Epidural analgesia with 0.75% bupivacaine for laparotomy in goats

Epidural nerve block with 0.75% bupivacaine (1 ml/4 kg of body weight) was performed in 17 goats tranquilized by IM administration of acetylpromazine (0.07 mg/kg). For comparison, epidural nerve block with 2% lidocaine containing 1:100,000 epinephrine (1 ml/5 kg) was performed in 7 goats. Transient signs of CNS stimulation were observed during injection of bupivacaine in 5 goats and of lidocaine in 2 goats. Analgesia of the flank was inadequate for laparotomy in 4 goats given bupivacaine (including 1 goat given a two-thirds dose) and in 2 goats given lidocaine. Analgesia for these goats was provided by local infiltration of the operative site with lidocaine. With bupivacaine, the onset of analgesia was up to 40 minutes, and the duration of analgesia was several hours; most goats were unable to stand for at least 11 hours. In comparison, epidural nerve block with lidocaine had a more rapid onset and much shorter duration. For both anesthetic drugs, despite adequate analgesia for laparotomy, response to manipulation of abdominal viscera was observed in 12 goats. Arterial blood pressure and blood gas tensions were measured in 8 goats given bupivacaine; 3 goats had mean arterial blood pressure less than 70 mm of Hg. Seven goats had normal PaCO2 but 2 goats had low PaO2; 1 goat sedated with xylazine had increased PaCO2 and hypoxemia.     

Epidural analgesia with morphine or buprenorphine in ponies with lipopolysaccharide (LPS)-induced carpal synovitis

This study evaluated the analgesia effects of the epidural administration of 0.1 mg/kg bodyweight (BW) of morphine or 5 μg/kg BW of buprenorphine in ponies with radiocarpal joint synovitis. Six ponies were submitted to 3 epidural treatments: the control group (C) received 0.15 mL/kg BW of a 0.9% sodium chloride (NaCl) solution; group M was administered 0.1 mg/kg BW of morphine; and group B was administered 5 μg/kg BW of buprenorphine, both diluted in 0.9% NaCl to a total volume of 0.15 mL/kg BW administered epidurally at 10 s/mL. The synovitis model was induced by injecting 0.5 ng of lipopolysaccharide (LPS) in the left or right radiocarpal joint. An epidural catheter was later introduced in the lumbosacral space and advanced up to the thoracolumbar level. The treatment started 6 h after synovitis induction. Lameness, maximum angle of carpal flexion, heart rate, systolic arterial pressure, respiratory rate, temperature, and intestinal motility were evaluated before LPS injection (baseline), 6 h after LPS injection (time 0), and 0.5, 1, 2, 4, 6, 8, 10, 12, 16, 20, and 24 h after treatments. Although the model of synovitis produced clear clinical signs of inflammation, the lameness scores in group C were different from the baseline for only up to 12 h. Both morphine and buprenorphine showed a reduction in the degree of lameness starting at 0.5 and 6 h, respectively. Reduced intestinal motility was observed at 0.5 h in group M and at 0.5 to 1 h in group B. Epidural morphine was a more effective analgesic that lasted for more than 12 h and without side effects. It was concluded that morphine would be a valuable analgesic option to alleviate joint pain in the thoracic limbs in ponies.     

A comparison of tepoxalin-buprenorphine combination and buprenorphine for postoperative analgesia in dogs: a clinical study

The present study compares the analgesic effect of a tepoxalin-buprenorphine combination to that of buprenorphine alone in the 24 h peri-operative period in 20 dogs undergoing cranial cruciate ligament repair, which were randomly assigned to the two treatment protocols (n = 10). Additionally, possible side effects induced by tepoxalin were investigated. Analgesia was compared using a visual analogue scale (VAS) and a multifactorial pain scale (MFPS), by an anaesthetist blinded from treatment. Analysis of the overall VAS-scores showed a significant decrease over time in both treatment groups. The decrease in the two groups was not significantly different from each other. No significant differences were found between the MFPS-scores of both protocols. Potential side effects of tepoxalin were investigated by venous blood sampling before premedication and 24 h after extubation, a buccal mucosal bleeding time test and recording of vomiting, diarrhoea and adverse effects at the surgical site. Analysis of the blood parameters showed that fibrinogen levels were overall higher 24 h after surgery in both protocols, but were significantly more elevated in the tepoxalin group. No significant differences were found for the other blood parameters. Statistically, tepoxalin failed to improve analgesia induced by buprenorphine. There was no convincing evidence that the administration of tepoxalin was not associated with gastrointestinal side effects. There were no significant adverse effects on renal function and primary haemostasis.     

Epidural anaesthesia using lignocaine, bupivacaine or a mixture of lignocaine and bupivacaine in dogs

The time to loss of interdigital reflex, duration of action, duration of muscle relaxation and cardiorespiratory effects were compared after epidural block using lignocaine, bupivacaine or a combination of lignocaine and bupivacaine in dogs. Dogs were pre-medicated with methotrimeprazine, anaesthesia was induced with thiopentone, in order to facilitate epidural puncture, and a lumbosacral epidural block was performed. Body temperature fell after pre-medication, thiopentone and epidural anaesthesia. Minimal changes were observed in arterial O₂ saturation, end tidal CO₂, respiratory rate, heart rate and mean arterial blood pressure. The combination of bupivacaine with lignocaine produced a shorter time to loss of interdigital reflex than bupivacaine alone, longer analgesia than lignocaine alone and longer muscle relaxation than either lignocaine or bupivacaine. The combination appeared to be the best choice when surgical time is prolonged.     

Two doses of dexmedetomidine in combination with buprenorphine for premedication in dogs; a comparison with acepromazine and buprenorphine

ObjectiveTo assess as premedicants, the sedative, cardiorespiratory and propofol-sparing effects in dogs of dexmedetomidine and buprenorphine compared to acepromazine and buprenorphine.Study designProspective, randomised, blinded clinical studyAnimalsSixty healthy dogs (ASA grades I/II). Mean (SD) body mass 28.0 ± 9.1 kg, and mean age 3.4 ± 2.3 years.MethodsDogs were allocated randomly to receive 15 μg kg^?1 buprenorphine combined with either 30 μg kg^?1 acepromazine (group 1), 62.5 μg m^?2 dexmedetomidine (group 2), or 125 μg m^?2 dexmedetomidine (group 3) intramuscularly. After 30 minutes, anaesthesia was induced using a propofol target controlled infusion. Heart rate, respiratory rate, and oscillometric arterial blood pressure were recorded prior to induction, at endotracheal intubation and at 3 and 5 minutes post-intubation. Induction quality and pre-induction sedation were scored on 4 point scales. Propofol target required for endotracheal intubation was recorded. Data were analysed using Chi-squared tests, Kruskal-Wallis, one way and general linear model anova (p < 0.05).ResultsAge was significantly lower in group 1 (1.0 (1.0–3.8) years) than group 2 (5.0 (2.0–7.0) years), (median, (IQR)). There were no significant differences in sedation or quality of induction between groups. After premedication, heart rate was significantly lower and arterial blood pressures higher in groups 2 and 3 than group 1, but there was no significant difference between groups 2 and 3. Propofol targets were significantly lower in group 3 (1.5 (1.0–2.5) μg mL^?1) than group 1 (2.5 (2.0–3.0) μg mL^?1); no significant differences existed between group 2 (2.0 (1.5–2.5) μg mL^?1) and the other groups (median, (interquartile range)).Conclusions and Clinical relevanceWhen administered with buprenorphine, at these doses, dexmedetomidine had no advantages in terms of sedation and induction quality over acepromazine. Both doses of dexmedetomidine produced characteristic cardiovascular and respiratory effects of a similar magnitude.     

Epidural anesthesia with bupivacaine, bupivacaine and fentanyl, or bupivacaine and sufentanil during intravenous administration of propofol for ovariohysterectomy in dogs

OBJECTIVE: To compare cardiovascular and systemic effects and analgesia during the postoperative period of epidural anesthesia performed with bupivacaine alone or with fentanyl or sufentanil in bitches maintained at a light plane of anesthesia with continuous infusion of propofol. STUDY DESIGN: Prospective randomized masked clinical trial. ANIMALS: 30 female dogs of various breeds. PROCEDURES: Dogs were allocated into 3 groups of 10 each. One group received fentanyl (2 microg/kg [0.91 microg/lb]) and bupivacaine (1 mg/kg [0.45 mg/lb]), 1 group received sufentanil (1 microg/kg) and bupivacaine (1 mg/kg), and 1 group received bupivacaine (1 mg/kg). All dogs received acepromazine (0.1 mg/kg [0.045 mg/lb]) and continuous infusion of propofol for sedation. The agents were administered into the lumbosacral space and diluted in saline (0.9% NaCl) solution to a total volume of 0.36 mL/kg (0.164 mL/lb). Cardiac and respiratory rates, arterial blood pressures, pH, and blood gases were evaluated. Analgesia, sedation level, serum cortisol concentrations, and plasma catecholamine concentrations were measured regularly for 6 hours. RESULTS: No important changes in cardiovascular, respiratory, or sedation variables were observed. Degree of analgesia in the postoperative period was higher in the sufentanil group, although use of fentanyl and bupivacaine also resulted in a sufficient level of analgesia. CONCLUSIONS AND CLINICAL RELEVANCE: Use of the 3 anesthetic techniques permitted ovariohysterectomy with sufficient analgesia and acceptable neuroendocrine modulation of pain with minimal adverse effects.     

Epidural analgesia and anesthesia.

This review describes the beneficial effects of the use of epidural drugs for pre-emptive analgesia, intraoperative analgesia with an inhalant-sparing effect, and prolonged postoperative analgesia. Epidural morphine oxymorphone, or hydromorphone is recommended for use in small animals in combination with a local anesthetic of appropriate duration for procedures involving the hind end, although epidural morphine or hydromorphone may be more appropriate for procedures on the thorax and forelimbs. Side effects are few and can usually be easily managed, with the benefits outweighing any detrimental effects that might occur.     

Epidural analgesia in the dog and cat

SUMMARY: A brief outline of the history of epidural analgesia is followed by a review of the anatomy of the epidural space with particular reference to epidural block. The technique of epidural injection in the dog is described as are the indications for the technique. These include the provision of anaesthesia for such procedures as orthopaedic surgery of the hind limb and caesarian section. The cardiovascular effects of epidural block are discussed and suggestions are made for the prevention of hypotension. The various drugs and their combinations which may be used for epidural administration are outlined. The commonest used local anaesthetic agents are bupivacaine and lidocaine. Epidural administration of opioid drugs is a relatively new technique which is used to provide intra- and post-operative analgesia. Morphine is the drug of choice for this indication.The use of other classes of drugs, such as the alpha 2 agonists and ketamine, are also considered. A variety of side-effects, contra-indications and complications are described together with methods for reducing their incidence and effects.     

Epidural anesthesia and analgesia in horses.

Intercoccygeal, or caudal, epidural injection of local anesthetics is a convenient method of producing analgesia and local anesthesia of the tail and perineal structures in conscious standing horses. This technique has been further developed to provide long duration analgesia and anesthesia by placement of catheters into the epidural space of horses. More recently, opioid, alpha-2 adrenergic agonists, ketamine and other analgesic agents have been administered by caudal epidural injection, providing pain relief in both conscious, standing and anesthetized, recumbent horses. This chapter describes the development of different anesthetic and analgesic epidural techniques in horses, methods for epidural injection and catheterization, and reviews the current literature related to epidural analgesia and pain control in horses.     

Postoperative urinary retention in a dog following morphine with bupivacaine epidural analgesia.

Urinary retention, overflow incontinence, and subsequent detrusor atony were observed following surgery in which a morphine with bupivacaine epidural injection was used for perioperative analgesia. The premise that the urinary retention may have been due to the effects of the morphine component of the epidural is discussed, along with other possible causes.     

Incisional block with bupivacaine for analgesia after celiotomy in dogs

A blind, placebo-controlled clinical trial was performed to evaluate the postoperative analgesic effect of preoperative infiltration of the incision site with bupivacaine in dogs undergoing celiotomy. Sixty dogs were randomly allocated into four groups: preoperative bupivacaine, postoperative bupivacaine, preoperative saline, and postoperative saline. All dogs were premedicated with acepromazine and meperidine; then they were anesthetized with thiopentone and isoflurane. Each group received either bupivacaine or normal saline before midline incision or just before skin closure. After surgery, pain scores were assigned using a numerical rating scale. Preoperative bupivacaine was associated with significantly lower pain scores and a significantly lower need for opioid administration. The authors conclude that a preoperative incisional block with bupivacaine seems to be a useful adjunct for controlling pain after celiotomy in dogs.     

End tidal halothane concentration and postoperative analgesia requirements in dogs: a comparison between intravenous oxymorphone and epidural bupivacaine alone and in combination with oxymorphone.

The purpose of this study was to compare the effects of epidural bupivacaine (BUP) and oxymorphone/bupivacaine (O/B) and intravenous (i.v.) oxymorphone (IVO) on halothane requirements during hind end surgery and postoperative analgesia in 24 dogs. Dogs were randomly assigned to treatment groups: O/B--oxymorphone (0.1 mg/kg) in 0.75% bupivacaine (1 mg/kg for a total volume of 0.2 ml/kg); BUP--0.5% bupivacaine (1 mg/kg for a total volume of 0.2 ml/kg) with i.v. oxymorphone (0.05 mg/kg) postoperatively; and IVO--oxymorphone (0.05 mg/kg) pre- and postoperatively. Heart rate (HR), respiratory rate, arterial blood pressure, end-tidal carbon dioxide and halothane, and arterial blood gases were recorded prior to treatment and every 15 minutes thereafter. Once surgery had begun, end-tidal halothane concentrations were decreased as low as possible while still maintaining a stable anesthetic plane. Data were analyzed using ANOVA with P < 0.05 considered significant. End-tidal halothane requirements did not differ significantly among treatments. Respiratory depression was increased and HR was decreased in the O/B and IVO groups. Postoperative analgesic requirements were significantly less in dogs receiving O/B.     

Anaesthesia with a combination of ketamine and medetomidine in the rabbit: effect of premedication with buprenorphine

ObjectiveTo assess the effects of premedication with buprenorphine on the characteristics of anaesthesia induced with ketamine/medetomidine.Study designProspective crossover laboratory study.AnimalsSix female New Zealand White rabbits.MethodsRabbits received, on occasions separated by 7 days, either buprenorphine (0.03 mg kg^?1) or saline subcutaneously (SC) as premedication, followed 1 hour later by SC ketamine (15 mg kg^?1) and medetomidine (0.25 mg kg^?1) (K/M). At pre-determined time points reflex responses and cardiopulmonary parameters were recorded and arterial blood samples taken for analysis. Total sleep time was the duration of loss of the righting reflex. Duration of surgical anaesthesia was the time of suppression of the ear pinch and pedal withdrawal reflexes. Wilcoxon signed-ranks tests were used to compare data before (T₀) and 10 minutes after (T₁₀) injection with K/M.ResultsAll animals lost all three reflex responses within 10 minutes of injection of K/M. The duration of loss of these reflexes significantly increased in animals that received buprenorphine. At induction, animals that had received buprenorphine tended to have a lower respiration rate but there were no significant differences in arterial PCO₂, PO₂ or pH between treatments. Hypoxaemia [median PaO₂ < 6.0 kPa (45 mmHg)] developed in both treatments at T₁₀ but there was no significant difference between treatments. Mean arterial pressure (MAP) was lower at T₁₀ in animals that had received buprenorphine.Conclusion and clinical relevancePremedication with buprenorphine significantly increased the duration of anaesthesia induced by K/M, with no significant depression of respiration further to the control treatment within the first 10 minutes of anaesthesia. The MAP decreased but this was not reflected in a difference in other physiological parameters. These data show that premedication with buprenorphine, before K/M anaesthesia in the rabbit, has few negative effects and may provide beneficial analgesia.