Jacqueline Reid

Evaluation and optimisation of a target-controlled infusion system for administering propofol to dogs as part of a total intravenous anaesthetic technique during dental surgery

The performance of a modified target-controlled infusion system was investigated in 16 dogs undergoing routine dental work, by comparing the predicted concentrations of propofol in venous blood samples with direct measurements; the optimum targets for the induction and maintenance of anaesthesia were also identified. The performance of a target-controlled infusion system is considered clinically acceptable when the median prediction error, a measure of bias, is not greater than ±10 to 20 per cent, and the median absolute performance error, a measure of the accuracy, is not greater than 20 to 30 per cent. The results fell within these limits indicating that the system performed adequately. The optimal induction target was 3 μg/ml, and anaesthesia of adequate depth and satisfactory quality was achieved with maintenance targets of between 2.5 and 4.7 μg/ml propofol. The system was easy to use and the quality of anaesthesia was adequate for dental work.

Beneficial effects of administering carprofen before surgery in dogs

These survival times were used to calculate the cumulative risk to estimate an expected number of cases in these animals, using a 10 per cent maternally-associated transmission rate by seven years of age, which is likely to be a maximum rate, as indicated by the results of the cohort study. This cumulative risk was calculated by the summation of the risk for each animal developing BSE, dependent on the proportion of the median incubation period for which they survived and assuming the incubation period was the same as that for feedborne transmission. That is, an animal which survived from 20 months to seven years would have contributed 0-1 to the expected number of cases, but animals surviving for shorter periods would make a proportionately smaller contribution to the expected cases. This results in an expected number of cases of BSE in these offspring of 7. If this estimation procedure is restricted to offspring born more than six months before the onset of BSE in the dams, then the expected number of BSE cases is reduced to 6. In fact, there was none. The results of this investigation are somewhat limited by the small number of pedigree beef suckler herds affected by BSE and the very low within-herd incidence among these herds due to feedbome infection (Wilesmith and others 1992). However, as indicated above, the estimation of the risk for offspring is less confounded by the feedborne source than in dairy herds, from which the majority of the animals for the cohort study were necessarily obtained. It was not possible to determine the use of commercial concentrates in these herds with any accuracy, because of the intermittent and low usage. Comparisons of the incidence of BSE-affected dairy herds compared to that of BSE-affected beef suckler herds, in which only homebred animals were affected, revealed that dairy herds had a 24-fold greater risk (J. W. Wilesmith and J. B. M. Ryan, unpublished observations). Two conclusions arise from this study. First, it seems highly unlikely that milk is a source of infection for cattle, as, collectively, it is estimated that the 132 offspring considered in this investigation would have consumed 111,500 litres of milk, and

Evaluation of facial expression in acute pain in cats.

OBJECTIVES To describe the development of a facial expression tool differentiating pain-free cats from those in acute pain. METHODS Observers shown facial images from painful and pain-free cats were asked to identify if they were in pain or not. From facial images, anatomical landmarks were identified and distances between these were mapped. Selected distances underwent statistical analysis to identify features discriminating pain-free and painful cats. Additionally, thumbnail photographs were reviewed by two experts to identify discriminating facial features between the groups. RESULTS Observers (n = 68) had difficulty in identifying pain-free from painful cats, with only 13% of observers being able to discriminate more than 80% of painful cats. Analysis of 78 facial landmarks and 80 distances identified six significant factors differentiating pain-free and painful faces including ear position and areas around the mouth/muzzle. Standardised mouth and ear distances when combined showed excellent discrimination properties, correctly differentiating pain-free and painful cats in 98% of cases. Expert review supported these findings and a cartoon-type picture scale was developed from thumbnail images. CLINICAL SIGNIFICANCE Initial investigation into facial features of painful and pain-free cats suggests potentially good discrimination properties of facial images. Further testing is required for development of a clinical tool.

Development of a behaviour‐based measurement tool with defined intervention level for assessing acute pain in cats

OBJECTIVES To develop a composite measure pain scale tool to assess acute pain in cats and derive an intervention score. METHODS To develop the prototype composite measure pain scale-feline, words describing painful cats were collected, grouped into behavioural categories and ranked. To assess prototype validity two observers independently assigned composite measure pain scale-feline and numerical rating scale scores to 25 hospitalised cats before and after analgesic treatment. Following interim analysis the prototype was revised (revised composite measure pain scale-feline). To determine intervention score, two observers independently assigned revised composite measure pain scale-feline and numerical rating scale scores to 116 cats. A further observer, a veterinarian, stated whether analgesia was necessary. RESULTS Mean ± sd decrease in revised composite measure pain scale-feline and numerical rating scale scores following analgesia were 2 · 4 ± 2 · 87 and 1 · 9 ± 2 · 34, respectively (95% confidence interval for mean change in revised composite measure pain scale-feline between 1 · 21 and 3 · 6). Changes in revised composite measure pain scale-feline and numerical rating scale were significantly correlated (r = 0 · 8) (P < 0001). Intervention level score of ≥4/16 was derived for revised composite measure pain scale-feline (26 · 7% misclassification) and ≥3/10 for numerical rating scale (14 · 5% misclassification). CLINICAL SIGNIFICANCE A valid instrument with a recommended analgesic intervention level has been developed to assess acute clinical pain in cats that should be readily applicable in practice.

The use of the plasma chemistry unit as an aid to the scanning electron microscope study of avian egg‐shell structure

1. In order to study the mammillary layer of the avian egg shell by scanning electron microscopy, it is necessary to separate the outer shell membrane from the calcified shell. 2. Chemical methods of effecting membrane removal are difficult to standardise due to variations in the strength of the membrane‐shell bond. 3. The use of reactive gas plasma provides an alternative, more efficient method for removing membranes without the risk of damage to underlying crystalline structures.

Definitive Glasgow acute pain scale for cats: validation and intervention level

The usefulness of a pain assessment instrument is enhanced in general practice if the score can be linked to an intervention level, which is informative as to whether or not an animal requires analgesic treatment. Previously the authors described the derivation of an intervention level for the Glasgow Composite Measure Pain Scale (CMPS) short form tool for assessing acute pain in dogs (Reid and others 2007). More recently, the authors reported the validation of a behaviour-based tool (the revised composite measure pain scale (rCMPS)-F) for the assessment of acute pain in cats that was developed using psychometric principles (Calvo and others 2014). It takes the form of a structured questionnaire completed by an observer following a standard protocol and includes assessment of spontaneous and evoked behaviours, interactions with the animal and clinical observations. Construction and clinical testing of the tool supported its validity and provided some evidence for responsiveness, but sensitivity was moderate (misclassification, 26.7 per cent). In order to improve the performance of the tool, a simple three-point facial scale, which in preliminary testing had performed very well in classifying cats in pain, was developed (Holden and others 2014) with the intention of embedding it within the behaviour-based cat tool, an approach adopted previously in paediatric medicine (CRIES (Krechel and others 1995); Premature Infant Pain Profile (Stevens and others 1996)). This communication describes a single, multicentre …