Modeling daily veterinary anesthetist patient care hours and probabilities of exceeding critical thresholds

OBJECTIVE

Use a referral dental clinic model to study how to calculate accurate 95% upper confidence limits for probabilities of workloads (total case duration, including turnover time) exceeding allocated times.

ANIMALS

Dogs and cats undergoing dental treatments.

METHODS

Managerial data (procedure date and duration) collected over 44 consecutive operative workdays were used to calculate the daily anesthetist workload. Workloads were compared with a normal distribution using the Shapiro-Wilk test, serial correlation was examined by runs test, and comparisons among weekdays were made using the Kruskal-Wallis test. The 95% confidence limits for normally distributed workloads exceeding allocated times were estimated with a generalized pivotal quantity. The impact of a number of procedures was assessed with scatterplots, Pearson linear correlation coefficients, and multivariable linear regression.

RESULTS

Mean anesthetist's workload was normally distributed (Shapiro-Wilk P = .25), without serial correlation (P = .45), and without significant differences among weekdays (P = .52). Daily workload, mean 9.39 hours and SD 3.06 hours, had 95% upper confidence limit of 4.47% for the probability that exceeding 16 hours (ie, 8 hours per each of 2 tables). There was a strong positive correlation between daily workload and the end of the workday (r = .85), significantly larger than the correlation between the end of the workday and the number of procedures (r = .64, P < .0001).

CLINICAL RELEVANCE

There are multiple managerial applications in veterinary anesthesia wherein the problem is to estimate risks of exceeding thresholds of workload, including the costs of hiring a locum, scheduling unplanned add-on cases, planning for late discharge of surgical patients to owners, and coordinating anesthetist breaks.

Medication errors in veterinary anesthesia: a literature review

OBJECTIVE

To provide an overview of medication errors (MEs) in veterinary medicine, with a focus on the perianesthetic period; to compare MEs in veterinary medicine with human anesthesia practice, and to describe factors contributing to the risk of MEs and strategies for error reduction.

DATABASES USED

PubMed and CAB abstracts; search terms: [("patient safety" or "medication error∗") AND veterin∗].

CONCLUSIONS

Human anesthesia is recognized as having a relatively high risk of MEs. In veterinary medicine, MEs were among the most commonly reported medical error. Predisposing factors for MEs in human and veterinary anesthesia include general (e.g. distraction, fatigue, workload, supervision) and specific factors (e.g. requirement for dose calculations when dosing for body mass, using several medications within a short time period and preparing syringes ahead of time). Data on MEs are most commonly collected in self-reporting systems, which very likely underestimate the true incidence, a problem acknowledged in human medicine. Case reports have described a variety of MEs in the perianesthetic period, including prescription, preparation and administration errors. Dogs and cats were the most frequently reported species, with MEs in cats more commonly associated with harmful outcomes compared with dogs. In addition to education and raising awareness, other strategies described for reducing the risk of MEs include behavioral, communication, identification, organizational, engineering and cognitive aids.

Uncontrolled pain: a call for better study design

Studies assessing animal pain in veterinary research are often performed primarily for the benefit of animals. Frequently, the goal of these studies is to determine whether the analgesic effect of a novel treatment is clinically meaningful, and therefore has the capacity to improve the welfare of treated animals. To determine the treatment effect of a potential analgesic, control groups are necessary to allow comparison. There are negative control groups (where pain is unattenuated) and positive control groups (where pain is attenuated). Arising out of animal welfare concerns, there is growing reluctance to use negative control groups in pain studies. But for studies where pain is experimentally induced, the absence of a negative control group removes the opportunity to demonstrate that the study methods could differentiate a positive control intervention from doing nothing at all. For studies that are controlled by a single comparison group, the capacity to distinguish treatment effects from experimental noise is more difficult; especially considering that pain studies often involve small sample sizes, small and variable treatment effects, systematic error and use pain assessment measures that are unreliable. Due to these limitations, and with a focus on farm animals, we argue that many pain studies would be enhanced by the simultaneous inclusion of positive and negative control groups. This would help provide study-specific definitions of pain and pain attenuation, thereby permitting more reliable estimates of treatment effects. Adoption of our suggested refinements could improve animal welfare outcomes for millions of animals globally.

Consistency in Reporting of Loss of Righting Reflex for Assessment of General Anesthesia in Rats and Mice: A Systematic Review

General anesthesia induces a reversible loss of consciousness (LOC), a state that is characterized by the inability to feel pain. Identifying LOC in animals poses unique challenges, because the method most commonly used in humans, responding to questions, cannot be used in animals. For over a century, loss of righting reflex (LORR) has been used to assess LOC in animals. This is the only animal method that correlates directly with LOC in humans and has become the standard proxy measure used in research. However, the reporting of how LORR is assessed varies extensively. This systematic literature review examined the consistency and completeness of LORR methods used in rats and mice. The terms 'righting reflex,' 'anesthesia,' 'conscious,' 'rats,' 'mice,' and their derivatives were used to search 5 electronic databases. The abstracts of the 985 articles identified were screened for indications that the study assessed LORR in mice or rats. Full texts of selected articles were reviewed for LORR methodological completeness, with reported methods categorized by 1) animal placement method, 2) behavioral presence of righting reflex, 3) duration of LORR testing, 4) behavioral LORR, and 5) animal position for testing LORR. Only 22 papers reported on all 5 methodological categories. Of the 22 papers, 21 used unique LORR methodologies, with descriptions of LORR methods differing in at least one category as compared with all other studies. This variability indicates that even papers that included all 5 categories still had substantial differences in their methodological descriptions. These findings reveal substantial inconsistencies in LORR methodology and reporting in the biomedical literature likely compromising study replicability and data interpretation.

Nerve stimulator-guided mandibular block in an alpaca undergoing dental extraction

General anesthesia of a 2-year-old castrated male alpaca undergoing mandibular tooth extraction was successfully managed via a mandibular nerve block with bupivacaine, using nerve stimulation to confirm correct needle placement. The local block was effective, with no cardiovascular or respiratory responses to surgical stimulation observed. Key clinical message: Use of a locoregional technique in dentistry confers anesthetic stability, blocks nociceptive responses to surgery, and promotes a smooth recovery and comfortable postoperative period.

Quality of reporting of prospective in vivo and ex vivo studies published in the Journal of Veterinary Emergency and Critical Care over a 10-year period (2009-2019)

OBJECTIVE

To evaluate the reporting of key items associated with risk of bias and weak study design over a 10-year period.

DESIGN

Literature survey.

SETTING

Not applicable.

ANIMALS

Not applicable.

INTERVENTIONS

Papers published in the Journal of Veterinary Emergency and Critical Care between 2009 and 2019 were screened for inclusion. Inclusion criteria consisted of prospective experimental studies describing in vivo or ex vivo research (or both), containing at least 2 comparison groups. Identified papers had identifying information (publication date, volume and issue, authors, affiliations) redacted by an individual not involved with paper selection or review. Two reviewers independently reviewed all papers and applied an operationalized checklist to categorize item reporting as fully reported, partially reported, not reported, or not applicable. Items assessed included randomization, blinding, data handling (inclusions and exclusions), and sample size estimation. Differences in assessment between reviewers were resolved by consensus with a third reviewer. A secondary aim was to document availability of data used to generate study results. Papers were screened for links to access data in the text and supporting information.

MEASUREMENTS AND MAIN RESULTS

After screening, 109 papers were included. Eleven papers were excluded during full-text review, with 98 papers included in the final analysis. Randomization was fully reported in 31.6% of papers (31/98). Blinding was fully reported in 31.6% of papers (31/98). Inclusion criteria were fully reported in all papers. Exclusion criteria were fully reported in 60.2% of papers (59/98). Sample size estimation was fully reported in 8.0% of papers (6/75). No papers (0/99) made data freely available without a requirement to contact study authors.

CONCLUSIONS

There is substantial room for improvement in reporting of randomization, blinding, data exclusions, and sample size estimations. Evaluation of study quality by readers is limited by the low reporting levels identified, and the risk of bias present indicates a potential for inflated effect sizes.

Successful blood transfusion in a Holstein cow experiencing hemorrhagic shock under general anesthesia

A 2-year-old Holstein cow weighing 530 kg at 2 mo gestation was scheduled for a paracostal laparotomy and abomasotomy following diagnosis of a reticular foreign body causing obstruction and abomasal impaction. Hemorrhagic shock occurred during surgery, with a rapid, approximately 60% decrease in arterial blood pressure, and reflex tachycardia with a 2-fold increase in heart rate. Following identification of hemorrhagic shock, arterial blood pressure was supported by reducing the inhalant anesthetic requirement, positive inotropic support (IV dobutamine infusion), and IV fluid therapy. Hypertonic saline was administered IV for initial resuscitation of arterial blood pressure, followed by a whole blood transfusion to replenish red blood cells, support oxygencarrying capacity, and provide intravascular volume to maintain cardiac output and tissue perfusion. A gradual increase in arterial blood pressure and a decrease in heart rate were observed in response to treatment. This case report demonstrates the physiologic compensatory response to hemorrhagic shock and the treatment to stabilize cardiovascular parameters in an anesthetized cow. Key clinical message: This case illustrates the physiological reponses to acute hemorrhage under general anesthesia and the effects of various treatment interventions.

Pain Recognition in Rodents

Available methods for recognizing and assessing pain in rodents have increased over the last 10 years, including the development of validated pain assessment scales. Much of this work has been driven by the needs of biomedical research, and there are specific challenges to applying these scales in the clinical environment. This article provides an introduction to pain assessment scale validation, reviews current methods of pain assessment, highlighting their strengths and weaknesses, and makes recommendations for assessing pain in a clinical environment.

Development of reference intervals for pupillometry in healthy dogs

BACKGROUND

Pupillometry, the measurement of pupil size and reactivity to a stimulus, has various uses in both human and veterinary medicine. These reflect autonomic tone, with the potential to assess nociception and emotion. Infrared pupillometry reduces inaccuracies that may occur when the pupillary light reflex is determined subjectively by the examiner. To our knowledge, there are no published studies outlining normal reference intervals for automated pupillometry in dogs.

OBJECTIVE

The objective of this study was to develop de novo automated pupillometry reference intervals from 126 healthy canine eyes.

METHODS

The pupillary light reflex (PLR) was measured with a handheld pupillometer (NeurOptics™ PLR-200™ Pupillometer). Parameters recorded included maximum pupil diameter (MAX), minimum pupil diameter (MIN), percent constriction (CON), latency (LAT), average constriction velocity (ACV), maximum constriction velocity (MCV), average dilation velocity (ADV) and time to 75% pupil diameter recovery (T75). One measurement was obtained for each eye.

RESULTS

The following reference intervals were developed: MAX (6.05-11.30 mm), MIN (3.76-9.44 mm), CON (-37.89 to -9.64 %), LAT (0.11-0.30 s), ACV (-6.39 to -2.63 mm/ s), MCV (-8.45 to -3.75 mm/s), ADV (-0.21-1.77 mm/s), and T75 (0.49-3.20 s).

CLINICAL SIGNIFICANCE

The reference intervals developed in this study are an essential first step to facilitate future research exploring pupillometry as a pain assessment method in dogs.

A disposable, canister-free negative-pressure wound therapy device proves feasible, but of inferior efficacy to conventional therapies for treating cutaneous wounds in dogs

OBJECTIVE

To assess the feasibility of a canister-free negative-pressure wound therapy (NPWT) device (PICO™ 1.6, Smith & Nephew Medical Ltd) and evaluate its effect on early phases of wound healing in canine experimental cutaneous wounds.

ANIMALS

5 adult spayed female research Beagles.

PROCEDURES

In a pilot experimental study, 1 full-thickness 2-cm X 2-cm cutaneous wound was surgically created on each hemithorax in each dog. Wounds were treated with either NPWT or a conventional wound dressing for 14 days. Bandage changes and wound evaluations were done at 7 time points. First macroscopic appearance of granulation tissue, smoothness of granulation tissue, and percentages of wound contraction and epithelialization were compared between treatments. Wounds were sampled at 3 time points for histopathologic analyses and semiquantitative scoring.

RESULTS

NPWT dressings were well tolerated by all dogs. Complete seal of the dressing required the application of adhesive spray, and maintenance of the vacuum lessened over time. Self-limiting skin irritations appeared in all dogs and hampered the attainment of negative pressure. Granulation tissue developed faster and was more abundant in control wounds. Wound contraction, epithelialization, and fibroblast proliferation were greater in control wounds at the end of the study.

CLINICAL RELEVANCE

This canister-free NPWT device is feasible but problematic in maintaining a vacuum, requiring frequent revisions of the dressing. Further studies are necessary to evaluate the effect of this device on early phases of wound healing. Its benefits in wound healing remain unknown.

Pre-warming following premedication limits hypothermia before and during anesthesia in Sprague-Dawley rats (Rattus norvegicus)

In humans and other mammals, general anesthesia impairs thermoregulation, leading to warm core blood redistributing to the periphery. This redistribution is an important contributor to hypothermia that can be reduced with pre-warming before anesthesia. Additionally, sedation following premedication has been associated with hypothermia in dogs. In a prospective, randomized, cross-over study, 8 adult male and female rats (weighing 388 to 755 g) were sedated with intramuscular ketamine-midazolam-hydromorphone, then placed in an unwarmed cage or warmed box for 14 minutes, followed by 30 minutes of isoflurane anesthesia with active warming. Core body temperature was monitored throughout. After sedation, warmed rats gained 0.28°C ± 0.13°C and unwarmed rats lost 0.19°C ± 0.43°C, a significant difference between groups (P = 0.004). After anesthesia, warmed rats maintained higher core temperatures (P < 0.0001) with 2/8 and 6/8 of warmed and unwarmed rats becoming hypothermic, respectively. Pre-warming during sedation and active warming during general anesthesia is effective in minimizing hypothermia.

Use of Clinical Audits to Evaluate Timing of Preoperative Antimicrobials in Equine Surgery at a Veterinary Teaching Hospital

Based on human surgical guidelines, intravenous antimicrobials are recommended to be administered within 60 min of surgical incision. Achieving this target in horses is reportedly challenging and influenced by hospital policies. The objectives of this study were to evaluate and improve: (1) the timing of antimicrobial administration to surgical incision (tAB-INC), (2) contributions of anesthesia pre-induction (tPRI) and surgical preparation (tPREP) periods to tAB-INC, and the (3) completeness of antimicrobial recording. Two clinical audits were conducted before and after the policy changes (patient preparation and anesthesia record keeping). tPRI, tPREP, and tAB-INC were calculated and compared for elective arthroscopies and emergency laparotomies within and between the audits. The percentage of procedures with a tAB-INC <60 min was calculated. Antimicrobial recording was classified as complete or incomplete. A median tAB-INC <60 min was achieved in laparotomies (audit 1; 45 min, audit 2; 53 min) with a shorter tPREP than arthroscopies (p < 0.0001, both audits). The percentage of procedures with tAB-INC <60 min, tAB-INC, tPRI, and tPREP durations did not improve between the audits. There was a positive correlation between the number of operated joints and tPREP (audit 1, p <0.001, r = 0.77; audit 2, p < 0.001, r = 0.59). Between audits, antimicrobial recording significantly improved for elective arthroscopies (82–97%, p = 0.008) but not emergency laparotomies (76–88%, p = 0.2). Clinical audits successfully quantified the impact of introduced changes and their adherence to antimicrobial prophylaxis guidelines. Antimicrobial recording was improved but further policy changes are required to achieve a tAB-INC <60 min for arthroscopies.

A practical guide to implementing clinical audit

Clinical audit is a quality improvement tool for evaluating and improving patient care and outcomes. This is achieved by systematically reviewing current practices against explicit criteria and measuring the impact of change(s) introduced to generate improvement. The clinical audit process can be described by "Plan," "Do," "Study," "Act" phases that comprise an audit cycle. The phases are moved through in turn to attempt quality improvement. Clinical audits are widely used in human medicine at both local (individual clinic or hospital) and national (to achieve nationwide improvements in care) levels. Substantial and sustained improvements in patient care have been attributed to the use of clinical audits. Clinical audits have been described in the veterinary literature since the 1990s, but their adoption does not appear widespread. This paper is intended as a practical, "how to" guide to applying clinical audit in veterinary practice.

Teleconsulting in the time of a global pandemic: Application to anesthesia and technological considerations

As a result of the various restrictions associated with the current COVID-19 pandemic, the practice of veterinary telehealth is likely to grow substantially. One area in which high quality care can be maintained while respecting physical distancing is teleconsulting, which describes the relationship between an attending and off-site consulting veterinarian. This guide uses a dentistry case to illustrate the provision of real-time anesthesia consulting, with a focus on the technological considerations central to facilitating live, 2-way video-communication. Case selection, teamwork, and patient safety are also discussed.

The development and use of facial grimace scales for pain measurement in animals

The measurement of pain in animals is surprisingly complex, and remains a critical issue in veterinary care and biomedical research. Based on the known utility of pain measurement via facial expression in verbal and especially non-verbal human populations, "grimace scales" were first developed a decade ago for use in rodents and now exist for 10 different mammalian species. This review details the background context, historical development, features (including duration), psychometric properties, modulatory factors, and impact of animal grimace scales for pain.

Management of a severe peripartum hemorrhage following cesarean section in a dog

This report describes the intensive blood pressure management and transfusion of a peripartum intrauterine hemorrhage following a cesarean section in a dog. The impact of pregnancy-associated physiologic changes and anesthesia on hemodynamic parameters along with potential alternate management techniques are discussed.

Impact of preanaesthetic echocardiography on the planned anaesthetic management of cats

OBJECTIVE

To assess the impact of preanaesthetic echocardiography on the subsequent intended anaesthetic management plan in cats with incidental clinical findings that may indicate cardiac disease.

STUDY DESIGN

Clinical study involving cats undergoing echocardiography and subsequent anaesthesia.

ANIMALS

A total of 40 client-owned cats.

METHODS

Echocardiography was performed in conscious cats and the information was used to plan anaesthesia or sedation. An information sheet including relevant history, temperament, body condition score, clinical examination findings, current medication and results of any relevant tests such as haematology, biochemistry or Doppler blood pressure measurement was sent to three specialist anaesthetists and virtual case management plans were designed for each cat in two steps: step 1) anaesthetists were unaware of echocardiography results; and step 2) anaesthetists were aware of echocardiography results. In the second step the anaesthetists documented any changes to their original management plan, as either 'step-up' or 'step-down'.

RESULTS

Of the 40 cats, 26 had murmurs, four had a gallop rhythm, four had both findings and six had other findings. Pathology of potential haemodynamic significance was found on echocardiography in 23 cats, 17 of which anaesthetists had correctly identified as having disease before echocardiography. A proportion of cats with murmurs were subsequently deemed to have no significant pathology after echocardiography. Echocardiography findings in these cases were: dynamic left ventricular outflow tract obstruction (DLVOTO) without hypertrophy; DLVOTO without hypertrophy + dynamic right ventricular outflow tract obstruction (DRVOTO); DRVOTO; valvular dysplasia; normal. In a median of 26/40 (range 16-38) of cases, the anaesthetic plan was changed after provision of further information; in 15/40 (8-20) cases, this was a 'step-up' in care and in eight/40 (6-23) it was a 'step-down' in care. In cases with atrial enlargement (left atrium to aortic ratio of >1.6) and deemed at risk of cardiac failure, alpha-2 agonist use changed considerably with availability of echocardiography findings.

CONCLUSION

and clinical relevance Where there are abnormal cardiac findings on clinical examination in cats, echocardiography is required to accurately assess anaesthetic risk . The availability of echocardiographic information positively influences anaesthetic management.

Clinical applicability of the Feline Grimace Scale: real-time versus image scoring and the influence of sedation and surgery

Background

The Feline Grimace Scale (FGS) is a facial expression-based scoring system for acute pain assessment in cats with reported validity using image assessment. The aims of this study were to investigate the clinical applicability of the FGS in real-time when compared with image assessment, and to evaluate the influence of sedation and surgery on FGS scores in cats.

Methods

Sixty-five female cats (age: 1.37 ± 0.9 years and body weight: 2.85 ± 0.76 kg) were included in a prospective, randomized, clinical trial. Cats were sedated with intramuscular acepromazine and buprenorphine. Following induction with propofol, anesthesia was maintained with isoflurane and cats underwent ovariohysterectomy (OVH). Pain was evaluated at baseline, 15 min after sedation, and at 0.5, 1, 2, 3, 4, 6, 8, 12 and 24 h after extubation using the FGS in real-time (FGS-RT). Cats were video-recorded simultaneously at baseline, 15 min after sedation, and at 2, 6, 12, and 24 h after extubation for subsequent image assessment (FGS-IMG), which was performed six months later by the same observer. The agreement between FGS-RT and FGS-IMG scores was calculated using the Bland & Altman method for repeated measures. The effects of sedation (baseline versus 15 min) and OVH (baseline versus 24 h) were assessed using linear mixed models. Responsiveness to the administration of rescue analgesia (FGS scores before versus one hour after) was assessed using paired t-tests.

Results

Minimal bias (-0.057) and narrow limits of agreement (-0.351 to 0.237) were observed between the FGS-IMG and FGS-RT. Scores at baseline (FGS-RT: 0.16 ± 0.13 and FGS-IMG: 0.14 ± 0.13) were not different after sedation (FGS-RT: 0.2 ± 0.15, p = 0.39 and FGS-IMG: 0.16 ± 0.15, p = 0.99) nor at 24 h after extubation (FGS-RT: 0.16 ± 0.12, p = 0.99 and FGS-IMG: 0.12 ± 0.12, p = 0.96). Thirteen cats required rescue analgesia; their FGS scores were lower one hour after analgesic administration (FGS-RT: 0.21 ± 0.18 and FGS-IMG: 0.18 ± 0.17) than before (FGS-RT: 0.47 ± 0.24, p = 0.0005 and FGS-IMG: 0.45 ± 0.19, p = 0.015).

Conclusions

Real-time assessment slightly overestimates image scoring; however, with minimal clinical impact. Sedation with acepromazine-buprenorphine and ovariohysterectomy using a balanced anesthetic protocol did not influence the FGS scores. Responsiveness to analgesic administration was observed with both the FGS-RT and FGS-IMG.

Pre-warming before general anesthesia with isoflurane delays the onset of hypothermia in rats

General anesthesia causes hypothermia by impairing normal thermoregulatory mechanisms. When using inhalational anesthetic agents, Redistribution of warm blood from the core to the periphery is the primary mechanism in the development of hypothermia and begins following induction of anesthesia. Raising skin temperature before anesthesia reduces the temperature gradient between core and periphery, decreasing the transfer of heat. This prospective, crossover study (n = 17 adult male and female SD rats) compared three treatment groups: PW1% (pre-warming to increase core temperature 1% over baseline), PW40 (pre-warming to increase core temperature to 40°C) and NW (no warming). The PW1% group was completed first to ensure tolerance of pre-warming. Treatment order was then randomized and alternated after a washout period. Once target temperature was achieved, anesthesia was induced and maintained with isoflurane in oxygen without further external temperature support. Pre-warming was effective at delaying the onset of hypothermia, with a significant difference between PW1% (12.4 minutes) and PW40 (19.3 minutes, p = 0.0044 (95%CI -12 to -2.2), PW40 and NW (7.1 minutes, p < 0.0001 (95%CI 8.1 to 16.0) and PW1% and NW (p = 0.003, 95%CI 1.8 to 8.7). The rate of heat loss in the pre-warmed groups exceed that of the NW group: PW1% versus NW (p = 0.005, 95%CI 0.004 to 0.027), PW40 versus NW (p < 0.0001, 95%CI 0.014 to 0.036) and PW1% versus PW40 (p = 0.07, 95%CI -0.021 to 0.00066). Pre-warming alone confers a protective effect against hypothermia during volatile anesthesia; however, longer duration procedures would require additional heating support.

Prevalence and management of pain in dogs in the emergency service of a veterinary teaching hospital

A prospective, observational, cross-sectional study documenting the prevalence of pain in dogs presented to the emergency service of a veterinary teaching hospital and their handling (times to triage, examination, treatment) was conducted. Pain was assessed and compared using a validated and an unvalidated pain assessment scale. Sedation was monitored using a validated scale. A first evaluation was completed in 109 dogs. A second evaluation was completed for 95 dogs: 36 (38%) were identified as painful and 53% (19/36) were provided analgesia in the clinic. The remainder either did not receive analgesia (6/36, 17%) or were prescribed an analgesic for administration at home (11/36, 31%). Of dogs receiving analgesia in the clinic, most showed a decrease in pain score (15/19, 79%). Pain assessment scales were positively correlated (r = 0.69, P < 0.0001) but the unvalidated scale was insensitive in discriminating changes. Between painful and non-painful dogs, progression did not differ: admission to treatment [P = 0.96, 95% confidence interval (CI): -23 to 22 minutes] and examination to treatment (P = 0.73, 95% CI: 14 to 20 minutes). Suboptimal analgesic use suggests focused training in pain assessment and analgesic use guided by a validated pain assessment scale, is warranted.

Predicting the duration of surgery and procedures in a veterinary referral center

OBJECTIVE

To evaluate the ability of veterinary personnel to predict the duration of surgery and associated procedures in a referral center.

STUDY DESIGN

Prospective observational study.

SAMPLE POPULATION

Experienced surgeons (ES; n = 2, board certified for 10+ years), inexperienced surgeons (IS; n = 2, residency completed, not board certified), anesthesia animal health technicians (AAHT; n = 3) and surgery animal health technicians (SAHT; n = 2).

METHODS

Surgeons and technicians predicted surgery duration (skin incision to final stitch/staple) and total procedure duration (TPD; from induction of anesthesia to extubation). Predictions were compared to actual durations with Bland-Altman plots to assess agreement (accuracy) as indicated by bias (mean of observed differences) and limits of agreement (LOA; bias ±1.96 SD).

RESULTS

All groups underestimated TPD. Experienced surgeons predicted their own TPD more accurately (bias -20.1 ± 30.4 minutes [±SD]) and more consistently (narrower LOA) than IS for their own TPD (-40.1 ± 41.0 minutes). Experienced surgeon TPD predictions by AAHT were more accurate than those by ES (bias -16.0 ± 28.9 minutes, LOA 5% narrower). Inexperienced surgeon TPD predictions by AAHT were less consistent (wider LOA) than those by IS. Own surgery duration predictions by surgeons were similar in magnitude (ES surgery duration [ESSD] 8.3 ± 18.3, IS surgery duration [ISSD] surgery duration -7.9 ± 27.2 minutes), with greater consistency by ES (LOA 30% narrower). Anesthesia animal health technician predictions were similar to those of surgeons (ESSD 3.0 ± 19.3, ISSD -9.0 ± 28.7 minutes). Surgery animal health technician predictions were similar to those of AAHT for ESSD but were less accurate for ISSD.

CONCLUSION

Surgery duration was more accurately predicted than TPD, which was most accurately predicted by anesthesia technicians.

CLINICAL SIGNIFICANCE

Surgical procedure planning should involve personnel best able to predict total procedure durations; in this case, anesthesia technicians. Accurate planning will promote efficient operating room and personnel use.

Investigating novel anatomical predictors for endotracheal tube selection in dogs

The selection of an appropriate endotracheal tube (ET) for orotracheal intubation in dogs is based largely on experience, with no well-established guidelines available. This study examined relationships between several novel and published methods for selecting endotracheal tubes in a heterogenous population of 79 adult dogs. The following measurements were included: left and right nare width, nasal septum width, sum of left and right nares width plus the nasal septum width, total nose width and height, tracheal width, metacarpal and digital footpad width and height, and body mass. Using the Bland and Altman ratio method, the calculation of Cube Root Mass provided the greatest accuracy and precision, predicting actual ET size use within 3 to 4 tube sizes. A simpler to calculate, but less precise method was Width of Nose/3. The majority of published methods for estimating ET size performed poorly, including nasal septum and tracheal width.

Incomplete reporting of experimental studies and items associated with risk of bias in veterinary research

In in vivo research, the reporting of core items of study design is persistently poor, limiting assessment of study quality and study reproducibility. This observational cohort study evaluated reporting levels in the veterinary literature across a range of species, journals and research fields. Four items (randomisation, sample size estimation, blinding and data exclusion) were assessed as well as availability of study data in publicly accessible repositories. From five general and five subject-specific journals, 120 consecutively published papers (12 per journal) describing in vivo experimental studies were selected. Item reporting was scored using a published scale (items ranked as fully, partially or not reported) according to completeness of reporting. Papers in subject-specific journals had higher median reporting levels (50.0 per cent vs 33.3 per cent, P=0.007). In subject-specific journals, randomisation (75.0 per cent vs 41.7 per cent, P=0.0002) and sample size estimation (35.0 per cent vs 16.7 per cent, P=0.025) reporting was approximately double that of general journals. Blinding (general 48.3 per cent, subject-specific 50.0 per cent, P=0.86) and data exclusion (general 53.3 per cent, subject-specific 63.3 per cent, P=0.27) were similarly reported. A single paper made study data readily accessible. Incomplete reporting remains prevalent in the veterinary literature irrespective of journal type, research subject or species. This impedes evaluation of study quality and reproducibility, raising concerns regarding wasted financial and animal resources.

CCL22 is a biomarker of cartilage injury and plays a functional role in chondrocyte apoptosis

BACKGROUND

Osteoarthritis (OA) is one of the leading causes of disability worldwide. Previous history of knee injury is a significant risk factor for OA. It has been established that low-level chronic inflammation plays a pivotal role in the onset and pathogenesis of OA. The primary aim of this research was to determine if a history of knee joint injury is associated with systemic inflammation. A secondary aim was to determine if systemic inflammation is related to knee pain and joint structure.

METHODS

Differences in serum cytokine association networks, knee joint structural changes (MRI), and self-reported pain (i.e., Knee Injury and Osteoarthritis Outcome Score Pain subscale, KOOS_PAIN and Intermittent and Constant Osteoarthritis Pain score, ICOAP) between individuals who had sustained a youth (aged 15-26 years) sport-related knee injury 3-10 years previously and age- and sex-matched controls were examined. Proteins of interest were also examined in an OA rat model.

RESULTS

Cytokine association networks were found to differ significantly between study groups, yet no significant associations were found between networks and KOOS_PAIN or MRI-defined OA. A group of cytokines (MCP1/CCL2, CCL22 and TNFα) were differentially associated with other cytokines between study groups. In a pre-clinical rat OA model, serum CCL22 levels were associated with pain (r = 0.255, p = 0.045) and structural changes to the cartilage. CCL22 expression was also observed in human OA cartilage and furthermore, CCL22 induced apoptosis of isolated human chondrocytes.

DISCUSSION

These results suggest that CCL22 may be an early factor in the onset/pathogenic process of cartilage degeneration and/or related to pain OA.

ARRIVE has not ARRIVEd: Support for the ARRIVE (Animal Research: Reporting of in vivo Experiments) guidelines does not improve the reporting quality of papers in animal welfare, analgesia or anesthesia

Poor research reporting is a major contributing factor to low study reproducibility, financial and animal waste. The ARRIVE (Animal Research: Reporting of In Vivo Experiments) guidelines were developed to improve reporting quality and many journals support these guidelines. The influence of this support is unknown. We hypothesized that papers published in journals supporting the ARRIVE guidelines would show improved reporting compared with those in non-supporting journals. In a retrospective, observational cohort study, papers from 5 ARRIVE supporting (SUPP) and 2 non-supporting (nonSUPP) journals, published before (2009) and 5 years after (2015) the ARRIVE guidelines, were selected. Adherence to the ARRIVE checklist of 20 items was independently evaluated by two reviewers and items assessed as fully, partially or not reported. Mean percentages of items reported were compared between journal types and years with an unequal variance t-test. Individual items and sub-items were compared with a chi-square test. From an initial cohort of 956, 236 papers were included: 120 from 2009 (SUPP; n = 52, nonSUPP; n = 68), 116 from 2015 (SUPP; n = 61, nonSUPP; n = 55). The percentage of fully reported items was similar between journal types in 2009 (SUPP: 55.3 ± 11.5% [SD]; nonSUPP: 51.8 ± 9.0%; p = 0.07, 95% CI of mean difference -0.3-7.3%) and 2015 (SUPP: 60.5 ± 11.2%; nonSUPP; 60.2 ± 10.0%; p = 0.89, 95%CI -3.6-4.2%). The small increase in fully reported items between years was similar for both journal types (p = 0.09, 95% CI -0.5-4.3%). No paper fully reported 100% of items on the ARRIVE checklist and measures associated with bias were poorly reported. These results suggest that journal support for the ARRIVE guidelines has not resulted in a meaningful improvement in reporting quality, contributing to ongoing waste in animal research.

Morbidity and Mortality Conferences: A Mini Review and Illustrated Application in Veterinary Medicine

This mini review presents current knowledge on the role of morbidity and mortality conferences (M&MCs) as a powerful educational tool and driver to improve patient care. Although M&MCs have existed since the early twentieth century, formal evaluation of their impact on education and patient care is relatively recent. Over time, M&MCs have evolved from single discipline discussions with a tendency to focus on individual errors and assign blame, to multidisciplinary, standardized presentations incorporating error analysis techniques, and educational theory. Current evidence shows that M&MCs can provide a valuable educational experience and have the potential to generate measurable improvements in patient care.

Accidental knotting and subsequent removal of a catheter from the epidural space in an adult cow: a case report

This is the first reported case in the veterinary literature of a knot in an epidural catheter. The report reviews this very rare complication and describes options for investigation and retrieval of catheters entrapped in the epidural space of any species.

Forced-air pre-warming prevents peri-anaesthetic hypothermia and shortens recovery in adult rats

General anaesthesia disrupts thermoregulation in mammals, which can cause hypothermia. Decreases in core body temperature of 1℃ cause significant postoperative complications in humans, and peri-anaesthetic hypothermia in mice increases data variability, which can potentially increase animal use. In rats, the impact of different temperature management strategies on the incidence and severity of hypothermia, and the accuracy of different temperature measurement methods, is unknown. Eighteen adult male and female SD rats were block-randomized to one of three treatment groups: no-warming (NW), limited-warming (LW, heat pad during anaesthesia), and pre-warming (PW, warm air exposure before anaesthesia, followed by heat pad). Anaesthesia (isoflurane) duration was for 40 min. Core body temperature (intra-abdominal telemetric temperature capsule) was recorded during anaesthesia and recovery. During anaesthesia, rectal, skin, and tail temperatures were also recorded. In the PW group, core temperature was maintained during anaesthesia and recovery. By contrast, the NW group was hypothermic (11% temperature decrease) during anaesthesia. The LW group showed a decrease in temperature during recovery. Recovery to sternal recumbency was significantly faster in the PW (125 [70-186] s, P = 0.0003) and the LW (188 [169-420] s, P = 0.04) groups than in the NW group (525 [229-652] s). Rectal temperature underestimated core temperature (bias -0.90℃, 95% limits of agreement -0.1 to 1.9℃). Skin and tail temperatures showed wide 95% limits of agreement, spanning 6 to 15℃, respectively. The novel strategy of PW was effective at maintaining core temperature during and after anaesthesia. Rectal temperature provided an acceptable proxy for core body temperature.

Sedation levels in dogs: a validation study

Background

The aim of this study was to assess validation evidence for a sedation scale for dogs. We hypothesized that the chosen sedation scale would be unreliable when used by different raters and show poor discrimination between sedation protocols.

A sedation scale (range 0–21) was used to score 62 dogs scheduled to receive sedation at two veterinary clinics in a prospective trial. Scores recorded by a single observer were used to assess internal consistency and construct validity of the scores. To assess inter-rater reliability, video-recordings of sedation assessment were randomized and blinded for viewing by 5 raters untrained in the scale. Videos were also edited to allow assessment of inter-rater reliability of an abbreviated scale (range 0–12) by 5 different raters.

Results

Both sedation scales exhibited excellent internal consistency and very good inter-rater reliability (full scale, intraclass correlation coefficient [ICC_single] = 0.95; abbreviated scale, ICC_single = 0.94). The full scale discriminated between the most common protocols: dexmedetomidine-hydromorphone (median [range] of sedation score, 11 [1–18], n = 20) and acepromazine-hydromorphone (5 [0–15], n = 36, p = 0.02).

Conclusions

The hypothesis was rejected. Full and abbreviated scales showed excellent internal consistency and very good reliability between multiple untrained raters. The full scale differentiated between levels of sedation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-017-1027-2) contains supplementary material, which is available to authorized users.

Comparison of a Supraglottic Airway Device (v-gel®) with Blind Orotracheal Intubation in Rabbits

INTRODUCTION

Achieving a secure airway in rabbits is generally considered more difficult than in cats or dogs. Their relatively large tongue, small oropharyngeal cavity and glottis limit direct visualization. A rabbit-specific supraglottic airway device (SGAD) may offer benefits over blind orotracheal intubation.

ANIMALS AND METHODS

Fifteen adult New Zealand white rabbits were randomized to SGAD or orotracheal intubation (ETT). All animals were sedated with dexmedetomidine (0.1 mg kg^-1 IM) and midazolam (0.5 mg kg^-1 IM), followed by induction with alfaxalone (0.3 mg kg^-1 IV). Two CT scans of the head and neck were performed, following sedation and SGAD/ETT placement. The following were recorded: time to successful device insertion, smallest cross-sectional airway area, airway sealing pressure, and histological score of tracheal tissue. Data were analyzed with a Mann-Whitney test.

RESULTS

Two rabbits were excluded following failed ETT. Body masses were similar [ETT; n = 6, 2.6 (2.3-4.5) kg, SGAD; n = 7, 2.7 (2.4-5.0) kg]. SGAD placement was significantly faster [33 (14-38) s] than ETT [59 (29-171) s]. Cross-sectional area (CSA) was significantly reduced from baseline [12.2 (6.9-3.4) mm²] but similar between groups [SGAD; 2.7 (2.0-12.3) mm², ETT; 3.8 (2.3-6.6) mm²]. In the SGAD group, the device tip migrated into the laryngeal vestibule in 6/7 rabbits, reducing the CSA. ETT airway seals were higher [15 (10-20) cmH₂O], but not significant [SGAD; 5 (5-20) cmH₂O, p = 0.06]. ETT resulted in significantly more mucosal damage [histological score 3.3 (1.0-5.0)], SGAD; 0.67 (0.33-3.67).

CONCLUSION

The SGAD studied was faster to place and caused less damage than orotracheal intubation, but resulted in a similar CSA.

Refinement of intraperitoneal injection of sodium pentobarbital for euthanasia in laboratory rats (Rattus norvegicus)

Background

The Canadian Council on Animal Care and American Veterinary Medical Association classify intraperitoneal (IP) pentobarbital as an acceptable euthanasia method in rats. However, national guidelines do not exist for a recommended dose or volume and IP euthanasia has been described as unreliable, with misinjections leading to variable success in ensuring a timely death. The aims of this study were to assess and improve efficacy and consistency of IP euthanasia.

In a randomized, blinded study, 51 adult female Sprague-Dawley rats (170–495 g) received one of four treatments: low-dose low-volume (LL) IP pentobarbital (n = 13, 200 mg/kg pentobarbital), low-dose high-volume (LH) IP pentobarbital (n = 14, 200 mg/kg diluted 1:3 with phosphate buffered saline), high-dose high-volume (HH, n = 14, 800 mg/kg pentobarbital), or saline. Times to loss of righting reflex (LORR) and cessation of heartbeat (CHB) were recorded. To identify misinjections, necropsy examinations were performed on all rats. Video recordings of LL and HH groups were analyzed for pain-associated behaviors. Between-group comparisons were performed with 1-way ANOVA and Games-Howell post hoc tests. Variability in CHB was assessed by calculating the coefficient of variation (CV).

Results

The fastest euthanasia method (CHB) was HH (283.7 ± 38.0 s), compared with LL (485.8 ± 140.7 s, p = 0.002) and LH (347.7 ± 72.0 s, p = 0.039). Values for CV were: HH, 13.4%; LH, 20.7%; LL, 29.0%. LORR time was longest in LL (139.5 ± 29.6 s), compared with HH (111.6 ± 19.7 s, p = 0.046) and LH (104.2 ± 19.3 s, p = 0.01). Misinjections occurred in 17.0% (7/41) of euthanasia attempts. Pain-associated behavior incidence ranged from 36% (4/11, LL) to 46% (5/11, HH).

Conclusions

These data illustrate refinement of the IP pentobarbital euthanasia technique. Both dose and volume contribute to speed of death, with a dose of 800 mg/kg (HH) being the most effective method. An increase in volume alone does not significantly reduce variability. The proportion of misinjections was similar to that of previous studies.

Assessment of Carbon Dioxide, Carbon Dioxide/Oxygen, Isoflurane and Pentobarbital Killing Methods in Adult Female Sprague-Dawley Rats

Background

Exposure to carbon dioxide (CO₂) gas as a killing method is aversive and exposure to high concentrations is likely to be painful. Bradycardia during exposure to CO₂ is associated with nociception and pain. However, it is unclear if bradycardia occurs before loss of consciousness as definitions of loss of consciousness vary in the literature. The objectives of this study were to explore the relationship between recumbency, loss of righting reflex (LORR) and a quiescent electromyograph as measures of loss of consciousness, and identify the onset of bradycardia in relation to these measures. Our primary hypothesis was that CO₂ exposure would result in bradycardia, which would precede LORR.

Methods

Thirty-two adult, female Sprague-Dawley rats were instrumented with a telemetry device and randomly assigned to one of four killing methods (concentrations of 100% CO₂, CO₂ (70%)/O₂ (30%), isoflurane (5%) and intraperitoneal pentobarbital (200 mg/kg). Time to achieve recumbency, LORR, quiescent electromyograph, isoelectric electrocorticograph, heart rate and apnea were recorded.

Results

The general order of progression was recumbency, LORR, quiescent electromyograph, isoelectric electrocorticograph and apnea. Recumbency preceded LORR in the majority of animals (CO₂; 7/8, CO₂/O₂; 8/8, isoflurane; 5/8, pentobarbital; 4/8). Bradycardia occurred before recumbency in the CO₂ (p = 0.0002) and CO₂/O₂ (p = 0.005) groups, with a 50% reduction in heart rate compared to baseline. The slowest (time to apnea) and least consistent killing methods were CO₂/O₂ (1180 ± 658.1s) and pentobarbital (875 [239 to 4680]s).

Conclusion

Bradycardia, and consequently nociception and pain, occurs before loss of consciousness during CO₂ exposure. Pentobarbital displayed an unexpected lack of consistency, questioning its classification as an acceptable euthanasia method in rats.

Application of fast-track surgery principles to evaluate effects of atipamezole on recovery and analgesia following ovariohysterectomy in cats anesthetized with dexmedetomidine-ketamine-hydromorphone

OBJECTIVE

To evaluate the effects of atipamezole hydrochloride on recovery and analgesia following ovariohysterectomy in cats anesthetized with a dexmedetomidine hydrochloride, ketamine hydrochloride, and hydromorphone hydrochloride combination, in accordance with fast-track surgery principles.

DESIGN

Prospective, randomized, clinical trial.

ANIMALS

44 cats.

PROCEDURES

Cats were anesthetized with a combination of dexmedetomidine (15 μg/kg [6.8 μg/lb]), ketamine (5 mg/kg [2.3 mg/lb]), and hydromorphone (0.05 mg/kg [0.023 mg/lb]), IM, supplemented with isoflurane in oxygen. Immediately after ovariohysterectomy, cats received meloxicam (0.2 mg/kg [0.09 mg/lb]) SC and either atipamezole (75 μg/kg [34.1 μg/lb]) or an equivalent volume of saline (0.9% NaCl) solution IM. Pain and sedation were scored at baseline (prior to surgery) and at predetermined intervals after surgery. Time to sternal recumbency was recorded.

RESULTS

The atipamezole group recovered to sternal recumbency faster (median, 15 minutes; range, 5 to 60 minutes) than the saline solution group (median, 60 minutes; range, 15 to 90 minutes]). Pain scores did not differ between groups or at any time, compared with baseline, and were below the intervention threshold for most cats. Sedation scores were significantly greater in the saline solution group (median, 0; range, 0 to 2) at 2 hours after surgery, compared with the atipamezole group (median, 0; range, 0 to 0).

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that administration of atipamezole, compared with saline solution, allowed for a faster recovery from anesthesia with dexmedetomidine-ketamine-hydromorphone in cats following ovariohysterectomy without compromising analgesia. These findings have implications for the provision of appropriate postoperative analgesia following ovariohysterectomy in cats.

A systematic review of clinical audit in companion animal veterinary medicine

Background

Clinical audit is a quality improvement process with the goal of continuously improving quality of patient care as assessed by explicit criteria. In human medicine clinical audit has become an integral and required component of the standard of care. In contrast, in veterinary medicine there appear to have been a limited number of clinical audits published, indicating that while clinical audit is recognised, its adoption in veterinary medicine is still in its infancy. A systematic review was designed to report and evaluate the veterinary literature on clinical audit in companion animal species (dog, cat, horse). A systematic search of English and French articles using Proquest Dissertations and Theses database (February 6, 2014), CAB Abstracts (March 21, 2014 and April 4, 2014), Scopus (March 21, 2014), Web of Science Citation index (March 21, 2014) and OVID Medline (March 21, 2014) was performed. Included articles were those either discussing clinical audit (such as review articles and editorials) or reporting parts of, or complete, audit cycles.

Results

The majority of articles describing clinical audit were reviews. From 89 articles identified, twenty-one articles were included and available for review. Twelve articles were reviews of clinical audit in veterinary medicine, five articles included at least one veterinary clinical audit, one thesis was identified, one report was of a veterinary clinical audit website and two articles reported incomplete clinical audits. There was no indication of an increase in the number of published clinical audits since the first report in 1998. However, there was evidence of article misclassification, with studies fulfilling the criteria of clinical audit not appropriately recognised. Quality of study design and reporting of findings varied considerably, with information missing on key components, including duration of study, changes in practice implemented between audits, development of explicit criteria and appropriate statistical analyses.

Conclusions

Available evidence suggests the application and reporting of clinical audit in veterinary medicine is sporadic despite the potential to improve patient care, though the true incidence of clinical audit reporting is likely to be underestimated due to incorrect indexing. Reporting standards of clinical audits are highly variable, limiting evaluation, application and repeatability of published work.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-016-0661-4) contains supplementary material, which is available to authorized users.

Sound Pressure Levels in 2 Veterinary Intensive Care Units

Background

Intensive care units (ICUs) in human hospitals are consistently noisy environments with sound levels sufficient to substantially decrease sleep quality. Sound levels in veterinary ICUs have not been studied previously, but environmental sound has been shown to alter activity in healthy dogs.

Hypothesis

Veterinary ICUs, like those in human medicine, will exceed international guidelines for hospital noise.

Animals

NA.

Methods

Prospective, observational study performed consecutively and simultaneously over 4 weeks in 2 veterinary ICUs. Conventional A‐weighted sound pressure levels (equivalent continuous level [a reflection of average sound], the sound level that is exceeded 90% of the recording period time [reflective of background noise], and maximum sound levels) were continuously recorded and the number of spikes in sound >80 dBA were manually counted.

Results

Noise levels were comparable to ICUs in human hospitals. The equivalent continuous sound level was higher in ICU1 than in ICU2 at every time point compared, with greatest differences observed on week day (ICU1, 60.1 ± 3.7 dBA; ICU2, 55.9 ± 2.5 dBA, P < .001) and weekend nights (ICU1, 59.9 ± 2.4 dBA; ICU2, 53.4 ± 1.7 dBA, P < .0001) reflecting a 50% difference in loudness. Similar patterns were observed for the maximum and background noise levels. The number of sound spikes was up to 4 times higher in ICU1 (162.3 ± 84.9 spikes) than in ICU2 (40.4 ± 12.2 spikes, P = .001).

Conclusions and Clinical Importance

These findings show that sound in veterinary ICUs is loud enough to potentially disrupt sleep in critically ill veterinary patients.

Student attainment of proficiency in a clinical skill: the assessment of individual learning curves

The aims of this study were to determine if the learning curve cumulative summation test (LC-CUSUM) can differentiate proficiency in placing intravenous catheters by novice learners, and identify the cause of failure when it occurred. In a prospective, observational study design 6 undergraduate students with no previous experience of placing intravenous catheters received standardized training by a board certified veterinary anesthesiologist in intravenous catheter placement technique. Immediately following training, each student attempted 60 intravenous catheterizations in a dog mannequin thoracic limb model. Results were scored as a success or failure based upon completion of four specific criteria, and where catheter placement failure occurred, the cause was recorded according to pre-defined criteria. Initial acceptable and unacceptable failure rates were set by the study team and the LC-CUSUM was used to generate a learning curve for each student. Using 10% and 25% acceptable and unacceptable failure rates, 3 out of 6 students attained proficiency, requiring between 26 to 48 attempts. Applying 25% and 50% acceptable and unacceptable failure rates, 5 of 6 students obtained proficiency, requiring between 18 and 55 attempts. Wide inter-individual variability was observed and the majority of failed catheterisation attempts were limited to two of the four pre-defined criteria. These data indicate that the LC-CUSUM can be used to generate individual learning curves, inter-individual variability in catheter placement ability is wide, and that specific steps in catheter placement are responsible for the majority of failures. These findings may have profound implications for how we teach and assess technical skills.

Carbon dioxide, but not isoflurane, elicits ultrasonic vocalizations in female rats

Gradual filling of a chamber with carbon dioxide is currently listed by the Canadian Council on Animal Care guidelines as a conditionally acceptable method of euthanasia for rats. Behavioural evidence suggests, however, that exposure to carbon dioxide gas is aversive. Isoflurane is less aversive than carbon dioxide and may be a viable alternative, though objective data are lacking for the period leading up to loss of consciousness. It has been shown that during negative states, such as pain and distress, rats produce ultrasonic vocalizations. The objective of this study was to detect ultrasonic vocalizations during exposure to carbon dioxide gas or isoflurane as an indicator of a negative state. Specialized recording equipment, with a frequency detection range of 10 to 200 kHz, was used to register these calls during administration of each agent. Nine female Sprague-Dawley rats were exposed to either carbon dioxide or isoflurane on two different occasions. All rats vocalized in the ultrasonic range (30 to 70 kHz) during exposure to carbon dioxide. When exposed to isoflurane, no calls were detected from any of the animals. The frequent occurrence of ultrasonic vocalizations during carbon dioxide exposure suggests that the common practice of carbon dioxide euthanasia is aversive to rats and that isoflurane may be a preferable alternative.

Post-anesthetic pulmonary edema in two horses

CASE 1: A two-year old, 462 kg Standard bred horse was anesthetized for arthroscopy and castration. During anesthesia, hyperemia of the mucosal membranes and urticaria were noticed. During 5 hours of anesthesia subcutaneous edema of the eyelids and neck region developed. In the recovery box, the orotracheal (OT) tube was left in situ and secured in place with tape. Following initial attempts to stand, the horse became highly agitated and signs consistent with pulmonary edema developed subsequently. Arterial hypoxemia (PaO(2): 3.7 kPa [28 mmHg]) and hypocapnia (PaCO(2): 3.1 kPa [23 mmHg]) were confirmed. Oxygen and furosemide were administered. The horse was assisted to standing with a sling. Therapy continued with bilateral intra-nasal oxygen insufflation. Ancillary medical therapy included flunixin meglumine, penicillin, gentamycin and dimethylsulfoxide. Following 7 hours of treatment the arterial oxygen tensions began to increase towards normal values. CASE 2: An 11-year old, 528 kg Paint horse was anesthetized for surgery of a submandibular mass. The 4-hour anesthetic period was unremarkable. The OT tube was left in situ for the recovery. During recovery, the horse was slightly agitated and stood after three attempts. Clinical signs consistent with pulmonary edema and arterial hypoxemia (PaO(2): 5 kPa [37.5 mmHg]) subsequently developed following extubation. Respiratory signs resolved with medical therapy, including unilateral nasal oxygen insufflation, furosemide, flunixin meglumine and dimethylsulfoxide. The diagnosis of pulmonary edema in these horses was made by clinical signs and arterial blood-gas analysis. While pulmonary radiographs were not taken to confirm the diagnosis, the clinical signs following anesthesia support the diagnosis in both cases. The etiology of pulmonary edema was most likely multifactorial.

Effects of prednisone on blood lactate concentrations in healthy dogs

BACKGROUND

Glucocorticoids affect carbohydrate and lactate metabolism.

HYPOTHESIS

Administration of prednisone to healthy dogs will result in clinically relevant hyperlactatemia.

ANIMALS

Twelve healthy adult Beagle dogs.

METHODS

Prospective, controlled experimental study. Twelve healthy adult Beagles were divided into 2 groups (3 of each sex per group). One group served as control. The other group received 2 treatments: low, 1 mg/kg prednisone PO q24h for 2 weeks; high, 4 mg/kg prednisone PO q24h for 2 weeks. A washout period of 6 weeks separated the treatments. Blood samples were drawn for whole blood lactate measurement on day (D) 0, D4, and D14 and measured in duplicate.

RESULTS

Compared with the control group, low and high groups had significantly higher blood lactate concentrations at D4 and D14. There was no difference at D0. There was no effect of time within the control group. In the low and high groups, blood lactate concentration was increased at D4 and D14 versus D0. Blood lactate concentration was greater in the high group than the low group at D14 only.

CONCLUSIONS AND CLINICAL IMPORTANCE

Dogs treated with prednisone experience statistically significant increases in blood lactate concentrations, which can result in type B hyperlactatemia. In such cases, improving tissue perfusion, treatment for the commonest form of hyperlactatemia (type A) would be unnecessary.

The effects of two dosages of midazolam on short-duration anesthesia in the harp seal (Phoca groenlandica)

The purpose of this study was to provide safe anesthesia for bronchoalveolar lavage and assess the utility of premedication with i.m. midazolam for short-duration anesthesia with isoflurane in harp seals (Phoca groenlandica). Fourteen yearling harp seal pups were anesthetized three times each as part of a prospective, cross-over, blinded study. Each animal received i.m. premedication with saline, low-dose, or high-dose midazolam (respectively 0.1 and 0.2 mg/ kg). Following premedication, anesthesia was induced with 4% isoflurane in oxygen delivered through a mask and connected to a Bain non-rebreathing system. A significantly longer time was taken from the end of general anesthesia to head movement in the high-dose group compared with the saline group (P = 0.002). A significantly longer time was taken from the end of general anesthesia to ambulation in the high-dose group compared with the saline group (P = 0.006). There were no significant differences between groups in the subjective assessment of anesthetic quality or ease of intubation. Premedication with i.m. midazolam at the dosages used did prolong recovery from anesthesia, although to a degree unlikely to be significant clinically.

Use of end-tidal partial pressure of carbon dioxide to predict arterial partial pressure of carbon dioxide in harp seals during isoflurane-induced anesthesia

OBJECTIVE

To evaluate the relationship between end-tidal partial pressure of CO(2) (ETCO(2)) and PaCO(2) in isoflurane-anesthetized harp seals.

ANIMALS

Three 5-month-old 25- to 47-kg harp seals (Phoca groenlandica).

PROCEDURES

PaCO(2) was determined in serial arterial samples from isoflurane-anesthetized seals and compared with concomitant ETCO(2) measured with a side-stream microstream capnograph. Twenty-four paired samples were subjected to linear regression analysis and the Bland-Altman method for assessment of clinical suitability of the 2 methods (ie, PaCO(2) and ETCO(2) determinations). The influence of ventilation rate per minute (VR) on the ETCO(2) to PaCO(2) difference (P[ET-a] CO(2)) was examined graphically.

RESULTS

The correlation coefficient between the 2 measurements was 0.94. The level of agreement between ETCO(2) and PaCO(2) varied considerably. Values of ETCO(2) obtained with a VR of < 5 underestimated PaCO(2) to a greater degree (mean bias, -4.01 mm Hg) and had wider limits of agreement of -13.10 to 5.07 mm Hg (-4.01 mm Hg +/- 1.96 SD), compared with a VR of > or = 5 (mean bias, -2.24 mm Hg; limits of agreement, -7.79 to 3.30 mm Hg).

CONCLUSIONS AND CLINICAL RELEVANCE

These results indicate that a microstream sidestream capnograph provides a noninvasive, sufficiently accurate estimation of PaCO(2) with intermittent positive ventilation at a VR > or = 5 in anesthetized harp seals.

Target-controlled infusion of propofol in dogs--evaluation of four targets for induction of anaesthesia

Four groups of 20 dogs were anaesthetised by means of target-controlled infusions of propofol designed to achieve 2.5 microg/ml, 3.0 microg/ml, 3.5 microg/ml or 4.0 microg/ml of propofol in blood. The dogs' pulse rate and respiratory rate were recorded before premedication and induction, immediately after endotracheal intubation and three and five minutes later (times 0, 3 and 5, respectively), and their arterial blood pressure was recorded oscillometrically just before induction and at times 0, 3 and 5. The targets of 2.5, 3.0, 3.5 and 4.0 microg/ml resulted in the successful induction of anaesthesia in 13 (65 per cent), 16 (80 per cent), 20 (100 per cent) and 20 (100 per cent) of the dogs, respectively. The incidence of postinduction apnoea was 0 (0 per cent), one (5 per cent), two (10 per cent) and eight (40 per cent) at time 5 for groups 2.5, 3.0, 3.5 and 4.0 mug/ml, respectively, and its incidence at time 5 was significantly higher in the 4.0 microg/ml group (P<0.05) than in the other groups. In all the groups there was a significant (P<0.05) decrease in blood pressure between just before induction and the later measurements. Although there were no statistically significant differences between the groups in terms of inducing anaesthesia at a specific target, a target of 3.5 microg/ml appears to ensure a successful induction of anaesthesia without a significant increase in the incidence of apnoea.