Results of preemptive epidural administration of morphine with or without bupivacaine in dogs and cats undergoing surgery: 265 cases (1997-1999)

OBJECTIVE: To determine prevalence of adverse effects associated with epidural administration of morphine with or without bupivacaine in dogs and cats undergoing surgery and evaluate effects of epidural administration of morphine on postoperative pain severity. DESIGN: Retrospective study. ANIMALS: 242 dogs and 23 cats. PROCEDURE: Morphine with or without bupivacaine was administered prior to surgery with a Tuohy needle, spinal needle, or epidural catheter. In 18 dogs that underwent surgery twice, results of preemptive epidural administration of morphine with or without bupivacaine were compared with results of systemic administration of oxymorphone and ketoprofen. RESULTS: The delivered fraction of isoflurane was significantly lower in animals given morphine and bupivacaine than in animals given morphine alone. Analgesia was of significantly longer duration in dogs given morphine and bupivacaine than in dogs given morphine alone. During anesthesia, mild respiratory and cardiovascular depression was reported. Seven dogs and 2 cats had urine retention, and 2 dogs developed pruritus. Six dogs vomited when a second dose of morphine was given epidurally the day after surgery. Eight of 72 dogs had delayed hair growth. In 18 dogs that underwent surgery twice, the delivered fraction of isoflurane was significantly lower and the duration of analgesia was significantly longer when morphine with or without bupivacaine was given epidurally than when oxymorphone and ketoprofen were given. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that preemptive epidural administration of morphine with or without bupivacaine is a safe and effective method of inducing long-lasting analgesia in dogs and cats and is superior to standard management of postoperative pain with repeated injection of oxymorphone and ketoprofen.     

Analgesia in Dogs after Intercostal Thoracotomy A Comparison of Morphine, Selective Intercostal Nerve Block, and Interpleural Regional Analgesia with Bupivacaine

Three postoperative analgesic protocols were assigned randomly to 24 healthy dogs after thoracotomy at the left fourth intercostal space. Morphine was administered parenterally to eight dogs after tracheal extubation; selective intercostal nerve blocks with bupivacaine hydrochloride and epinephrine were administered to eight dogs before closure of the thorax; and bupivacaine hydrochloride and epinephrine were administered through an interpleural catheter to eight dogs after tracheal extubation. Heart rate, respiratory rate, rectal temperature, hematocrit, plasma protein, blood gas, and pain score evaluations were recorded before surgery and 30 minutes, 1 hour, 2 hours, and 3 hours after extubation. Morphine caused significant decreases in blood pH and blood oxygen tensions, and significant increases in carbon dioxide tensions. Dogs treated with intercostal nerve blocks had no significant changes in these parameters, and dogs treated with interpleural bupivacaine had significant decreases in blood oxygen tension. All dogs had significant decreases in rectal temperature, and hypothermia was prolonged after morphine. Analgesia was initially adequate in most dogs, but some dogs in each treatment group had recurrence of pain and were treated with interpleural bupivacaine. One dog developed pneumothorax. Interpleural administration of bupivacaine produced analgesia equal to that produced by systemic administration of morphine or selective intercostal nerve block with bupivacaine. Bupivacaine was easily readministered through an interpleural catheter. Respiratory compromise was less in dogs treated with bupivacaine than in dogs treated with morphine. After intercostal thoracotomy, interpleural bupivacaine provided prolonged analgesia with fewer blood gas alterations than morphine.     

A retrospective study of efficacy and side effects of intrathecal administration of hyperbaric bupivacaine and morphine solution in 39 dogs undergoing hind limb orthopaedic surgery

ObjectiveTo evaluate the intraoperative efficacy of intrathecal anaesthesia with hyperbaric bupivacaine 0.5% and morphine 1% solution (HIA) in dogs undergoing hind limb orthopaedic surgery, using the cardiovascular response to surgical stimulation and to report the perioperative side effects.Study designRetrospective clinical study.AnimalsForty-three dogs that underwent general anaesthesia for hind limb orthopaedic surgery between 2010 and 2011.MethodsThe anaesthesia records of dogs that received HIA were reviewed. The bupivacaine and morphine doses were calculated based on body mass (BM) and spinal cord length (SCL). Cardiovascular response (CR) to surgical stimulation, the incidence of hypotension, bradycardia, urinary retention, pruritus and offset of motor block were all reported. The intraoperative time-to-event probability of CR was analyzed using Kaplan–Meier survival analysis.ResultsThe median (range) bupivacaine dose related to BM was 0.57 (0.40–0.78) mg kg^?1, while that related to SCL was 0.13 (0.08–0.19) mg cm^?1. A CR was observed in 3/39 (8%) dogs within the first hour after intrathecal injection (Ii) and in 9/39 (23%) dogs over the entire duration of surgery. At 70 minutes from Ii the event-free probability of CR fell below 80%. Hypotension was observed in 12/39 (31%), bradycardia in 6/39 (15%), pruritus in 3/39 (8%), and urinary retention in 3/39 (8%) dogs respectively. Five hours after Ii, 35/39 (89%) dogs were able to walk with only residual ataxia.Conclusions and clinical relevanceIntrathecal anaesthesia with hyperbaric bupivacaine 0.5% and morphine 1% solution provided effective intraoperative antinociception up to 70 minutes in dogs undergoing hind limb surgery. The technique of HIA can provide effective analgesia during short hind limb surgeries in dogs.     

Comparison of Analgesic Effects of Caudal Epidural 0.25% Bupivacaine with Bupivacaine Plus Morphine or Bupivacaine Plus Ketamine for Analgesia in Conscious Horses

The aim of this study was to compare the effects of caudal epidural bupivacaine alone (BP), bupivacaine plus morphine (BPMP), and bupivacaine plus ketamine (BPKE) for perineal analgesia in horses. Each of the six saddle horses received a caudal epidural catheter and underwent 3 treatments: BP, 0.25% (0.04 mg/kg) bupivacaine hydrochloride without epinephrine; BPMP, 0.02 mg/kg of bupivacaine combined with 0.1 mg/kg of morphine-preservative free; and BPKE, 0.02 mg/kg of bupivacaine combined with 0.5 mg/kg of ketamine. The order of treatments was randomized. The cardiovascular system, respiratory rate, quality of analgesia, sedation, and motor blockade were assessed before drug administration (baseline), at 5, 10, 15, and 30 minutes, and every 30 minutes thereafter until loss of analgesia. The median time to onset of analgesia was 5 minutes after BP treatment, faster than after BPKE or BPMP treatments, which were 10 minutes and 15 minutes, respectively (P < .05). The BPMP treatment produced analgesia (315 minutes) for a longer duration than BP treatment (210 minutes) or BPKE treatment (240 minutes), in the regions of the tail, perineum, and upper hind limb in horses. All treatments presented mild sedation or motor blockade. There were minimal effects on the cardiovascular system and respiratory rate. BPMP may be preferable to a high dose of BP or BPKE. Caudal epidural BPMP can be an appropriate choice for regional perineal analgesia in horses.     

Cardiorespiratory effects of epidural administration of morphine and fentanyl in dogs anesthetized with sevoflurane

OBJECTIVE: To determine the cardiorespiratory effects of epidural administration of morphine alone and in combination with fentanyl in dogs anesthetized with sevoflurane. DESIGN: Prospective study. ANIMALS: 6 dogs. PROCEDURE: Dogs were anesthetized with sevoflurane and allowed to breathe spontaneously. After a stable plane of anesthesia was achieved, morphine (0.1 mg/kg [0.045 mg/lb]) or a combination of morphine and fentanyl (10 microg/kg [4.5 microg/lb]) was administered through an epidural catheter, the tip of which was positioned at the level of L6 or L7. Cardiorespiratory variables were measured for 90 minutes. RESULTS: Epidural administration of morphine alone did not cause any significant changes in cardiorespiratory measurements. However, epidural administration of morphine and fentanyl induced significant decreases in diastolic and mean arterial blood pressures and total peripheral resistance. Stroke volume was unchanged, PaCO2 was significantly increased, and arterial pH and base excess were significantly decreased. Heart rate was significantly lower after epidural administration of morphine and fentanyl than after administration of morphine alone. None of the dogs had any evidence of urine retention, vomiting, or pruritus after recovery from anesthesia. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that epidural administration of morphine at a dose of 0.1 mg/kg in combination with fentanyl at a dose of 10 microg/kg can cause cardiorespiratory depression in dogs anesthetized with sevoflurane.     

Severe pruritus and myoclonus following intrathecal morphine administration in a dog

During epidural needle placement in a 32-kg dog the subarachnoid space was punctured and half the intended dose of lidocaine, bupivacaine, and morphine was injected. After recovery from anesthesia the dog showed signs of severe pruritus of the tail base and limbs and myoclonus of the tail and hind limbs. Methadone, acepromazine, ketamine, buprenorphine, and butorphanol were administered to control myoclonus and pruritus, but were unsuccessful. Diazepam was used to control myoclonus until the effects of morphine abated.     

Epidural analgesia with a combination of bupivacaine and buprenorphine in rats

We determined the analgesic effects of epidural administration of either bupivacaine at 62.5, 125, 250, and 500 micrograms/kg; buprenorphine at 5 and 10 micrograms/kg; and the combination of bupivacaine at 125 micrograms/kg and buprenorphine at 5 or 10 micrograms/kg, using the tail flick (TF) and colorectal distension (CD) tests in rats and compared the results with those obtained using morphine at 100 micrograms/kg. In both the TF and CD tests, all doses of bupivacaine alone produced potent anti-nociceptive effects, although the effect rapidly diminished after 20-30 min of administration. The administration of buprenorphine at 10 and 5 micrograms/kg produced mild to moderate anti-nociceptive effects in both the TF and CD tests, and the effects were relatively constant throughout the 2-h experimental period. Combinations of 5 or 10 micrograms/kg of buprenorphine with 125 mg/kg of bupivacaine produced a significantly higher percentage of maximum possible analgesic effect (%MPE) than that of the calculated additive effect of each drug alone in the TF and CD tests. The analgesic effect of this combination was similar to that of morphine. Minimal ataxia was observed in rats administered this combination.     

The effects of preoperative extradural bupivacaine and morphine on the stress response in dogs undergoing femoro-tibial joint surgery

OBJECTIVE: To evaluate the efficacy of preoperative extradural bupivacaine and morphine in attenuating the stress response in dogs undergoing femoro-tibial joint surgery. STUDY DESIGN: Prospective clinical study. Animal population Twelve client-owned dogs undergoing surgery for either repair of cruciate ligament rupture (ten) or correction of luxating patella (two). Body masses ranged from 12 to 45 kg (mean: 28.58 +/- 18.38). Age ranged from 19 to 121 months (mean: 66.5 +/- 49.5). MATERIALS AND METHODS: Six of the dogs received extradural bupivacaine (up to 1.5 mg kg(-1)) combined with morphine (0.1 mg kg(-1); ED) while the other six received no extradural analgesia (C). The levels of cortisol, acute phase proteins (APPs), and red and white blood cell variables were measured in both groups of dogs before, and at various times after surgery. Pain was also assessed at various times after surgery. The number of postoperative morphine doses required, and their time of administration, was recorded for each animal. Method of statistical analysis Data were analysed using anova for repeated measures with p-values of <0.05 considered significant. RESULTS: Cortisol levels in the ED group were significantly (p < 0.05) lower than those of the control group at the end of surgery. No statistically significant differences were found in APPs or red and white cell variables between dogs receiving, and those not receiving extradural bupivacaine and morphine. Four dogs in the control group and one in the ED group required postoperative morphine. CONCLUSIONS AND CLINICAL RELEVANCE: Pre-emptive extradural bupivacaine and morphine was effective in lowering the neuroendocrine stress response (cortisol) in the ED group but had no effect on the inflammatory response (acute phase response).     

Estimated plasma bupivacaine concentration after single dose and eight-hour continuous intra-articular infusion of bupivacaine in normal dogs

Objective— To estimate maximum plasma concentration (C_max) and time to maximum plasma (t_max) bupivacaine concentration after intra‐articular administration of bupivacaine for single injection (SI) and injection followed by continuous infusion (CI) in normal dogs. Study Design— Cross‐over design with a 2‐week washout period. Animals— Healthy Coon Hound dogs (n=8). Methods— Using gas chromatography/mass spectrometry, canine plasma bupivacaine concentration was measured before and after SI (1.5 mg/kg) and CI (1.5 mg/kg and 0.3 mg/kg/h). Software was used to establish plasma concentration–time curves and estimate C_max, T_max and other pharmacokinetic variables for comparison of SI and CI. Results— Bupivacaine plasma concentration after SI and CI best fit a 3 exponential model. For SI, mean maximum concentration (C_max, 1.33±0.954 μg/mL) occurred at 11.37±4.546 minutes. For CI, mean C_max (1.13±0.509 μg/mL) occurred at 10.37±4.109 minutes. The area under the concentration–time curve was smaller for SI (143.59±118.390 μg/mL × min) than for CI (626.502±423.653 μg/mL × min, P=.02) and half‐life was shorter for SI (61.33±77.706 minutes) than for CI (245.363±104.415 minutes, P=.01). The highest plasma bupivacaine concentration for any dog was 3.2 μg/mL for SI and 2.3 μg/mL for CI. Conclusion— Intra‐articular bupivacaine administration results in delayed absorption from the stifle into the systemic circulation with mean C_max below that considered toxic and no systemic drug accumulation. Clinical Relevance— Intra‐articular bupivacaine can be administered with small risk of reaching toxic plasma concentrations in dogs, though toxic concentrations may be approached. Caution should be exercised with multimodal bupivacaine administration because plasma drug concentration may rise higher than with single intra‐articular injection.     

Use of a continuous, local infusion of bupivacaine for postoperative analgesia in dogs undergoing total ear canal ablation

OBJECTIVE: To determine whether addition of a continuous, local infusion of bupivacaine would improve postoperative analgesia in dogs undergoing total ear canal ablation. DESIGN: Randomized controlled trial. ANIMALS: 16 dogs undergoing total ear canal ablation (12 unilaterally and 4 bilaterally with > 1 month between procedures). PROCEDURE: Dogs were randomly allocated to receive morphine (0.25 mg/kg [0.11 mg/lb]) at the end of the procedure (10 procedures) or morphine and a continuous, local infusion of bupivacaine (0.13 to 0.21 mg/kg/h [0.06 to 0.1 mg/lb/h]; 10 procedures). Dogs were observed for 48 hours after surgery. Additional doses of morphine were administered up to every 4 hours in dogs with signs of severe pain. RESULTS: Temperament, sedation, analgesia, and cumulative pain scores were not significantly different between groups any time after surgery. Recovery score was significantly higher for dogs that received bupivacaine than for control dogs 2 hours after extubation but not at any other time. Serum cortisol concentration was not significantly different between groups at any time but, in both groups, was significantly increased at the time of extubation, compared with all other observation times. Total number of additional doses of morphine administered was not significantly different between groups. Bupivacaine was not detected in the plasma of any of the dogs that received the local bupivacaine infusion. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that addition of a continuous, local infusion of bupivacaine did not significantly increase the degree of postoperative analgesia in dogs that underwent total ear canal ablation and were given morphine at the end of surgery.     

Perineal analgesia and hemodynamic effects of the epidural administration of meperidine or hyperbaric bupivacaine in conscious horses

Epidural administration of bupivacaine and meperidine produces analgesia in several animal species and in humans. A prospective randomized study was conducted in 18 healthy horses to compare the effect of these 2 drugs administered by the epidural route. Animals were divided into 3 treatment groups of 6 animals each. All drugs were injected by the epidural route in all animals between the 1st and 2nd coccygeal vertebrae. Treatment 1 (BUP)--0.06 mg/kg of body weight of 0.5% hyperbaric bupivacaine; treatment 2 (MEP)--0.6 mg/kg of body weight of 5% meperidine; treatment 3 (SS)--0.9% saline solution (control group). Heart rate, arterial pressure, respiratory rate, rectal temperature, analgesia, sedation, and motor-blocking were determined before drug administration (baseline values); at 5, 10, 15, and 30 minutes after drug administration, and then at 30-minute intervals thereafter. Both hyperbaric bupivacaine and meperidine administered epidurally produced complete bilateral perineal analgesia in all horses. The onset of analgesia was 6, s = 2.6 minutes after injection of bupivacaine, as opposed to 9, s = 2 minutes after meperidine. The duration of analgesia was 240, s = 57 minutes for meperidine and 320, s = 30 minutes for bupivacaine. Heart and respiratory rates, arterial pressure, and rectal temperature did not change (P < 0.05) significantly from basal values after the epidural administration of bupivacaine, meperidine, or saline solution. To conclude, both bupivacaine and meperidine induced long-lasting perineal analgesia, with minimal cardiovascular effects. Analgesia was induced faster and lasted longer with bupivacaine.     

A comparison of epidural morphine with low dose bupivacaine versus epidural morphine alone on motor and respiratory function in dogs following splenectomy

ObjectiveTo compare post-operative motor function in dogs that received epidural morphine and low dose bupivacaine versus epidural morphine alone following splenectomy.Study designProspective, randomized study.Animals16 client owned dogs undergoing routine splenectomy.MethodsFollowing splenectomy dogs were randomly allocated into one of two groups. The morphine group (MOR) was administered epidural morphine (0.1 mg kg^?1); the morphine-bupivacaine group (MORB) received epidural morphine (0.1 mg kg^?1) and low dose bupivacaine [0.25 mg kg^?1, (0.167%)]. The adjusted final volume was 0.15 mL kg^?1 in both groups. Motor function and pain assessment were performed at pre-determined times using a simple numerical motor score and the University of Melbourne Pain Scale (UMPS) respectively. An arterial blood gas was performed 2 hours following epidural administration to check for respiratory compromise. If patients scored >7 on the UMPS or were deemed painful by the observer they were administered hydromorphone intravenously and dose and time of rescue analgesia were recorded.ResultsThere were no statistically significant differences in motor scores, pain scores, amount of rescue analgesia administered or PaCO₂ between treatment groups. No dogs demonstrated respiratory depression or profound motor dysfunction at any time point during the study. 9/16 (56%) dogs did not require rescue analgesia during the first 18 hours following splenectomy.Conclusions and clinical relevanceThe combination of low dose bupivacaine (0.25 mg kg^?1) and morphine (0.1 mg kg^?1) when administered epidurally has little effect on post-operative motor function. This combination can be used without concern of motor paralysis in healthy animals.     

Intra‐articular opioid analgesia is effective in reducing pain and inflammation in an equine LPS induced synovitis model

Reasons for performing study: Intra‐articular administration of morphine as a local analgesic and anti‐inflammatory drug is widely used in human medicine. In equids, little is known about its clinical analgesic and anti‐inflammatory efficacy. Objectives: To use an inflammatory orthopaedic pain model to investigate the analgesic and anti‐inflammatory effects of intra‐articularly administered morphine as a new treatment modality in horses with acute arthritis. Methods: In a crossover study design, synovitis was induced in the left or right talocrural joint by means of intra‐articular injection of 0.5 ng lipopolyssacharide (LPS). The effect of 120 mg morphine, intra‐articularly administered at 1 h after induction of synovitis, was evaluated using both physiological and behavioural pain variables. Synovial fluid was sampled at 0, 4, 8, 28 and 52 h after induction of synovitis and analysed for total protein concentration, leucocyte count and for prostaglandin E₂, bradykinin and substance P concentrations by ELISA. Ranges of motion of metatarsophalangeal and talocrural joints were measured as kinematic variables with the horses walking and trotting on a treadmill under sound and lame conditions. Clinical lameness scores and several behavioural variables related to the perception of pain were obtained. Results: LPS injection caused marked transient synovitis, resulting in increased concentrations of inflammatory synovial fluid markers, clinical lameness, joint effusion and several behavioural changes, such as increased time spent recumbent, decreased limb loading at rest and decreased time spent eating silage. Intra‐articular morphine resulted in a significant decrease in synovial white blood cell count, prostaglandin E₂ and bradykinin levels and improvement in clinical lameness, kinematic and behavioural parameters, compared to placebo treatment. Conclusions: Intra‐articular morphine offers potent analgesic and anti‐inflammatory effects in horses suffering from acute synovitis. Potential relevance: Local administration of opioids may be useful for horses with acute inflammatory joint pain and offers possibilities for multimodal analgesic therapies without opioid‐related systemic side effects.     

A Comparison of Epidural Saline, Morphine, and Bupivacaine for Pain Relief After Abdominal Surgery in Goats

The purpose of this study was to determine the analgesic efficacy of bupivacaine, morphine, or saline (control) when injected epidurally into the lumbosacral epidural space in goats after abdominal surgery. Goats received either bupivacaine (0.5%; 1.5 mg/kg in 0.9% sodium chloride solution), 0.9% sodium chloride solution (0.2 mL/kg), or preservative-free morphine (0.1 mg/kg). Total volume injected into the epidural space was 0.2 mL/kg for all groups. The variables evaluated were times to extubation, sternal recumbency, standing, and eating; heart and respiratory rates; and pain score. Only two of the goats in the bupivacaine group were able to stand on their hindlimbs before 6 hours. Time to eating was shorter for the saline group when compared with the bupivacaine group. Heart rate over all time in the saline group (137 ± 4 beats/min, mean ± SEM) was higher than the morphine (125 ± 3 beats/min) and bupivacaine groups (121 ± 3 beats/min). Respiratory rate over all time was increased in the saline group (26 ± 1 breaths/min) compared with the bupivacaine (24 ± 1 breaths/min) or morphine (24 ± 1 breaths/min) groups. At 50 minutes, the pain score for the saline group was higher than the morphine group. Pain score over all time in the saline group (1.5 ± 0.10) was higher than the morphine (1.2 ± 0.07) and bupivacaine (1.2 ± 0.04) groups. One goat in the saline group required two intravenous injections of flunixin meglumine for pain.     

Effect of postoperative analgesic protocol on limb function following onychectomy in cats

OBJECTIVE: To evaluate the analgesic effects of topical administration of bupivacaine, i.m. administration of butorphanol, and transdermal administration of fentanyl in cats undergoing onychectomy. DESIGN: Prospective study. ANIMALS: 27 healthy adult cats. PROCEDURE: Cats were randomly assigned to 1 of 3 treatment groups, and unilateral (left forefoot) onychectomy was performed. Gait analysis was performed before and 1, 2, 3, and 12 days after surgery. All forces were expressed as a percentage of the cat's body weight. RESULTS: On day 2, peak vertical force (PVF) was significantly decreased in cats treated with bupivacaine, compared with cats treated with butorphanol or fentanyl. The ratio of left forelimb PVF to PVF of the other 3 limbs was significantly lower on day 2 in cats treated with bupivacaine than in cats treated with fentanyl. No significant differences in vertical impulse (VI) were found between groups on any day. Values for PVF, VI, and the PVF ratio increased progressively following surgery. However, for all 3 groups, values were still significantly decreased, compared with baseline values, 12 days after surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that limb function following onychectomy is significantly better in cats treated with fentanyl transdermally or butorphanol i.m. than in cats treated with bupivacaine topically. Regardless of the analgesic regimen, limb function was still significantly reduced 12 days after surgery, suggesting that long-term analgesic treatment should be considered for cats undergoing onychectomy. Irrigation of the surgical incisions with bupivacaine prior to wound closure cannot be recommended as the sole method for providing postoperative analgesia in cats undergoing onychectomy.     

Neuraxial morphine induced pruritus in two cats and treatment with sub anaesthetic doses of propofol

HistoryTwo cats were presented for orthopaedic surgery.Physical ExaminationWith the exception of the orthopaedic injuries found, clinical examination showed no abnormality.ManagementAs part of anaesthetic management, one cat received intrathecal morphine, the other epidural morphine. Following recovery, intense grooming was observed. After ensuring adequate analgesia this behaviour was interpreted as pruritus.In the first cat, pruritus was initially managed with medetomidine constant rate infusion (CRI) at 1 and 1.5 μg kg^?1 hour^?1. The lower dose produced sedation and no relief from pruritus, the higher dose ablated pruritus but induced sedation. Two propofol (lipid emulsion formulation) boli of 0.1 mg kg^?1 ablated pruritus without causing sedation. The second cat was successfully treated with four boli of 0.1 mg kg^?1 propofol over 20 minutes.Follow–upFollowing treatment with propofol, pruritus did not recur in either cat and both were discharged from the hospital.ConclusionsThis is the first clinical report of morphine–induced pruritus in cats and management with low–dose propofol. These cases suggest an antipruritic mechanism for lipid–formulation propofol.     

Thymoma removal in a cat with acquired myasthenia gravis: a case report and literature review of anesthetic techniques

History and presentation A 12 year old, 4.2 kg, domestic long hair, castrated male cat was presented with regurgitation, inability to retract the claws, general weakness, cervical ventroflexion and weight loss. A thymic mass was evident on radiographs. Acetylcholine receptor antibody titer was positive for acquired myasthenia gravis (MG). Thymectomy via midline sternotomy was scheduled. Anesthetic management Oxymorphone and atropine were administered subcutaneously as premedication, and anesthesia was induced with etomidate and diazepam given intravenously to effect. The cat’s trachea was intubated and anesthesia was maintained with isoflurane in oxygen, and continuous infusions of remifentanil and ketamine. Epidural analgesia with preservative‐free morphine was administered prior to surgery. Postoperative analgesia was provided by oxymorphone subcutaneously, interpleural bupivacaine, and fentanyl infusion. Postoperative complications included airway obstruction, hypoxemia and hypercapnia. Follow‐up The cat was discharged 3 days after surgery. Discharge medications included pyridostigmine and prednisone. Nine days after surgery, the cat had a significant increase in its activity level, and medications were discontinued. Histopathologically, the mass was consistent with a thymoma. Approximately 6 weeks later the cat became weak again and pyridostigmine and prednisone administration was resumed. Conclusion The perioperative management of patients with MG for transsternal thymectomy is a complex task. The increased potential for respiratory compromise requires the anesthesiologist to be familiar with the underlying disease state, and the interaction of anesthetic and non‐anesthetic drugs with MG. Careful monitoring of ventilation and oxygenation is indicated postoperatively.     

Bovine Chlamydophila spp. infection: Do we underestimate the impact on fertility?

The efficacy of ketamine and bupivacaine in enhancing the epidural analgesia induced by medetomidine was evaluated in 10 buffalo calves utilized repeatedly after a gap of 10 days so that each drug combination was tested in 4 randomly selected animals. In group A, medetomidine (15 microg/kg), in group B ketamine (2.0 mg/kg), in group C bupivacaine (0.125 mg/kg), in group D medetomidine and ketamine (15 microg/kg and 2.0 mg/kg), and in group E medetomidine and bupivacaine (15 microg/kg and 0.125 mg/kg) was administered epidurally. Onset of analgesia was significantly earlier in animals of groups B and D compared to the animals of groups A, C and E. Medetomidine alone or in combination with ketamine/bupivacaine produced complete analgesia of the tail, perineum, inguinal region and upper parts of hind limbs. Ketamine produced a very short duration of complete analgesia at the tail and perineum. Bupivacaine alone produced only mild to moderate analgesia. Both ketamine and bupivacaine prolonged the duration of analgesia. Motor incoordination was mild to moderate in animals of all the groups, but animals remained standing throughout the period of observation. Animals of groups A, D and E showed mild to moderate sedation during the observation period. Ruminal movements decreased nonsignificantly in animals of groups A and E. Mild salivation was observed in animals of all the groups except group C. Significant decrease in heart rate (HR) was recorded after epidural administration of medetomidine or bupivacaine; however, ketamine caused short duration of tachycardia. The administration of ketamine with medetomidine caused lesser decrease in HR compared to medetomidine alone or in combination with bupivacaine. Significant fall in respiratory rate (RR) was recorded after epidural administration of medetomidine or bupivacaine alone, but an increase in RR was recorded after ketamine administration. The fall in RR was less pronounced in animals in which medetomidine was used with ketamine compared to the animals in which medetomidine was used alone or in combination with bupivacaine. Mean arterial pressure (MAP) decreased and central venous pressure (CVP) increased significantly after epidural administration of medetomidine in combination with ketamine or bupivacaine. The ECG changes included tall T wave, QS pattern, RS pattern and ST elevation and heart blocks at different intervals, which were more frequent and pronounced in animals given bupivacaine with medetomidine. It can be concluded that epidural administration of medetomidine can produce complete analgesia of the tail, perineum, inguinal region and upper hind limbs in buffaloes. However, significant depression of cardiovascular parameters was recorded. Administration of ketamine along with medetomidine resulted in significantly early onset and slightly longer duration of analgesia with lesser cardiopulmonary side-effects compared to medetomidine alone or medetomidine with bupivacaine. Addition of ketamine to medetomidine thus seems to be useful for producing epidural analgesia; however, addition of bupivacaine failed to provide any advantage over medetomidine alone.     

A comparison of preoperative tramadol and morphine for the control of early postoperative pain in canine ovariohysterectomy

Objective To compare morphine with tramadol for the management of early postoperative pain following ovariohysterectomy after pyometra in dogs. Study design Prospective randomized blinded clinical trial. Animals Thirty female dogs, 2–14 years old. Methods Animals were randomly divided into two equal groups. Group 1 received 0.2 mg kg^?1 of morphine IV and group 2 received 2 mg kg^?1 of tramadol IV after the induction of anesthesia. The dogs were premedicated with acepromazine, and anesthesia was induced with intravenous midazolam and ketamine. Isoflurane was used for the maintenance of anesthesia. The variables measured were: analgesia; sedation; cardiac and respiratory rates; arterial blood pressure; end‐tidal isoflurane and carbon dioxide (Pe ′CO₂); oxyhemoglobin saturation (SpO₂); plasma catecholamines; serum cortisol and glucose concentrations; pH and blood gases. The animals were monitored for 6 hours after the administration of the analgesic agent. Results There were no differences between the two groups with regard to analgesia, sedation, SpO₂, pH and blood gases, cardiovascular variables, glucose, catecholamine and cortisol concentrations. Forty minutes postopioid administration, the end‐tidal isoflurane concentration was significantly lower in the morphine‐treated group as compared to the tramadol group. At 30 minutes following opioid injection, Pe ′CO₂ was significantly higher in the morphine group than in the tramadol group. Two dogs in the tramadol group and one in the morphine group were given morphine postoperatively because of increasing pain scores. Conclusion and clinical relevance Morphine and tramadol, administered preemptively can be used safely in dogs to control early pain after ovariohysterectomy without significant adverse effects.