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Item The effects of three different types of distraction on pain induced by the iontophoretic administration of potassium ions : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Arts in Psychology at Massey University(Massey University, 1992) Breakwell, GuyDistraction of attention away from painful sensations is a widely accepted technique for reducing both clinical pain (Copp, 1974; Turk, Meichenbaum, & Genest, 1983), and instances of experimentally induced pain (Fernandez & Turk, 1989; McCaul & Malott, 1984). However there is little research regarding the relative efficacy of different types of distracters. According to a model proposed by McCaul and Malott (1984), distraction is thought to modify pain perception by competing with pain-sensory information for limited attentional resources. Extending this model to accommodate the multiple resource model of attention (Wickens, 1984), suggests that somatic distraction may be analgesically more potent than visual distraction, while a recent meta-analysis (Fernandez & Turk, 1989) suggests that imagery may be the most effective form of distraction. The present study examined the effects of three different distracters on pain induced by the iontophoretic administration of potassium ions. 20 subjects underwent four conditions of a repeated measures experimental procedure: somatic distraction; visual distraction; imaginal distraction; and no-distraction control conditions. It was hypothesised that under these conditions; (1) the distracters would raise pain threshold when compared to no-distraction conditions, and (2) that either pain threshold would be raised more or distracter performance would be lowered more (or both) under somatic conditions than under comparable visual conditions. Findings revealed that all three distraction conditions significantly raised pain threshold when compared to no-distraction control. Of all the distracters, the imaginal task was found to be least effective in raising pain threshold, and despite predictions the somatic distracter was not demonstrated to be any more effective than its visual counterpart. Additionally, the prediction that somatic task performance would be lowered more than visual performance was not confirmed. These findings were discussed in relation to research by Riley and Levine (1988), and the value of the multiple resource model for extending McCaul and Malott's (1984) information processing model for distraction analgesia was also discussed.Item Does distraction affect various parameters of pain differently?: an investigation of the effects of two distractors on three measures of pain : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Psychology at Massey University(Massey University, 1994) Douglas, WandaGenerally, research indicates that the distraction of attention away from painful sensations reduces both experimental and clinical pain. In addition, the literature suggests that different distracters may influence different parts of the pain experience. The present study used thirty subjects and compared the effects of visual distraction, imaginal distraction, and no-distraction on pain threshold, pain tolerance, and pain ratings. Pain was induced through potassium iontophoresis. The present study tested the assumptions that (1) Both distracter tasks will be effective in raising pain threshold and pain tolerance in comparison with the control condition (2) The visual distracter will be more effective in raising pain threshold than the imaginal distracter (3) The imaginal distracter will be more effective in raising pain tolerance than the visual distracter (4) Pain ratings will be reduced in both distraction conditions in comparison with the control condition (5) Males will have higher pain threshold and pain tolerance levels than females. Findings revealed that none of the distracters heightened pain threshold in comparison with the control condition. However, the visual detection task proved to be the most effective in increasing pain tolerance. This is contrary to predictions that the imaginal distracter would have the most influence on pain tolerance. The data showed that there was no significant difference found between males and females regarding both pain threshold and pain tolerance. The implications of findings for the management of clinical pain are discussed.Item Pain assessment and alleviation in the domestic cat (Felis catus) : a thesis presented in fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science at Massey University, Manawatu, New Zealand(Massey University, 2014) Farnworth, Mark JamesThis thesis begins by exploring current knowledge around the domestic cat population and gonadectomy as well as pain assessment tools and pain alleviation for cats. It identifies a number of areas where knowledge is either absent or in need of updating and limitations in tools for the assessment of pain in cats. It therefore proposes the undertaking of the projects which can be found in the subsequent chapters. Chapters two and three compared the attitudes and practices of veterinarians in New Zealand, Australia and the United Kingdom (UK) around pre-pubertal gonadectomy and provision of analgesia for cats. This used an electronic questionnaire which received 717 responses. Most respondents believed pre-pubertal gonadectomy was either entirely or ‘sometimes’ desirable (556/621). Age of patient at gonadectomy was significantly affected by country surveyed and respondents’ provision or nonprovision of services for pounds. Post hoc Tukey HSD analysis indicated the mean age of both spaying and castration (both 4.3 months) in the UK was significantly different from both Australia (spaying: 3.4 months, castration: 3.2 months) and New Zealand (spaying: 3.4 months, castration: 3.2 months) (all p < 0.001). Mean ages at spaying and castration were also significantly different (p=0.008; p=0.019 respectively) for non-providers (spaying: 3.9 months, castration: 3.8 months) of services to pounds when compared to providers (spaying and castration: both 3.6 months). With respect to the use of analgesics there has been a substantial increase in provision of analgesia to cats undergoing gonadectomy when compared to the early literature. There were significant differences in prevalence of analgesia provision prior to and following spaying and castration (both p < 0.001). There were also significant postoperative and post-discharge differences in provision of analgesia for castration, as compared to spaying (both p < 0.001), and a similar effect was seen pre/intraoperatively (p = 0.002). Significant effects amongst countries and between genders relative to the desirability of pre-pubertal gonadectomy were identified. Respondents from the UK were more likely to answer ‘no’ (p=0.004) or ‘sometimes’ (p=0.05) as compared to those from New Zealand or Australia. Females were more likely to respond with ‘sometimes’ as opposed to ‘yes’ than males. Reasons for considering pre-pubertal gonadectomy desirable or sometimes desirable focussed on reducing unwanted pregnancies and improving population control, as well as improving rates of adoption, owner compliance and cat behaviour and health. Post-operative provision of analgesia following both castration (p < 0.001) and spaying (p < 0.001) also differed amongst countries of practice. Veterinarians in Australia and New Zealand were more likely to provide post-operative analgesia than those from the UK. Veterinarians from the UK more commonly used non-steroidal anti-inflammatory drugs (NSAID) in the pre/intraoperative phase (P < 0.001) than veterinarians from either New Zealand or Australia. Differences in attitudes towards pre-pubertal gonadectomy amongst countries may relate to the specific Veterinary Association’s guidelines or possibly differences in social discourse which affect perception of cats. There is substantial overlap between the reported minimum age of gonadectomy and the age at which cats can enter early puberty, allowing a window for unintentional pregnancy when pre-pubertal gonadectomy does not occur. The differences in use of analgesics amongst the UK, Australia and New Zealand may reflect differing professional considerations of the risks associated with the use of NSAID. In the interests of animal welfare, pain relief should perhaps be provided or offered more frequently for owner administration. Chapters four through six explored the value of a thermal carbon dioxide (CO2) laser for the assessment of nociceptive thresholds in cats. To begin repeatabilites were established based on individual responses to three thermal tests on the same day and across 4 consecutive days. A total of 12 thermal tests were conducted on 16 adult cats (50% male). A non-thermal helium aiming laser was used as a control to ensure the animals were responding to the thermal component of the device. All thermal tests elicited a behavioural response 97% of which were a skin twitch known as the panniculus reflex. No control tests resulted in this reflex behaviour. There was no evidence that cats became sensitised or habituated to the low power thermal stimulus on any given day (p=0.426) or across days (p=0.115). There was also no difference in latency to respond between males and females (p=0.094), although there was a significant day of testing and sex interation (p=0.042). Significant intra-class correlations (ICC) demonstrated that individual responses were repeatable over days 1 to 3 (all p<0.05) but not over day 4 (p=0.096). A significant intra-class correlation was also evident across all days when data were combined (p<0.0001). Significant repeatabilities in the first laser-based experiment were low ranging from 0.241 to 0.414 therefore a larger sample was used (n=113) to establish any other factors, including age or sex effects, that impacted upon thermal sensitivity. In this next phase cats were exposed to a more powerful (500mW) CO2 thermal laser three times during a 45-60 min test period with a minimum of 15 min elapsed between consecutive tests on any one individual. Again time to display a behavioural response was repeatable across tests for any given cat (ICC=0.482; p<0.001). Analyses of covariance established that the body weight of females significantly affected response threshold (p=0.013) but for males this effect was marginal (p=0.058). All other factors included in the analyses were non-significant. A post hoc t-test for males and females with overlapping body weights found no significant differences between the sexes (p=0.721). The precise reason for the effect of body weight on latency to respond is unknown and further exploration is needed. Finally the CO2 laser’s ability to assess analgesia in pain-free cats was explored. Sixty healthy adult female cats were used and randomly allocated to one of six treatments 1) saline 0.2 ml/cat; 2) morphine 0.5 mg/kg; 3) buprenorphine 20μg/kg; 4) medetomidine 2 μg/kg; 5) tramadol 2mg/kg; 6) ketoprofen 2mg/kg. Latency to respond to thermal stimulation was assessed prior to intramuscular injection and at 6 time periods following injection (15-30; 30-45; 45-60; 60-75; 90-105; 120-135 min). Thermal thresholds were again assessed using time to respond behaviourally to stimulation with a 500mW CO2 laser. Maximum latency to respond was set at 60 sec but given that this technique was found to cause minor skin blistering in individuals that reached the 60s exposure limit, a cut off time of <45s is recommended.. Differences in response latency for each treatment across the duration of the experiment were assessed using a Friedman’s test. Differences between treatments at any given time were assessed using an independent Kruskal-Wallis test. Where significant effects were identified, pair-wise comparisons were conducted to further explain the direction of the effect. Cats treated with morphine (p=0.045) and tramadol (p=0.002) showed significant increases in latency to respond over the duration of the test period. Treatment with buprenorphine also resulted in increases in latency to respond although only at the level of a statistical trend (p=0.091). Injection of saline, ketoprofen or medetomidine showed no significant effect on latency to respond. The longest latency to respond after injection of morphine was achieved at 60-75 min whilst that of buprenorphine occurred at 90-105 min. These projects validated the CO2 laser technique for use in cats and demonstrate that it can be used for assessment of analgesia and may be useful for differentiating amongst analgesic treatments. This technique may provide a simpler alternative to existing systems although further exploration is required both in terms of its sensitivity and comparative utility (i.e. relative to other thermal threshold systems). Future possible experiments using this technique are to be found in the discussion chapter.Item Studies of local anaesthetics for velvet antler analgesia : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science at Massey University(Massey University, 2002) Bartels, MicheleVelvet antler removal on commercial deer farms is the elective surgical amputation of a live, vascular and innervated tissue. This is ethically defensible only if the well-being of the stag is not unacceptably compromised, particularly in relation to operative and post-operative pain. Those removing velvet antlers are ethically bound to employ "best practice" analgesic techniques. Previous studies have shown that the local anaesthetic lignocaine HCL (2%) is most effective using the high dose ring block around the antler pedicle. The antlers from deer at the Massey University Deer Research Unit or a commercial deer farm in the Pohangina Valley, Manawatu were used for these analgesia onset and duration studies. The onset of analgesia was determined by electrically stimulating the velvet antler at 15-second intervals until behavioural responses ceased. Duration of analgesia was determined using a novel remote electrical stimulus, which registered the return of sensation in the antlers using behavioural responses. All treatments were administered in a ring block at dose rate of 1 ml/cm pedicle circumference. In Study 1(a), the onset times of analgesia after application of one of three treatments (2% lignocaine hydrochloride (L), 2% lignocaine hydrochloride with 8.4% sodium bicarbonate (LBC) and 0.5% commercially available bupivacaine (BC) were determined in antlers of 21 rising 1-year-old red, and wapiti hybrid stags. Each antler received two treatments (28 antlers per treatment). The mean onset time was 31(SE> 7.0) seconds for L, 21(SE>2.5) seconds for LBC and 48(SE>12.7) seconds for BC. The difference in mean onset between BC and LBC was significant (p=0.0225). In Study 1(b). antlers of 26 stags 2 years-of-age and older were allocated either L or LBC. Mean time of onset of analgesia for L was 31(SE>5.94) seconds and LBC was 36(SE>5.95) seconds. There was no significant difference between the two treatments. Duration of analgesia in Study 1 (a) was measured in eight antlers given L and nine antlers given BC. The mean duration for L was 88(SE>7.7) minutes, and for BC 273(SE>19) minutes (p>0.001). Antlers of 39 rising 1-year old stags were used for Study 2. The onset and duration of analgesia were compared following two combinations of L and a novel formulation of bupivacaine (BN). In study 2(a), "higt"(HLBN) (1.5% L and 0.5% BN) and "low"(LLBN) (1.0% L and 0.25% BN) concentrations of a mixture of Hgnocaine and bupivacaine were investigated for onset of analgesia on 25 antlers each. The mean time for onset of analgesia for HLBN was 37(SE>4.4) seconds and for LLBN, 55(SE >8.8) seconds (p=0.049). The mean duration (n=10 antlers/treatment) for HLBN was 406(SE >28.9) minutes compared with 333(SE>25.2) minutes for LLBN (p=0.041). In Study 2(b) antlers were treated with either 2% mepivacaine HC1 (M), 1.5% mepivacaine/I.5% lignocaine (ML), 1.5% mepivacaine/0.5% bupivacaine (BN) (MB) or 0.5% bupivacaine (BN) (n=7/treatment). Mean onset times were 30(SE ±12.3) seconds for M, 30(SE >6.6) seconds for MB, 34(SE>7.8) seconds for ML, and 86(SE >37.3) seconds for BN. There was no significant difference in mean onset times. Duration of the four treatments (n=7 antlers/treatment) was 271(SE> 26) minutes for M, 221(SE >19) minutes for ML, 421(SE >41) minutes for MB, and 461(SE >37) minutes for BN. There were differences in duration between treatments with bupivacaine and those without (p=±0.0001). The mean duration of analgesia following the novel bupivacaine formulation was significantly longer than that for the commercial formulation (p=0.001). In study 3, each step in the velvet antler removal procedure was timed and recorded. When both antlers on stags were given local anaesthetics together (n=16 antlers/treatment), the mean time between completion of the first ring block to the nick test on the first antler was 72 (range 52-151) seconds, while the mean time between completion of the second ring block and the nick test on the second antler was 70 (range 61-183) seconds. When only one antler was given a ring block, the time between completion of the block and the nick test was 42 (range 25-40) seconds. This study showed that the time interval between injection of a high dose ring block and application of the nick test by the experienced operator would rarely be less than 60 seconds when both antlers are treated together. Velvet antler removal can therefore be undertaken in a continuous sequence of activity eliminating the necessity of a wait time if 2% lignocaine is used at 1ml/cm antler pedicle circumference. In anticipation that studies of postoperative pain control will be needed in the future, a pilot trial testing one proposed method was undertaken. Fifteen 2-year old stags were given the tranquilliser, azaperone, to test whether it reduced the confounding effects of handling stress on plasma Cortisol concentrations. In addition, nine were given the non-steroidal inflammatory drug, flunixin meglumine, after velvet antler removal. Plasma cortisol concentrations were elevated in both groups. No significant difference was detected between the means of the control and NSAID treated groups over 5 hours.Item Pharmacology of analgesic drugs in birds : thesis in fulfilment of the degree of Doctor of Philosophy in Animal Science(Massey University, 2011) Singh, Preet MohinderAnalgesics drugs are widely used to alleviate pain in mammals and birds. However, in the case of birds, there is a scarcity of information on their usage and dosing regimen. A lack of pharmacokinetic knowledge can result in under or over-dosing of drugs with subsequent loss of efficacy or side-effects. Complete understanding of a drug requires knowledge of its pharmacokinetics as well as pharmacodynamics. Considering the various voids in pharmacological research in birds and in an effort to know more about pain and welfare in birds, this study was designed to study the pharmacokinetics of morphine, butorphanol, aspirin and salicylic acid in broiler chickens. Broiler chickens were used as a model for wild and rare birds. Morphine and butorphanol were injected intravenously at 2 mg/kg, while aspirin and salicylic acid were injected intravenously at 50 mg/kg. All the analgesic drugs were well distributed in chickens. The plasma clearance for these drugs was much higher than in mammals, resulting in shorter half-lives. All the drugs remained within the theoretical therapeutic range for 2 hours. For analgesic efficacy testing, all the drugs except aspirin were injected in lame broiler chickens at similar dose rates as in the pharmacokinetics experiment. The results from the efficacy tests suggest that butorphanol and salicylic acid provided adequate analgesia which lasted for less than 2 hours. Morphine at 2 mg/kg intravenously induced sedation and drowsiness in chickens, which might be due to the high dose. It may have analgesic effects at lower dose rates, however this needs to be further evaluated. The approximate therapeutic range in broiler chickens for butorphanol is 50 to 80 ng/mL and for salicylic acid is 50 to 110 ng/mL. The therapeutic range for butorphanol is much higher in birds as compared to mammals while for salicylic acid it is in the mammalian range. The duration of analgesia in birds could be increased by using sustained released formulation or drug delivery systems, which warrants further research. Plasma concentrations after butorphanol given at 4 mg/kg in an injured Northern Royal Albatross under surgical conditions were also evaluated. This is the only pharmacokinetic study of an analgesic drug in a sea bird. The pharmacokinetics of butorphanol in this albatross differed significantly from chickens, with slower clearance and lower tissue distribution, although these were much higher than in mammals. The difference in pharmacokinetic parameters could either be due to species variation or due to the continuous fluid therapy along with butorphanol administration. This albatross was suffering from a major femur fracture, which potentially altered its normal physiology and metabolism. Chickens may be used as a model of drug research for wild and rare avian species, especially for preclinical trials. The dosing regimens can be extrapolated from chicken pharmacokinetics data, but this should be done with extreme caution as pharmacokinetics are highly variable between the species.Item Pain-induced distress and its alleviation using butorphanol after ovariohysterectomy of bitches : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Clinical Science at Massey University(Massey University, 1995) Fox, Steven M.Ovariohysterectomy is the most frequently performed surgical procedure in companion animal veterinary practice. It is regarded by many as being quite benign; however, questioning of that premise prompted this investigation. There were no satisfactory data available to determine how benign or noxious this procedure might be, yet this query is of considerable clinical importance. There exists the further vagary of assessment for pain-relief measures, whether associated with surgery or injury. Great value would lie in establishing a routinely available criterion for pain assessment. The present work was therefore undertaken to examine this area of clinical relevance and to establish a model for further study of postsurgical pain-induced distress and its alleviation. Most previous studies in this area had omitted Satisfactory control or baseline animals in that the anaesthetic or analgesic treatments were rarely, if ever, applied to animals that were not also subjected to surgery. Accordingly, the following nine treatments were made: Control, Anaesthesia, Analgesia, Analgesia plus Anaesthesia, Anaesthesia plus Analgesia at intubation, Anaesthesia plus Analgesia at extubation, Anaesthesia plus Surgery, Analgesia plus Anaesthesia plus Surgery, and Anaesthesia plus Surgery plus Analgesia. These were designed so that, with the inclusion of surgery, all the major variations in treatment were independently examined. The parameters used to evaluate the extent of pain-induced distress were changes in plasma cortisol concentration and behaviour. Cortisol is a well established physiological parameter of distress, and behaviour is a cue used by most clinicians. Butorphanol was selected as the analgesic of choice in this investigation based upon its wide use, margin of safety, across-species efficacy, versatility in route of administration, long shelf-life, competitive pricing, and freedom from the requirement for documented use by controlling authorities. The following conclusions were drawn from the cortisol data. Psychogenic stimuli in conscious control bitches were responsible for a transient rise in Cortisol concentrations not seen in anaesthetised dogs which were unconscious. Butorphanol elicited a large cortisol response, attributable to dysphoria, which was again prevented by anaesthetic administration. As judged by cortisol response there was no apparent benefit of preoperative butorphanol administered intravenously 30 minutes prior to or at the time of anaesthetic induction. However, there was an earlier decline in cortisol concentration when butorphanol was given at extubation and this was interpreted to reflect an earlier decrease in postoperative pain-induced distress. The study commenced with 166 behavioural parameters (interactive and noninteractive) from which it was found that 76 occurred at insufficient frequencies as to be valuable as indices of postoperative pain-induced distress. Among the discriminating behaviours, noninteractive parameters characteristic of the nonanalgesic surgery group were drawing the rear limbs up into a pike position, lip licking, cage circling, incision licking, vomition, and 'look back' (flank gazing), while the only characteristic interactive behaviour was an extended neck. Vocalisation was associated with the dysphoria of analgesia rather than pain-induced distress. The major contributions of this research were: (1) establishing ovariohysterectomy as a model of pain-induced distress to examine the benefit of various pain-control strategies, (2) elimination of a number of commonly seen behaviours and identification of useful behaviours for identifying pain-induced distress, (3) clarification of the responses to control and 'base-comparison' treatments with regard to both cortisol and behavioural responses, (4) identification of specific pain-induced behaviours, (5) derivation of a mathematical function representing a numerical expression for the clinical intuition of the subjective impression of pain experience in dogs, and (6) identifying behaviours that can be used by the clinician to indicate the presence or absence of pain-induced distress following ovariohysterectomy. Results suggest that the ovariohysterectomy is associated with sufficient pain-induced distress to warrant the associated use of analgesia.