Massey Documents by Type

Permanent URI for this communityhttps://mro.massey.ac.nz/handle/10179/294

Browse

Subject: search.filters.subject.Veterinary anaesthesia

Search Results

Now showing 1 - 7 of 7
  • Thumbnail Image
    Item
    The applications of sub-Tenon's anaesthesia for canine ophthalmic surgery : a thesis presented in fulfilment of the requirements for the degree of Master of Veterinary Science (MVSc) at Massey University, Manawatu, New Zealand
    (Massey University, 2016) Bayley, Kellam David
    Sub-Tenon's anaesthesia is an indispensable anaesthetic technique in human ophthalmic surgery. It produces highly effective regional anaesthesia and has a significantly lower complication rate than the previously used peribulbar and retrobulbar injections. Although this technique has potential application to veterinary ophthalmology it has not yet been reported in clinical cases. This thesis reviews the literature that references local anaesthesia for ocular surgery in human and veterinary ophthalmology. A sub-Tenon's block technique that was specifically developed for use in dogs is also described. This technique is assessed with a prospective controlled clinical study testing this technique across a variety of ocular surgeries including enucleation, intrascleral prosthesis, keratectomy with a third eyelid flap and cataract surgery. The effect of sub-Tenon's anaesthesia on specific parameters was recorded and compared to the controls such as; globe position and rotation, pupillary dilation, general anaesthetic monitoring parameters, intraocular pressure, vitreal expansion and post-operative pain scores. Analysis of these parameters has indicated that sub-Tenon's anaesthesia was an effective option for controlling post-operative pain when used in conjunction with systemic analgesics and was an excellent alternative to systemic neuromuscular blockade for canine cataract surgery.
  • Thumbnail Image
    Item
    Velvet antler removal from red deer : a thesis presented in partial fulfilment of the degree of Doctor of Philosophy in Veterinary Medicine at Massey University, Manawatu, New Zealand
    (Massey University, 2012) Flint, Pania
    Antlers are unique structures specific to deer that are cast and regrown annually. The harvest of velvet antler is a surgical procedure requiring analgesia and haemostasis. Analgesia is provided by lignocaine ring blocks around the base of the antler in adult stags or compression analgesia with a rubber (NaturOTM) ring in yearlings. Stags are often sedated with xylazine for velvet removal. This thesis covers four topics requiring refinement or further understanding: variability in local analgesia using lignocaine; the efficacy or noxiousness of NaturOTM rings; lignocaine residues in antlers; and post- xylazine stag death. In a video observational study of antler harvest on commercial velvet farms, successful analgesia was characterised by fewer “gaps” in the ring block, greater volume of lignocaine per antler, greater time taken to inject lignocaine, greater number of injections, lower stag age, and other stag factors. There was significant confounding in the data and multiple variables are likely to be important. In a series of studies investigating the use of NaturOTM rings, the rings prevented behavioural responses and partially prevented EEG responses to antler removal. On application of the NaturOTM ring, some animals demonstrated behavioural and EEG responses indicative of noxious sensation. NaturOTM rings provide analgesia during antler removal and may cause discomfort on application. It is believed that lignocaine reaches the antler via the blood stream, resulting in tissue residues. Blood flow to the antler was investigated using acrylic models, fluorescent microspheres and cineangiography. Different tourniquet types were tested to determine whether they could prevent lignocaine residues. The arterial supply to the antler is elaborate and tourniquets minimised arterial flow at tensions less than 2kg but did not prevent lignocaine residues. Occasionally, stags die within 48 hours of sedation with xylazine. In an epizoological survey, this was not related to drug or environmental factors. Reactions involved either acute respiratory distress or delayed death with severe pulmonary oedema. During observations of yearlings sedated with xylazine most demonstrated hypoxaemia that could be reversed by oxygen supplementation or yohimbine administration. This work provides indicators of how best practice in velvet antler removal may be improved.
  • Thumbnail Image
    Item
    Alleviation of the distress caused by ring castration plus tailing of lambs and dehorning of calves : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Physiology at Massey University
    (Massey University, 1999) Sutherland, Mhàiri Anne
    There is increasing social and economic pressure to improve the welfare of animals in our care. In the present study plasma cortisol concentrations were measured to assess the pain-induced distress caused by ring castration plus tailing in lambs and dehorning in calves and the extent to which the distress caused by these procedures can be reduced by using different alleviation strategies. Local anaesthetic injected into the neck of the scrotum just before ring application significantly reduced the cortisol response to ring castration plus tailing in lambs, but local anaesthetic injected into the testes just after ring application only marginally reduced this response. A castration clamp was applied across the full width of the scrotum of lambs for 6 or 10 seconds after ring castration plus tailing to disable the innervation from the scrotal area. The application of the castration clamp for 6 seconds after placement of the ring did not reduce the cortisol response to ring castration plus tailing, whereas application for 10 seconds slightly, but significantly, reduced the peak cortisol concentration. Healing of the castration wound was not complicated by the application of the castration clamp after ring castration plus tailing. Therefore injecting local anaesthetic into the neck of the scrotum just before ring castration plus tailing significantly alleviates the pain-induced distress associated with ring castration plus tailing, but applying the castration clamp in combination with ring castration plus tailing has little benefit. Local anaesthetic given prior to dehorning virtually abolishes the cortisol response to dehorning for the duration of action of the local anaesthetic, but once the local anaesthetic wears off cortisol concentrations increase resulting in a delayed cortisol response equivalent to the overall cortisol response to dehorning when local anaesthetic is not used. This delayed cortisol response is thought to be stimulated by inflammation-related pain. The non-steroidal anti-inflammatory drugs (NSAIDs) ketoprofen and phenylbutazone and an endogenous cortisol surge stimulated by iniecting ACTH were used to assess whether this delayed cortisol response is associated with inflammation-related pain. Local anaesthetic (5 hour duration of action) plus ketoprofen given prior to scoop dehorning marginally reduced the delayed cortisol response observed once the local anaesthetic wore off, but giving local anaesthetic and phenylbutazone prior to dehorning had no significant effect on this delayed cortisol response. The antinociceptive action and a greater anti-inflammatory potency of ketoprofen compared to phenylbutazone may explain why ketoprofen was more effective than phenylbutazone in reducing this delayed cortisol response. ACTH plus local anaesthetic given prior to dehorning only marginally reduced the delayed cortisol response observed once the local anaesthetic wore off, suggesting that the delayed cortisol response seen when the local anaesthetic wears off is not due primarily to inflammation-related pain Giving local anaesthetic prior to dehorning and cauterising the amputation wounds prevented the delayed cortisol response after the local anaesthetic wore off and significantly reduced the overall cortisol response to dehorning. Thus, in the present study long acting local anaesthetic (5 hour duration of action) in combination with NSAIDs had minimal alleviating effects on the pain-induced distress caused by dehorning compared to local anaesthetic alone, but local anaesthetic and cautery provided effective pain-relief.
  • Thumbnail Image
    Item
    Evaluation of dehorning distress and its alleviation in calves : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Physiology at Massey University
    (Massey University, 2002) Sylvester, Shauna P
    In this thesis, the pain-induced distress caused by the husbandry practice of dehorning cattle is assessed and methods to alleviate it are evaluated. At the time this work was conducted there were no comprehensive studies on the effects of amputation dehorning upon the welfare of the cattle. The aims of the study were to assess the distress response after dehorning and to explore the possibilities of alleviating that distress through the use of different dehorning tools, local anaesthetic and/or cautery of the scoop wound. Changes in plasma Cortisol concentrations and behaviour were used as indices of distress. It was anticipated that this research would provide scientific data to aid in the writing of welfare codes and advisory material concerning the dehorning of cattle. The Cortisol and behavioural responses of six-month-old male Friesian calves after treatment were studied. In the Cortisol studies, blood samples were taken by venipuncture from the jugular vein of each calf prior to, for the first 9 hours and at 36 h after treatment. Behavioural responses were scored by point scan behaviour sampling for the first 10 h after and on day two between 26 and 29 h after treatment. Amputation dehorning elicited a marked, biphasic Cortisol response that lasted six hours. Dehorning elicited similar Cortisol responses irrespective of the tool employed. ACTH bolus (iv. 0.28μg/kg) elicited a maximal Cortisol response. The similarity of the magnitude of the dehorning and ACTH responses suggests that dehorning was extremely distressing. The plateauing of the plasma Cortisol values between 1.5 and 3 hours after dehorning suggests the appearance of a second phase of pain, presumably from inflammation. Local anaesthesia virtually abolished the first three hours of the Cortisol response after dehorning, after which Cortisol concentrations rose transiently. Overall, this equated to a 50% reduction in the integrated Cortisol response. Cauterizing the scoop wounds effected a marginal reduction in the Cortisol response. The combination of local anaesthesia plus cauterizing the scoop wound virtually abolished the Cortisol response to amputation dehorning. This striking result is reminiscent of pre-emptive analgesia. The destruction of, and the prevention of sensitization of, nociceptors in the wound is thought to contribute to this effect. The four behaviours of tail shaking, head shaking, ear flicking and rumination, met the criteria required to use behaviour as evidence of distress. The interpretation of the behaviour data corresponded with that of the Cortisol data. Taken together, the Cortisol and behaviour data from this study, along with the subsequent work it generated, indicate that scoop dehorning is extremely noxious. If the cattle are older and amputation dehorning is necessary, it is recommended that local anaesthetic be given and if practicable combined with either ketoprofen (McMeekan et al., 1998b) or wound cautery. However, it is preferable to dehorn calves when they are younger by cautery disbudding (Petrie et al., 1996b).
  • Thumbnail Image
    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, Michele
    Velvet 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.
  • Thumbnail Image
    Item
    The effects of four different induction techniques on anaesthetic maintenance and recovery in horses : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Science at Massey University
    (Massey University, 1991) Dickson, Linda Rose
    Anaesthetic recoveries have been the target of little research, and the information available on the effect of anaesthetic induction agents on recovery lacks detail and specificity. The aim of this study was to compare the anaesthetic recovery periods after 4 different induction procedures: (1) acetylpromazine, glycerol guaiacolate, thiopentone; (2) xylazine, glycerol guaiacolate, thiopentone; (3) xylazine, ketamine; (4) acetylpromazine, glycerol guaiacolate, ketamine, which were followed by 1 hour of halothane in oxygen anaesthesia . Ten horses each received all 4 techniques with at least 1 week between successive anaesthetics. The 10 results for each induction technique were grouped, means determined, and statistical analysis performed on these group means. Strikingly, the use of thiopentone, when compared to ketamine combinations, resulted in consistently poorer recoveries. The possibility that this may be due to the persistence of subanaesthetic barbiturate levels during the recovery period is discussed. In man, residual barbiturate levels have been shown to increase the awareness of pain, and it is possible that a similar effect may be present in horses, detrimentally affecting their anaesthetic recoveries. The role of ketamine in the consistently better recoveries is unclear. It is hypothesised that it may be due to residual ketamine levels in plasma exerting a stimulatory effect on areas of the central nervous system. Interestingly, the use of acctylpromazine as a premedicant before both thiopentone and ketamine combinations, prolongs recovery and significantly increases 3 hour post anaesthetic creatinine phosphokinase (CPK) levels. No statistical relationship was found between longer recumbency times and elevated CPK levels, and it is postulated that the CPK rise may have been indirectly caused by acetylpromazine lowering the packed cell volume, and therefore muscle tissue oxygen supply. The difference in pharmacokinetics of the individual drugs used apparently influenced the smoothness and the rate of recovery observed. It cannot be assumed therefore, that horses experiencing longer or shorter anaesthetic periods would show similar recovery atttributes to those found in this study. It was concluded that, after 1 hour of anaesthetic maintenance using halothane in oxygen mixtures, there is a better chance of horses having a coordinate recovery if ketamine combinations are used as induction agents; and a more rapid recovery if xylazine/ketamine is used to induce anaesthesia.
  • Thumbnail Image
    Item
    Warming and humidification of inspired gases : its effectiveness in minimizing hypothermia in anaesthetized cats : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Science at Massey University
    (Massey University, 1993) Machon, Roslyn
    Body temperature is governed by a complex, highly integrated control system which carefully balances heat production and heat loss. Heat is produced as a byproduct of metabolism, and as the result of muscular work, shivering and chemical thermogenesis; while heat is lost from the body via the channels of heat exchange - radiation, conduction, convection and evaporation. General anaesthetic agents interfere with the normal mechanisms of temperature control by reducing heat production in the face of increased heat loss. Six adult domestic short-haired cats were included in a randomized cross-over study, to evaluate the effectiveness of warming and humidification of inspired gases in the prevention of anaesthetic induced hypothermia. General anaesthesia was maintained with halothane in 100% oxygen, delivered via a Mapelson type E non-rebreathing anaesthetic circuit. Both passive and active methods of inspired gas warming and humidification were investigated in this study: the passive technique evaluated the effectiveness of a human neonatal Heat and Moisture Exchanger (HME), while the active technique used an electrical heating unit to supplement the warming capabilities of the HME. Rectal and oesophageal temperatures continued to fall throughout each of the 120 minute experimental periods. Body temperature did not vary significantly between the three trials. The effectiveness of the HME in preserving normothermia in anaesthetized animals has not been reported previously. Despite the success of similar techniques in human neonates and infants, the results of this study indicate that warming and humidification of inspired gases is ineffective in minimizing hypothermia in halothane anaesthetized cats.