and neoplastic brain diseases in high-risk breeds. This same training can be used to image other body regions, such as the abdomen, enabling clinicians to screen for abdominal disease using cross sectional imaging without the need for anesthesia and without exposing the patient to ionizing radiation. We present four examples of dogs trained for awake-MRI who developed: (1) nasal carcinoma; (2) brain tumor; (3) abdominal lipoma; (4) idiopathic epilepsy.

Sub-Tenon's anesthesia for canine cataract surgery

OBJECTIVE

To test a sub-Tenon's anesthesia technique in dogs as an alternative to systemic neuromuscular blockade to aid in canine cataract surgery under general anesthesia.

PROCEDURES

A prospective controlled clinical study was performed involving 12 dogs undergoing bilateral cataract surgery under general anesthesia. One eye was randomly assigned to have phacoemulsification and prosthetic lens implantation performed with sub-Tenon's anesthesia (STA), and the control eye had surgery performed with systemic neuromuscular blockade (NMB). Intraocular pressure (IOP) was measured immediately before and after STA administration. Globe position, globe rotation, pupillary dilation, and vitreal expansion were assessed for both STA and NMB eyes during surgery.

RESULTS

Sub-Tenon's anesthesia produced a globe position suitable for cataract surgery with the degree of vitreal expansion not significantly different to control NMB eyes. STA produced greater anterior globe displacement than NMB in all cases. STA had no significant effect on IOP.

CONCLUSION

Sub-Tenon's anesthesia was an effective alternative to systemic neuromuscular blockade for canine cataract surgery and may be beneficial for surgical exposure in deep orbited breeds.

Avaliação metabólica e hemodinâmica de dois protocolos de sedação prolongada em cães

RESUMO Objetivou-se determinar a viabilidade de dois protocolos de sedação para ventilação prolongada em cães e seus efeitos hemodinâmicos e metabólicos. Doze cães, alocados aleatoriamente em dois grupos (n=6), receberam infusão contínua de midazolam (0,5mg/kg/h), fentanil (10µg/kg/h) e propofol (18mg/kg/h) no GMF ou cetamina (0,6mg/kg/h), morfina (0,26mg/kg/h) e propofol (18mg/kg/h) no GCM, durante 24 horas. Os cães foram ventilados mecanicamente com FiO2 de 40%, mantendo-se a normocapnia. A FC diminuiu 32% no GMF e 34% no GCM ao longo do tempo, reduzindo o IC em 24% no GMF e em 29% no GCM. A CaO2, o CvmO2, a DO2 e o VO2 diminuíram no GCM (5%, 16%, 31% e 7%) e no GMF (4%, 19%, 26% e 15%), respectivamente. A TEO2 aumentou 32% no GMF e 36% no GCM, sem diferenças entre grupos, porém a calorimetria indireta demonstrou diminuição do VO2, minimizando a redução da DO2. Não houve diferença entre os tempos para extubação, deambulação e recuperação total, com médias globais (minutos) de 33,8±15,9, 134,8±60,7 e 208±77,5, respectivamente. Conclui-se que ambos os protocolos permitiram a ventilação mecânica, com redução do IC e da DO2, porém sem prejuízos hemodinâmicos e metabólicos, podendo ser utilizados com segurança em cães hígidos.

The pharmacological effects of intramuscular administration of alfaxalone combined with medetomidine and butorphanol in dogs

The pharmacological effects of intramuscular (IM) administration of alfaxalone combined with medetomidine and butorphanol were evaluated in 6 healthy beagle dogs. Each dog received three treatments with a minimum 10-day interval between treatments. The dogs received an IM injection of alfaxalone 2.5 mg/kg (ALFX), medetomidine 2.5 µg/kg and butorphanol 0.25 mg/kg (MB), or their combination (MBA) 1 hr after the recovery from their instrumentation. Endotracheal intubation was attempted, and dogs were allowed to breath room air. Neuro-depressive effects (behavior changes and subjective scores) and cardiorespiratory parameters (rectal temperature, heart rate, respiratory rate, direct blood pressure, central venous pressure and blood gases) were evaluated before and at 2 to 120 min after IM treatment. Each dog became lateral recumbency, except for two dogs administered the MB treatment. The duration was longer in the MBA treatment compared with the ALFX treatment (100 ± 48 min vs 46 ± 13 min). Maintenance of the endotracheal tube lasted for 60 ± 24 min in five dogs administered the MBA treatment and for 20 min in one dog administered the ALFX treatment. Cardiorespiratory variables were maintained within clinically acceptable ranges, although decreases in heart and respiratory rates, and increases in central venous pressure occurred after the MBA and MB treatments. The MBA treatment provided an anesthetic effect that permitted endotracheal intubation without severe cardiorespiratory depression in healthy dogs.

EFEITOS HEMODINÂMICOS DA INFUSÃO CONTÍNUA DE BUTORFANOL EM CÃES ANESTESIADOS COM PROPOFOL

Resumo Objetivou-se avaliar os efeitos hemodinâmicos decorrentes da anestesia total intravenosa com propofol e butorfanol em cães. Para tal, foram utilizados 20 animais adultos hígidos, sem raça definida, distribuídos em dois grupos, designados como GB e GP, induzidos à anestesia com propofol (10 mg/kg). Após a intubação orotraqueal, instituiu-se ventilação controlada com oxigênio a 60% e fluxo de 30 mL/kg/min em circuito fechado, com volume controlado. A manutenção anestésica foi realizada com a administração de 0,6 mg/kg/min de propofol. O grupo butorfanol (GB) recebeu butorfanol 0,1 mg/kg IV, seguido de infusão contínua (40 μg/kg/h). O grupo placebo (GP) recebeu somente NaCl 0,9% em bolus, seguido de infusão venosa, em volume idêntico ao do GB. As variáveis hemodinâmicas foram avaliadas antes da aplicação do opioide ou da solução de NaCl a 0,9% (M0) e imediatamente após, em intervalos de 15 minutos (M15 a M75). A administração de butorfanol resultou em redução da resistência periférica total (RPT), das pressões arteriais (PAS, PAD e PAM) e do débito cardíaco (DC), sem relevância clínica. Os resultados permitem concluir que a associação proporciona anestesia segura para pacientes com suporte ventilatório.

Agreement Between Doppler and Invasive Blood Pressure Monitoring in Anesthetized Dogs Weighing <5 kg

The objectives of this study were to determine if Doppler (DOP) blood pressure measurements more closely estimate either invasive systolic or invasive mean arterial blood pressures (ISAP or IMAP, respectively) in small dogs under general anesthesia and to assess the ability of DOP to detect anesthesia-related hypotension in small dogs. Blood pressure measurements (n = 203) were obtained from 10 client-owned dogs. DOP, ISAP, and IMAP were recorded simultaneously, and the data were categorized into two groups: hypotensive (ISAP &lt;90 mm Hg) and normotensive (ISAP ≥90 mm Hg and ≤160 mm Hg). DOP overestimated ISAP and IMAP in both the normotensive and hypotensive groups. The DOP was highly specific (97%) but poorly sensitive (56%) for detecting hypotension. The smallest bias was achieved when using DOP as an estimate of systolic arterial blood pressure in both normotensive and hypotensive dogs, suggesting that DOP measures systolic arterial blood pressure in dogs &lt;5 kg. For dogs with hypotension, DOP met all of the performance criteria for noninvasive blood pressure monitors recommended by the American College of Veterinary Internal Medicine. DOP is an acceptably accurate and highly specific means of detecting hypotension in small dogs under general anesthesia.

Effect of pulse width on transesophageal atrial pacing in dogs

OBJECTIVE

To determine the impact of stimulus pulse width (PW) on pacing threshold (PT), zone of capture (ZOC) and extraneous muscular stimulation (EMS).

STUDY DESIGN

Experimental trial in client-owned dogs.

ANIMALS

Seventeen dogs, median weight 16.1 kg (interquartile range: 11.4-21.5).

METHODS

Transesophageal atrial pacing (TAP) involved a 6 Fr pacing catheter inserted trans-orally into the esophagus to a position aboral to the heart in anesthetized dogs. The catheter was slowly withdrawn until atrial pacing was noted on an electrocardiogram. The catheter was withdrawn in 1 cm increments until TAP could not be achieved. PTs were recorded at each pacing site using PWs of 10.0, 5.0, 2.0 and 1.8 ms, always in that order.

RESULTS

The overall lowest mean PTs for all dogs were 6 ± 3 mA, 9 ± 4 mA, 11 ± 5 mA and 13 ± 5 mA at PWs of 10.0, 5.0, 2.0 and 1.8 ms, respectively. A significant decrease in overall minimum PT was noted using a PW of 10.0 ms compared with either 2.0 or 1.8 ms (p = 0.043 and p = 0.001, respectively) and pacing using 5.0 ms compared with 1.8 ms (p = 0.028). A significant increase in ZOC was noted using a PW of 10.0 ms compared with PWs of 5.0, 2.0 and 1.8 ms (p = 0.0047, p = 0.0006 and p = 0.0003, respectively), using a PW of 5.0 ms compared with PWs of 2.0 and 1.8 ms (p = 0.0011 and p = 0.0003, respectively) and using a PW of 2.0 compared with one of 1.8 ms (p = 0.0084).

CONCLUSIONS AND CLINICAL RELEVANCE

Use of 10.0 or 5.0 ms PW to perform TAP minimized the power required to pace the atria, while a PW of 10.0 ms maximized the size of the ZOC.

Microcirculatory effects of intravenous fluid administration in anesthetized dogs undergoing elective ovariohysterectomy

OBJECTIVE

To assess the microcirculatory effects of IV fluid administration in healthy anesthetized dogs undergoing elective ovariohysterectomy.

ANIMALS

49 client-owned dogs.

PROCEDURES

Dogs were sedated, and anesthesia was induced with propofol and diazepam and maintained with isoflurane in oxygen. Dogs received lactated Ringer's solution (LRS) IV at rates of 0, 10, or 20 mL/kg/h. Videomicroscopy was used to assess and record effects of LRS administration on microcirculation in the buccal mucosa. Measurements of microcirculatory (total vessel density, proportion of perfused vessels, microcirculatory flow index, and perfused vessel density by vessel size [< 20 μm, ≥ 20 μm, and all diameters]) and other physiologic variables (heart rate, Doppler-measured blood pressure, oxygen saturation as measured by pulse oximetry, capillary refill time, and body temperature) were compared among groups at baseline (immediately after anesthetic induction), 30 and 60 minutes afterward, and overall.

RESULTS

Neither the proportion of perfused vessels nor microcirculatory flow index varied among treatment groups at any time point, regardless of vessel size. For vessels < 20 μm in diameter and for all vessels combined, total and perfused vessel density were similar among groups. For vessels ≥ 20 μm in diameter, total vessel density was significantly greater in the 20 mL/kg/h group than in other groups, and perfused vessel density was significantly greater in the 20 mL/kg/h group than in the 0 mL/kg/h group, when all time points were considered. Other physiologic variables were similar among groups.

CONCLUSIONS AND CLINICAL RELEVANCE

Total and perfused vessel density of vessels ≥ 20 μm in diameter (mostly venules) were greatest in dogs that received 20 mL of LRS/kg/h. Further research is required to evaluate clinical importance of these findings.

Perianesthetic complications in dogs undergoing magnetic resonance imaging of the brain for suspected intracranial disease

OBJECTIVE

To evaluate the occurrence of perianesthetic complications in dogs undergoing MRI for suspected intracranial disease and identify risk factors associated with observed complications.

DESIGN

Retrospective case-control study.

ANIMALS

238 client-owned dogs undergoing MRI of the brain.

PROCEDURES

Signalment, clinical signs, neurologic examination findings, presumptive diagnosis, anesthesia-related variables, whether CSF was collected and CSF analysis results, severe perianesthetic complications (need for a ventilator following anesthesia or perianesthetic death), and anesthetic recovery time were recorded. Selected factors were compared between dogs with and without intracranial lesions and dogs with and without perianesthetic complications (including severe complications and prolonged anesthetic recovery [> 20 minutes from the end of anesthesia to extubation]).

RESULTS

3 of 149 (2%) dogs with and 0 of 89 dogs without intracranial lesions required ventilation following anesthesia; the difference was nonsignificant. Recovery time was significantly longer in dogs with (median, 15 minutes) than in dogs without (10 minutes) intracranial lesions. Abnormal mentation prior to anesthesia was the only clinical sign that differed significantly between dogs with (15/26 [58%]) and without (70/212 [33%]) perianesthetic complications. A significantly larger proportion of dogs with perianesthetic complications had intracranial masses (13/26 [50%]), compared with dogs without these complications (56/212 [26%]).

CONCLUSIONS AND CLINICAL RELEVANCE

Dogs with complications were more likely to have had intracranial lesions than were dogs without complications, but few dogs had severe complications. Abnormal mentation was more common in dogs with than in dogs without complications. Prospective studies to further evaluate perianesthetic risk factors and procedures for improving outcomes in these patients are warranted.