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Objective: To compare motor effects and analgesic efficacy following an ultrasound-guided lateral approach to lumbar plexus blockade at L7 and sciatic nerve blockade (LPSNB) against epidural injection in dogs undergoing tibial plateau leveling osteotomy (TPLO)., Study Design: Prospective, randomized, blinded clinical trial., Animals: A total of 27 healthy adult dogs undergoing unilateral TPLO surgery., Methods: Dogs were allocated to either LPSNB (bupivacaine 2 mg kg -1 , 0.75%) or epidural (morphine PF 0.1 mg kg -1 and bupivacaine 0.5 mg kg -1 , 0.75%). Other aspects of clinical management were identical, including anesthetic drug protocol, area of presurgical clipping and bladder care. Time to perform the block, response to surgical stimuli, pain scores, rescue analgesia, time to stand and walk, motor score and time to first urination were recorded. One evaluator, unaware of treatment status, performed all evaluations. Student's t-test or Mann-Whitney U test was used to compare continuous variables between groups, and Fisher's exact test for categorical variables., Results: Median (range) times to stand and walk were shorter for LPSNB [60 (40-120) minutes and 90 (60-150) minutes, respectively, p = 0.003] than for epidural [150 (120-240) minutes and 180 (120-360) minutes, respectively, p = 0.006]. Four dogs required rescue intraoperatively (three in epidural group, one in LPSNB group, p = 0.438). Pain scores over the 24 hour evaluation period were similar, and not significantly different, for each group. Time to spontaneous urination [LPSNB, 330 (240-360) minutes; epidural, 300 (120-1440) minutes, p = 1.0] did not differ between groups., Conclusions and Clinical Relevance: An ultrasound-guided lateral paravertebral approach to the lumbar plexus within the psoas compartment at L7, combined with sciatic nerve blockade, allows faster return to normal motor function, with similar pain control and impact on urination when compared with epidural in dogs after TPLO surgery., (Copyright © 2023 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: To test the influence of increasing injectate volumes on the regional effects of xylazine and morphine epidural analgesia, with the hypothesis that increasing volume produces more cranial spread of analgesia as determined by thermal threshold (TT) testing., Animals: 6 university-owned research/teaching horses (2 mares, 4 geldings) deemed healthy on physical examination and basic lameness evaluation, aged 6-19 years and weighing 420-560 kg, were used in this prospective, randomized, blinded, cross-over experimental study., Methods: After routine placement of a caudal epidural catheter, all animals were subsequently instrumented with a TT testing system at the withers (Location A), the cranial (Location B), and caudal (Location C) abdominal area, over the tuber coxae (Location D), and the hind limb dorsal pasterns (Location E). All horses underwent five testing cycles with 0.2 mg/kg morphine and 0.2 mg/kg xylazine diluted to 20, 35, 50, 75, and 100 mL. TT testing was performed at 2, 4, 6, 8, and 10 hours by blinded investigators., Results: With increased epidural volume, significantly greater cranial spread of analgesic effect was noted. All epidural volumes caused significant changes in TT testing at location E but only the largest volume resulted in a significant TT testing change at location A., Clinical Relevance: Volume influences the regional effects of caudal epidural analgesia in horses but might affect analgesic reliability.

Background: Epidural analgesia using the alpha-2 agonist detomidine (DE), alone or in combination with lidocaine (LD), is frequently employed for standing surgical procedures in horses, but its use has not been evaluated in donkeys., Methods: In a randomised controlled prospective trial, 24 healthy adult donkeys were assigned to four groups (n = 6), each receiving 40 μg/kg of DE, 0.22 mg/kg of LD, combined DE and LD (DELD) or 0.9% sterile normal saline epidurally. After epidural injection of each treatment, the onset, degree and duration of sedation and anatomical extension of anti-nociception were observed., Results: DE and DELD treatments resulted in complete bilateral analgesia with loss of sensation in the tail, perineum, inguinal area, chest and the caudal aspect of the upper pelvic limb, and extended distally to the dorsal metatarsal area. DE and DELD resulted in a significantly (p < 0.05) longer duration of anti-nociception (110 ± 15.4 min and 141.6 ± 14.7 min, respectively) than LD (75.8 ± 4.9 min). The DELD duration of sedation was significantly (p < 0.05) longer than the DE duration (118.3 ± 19.4 min and 108.3 ± 7.5 min, respectively)., Limitation: The current study's main limitation is using only one dose of DE., Conclusion: DE and DELD produced a very effective, safe and acceptable sedative and analgesic effect in the perineal and inguinal regions of donkeys., (© 2022 British Veterinary Association.)

Objective: To test whether the use of low-dose epidural anesthesia (EA) in goats undergoing lower urinary tract surgery reduces the requirements of perioperative analgesics, contributes to intraoperative hypotension, and improves postoperative comfort during the first 24 hours after surgery., Animals: Retrospective analysis of 38 goats between January 2019 and July 2022., Procedures: Goats were divided into 2 groups (EA or no EA). Demographic characteristics, surgical procedure, time of anesthesia, and anesthetic agents used were compared between treatment groups. Outcome variables potentially related to the use of EA included dose of inhalational anesthetics, incidence of hypotension (mean arterial pressure < 60 mm Hg), intraoperative and postoperative administration of morphine, and time to first meal after surgery., Results: EA (n = 21) consisted of bupivacaine or ropivacaine 0.1% to 0.2% with an opioid. There were no differences between groups except for age (EA group was younger). Less inhalational anesthetic (P = .03) and less intraoperative morphine (P = .008) were used in the EA group. The incidence of hypotension was 52% for EA and 58% for no EA (P = .691). Administration of postoperative morphine was not different between groups (EA, 67%, and no EA, 53%; P = .686). Time to first meal was 7.5 hours (3 to 18 hours) for EA and 11 hours (2 to 24 hours) for no EA (P = .057)., Clinical Relevance: Low-dose EA reduced the use of intraoperative anesthetics/analgesics in goats undergoing lower urinary tract surgery without an increased incidence of hypotension. Postoperative morphine administration was not reduced.

The purpose of this study was to assess perioperative analgesia provided by the combination of epidural dexmedetomidine and morphine in bitches undergoing elective ovariohysterectomy. Twenty-four bitches were included in the study and allocated into 3 groups: GM, morphine 0.1 mg/kg; GD, dexmedetomidine 2 µg/kg; and GDM, dexmedetomidine and morphine at the same doses. All solutions were diluted in saline to a total of 0.36 mL/kg. Heart rate (HR), respiratory rate (FR) and systolic blood pressure (SAP) were recorded prior to epidural analgesia (TB), immediately following epidural analgesia (TEA), at surgical incision (TSI), at the first ovarian pedicle clamping (TOP1), at the second pedicle clamping (TOP2), at uterine stump clamping (TUC), at the start of abdominal cavity closure (TSC) and at the end of skin closure (TEC). Rescue analgesia with fentanyl was administered at 2 µg/kg IV if nociception corresponding to a 20% increase of any cardiorespiratory variables was noted. Postoperative pain assessment was performed using a modified composite Glasgow pain scale along the first 6 hours following the end of surgery. Numeric data were compared using ANOVA for repeated measures followed by Tukey test and ovarian ligament relaxation was analyzed using chi-square test under 5% significance. No differences were found on FR among times or groups, although HR showed significant differences between GM and GD at TSI, TOP1, TOP2, TSC and TEC and between GM and GDM at TEA and TSI (significantly lower HR values recorded in dexmedetomidine groups). Differences among time points were found on HR between TB and TEA in GD and on PAS between TOP1 and TSC in GM and between TOP1 and TUC in GDM (P < .05). Ovarian ligament relaxation was significantly more present in groups using dexmedetomidine, although the number of rescue analgesia administrations did not differ among groups. Kaplan-Meyer analysis failed to show significant differences on time of rescue analgesia administration among groups (P > .05). In conclusion, the combination of epidural dexmedetomidine and morphine is a more interesting choice for elective ovariohysterectomy in bitches for producing analgesia comparable to that of each drug alone, with noticeable relaxation of ovarian ligaments and lesser cardiovascular consequences., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objective: To compare the antinociceptive effects of morphine administered via cervical epidural catheter to intravenously administered morphine using a thermal threshold (TT) testing model in healthy adult horses., Study Design: Prospective, randomized, blinded experimental study., Animals: A total of six university-owned adult horses., Methods: Horses were instrumented with a cervical (C1-C2) epidural catheter and TT testing device with probes at withers and thoracic limb coronary bands. All horses underwent three TT testing cycles including cervical epidural morphine administration (treatment EpiM; 0.1 mg kg -1 ), systemic morphine administration (treatment SystM; 0.1 mg kg -1 ) and no morphine administration (treatment Control). Baseline TT was established prior to treatments, and TT was tested at 15, 30, 60, 90, 120, 150, 180, 240, 300, 360, 420, 480, 600 and 720 minutes following treatment. Horses underwent a 5 day washout period between treatments and the order of treatment was randomized. Differences between treatments were analyzed with repeated measures anova., Results: Systemic and epidural morphine administration resulted in significantly higher TT values compared with baseline and control treatment. The duration of effect was significantly longer in treatment EpiM (10-12 hours) than in treatment SystM (1.5-2.0 hours). Horses in treatment EpiM had significantly higher TT values at time points 180-600 minutes (withers) and 300-600 minutes (coronary band) than horses in treatment SystM., Conclusions and Clinical Relevance: Cervical epidural administration of morphine provided antinociceptive effects as measured by increased TT for 10-12 hours compared with 1.5-2.0 hours for intravenously administered morphine. No complications or adverse effects were noticed following epidural placement of a C1-C2 catheter and administration of morphine. The use of a cervical epidural catheter can be considered for analgesia administration in treatment of thoracic limb and cervical pain in the horse., (Copyright © 2022 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Aim: The current study aimed to evaluate the antinociceptive effect of lidocaine, tramadol, and their combination for lumbosacral epidural analgesia in rabbits undergoing knee surgery., Materials and Methods: This study was performed on 24 male New Zealand white rabbits weighing 2.8 to 3.0 kg and was allocated into three groups. All groups were anaesthetized by intramuscular (IM) injection of 35 mg/kg ketamine and 5 mg/kg xylazine, 0.1 mg/kg butorphanol. Rabbits in Group A received epidural analgesia of 4 mg/kg lidocaine 2%; Group B rabbits received epidural analgesia of 4 mg/kg tramadol 5%, and Group C rabbits received epidural analgesia of a combination of 4 mg/kg lidocaine and 4 mg/kg tramadol. Prior to and during surgery, the following parameters were recorded in a regular pre-set time interval: onset time of analgesia (OT), duration of flaccid paralysis (DFP), duration of analgesia (DA), onset and duration of sensory blockade, onset and duration of motor blockade, heart rate (HR), respiratory rate (RR), and rectal temperature (RT)., Results: The mean OT demonstrated a significant decrease (P < 0.05) in Group C (46.5 ± 1.4 sec) compared to Group A and B (61.0 ± 2.4 and 54.5 ± 3.5 sec), respectively. DFP was significantly lower (P < 0.05) in Group C (35.5 ± 2.9 min) than in Group A and B (17.6 ± 1.4 and 21.8 ± 3.6), respectively. DA showed a significant increase (P < 0.05) in group C (45.8 ± 3.3 min) compared to groups A and B, respectively (23.3 ± 1.1 and 31.5 ± 2.3). Heart rate, RR, and RT significantly decreased in Group C compared to the other groups., Conclusion: According to the current study findings, lumbosacral epidural administration of lidocaine combined with tramadol could be a better choice for potentiating the analgesia than administration of either drug separately and may be safely used in rabbits undergoing knee surgery., (© 2022. The Author(s).)

Objective: To assess the effect of continuous wound infusion (CWI) with preperitoneal ropivacaine on postoperative analgesia and compare it with the epidural administration of ropivacaine and morphine in bitches undergoing ovariohysterectomy., Study Design: A parallel, randomized, clinical, prospective and nonblinded study., Animals: A group of 38 Greyhound bitches., Methods: In the catheter group (CathG), CWI with ropivacaine 1% (1 mg kg -1  + 0.8 mg kg -1 hour -1 ) was applied to the preperitoneal space over the surgical incision. In the epidural group (EpiG), ropivacaine 0.5% (1.3 mg kg -1 ) and morphine (0.1 mg kg -1 ) were epidurally administered. Occipital-coccygeal length was used to calculate the volume for the epidural. Pain was scored using a dynamic interactive visual analogue scale (DIVAS) and Glasgow composite measure pain scale-short form (CMPS-SF) before anaesthesia and at 2, 4, 6, 18, 21 and 24 hours after extubation. Incisional sensitivity using a dynamometer (MWTs-incision) was evaluated simultaneously. Plasma ropivacaine and cortisol concentrations, degree of sedation, motor blockade and response to interdigital clamping were measured or assessed. A two-way mixed analysis of variance and a Mann-Whitney U test were used to analyse data; p < 0.05., Results: No differences were detected in the DIVAS (p = 0.301), CMPS-SF (p = 0.600) scores, MWTs-incision measurements (p = 0.257) and cortisol values (p = 0.878) between the groups. Rescue analgesia was required in two dogs, one in each group, at 2 hours. Sedation, motor blockade and negative response to interdigital clamping were detected in EpiG at 2, 4 and 6 hours. Mean plasma ropivacaine values were higher in CathG (0.475 ± 0.164 ng mL -1 ) than in EpiG (0.184 ± 0.213 ng mL -1 ; p = 0.001)., Conclusion and Clinical Relevance: Compared with epidural ropivacaine and morphine, CWI with preperitoneal ropivacaine is an effective analgesic technique for postoperative pain management in bitches undergoing ovariohysterectomy without motor blockade., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: We evaluated the use of lumbosacral epidural anaesthesia (LEA) in dogs undergoing caesarean section over 10 years., Methods: Anaesthetic records were reviewed and divided into two treatment groups: LEA and control. Outcome variables identified a priori as potentially affected by LEA were compared between groups. Results are frequency or median (minimum-maximum)., Results: Ninety-five dogs received LEA and 87 did not. LEA consisted of 0.2 (0.1-0.3) ml/kg containing bupivacaine (n = 63), ropivacaine (n = 15), or lidocaine (n = 12) at concentrations ranging between 0.06% and 2%. Morphine, fentanyl, or buprenorphine were used as part of LEA. Groups were similar for demographic variables (all p > 0.06). Intravenous opioids were used more often in control than in LEA (p < 0.0005). Incidence of hypotension (MAP < 60 mm Hg) was LEA 68% and control 56% (p = 0.12). Duration of hypotension was longer in LEA (p = 0.03). Use of crystalloids and vasoactive drugs did not differ (all p > 0.1). Time from induction to operating room was 30 (8-75) min for control and 35 (18-65) min for LEA (p = 0.003)., Discussion: LEA during caesarean section in dogs was associated with lower rates of opioid administration and did not exacerbate the incidence of hypotension., (© 2021 British Veterinary Association.)

Background: The effects of epidural anesthesia in dogs undergoing cystoscopy are unknown., Objective: To investigate the effect of epidural analgesia on postcystoscopy pain in dogs., Animals: Twenty-six dogs undergoing routine cystoscopy for lower urinary tract disease., Methods: Prospective, randomized, blinded observational study. Dogs were assigned either to a treatment group that received epidural anesthesia (preservative free morphine sulfate, 0.09 mg/kg; 1% ropivacaine, 0.2 mg/kg; total volume delivered, 1 mL/4.5 kg of body weight to a maximum of 10 mL; n = 9) or to a nonepidural control group (n = 13). Vital signs were monitored for 24 hours, and sedation and pain scores, behavioral assessments, and presence or absence of complications was evaluated for 5 days postprocedure., Results: All dogs tolerated the epidural without complications. Four dogs were removed from the study because of status unblinding, lack of patient cooperation, or incomplete follow-up. No significant differences were noted in postprocedural pain scores in dogs that received epidural analgesia. Significant differences in postprocedural pain scores were noted in the nonepidural control group. No significant differences were noted in vital signs, behavioral assessments, or the proportion of dogs with a 50% increase in pain scores between the epidural and nonepidural groups., Conclusions and Clinical Importance: Epidural anesthesia was well-tolerated. Dogs not receiving the epidural had poor postprocedural pain control. A consistent benefit for the epidural vs nonepidural group could not be identified. Additional studies are required to better assess the impact and efficacy of epidural anesthesia for cystoscopic procedures., (© 2021 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC. on behalf of the American College of Veterinary Internal Medicine.)

The objective of the study was to compare the effects of caudal epidural bupivacaine and dexmedetomidine (DEX) combination, with bupivacaine or DEX plain for perineal analgesia in mares. Six healthy saddle mares weighing 330-370 kg and aged 10-15 years were used in this study. Each mare was assigned to receive three treatments: 0.04 mg/kg 0.25% bupivacaine (BP), 2 μg/kg DEX (DX), or 0.02 mg/kg bupivacaine and 1 μg/kg DEX (BPDX). The order of treatments was randomized. All drugs were injected into the caudal epidural space (Co1-Co2) through a 16-G Tuohy epidural needle. After the epidural injections, heart rate, respiratory rate, arterial blood pressures (systolic, diastolic, and mean), and rectal temperature were measured at 5, 10, 15, 30, 60, 90, and 120 minutes, and after this time, every 60 minutes until the end of the experiments. A subjective score system was used to assess analgesia, behavioral and motor blockade at the same time points. The BPDX treatment produced analgesic action with twice the duration (200 minutes) of the BP treatment (97 minutes), but with an analgesic duration shorter than the DX treatment (240 minutes) in the regions of the tail, perineum, and upper hind limbs in mares. All treatments showed mild motor blockade. No behavioral changes were observed in any of the animals. There was hemodynamic stability without significant changes in respiratory rate for all treatments. Epidural analgesia using DEX alone or the combination of DEX and bupivacaine may be an option for painful obstetric and gynecological procedures in mares., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: To investigate the efficacy and safety of the caudal epidural technique in cats with urethral obstruction (UO)., Design: Prospective, double-blinded, randomized, sham-controlled study., Animals: Eighty-eight male cats with UO., Interventions: Thirty cats randomized to bupivacaine epidural (BUP), 28 cats to bupivacaine-morphine epidural (BUP/MOR), and 30 cats to sham epidural (SHAM)., Measurements and Main Results: Time to perform the epidural and efficacy of the epidural was assessed by evaluation of tail and perineal responses. The amount of propofol for urinary catheterization and time to administration of rescue analgesia (buprenorphine) was recorded. Cats were monitored for epidural complications. The median time to perform the epidural was 2 min (range, 0.2-13 min and range, 0.5-13 min), with an epidural success rate of 70%. The median amount of propofol administered for urinary catheterization was significantly less in the BUP (2.1 mg/kg; range, 0-7.5 mg/kg) and MOR/BUP cats (1.85 mg/kg; range, 0-8.6 mg/kg) as compared to SHAM cats (4 mg/kg; range, 0-12.7 mg/kg) (P = 0.006, P = 0.0008, respectively). The median time to administration of rescue analgesia was also significantly longer in the BUP (10 h; range, 2-32 h) and MOR/BUP cats (10 h; range, 4-45 h) as compared to SHAM cats (4 h; range, 2-36 h) (P = 0.0026, P = 0.0004, respectively). There were no recognized complications related to the epidural., Conclusion: Caudal epidural appears to be safe, may reduce the amount of IV anesthesia needed to facilitate urinary catheterization, and can be used to provide long-term analgesia in the hospital., (© Veterinary Emergency and Critical Care Society 2020.)

Objective: To investigate the analgesic effect of epidural morphine after surgical extrahepatic portosystemic shunt (EHPSS) attenuation., Study Design: Randomized clinical trial., Animals: A total of 20 dogs with a congenital EHPSS., Methods: Dogs were randomly allocated to be given either a single epidural dose of 0.2 mg kg -1 preservative-free morphine (group M) or not (group C) before surgery. All dogs were administered 0.3 mg kg -1 methadone intravenously (IV) as preanaesthetic medication. Pain scores were determined every 2 hours for the first 24 hours postoperatively using the short-form Glasgow Composite Measure Pain Scale (GCMPS-SF). Dogs with a GCMPS-SF pain score >4/20 or >5/24 received 0.1 mg kg -1 methadone IV as rescue analgesia and were reassessed 30 minutes later. If more than three doses of methadone were administered in a 2 hour period, alternative pain relief was provided and a treatment failure recorded. The GCMPS-SF pain scores and number of rescue analgesia injections were analysed over 24 hours. The last observation carried forward method was applied in case of treatment failure. Food consumption and time to first urination were recorded. Data were analysed using a Mann-Whitney U test and presented as median (minimum-maximum range), with significance set at p < 0.05., Results: Group M showed lower GCMPS-SF pain scores [15 (11-41) versus 31 (11-86); p = 0.023] and lower postoperative methadone requirements [0 (0-0.2) versus 0.25 (0-0.5) mg kg -1 ; p = 0.029] than group C. There were three treatment failures in group C only. Food consumption and time to first urination did not differ between groups., Conclusions and Clinical Relevance: Epidural morphine reduced the requirement for postoperative analgesia in this study population., (Copyright © 2019 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: To compare perioperative opioid consumption and duration of hospitalization (DOH) in anesthetized dogs receiving opioid-based analgesia (OBA) vs those receiving bupivacaine epidural-based analgesia (EPID) during cystotomy., Study Design: Retrospective cross-sectional study., Animals: Fifty-six client-owned dogs undergoing cystotomy., Methods: Clinical records of dogs undergoing cystotomy between January 2015 and December 2017 were reviewed. Demographic data, duration of anesthesia and surgery, anesthetic management, perioperative opioid consumption expressed in morphine equivalents (ME), perioperative use of adjuvant analgesics, time to first micturition, time to eat, time to ambulate, and DOH were recorded. Opioid consumption and DOH were compared with a Wilcoxon rank-sum test, followed by linear regression analysis as appropriate. Time to first micturition, time to eat, and time to walk unassisted were modeled with Cox-proportional hazard models., Results: Dogs treated with EPID during surgery required 1.5 mg/kg ME less compared with those treated with OBA (P = .04) during surgery. Three of 19 dogs treated with EPID vs 15 of 37 dogs receiving OBA required intraoperative adjuvant analgesics (P = .06). Dogs treated with EPID regained motor function slower than dogs treated with OBA (P = .01); however, there was no difference in time to urinate, time to eat, or DOH between treatments., Conclusion: Perioperative lumbosacral epidural with bupivacaine reduced intraoperative opioid consumption in dogs anesthetized for cystotomy., Clinical Significance: The use of epidural bupivacaine in dogs undergoing cystotomy may reduce intraoperative opioid requirements without affecting return of bladder function or DOH., (© 2019 The American College of Veterinary Surgeons.)

Objective: To determine the influence of epidural detomidine and morphine on serum corticosteroid concentrations and pain-related behavioral responses in mares during and after ovariectomy via colpotomy., Study Design: Blinded prospective study., Animals: Nine university-owned mares., Methods: Five of 9 horses received caudal epidural detomidine hydrochloride (0.01 mg/kg) and morphine sulfate (0.1 mg/kg) prior to surgery. All horses received local anesthetic around the ovarian pedicle, 0.02 mg/kg butorphanol IV at the start of the procedure and after first ovary removal, were sedated as required throughout the procedure, and were monitored for leg lifting, grunting, and abdominal tensing. Horses were monitored hourly for pain postoperatively. Heart rate was recorded every 4 hours, and photographs were taken to assess pain according to the horse grimace scale (HGS). Control group horses (n = 4) were treated with butorphanol (0.02 mg/kg IV) every 4 hours for 24 hours postoperatively. All horses received oral phenylbutazone 18 hours postoperatively. Serum cortisol was measured prior to the procedure, after first and second ovary removal, and 8 and 24 hours postoperatively., Results: No differences were detected between horses receiving caudal epidural detomidine and morphine and those that received systemic opioids. A decrease in HGS score occurred after phenylbutazone administration., Conclusion: Administration of caudal epidural detomidine and morphine resulted in similar pain-related behavior and corticosteroid concentrations as did administration of systemic butorphanol every 4 hours for 24 hours postoperatively., Clinical Significance: Caudal epidural detomidine and morphine may mitigate the requirement for frequent systemic opioid administration after a potentially painful procedure., (© 2018 The American College of Veterinary Surgeons.)

This study compared the efficacy of intravenous (IV) fentanyl and ketamine with lumbosacral epidural lidocaine in dogs undergoing ovariohysterectomy. Dogs with esophageal Doppler monitoring ( n = 112) were included in this retrospective study. All dogs were premedicated with dexmedetomidine and methadone, induced with IV propofol or alfaxalone and maintained using isoflurane and IV fentanyl, IV ketamine, or epidural lidocaine. Heart rate (HR), mean arterial pressure (MAP), expired fraction of isoflurane (ETIso), stroke distance (SD), minute distance (MD), peak velocity (PV) and mean acceleration (MA) were recorded before and after ligation of the ovarian pedicle (OvP). There were no differences for ETIso, HR, and MAP among fentanyl, ketamine, and control groups. Minute Distance, SD, MA and PV significantly decreased after OvP in fentanyl, ketamine, and control groups, but remained stable in the epidural group. Lumbosacral epidural lidocaine prevented hemodynamic depression changes caused by OvP ligation, whereas fentanyl and ketamine failed to do so., Competing Interests: The authors have no conflicts of interest to report.

In this study, comparative antinociceptive and sedative effects of epidural administration of romifidine and detomidine in buffalo were evaluated. Eighteen healthy adult buffalo, allocated randomly in three groups (two experimental and one control; n=6) received either 50 μg/kg of romifidine or detomidine diluted in sterile saline (0.9 per cent) to a final volume of 20 ml, or an equivalent volume of sterile saline epidurally. Antinociception, sedation and ataxia parameters were recorded immediately after drug administration. Epidural romifidine and detomidine produced mild to deep sedation and complete antinociception of the perineum, inguinal area and flank, and extended distally to the coronary band of the hindlimbs and cranially to the chest area. Times to onset of antinociception and sedation were significantly shorter with romifidine than with detomidine. The antinociceptive and sedative effects were significantly longer with romifidine than with detomidine. Romifidine or detomidine could be used to provide a reliable, long-lasting and cost-effective method for achieving epidural anaesthesia for standing surgical procedures in buffalo. Romifidine induces a longer antinociceptive effect and a more rapid onset than detomidine. Consequently, epidural romifidine may offer better therapeutic benefits in the management of acute postoperative pain., (British Veterinary Association.)

Five healthy beagle dogs anesthetized with isoflurane were administered medetomidine (α-2 adrenoceptor agonist) by the epidural route. Mean arterial pressure (MAP) and end-tidal concentration of isoflurane (ISO) were measured 1, 2.5, and 4 h after administration. Epidural administration of medetomidine reduced the isoflurane dose required to prevent changes in vital parameters following mechanical stimulation and maintained the MAP at a higher level compared to the control.

Purpose:: To evaluate the postoperative analgesic and adverse effects of three doses of dexamethasone, administered epidurally in combination with lignocaine, in dogs undergoing ovariohysterectomy (OVH)., Methods:: Twenty-four female dogs undergoing ovariohysterectomy were pre-medicated with acepromazine and general anaesthesia was induced and maintained with propofol. Animals were randomly allocated into four groups of six. The control group was given lignocaine 2% (LI) and the treatment groups were given lignocaine with either 2 mg dexamethasone (LIDEX2), 4 mg dexamethasone (LIDEX4) or 8 mg dexamethasone (LIDEX8) administered at the lumbosacral epidural space. Duration of postoperative analgesia, first analgesic rescue, motor blockade, heart rate, blood pressure, respiratory rate, and rectal temperature were evaluated., Results:: The duration of postoperative analgesia was 19.5 (SD 6) hours for LIDEX8 (p=0.001), 10 (SD 2) hours for LIDEX4 (p=0.002), 4 (SD 2) hours for LIDEX2 (p=0.074) treatments compared with values for the LI control treatment 2.2 (SD 1.6) hours. All treatments had significant cardiovascular and respiratory alterations but they were within acceptable range in these clinically healthy female dogs., Conclusion:: Dexamethasone added to epidural lignocaine significantly extends the postoperative analgesia after ovariohysterectomy in female dogs.

Objective: To evaluate the efficacy, in terms of the amount of rescue analgesia required, and the clinical usefulness of epidural injection of morphine with bupivacaine or levobupivacaine for elective pelvic limb surgery in dogs during a 24-hour perioperative period., Study Design: Prospective, blinded, randomized clinical study., Animals: A group of 26 dogs weighing 31.7 ± 14.2 (mean ± standard deviation) kg and aged 54 ± 36 months., Methods: All dogs were premedicated with methadone intravenously (0.2 mg kg -1 ) and anaesthesia induced with diazepam (0.2 mg kg -1 ) and propofol intravenously to effect. After induction of anaesthesia, dogs randomly received a lumbosacral epidural injection of morphine 0.1 mg kg -1 with either levobupivacaine 0.5% (1 mg kg -1 ; group LevoBM) or bupivacaine 0.5% (1 mg kg -1 ; group BM). Cardiovascular, respiratory and temperature values were recorded during the intra- and postoperative period. A visual analogue scale, subjective pain scale, sedation scale and the short form of the Glasgow pain scale were assessed every 6 hours after epidural injection during 24 hours. The ability to stand and walk, neurological deficits and other side effects were assessed at the same time points. The amount of rescue analgesia (sufentanil intraoperatively and methadone postoperatively) was recorded., Results: No statistically significant differences were found between groups for any of the recorded data, with the exception of the incidence of spontaneous urination and postoperative rescue analgesia requirement. In group LevoBM four dogs spontaneously urinated at recovery while none of the dogs in group BM did (p = 0.03) and seven dogs of group LevoBM required postoperative rescue analgesia versus none of the dogs in the BM group (p = 0.005)., Conclusions: and clinical relevance Epidural LevoBM is a suitable alternative to BM in healthy dogs during elective pelvic limb surgery. Epidural BM produced more urinary retention but better pain control compared to the same concentration and dose of LevoBM in dogs., (Copyright © 2017 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Six healthy, female, mixed-breed 18-24-month-old sheep weighing 30-48 kg were submitted to lumbosacral epidural bupivacaine in combination with either methadone or fentanyl. Epidural catheters were placed in six sheep that were given three treatments: (Bup) bupivacaine (0.5 mg/kg) alone; (BupMet) bupivacaine (0.25 mg/kg) plus methadone (0.3 mg/kg); and (BupFent) bupivacaine (0.25 mg/kg) plus fentanyl (0.002 mg/kg). Haemodynamic variables, respiratory rate, rectal temperature, analgesia by applying a standard painful stimulus, motor block and sedative scores were compared among the three treatments. These parameters were determined before epidural administration and at 5, 10, 20, 30, 60, 90, 120 minutes after treatment administration, and then every 60 minutes thereafter until the end of analgesic effect. Parametrical data were analysed by proc glimmix (SAS) for repeated measures on time and means tested by ls-means. Non-parametrical data were analysed by Fisher's exact test. Duration of analgesia was longer with BupMet (240 minutes) compared with BupFent (180 minutes; P=0.0127), but BupMet was similar to Bup (240 minutes). Both treatments with opioids produced moderate motor blockade. BupMet and BupFent produced mild sedation. Only treatment with bupivacaine alone induced cardiovascular and respiratory rate changes that stayed within acceptable limits., (British Veterinary Association.)

This is a retrospective study evaluating femoral-sciatic nerve blocks (FSBs), epidural analgesia, and non-regional analgesia (NRA) in dogs undergoing tibia-plateau-leveling-osteotomy surgery. Thirty-five records met the criteria for each of the FSB and epidural analgesia groups. Seventeen anesthesia records met the criteria for the NRA or control group. The parameters reported were: isoflurane vaporizer setting, rescue analgesia/anesthesia drugs received, heart rate, systolic blood pressure, and recovery quality (0-4, with 0 being poor and 4 being good). Rescue analgesia-anesthesia during surgery was performed with either fentanyl, ketamine, or propofol. A larger percentage of dogs in the NRA group required rescue analgesia during surgery. The FSB group had a higher recovery quality with median (95% confidence interval of four (±0.3) when compared to two (±0.8) in NRA (p < 0.01). No difference between groups was observed on any other parameter reported. As part of a multimodal analgesia approach for tibia-plateau-leveling-osteotomy surgery, the use of femoral and sciatic nerves blocks with bupivacaine appears to be an alternative technique to help with analgesia and anesthesia during surgery.

The objective of this study was to evaluate the antinociceptive and sedative effects of epidural administration of romifidine in dairy cattle. Twenty-four dairy cows, divided randomly into four groups (three experimental and one control; n=6) received one of three doses of romifidine (30, 40 or 50 μg/kg) diluted in sterile saline (0.9 per cent) to a final volume of 25 ml or an equivalent volume of sterile saline. Antinociception and its anatomical extent was assessed by applying a standard stimulus (needle pin pricks) in different areas and by applying an electrical stimulus to the flank. The antinociceptive effect of romifidine was produced not only in the tail, anus, perineum, vulva and inguinal area but extended up to the coronary band of the hindlimbs and chest areas. Epidural romifidine induced mild-to-moderate sedation at 30 and 40 μg/kg doses and deep sedation at the 50 μg/kg dose. The antinociceptive and sedative effect was dose-dependent in terms of intensity and duration. Thus, epidural administration of romifidine was effective in providing antinociception and sedation in cattle, and can be used in standing flank and udder surgery in cattle., (British Veterinary Association.)

Objective: The aim of this study was to evaluate the combination of bupivacaine and methadone administered epidurally in sheep., Methods: Six healthy female mixed-breed sheep weighing 35-46 kg and aged 12-18 months were included. Each sheep was assigned to receive three treatments: 0.5 mg/kg 0.25% bupivacaine (BP), 0.3 mg/kg 1% methadone (MT) or 0.25 mg/kg bupivacaine and 0.15 mg/kg methadone (BPMT). All drugs were injected into the lumbosacral space through an epidural catheter. Each animal received each treatment at random. Heart rate, arterial blood pressure (systolic, diastolic and mean), respiratory rate, rectal temperature, analgesia, sedation and motor block were determined before treatment and at predetermined intervals., Results: The duration of analgesia was 240, 220, and 180 min for BP, MT and BPMT, respectively (P < 0.05). Motor block for all agents was mild to moderate. None or the treatments significantly altered the heart rate, blood pressure or respiratory rate., Conclusion: Our findings suggest that lumbosacral epidural administration of bupivacaine, methadone or a combination of the two drugs can provide perioperative analgesia in sheep as part of their management for surgical procedures in the flank and hindlimbs., (© 2015 Australian Veterinary Association.)

Objective: To compare the antinociceptive effects of magnesium sulphate (MgSO(4)) when administered epidurally alone and in combination with morphine., Study Design: Experimental, randomized, 'blinded', crossover study., Animals: Six healthy adult Beagle dogs., Methods: Evaluated treatments were MgSO(4) (2.5 mg kg(-1)) alone (Mg), morphine (0.1 mg kg(-1)) alone (Mo), MgSO(4) in combination with morphine (Mm), and sterile water (0.115 mL kg(-1) ; Co) that were injected in the lumbosacral epidural space using an epidural catheter. Antinociception was measured using the von Frey mechanical threshold device applied to the carpal pads, both sides of the thorax and metatarsi. Measurements were obtained at time points: before treatment (baseline) and 0.5, 1, 2, 4, 6, 12, 18 and 24 hours after the epidural injection. Sedation, behaviour score and presence of motor deficits were assessed. Data were analyzed using a linear mixed model and Bonferroni adjustments, with significance set at p < 0.05., Results: There were significant effects of treatment and time in all regions. Overall threshold values in grammes force [median (interquartile range)] when stimulation regions were combined were significantly higher in Mg [164 (135-200)], Mo [156 (129-195)] and Mm [158 (131-192)] compared to Co [145 (120-179)]. Thresholds were significantly higher compared to Co in Mg, Mo and Mm at the thorax and metatarsi, but only in Mg and Mo at the carpal pads. No motor deficits were observed at any time point. Thresholds (combined regions) were increased from baseline at one or more time points with all treatments, including control., Conclusion and Clinical Relevance: Epidural MgSO(4) produced an antinociceptive effect characterised by an increase in the mechanical thresholds of similar magnitude to that produced by epidural morphine, compared with the control group, without causing any motor deficits. No potentiation of morphine antinociception was observed. The onset and offset times of antinociception could not be clearly established. To what extent these results can be extrapolated to clinical cases requires further investigation., (© 2014 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.)

Aims: The objective of this study was to describe the use of indwelling epidural catheters post-operatively in dogs in a home environment, and to report associated complications., Methods: Dogs undergoing surgical procedures of the hind limb (n=83) were included in the study and were administered 0.05 or 0.10 mg/kg epidural morphine via an indwelling epidural catheter every 6 hours. Data compiled relating to catheter placement included time of placement, ease of placement and problems encountered, number of attempts of placement, and individual placing the catheter. A client questionnaire was provided to evaluate side effects, complications, pain, and ease of use of the epidural catheter system after discharge from the hospital and catheter removal at home. Side effects were compared between the dogs receiving 0.05 or 0.1 mg/kg epidural morphine., Results: The most common patient complication was abnormal urination patterns (32/82, 39%); specifically dribbling urine where laying, emptying the entire bladder where laying, not urinating for extended periods of time, and taking a longer time to pass urine were reported. There were no significant differences in the number or types of side effects reported in either dosing group. The most common technical issues reported by owners were difficulty getting the needle into the injection port (10/81, 12%) and removing the adhesive covering keeping the epidural catheter system in place (19/78, 24%). There were no reports of inflammation or discharge at the catheter site in any of the dogs. Of the respondents surveyed, 76/79 (97%) found the epidural catheter system easy to use at home in the post-operative period., Conclusions: Indwelling epidural catheters are a feasible method of administration of post-operative analgesia in the immediate post-operative period in the home environment and were associated with only a few minor complications in this population.

Objective: To compare anti-nociceptive and sedative effects of tramadol, a combination of tramadol-lidocaine, and lidocaine alone for perineal analgesia in donkeys., Study Design: Experimental 'blinded' randomized cross-over study., Animals: Six healthy adult donkeys., Methods: Treatments were tramadol (TR) (1.0 mg kg(-1) ), tramadol-lidocaine (TRLD) (0.5 and 0.2 mg kg(-1) respectively) and lidocaine (LD) (0.4 mg kg(-1) ) given into the epidural space. The volume of all treatments was 0.02 mL kg(-1) . Nociception was tested at the perineal region by pin prick, followed, if no reaction, by pressure from a haemostat clamp. Times to onset, degree and duration of anti-nociception of the perineal region were recorded. Response was tested immediately after drug administration and at: 2, 5, 10, 15, 30, 45, and 60 minutes post-administration and then at 30 minute intervals thereafter until a response re-occurred. Physiologic data and degree of sedation and ataxia were recorded pre-administration and at intervals for 240 minutes post-administration. Results were analyzed using anova, Kruskal-Wallis tests, and Wilks' Lambda test as relevant. Significance was taken as p < 0.05., Results: Times (minutes, mean ± SD) to onset and duration of anti-nociception, respectively were; TR 13 ± 1.6 and 220 ± 4.6; TRLD 6 ± 0.8 and 180 ± 8.5; LD 4 ± 1.4 and 75 ± 4. Onset and duration times were significantly longer with TR than the other two treatments. TR never produced complete anti-nociception, whereas the TRLD and LD induced complete anti-nociceptive effects. Duration was significantly longer with TRLD than with LD alone. Epidural injections of TR and TRLD induced mild sedation., Conclusions and Clinical Relevance: Epidural combination of TRLD produced an anti-nociceptive effect in the perineum, which was rapid in onset and had a longer duration of action than LD alone. An epidural single dose of TRLD combination would appear to provide an acceptable analgesic effect in the perineal region of donkeys., (© 2014 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.)

Objective: To evaluate the postoperative analgesic effects of epidural administration of morphine and neostigmine, either alone or in combination, in dogs., Animals: 30 dogs undergoing orthopedic surgery on a pelvic limb., Procedures: Anesthetic protocols were standardized. At the end of surgery, 10 dogs each received 1 of 3 epidural treatments: morphine (0.1 mg/kg), neostigmine (5 μg/kg), or morphine plus neostigmine (0.1 mg/kg and 5 μg/kg, respectively). Postoperative pain scores and the need for rescue analgesia were evaluated for 24 hours., Results: Pain scores were higher in the neostigmine group, compared with scores for the morphine-neostigmine group, at 2 and 24 hours after surgery and higher in the morphine group than in the morphine-neostigmine group at 2 and 4 hours. During 24 hours, rescue analgesia was provided for 4, 7, and 2 of 10 dogs each in the morphine, neostigmine, and morphine-neostigmine groups, respectively. The number of dogs given rescue analgesia was significantly different among groups at 2, 3, 4, and 6 hours after surgery. Dogs in the morphine and morphine-neostigmine groups had a lower probability of receiving rescue analgesia within 24 hours than did dogs in the neostigmine group., Conclusions and Clinical Relevance: When administered epidurally, morphine alone or in combination with neostigmine provided effective postoperative analgesia in most dogs after orthopedic surgery, whereas neostigmine alone did not. Findings for this study suggested a potential role for neostigmine as an adjuvant for epidural analgesia in dogs undergoing orthopedic surgeries on the pelvic limbs.

Objective: To determine whether epidural administration of opioids was associated with clinically important urinary retention in dogs undergoing elective orthopedic procedures., Design: Retrospective cohort study., Animals: 179 client-owned dogs undergoing elective surgery for cranial cruciate ligament rupture., Procedures: Medical records of 179 dogs that underwent surgical correction for cranial cruciate rupture between January 2009 and October 2012 were reviewed; 120 received epidural administration of opioids and 59 did not. Signalment, type of procedure, administration of epidural analgesia, time to first postanesthetic urination, and number of urinations during the first 24 hours were evaluated and compared between groups., Results: Administration of preservative-free morphine into the epidural space was not significantly associated with time to first urination following anesthetic recovery or the total number of urinations within the first 24 hours of anesthetic recovery. Administration of a hydromorphone bolus IV following surgery was significantly associated with urinary retention, compared with administration of either morphine boluses or fentanyl constant rate infusions following surgery. No other variables were significantly associated with urinary retention., Conclusions and Clinical Relevance: Administration of preservative-free morphine into the epidural space was not associated with clinically important urinary retention in dogs undergoing elective orthopedic procedures. Systemic administration of opioids may be associated with urinary retention.

Objective: To evaluate the analgesic and physiological effects of epidural morphine administered at the sixth and seventh lumbar or the fifth and sixth thoracic vertebrae in dogs undergoing thoracotomy., Study Design: Prospective, randomized, blinded trial., Animals: Fourteen mixed-breed dogs, weighing 8.6 ± 1.4 kg., Methods: The animals received acepromazine (0.1 mg kg⁻¹) IM and anesthesia was induced with propofol (4 mg kg)⁻¹ IV. The lumbosacral space was punctured and an epidural catheter was inserted up to the region between the sixth and seventh lumbar vertebrae (L, n = 6) or up to the fifth or sixth intercostal space (T, n = 8). The dogs were allowed to recover and after radiographic confirmation of correct catheter position, anesthesia was reinduced with propofol IV and maintained with 1.7% isoflurane. Following stabilization of monitored parameters, animals received morphine (0.1 mg kg⁻¹) diluted in 0.9% NaCl to a final volume of 0.25 mL kg⁻¹ via the epidural catheter, and after 40 minutes, thoracotomy was initiated. Heart rate and rhythm, systolic, mean and diastolic arterial pressures, respiratory rate, arterial hemoglobin oxygen saturation, partial pressure of expired CO₂ and body temperature were measured immediately before the epidural administration of morphine (0 minute) and every 10 minutes during the anesthetic period. The Melbourne pain scale and the visual analog scale were used to assess postoperative pain. The evaluation began 3 hours after the epidural administration of morphine and occurred each hour until rescue analgesia., Results: There were no important variations in the physiological parameters during the anesthetic period. The post-operative analgesic period differed between the groups, being longer in T (9.9 01.6 hours) compared with L (5.8 ± 0.8 hours)., Conclusions: The use of morphine, at a volume of 0.25 mL kg 0.1, administered epidurally over the thoracic vertebrae provided longer lasting analgesia than when deposited over the lumbar vertebrae.

This study was performed to investigate the analgesic effect of lidocaine and a combination of lidocaine and ketamine following epidural administration in dromedary camels. Ten 12-18-month-old camels were randomly divided into two equal groups. In group L, the animals received 2% lidocaine (0.22 mg/kg) and in group LK the animals received a mixture of 10% ketamine (1 mg/kg) and 2% lidocaine (0.22 mg/kg) administered into the first intercoccygeal (Co1-Co2) epidural space while standing. Onset time and duration of caudal analgesia, sedation level and ataxia were recorded after drug administration. Data were analysed by U Mann-Whitney tests and significance was taken as p &lt; 0.05. The results showed that epidural lidocaine and co-administration of lidocaine and ketamine produced complete analgesia in the tail, anus and perineum. Epidural administration of the lidocaine-ketamine mixture resulted in mild to moderate sedation, whilst the animals that received epidural lidocaine alone were alert and nervous during the study. Ataxia was observed in all test subjects and was slightly more severe in camels that received the lidocaine-ketamine mixture. It was concluded that epidural administration of lidocaine plus ketamine resulted in longer caudal analgesia in standing conscious dromedary camels compared with the effect of administering lidocaine alone.

Purpose: To measure the change in the minimum alveolar concentration of isoflurane (EtISO) associated with epidural nalbuphine and the postoperative analgesic requirements in dogs after ovariohysterectomy., Methods: Twenty four healthy female dogs were randomly assigned to receive saline or nalbuphine at 0.3 or 0.6 mg/kg (n=8 for each group) administered via lumbosacral epidural catheter introduced cranially into the epidural canal. Changes in heart and respiratory rates and arterial blood pressure during surgery were recorded along with the corresponding EtISO. Immediately after tracheal extubation, analgesia, sedation, heart rate, respiratory rate, and arterial blood pressure were measured at predetermined intervals and every 60 min thereafter until the first rescue analgesic., Results: A significant decrease in EtISO was associated with epidural nalbuphine at 0.3 mg/kg (26.3%) and 0.6 mg/kg (38.4%) but not with saline in ovariohysterectomized dogs. In the postoperative period, VAS and Colorado analgesic scores were lower for the dogs that received the higher nalbuphine dose, which only required supplemental analgesia 10 h following its administration, compared with dogs that received the lower dose., Conclusion: Epidural nalbuphine significantly reduces the intra-operative isoflurane requirement and provides prolonged postoperative analgesia after ovariohysterectomy in dogs.

The objectives of this study were to determine the analgesic and motor effects of a high-volume intercoccygeal epidural injection of bupivacaine at 2 concentrations in cows. A prospective, randomized, blinded, crossover trial was conducted on 6 adult cows. An indwelling epidural catheter was placed in the first intercoccygeal space and advanced 10 cm cranially. All the cows received 3 treatments with a washout period of 48 h: saline (control), 0.125% bupivacaine (high dose), or 0.0625% bupivacaine (low dose), at a final volume of 0.15 mL per kilogram of body weight, infused manually into the epidural space over a period of 15 min. The anal and tail tone and motor deficits of the pelvic limbs were evaluated in 5 of the cows with use of a numerical rating scale and a visual analogue scale (VAS). Sensory block was assessed in 4 of the cows by the response to needle pricks in different regions with the use of a VAS. Measurements were obtained before and at different time points after injection, up to 360 min. Analysis of variance for repeated measures and post-hoc Tukey's and Dunnett's tests were used. Differences were considered significant when the P-value was ≤ 0.05. One cow became recumbent 6 h after injection. Anal and tail tones were significantly decreased and motor deficits of the pelvic limbs were significantly increased after bupivacaine treatment compared with control treatment. The overall mean VASpain scores ± standard deviation were 66 ± 8 after control treatment, 52 ± 5 after low-dose bupivacaine treatment, and 43 ± 5 after high-dose bupivacaine treatment. The pain scores were significantly lower in caudal regions up to the saphenous nerve after high-dose bupivacaine treatment compared with control treatment and significantly lower in the anus, vulva, and tail after low-dose bupivacaine treatment compared with control treatment. Thus, analgesia with moderate motor deficits of the pelvic limbs may be obtained with 0.125% bupivacaine administered epidurally.

Objective: To compare the analgesic efficacy of bupivacaine, bupivacaine + morphine, or bupivacaine + dexmedetomidine administered epidurally in dogs undergoing pelvic limb orthopedic surgery., Study Design: Prospective, randomized, double blinded clinical trial., Animals: Sixty dogs weighing (mean ± SD) 35 ± 15.7 kg, aged 5 ± 3 years., Methods: Dogs were assigned to receive a lumbosacral epidural containing bupivacaine (B) 0.5%, 1 mg kg(-1) ; B, bupivacaine 0.5%, 1 mg kg(-1)  + morphine 1%, 0.1 mg kg(-1) ; B + M, or bupivacaine 0.5%, 1 mg kg(-1)  + dexmedetomidine 0.05%, 4 μg kg(-1) ; B + D. The anesthetic protocol was standardized. The median expired isoflurane concentration (E'Iso) and requirement for additional induction agent preventing purposeful movement were recorded. Pain was scored using visual analog (VAS) and modified University of Melbourne (UMPS) pain scales. Sedation was assessed using a 0-4 scale. All parameters were recorded preoperatively, and at extubation (t = 0), then at 1, 2, 4, 8, 12, 16, and 20-24 hours. Hydromorphone was administered postoperatively to patients with a VAS ≥ 35 and/or UMPS ≥ 9. Time to first voluntary urination and first motor activity were recorded., Results: Postoperatively, B + D had a lower UMPS pain score than B at t = 1 hour (p = 0.013), but not compared to B + M. The B + D group had a shorter time to urination (p = 0.0131) and a longer time for return of motor function (p = 0.0068). There were no other differences between the treatments., Conclusion and Clinical Relevance: Epidurally administered B, B + M, or B + D in dogs all provided acceptable analgesia to manage post-operative orthopedic pelvic limb pain. Epidural administration of B + D is an effective alternative to the analgesia provided by B or B + M, but is associated with increased time to return of motor function. The direct neurotoxic effects of epidural dexmedetomidine have not been fully tested., (© 2013 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.)

Objective: To evaluate the anti-nociceptive effects of lidocaine, lidocaine-bupivacaine combination or bupivacaine following caudal epidural administration in cows undergoing reproductive procedures., Study Design: Blinded, randomized experimental study., Animals: Thirty seven healthy Holstein cows (mean weight ± SD, 633 ± 41 kg)., Methods: Animals were allocated randomly to receive one of four treatments: group LID, 0.2 mg kg(-1) lidocaine 2%; group LID-BUP, lidocaine-bupivacaine mixture in a 1:1 volume ratio (0.1 mg kg(-1) and 0.025 mg kg(-1), respectively); group BUP-LD, 0.05 mg kg(-1) bupivacaine 0.5%; and group BUP-HD, 0.06 mg kg(-1) bupivacaine 0.5%. The onset and duration of perineal anti-nociception were determined using superficial and deep pin pricks and the number of cows with complete perineal anti-nociception was recorded. Parameters were compared using anova followed by Duncan's test where relevant., Results: Mean ± SD time to onset of anti-nociception following epidural administration of BUP-LD was significantly longer than for LID-BUP (p < 0.05). The duration (in minutes) of perineal anti-nociception was significantly longer following epidural administration of BUP-HD (247 ± 31) versus LID-BUP (181 ± 33) and LID (127 ± 25) minutes respectively. The % of cows with complete anti-nociception was increased in the group treated with BUP-HD compared to BUP-LD. Severe ataxia or recumbency did not occur in any groups., Conclusions and Clinical Relevance: Epidurally administered bupivacaine, at a dose of 0.06 mg kg(-1), may provide satisfactory caudal epidural anti-nociception for longer-duration obstetric and surgical procedures., (© 2012 The Authors. Veterinary Anaesthesia and Analgesia. © 2012 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.)

Objective: To evaluate efficacy of a topical epidural analgesia used alone, or in combination with hydromorphone, against a standard pain protocol for the 48 hours immediately after hemilaminectomy., Study Design: Randomized, blinded, controlled, clinical trial., Animals: Dogs (n = 30) with thoracolumbar intervertebral disc disease treated with hemilaminectomy., Methods: Dogs were randomly divided into 3 groups: group 1 received intermittent hydromorphone postoperatively, group 2 received a topical epidural of preservative-free morphine and dexmedetomidine administered via gel foam, group 3 received both forms of analgesia. All dogs were monitored and assessed for pain for 48 hours immediately postoperatively. Data were analyzed using MANOVA and Wilcoxon Rank Sum Tests., Results: There was a significant temporal difference in treatment groups 1 and 3 when using a 0-10 pain scale (MANOVA, P = .02). There was also a significant difference at the 48th hour postoperatively between groups 1 and 3 (Wilcoxon Rank Sum Test)., Conclusion: Topical epidural of preservative-free morphine and dexmedetomidine administered via gelfoam is not sufficient analgesia alone post hemilaminectomy but in conjunction with other opioid administration may lead to superior pain relief., (© Copyright 2012 by The American College of Veterinary Surgeons.)

Aim: To compare the effect of a single epidural injection of either lignocaine or tramadol on behavioural changes, anaesthetic indices, leucocyte parameters, erythrocyte sedimentation rates and concentration of cortisol in plasma in goats subjected to castration by high tension band., Methods: Ten male goats weighing 14.4 (SD 0.7) kg were randomly allocated to anaesthesia with epidural injections of tramadol (3 mg/kg), or lignocaine (4 mg/kg). Following anaesthesia, a rubber ring was applied and tensioned to the scrotal neck of each goat. Behavioural changes were noted as they occurred, and the onset of drug action (time between epidural injection and loss of pedal reflex) and duration of antinociception (time interval between disappearance and reappearance of pedal withdrawal reflex) were determined. Hearts rates, respiratory rates and rectal temperatures were determined every 15 minutes for a 90-minute period, while blood was obtained for determination of white cell counts, erythrocyte sedimentation rates and concentrations of cortisol. Anaesthetic indices were compared using Student's t-test, while physiological parameters were compared using an ANOVA for repeated measurements., Results: Goats treated with epidural tramadol were not recumbent and continued rumination while goats treated with epidural lignocaine were recumbent and did not continue rumination. The onset of analgesia was longer (p=0.01) in goats treated with epidural tramadol (5.0 minutes; SD 1.2) than goats treated with epidural lignocaine (3.0 minutes; SD 1.1), while duration of analgesia was shorter (p=0.003) in goats treated with epidural tramadol (47.2 minutes; SD 13.1) than goats treated with epidural lignocaine (89.8 minutes; SD 23.1). There was no significant difference in heart rates, respiratory rates and erythrocyte sedimentation rates, while the concentration of cortisol in plasma differed (p<0.05) between goats treated with epidural tramadol and lignocaine., Conclusions: Epidural lignocaine injection produced longer duration of antinociception with lower frequency of pain-associated behavioural changes; while treatment with epidural tramadol injection allowed the goats to continue grazing once the rubber ring has been applied., Clinical Relevance: Epidural tramadol produced partial pain relief, while epidural lignocaine injection provided the most effective pain control. However, epidural tramadol has an advantage over epidural lignocaine in conditions such as perineal surgery and caesarian section in cattle and where the ability of the animal to maintain standing is desired.

The purpose of this study was to compare four epidural protocols for peri-operative analgesia in dogs undergoing tibial plateau levelling osteotomy. Forty client-owned dogs were randomly assigned to one of four treatments - groups R0.5 and R1 received 0.5mg/kg and 1mg/kg ropivacaine, respectively. Group SR0.5 received 1 μg/kg sufentanil plus 0.5mg/kg ropivacaine, and group SER0.5 received 1 μg/kg sufentanil, 0.5mg/kg ropivacaine plus 6 μg/kg epinephrine. Dilution, when required, was performed with saline, so that the injected volume was always 0.2 mL/kg. Intra-operatively, nociception assessment was based on the evaluation of changes in heart rate, respiratory rate and mean arterial pressure. Post-operative pain assessment was performed using the Glasgow visual analogue pain scale, and an ad hoc multifactorial pain score. Motor block was evaluated using a modified Bromage score. Intra-operatively, none of the animals was hypotensive. All groups except SER0.5 required rescue intra-operative fentanyl (40%, 30% and 40% of the animals in groups R0.5, R1 and SR0.5, respectively). Group SER0.5 showed lower post-operative pain scores, and group R1 significantly greater motor block, compared to the other treatment groups. None of the dogs had urinary retention. Epidural sufentanil-epinephrine-ropivacaine provided superior peri-operative analgesia compared to the other treatments, without producing clinically relevant side effects., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Objective: To describe a technique for insertion of a thoracic epidural catheter., Study Design: Clinical report., Animals: Dogs (n = 3) undergoing thoracic wall resection and thoracotomy., Methods: A paramedian approach with cephalic angulation was used to place a 24-g epidural catheter in 3 dogs. Dogs 1 and 2 had left caudal thoracic wall resection and dog 3 had left thoracotomy. In dog 1, the epidural catheter was inserted at L2-L3 intervertebral space and the tip of the catheter advanced to the level of T13 vertebral body. In dog 2, the epidural catheter was inserted at T12-T13 intervertebral space and the tip of the catheter was advanced to the level of T8 vertebral body. In dog 3, the epidural catheter was inserted at T13-L1 intervertebral space and its tip advanced until reaching the vertebral body of T10. All dogs were administered a combination of bupivacaine and morphine through the epidural catheter to provide intra- and postoperative analgesia., Results: The peridural space was identified and the tip of the catheter was positioned where intended in all dogs. Dog 1 developed transient Horner's syndrome and dog 3 required intraoperative fentanyl during the first part of the procedure., Conclusion: Paramedian approach with cephalad angulation is a suitable technique to place thoracic epidural catheters in dogs., (© Copyright 2012 by The American College of Veterinary Surgeons.)

Although preventive epidural morphine administration with bupivacaine is effective in producing long-lasting analgesia, neuraxial anaesthesia can cause cardiovascular depression and pruritus. This report presents the development and treatment of hypotension and pruritus after intrathecal morphine and bupivacaine administration in a 3-year-old female spayed Domestic Short-hair cat presented for surgical repair of a torn right cranial cruciate ligament. Opioid-induced pruritus is not usually considered a frequently occurring complication, but may be easily misinterpreted as being dysphoria in recovery. It can be treated by administration of ondansetron, with human patients usually responding within 30 min after treatment., (© 2012 The Author. Australian Veterinary Journal © 2012 Australian Veterinary Association.)

Objective: To evaluate perineal analgesic effects of 3 doses of neostigmine coadministered epidurally with lidocaine to geldings., Animals: 6 healthy geldings., Procedures: A few days before each treatment, a catheter was inserted between the first and second coccygeal vertebrae via the caudal approach in each gelding; the catheter tip was threaded approximately 10 cm cranial into the midsacral region. Each horse received 4 epidural treatments: 2% lidocaine (0.2 mg/kg) alone and 3 doses of neostigmine (0.5, 1, or 2 μg/kg) coadministered with that same dose of lidocaine. Horses were restrained in stocks in a standing position. Heart rate, blood pressure, respiratory rate, rectal temperature, intestinal motility, analgesia, behavior, and ataxia were determined before treatment (time 0; baseline); at 5, 10, 15, 30, 45, 60, 75, and 90 minutes; and every 30 minutes thereafter until the cessation of analgesia., Results: All doses of neostigmine coadministered with lidocaine improved and extended the duration of analgesia in the perineal region of the geldings. Total duration of analgesia was not a dose-dependent effect (120, 150, and 150 minutes for 0.5, 1, and 2 μg/kg, respectively). All treatments induced mild or moderate ataxia. Cardiovascular changes were within acceptable limits., Conclusions and Clinical Relevance: Administration of neostigmine (1 μg/kg) combined with lidocaine (0.2 mg/kg) in the caudal epidural space induced analgesia for 2.5 hours with a low prevalence of adverse effects in standing conscious geldings. Epidural doses of neostigmine greater than these should be avoided because they may cause undesirable effects in geldings.