Effect of 5% transdermal lidocaine patches on postoperative analgesia in dogs undergoing hemilaminectomy.

OBJECTIVES: To investigate the effect of 5% lidocaine patches on postoperative analgesia in dogs undergoing hemilaminectomy. MATERIALS AND METHODS: Client-owned dogs undergoing hemilaminectomy for a single acute intervertebral thoracolumbar disc extrusion were enrolled in this prospective, randomised, blinded clinical trial. Following methadone administration, anaesthesia was induced with propofol, and maintained with isoflurane in oxygen and fentanyl infusion, in both groups. After skin closure, two 1∙5 cm wide 5% lidocaine patch strips were attached along both sides of the wound in dogs allocated to Group L. In Group C, the two lidocaine patch strips were applied but the transparent isolating liner was not removed. Postoperatively, all dogs received a non-steroidal anti-inflammatory drug, gabapentin and diazepam. Methadone was administered according to the short form of Glasgow Composite Pain Scale with pain assessed every 2 hours for 48 hours by observers unaware of the treatment. RESULTS: Thirty-nine dogs completed the study. Demographic data, end-expiratory fraction of isoflurane, fentanyl consumption, anaesthesia and surgical times were similar between groups. The number of dogs requiring postoperative methadone and the number of doses of methadone administered were not different between groups. No macroscopic skin reaction was noticed once the patches were removed. CLINICAL SIGNIFICANCE: In this setting, 5% lidocaine patches did not provide additional postoperative analgesia in dogs undergoing hemilaminectomy.

Parasagittal fractures of the proximal phalanx in Thoroughbred racehorses in the UK: Outcome of repaired fractures in 113 cases (2007-2011).

BACKGROUND: Thirty years have elapsed since the last published review of outcome following fracture of the proximal phalanx in Thoroughbred racehorses in the UK and contemporary results are needed to be able to advise of expected outcome. OBJECTIVES: Collect and analyse outcome data following repair of fractures of the proximal phalanx in Thoroughbred racehorses in the UK. STUDY DESIGN: Retrospective case series. METHODS: Case records of all Thoroughbred racehorses admitted to Newmarket Equine Hospital for evaluation of a parasagittal fracture of the proximal phalanx during a 5 years period were reviewed. Follow-up data regarding racing careers was collected for horses that underwent repair. Following exclusion of outliers, cases with incomplete data sets and comminuted fractures, mixed effect logistic regression was used to identify variables affecting returning to racing and odds ratios and confidence intervals calculated. RESULTS: Of 113 repaired cases, fracture configurations included short incomplete parasagittal (n = 12), long incomplete parasagittal (n = 86), complete parasagittal (n = 12) and comminuted (n = 3). A total of 54 (48%) cases raced after surgery. Horses that fractured at 2 years of age had increased odds of racing following surgery than those older than 2 years of age (OR 1.34; 95% CI 1.13-1.59, P = 0.002). Horses sustaining short incomplete parasagittal fractures had increased odds of racing following surgery compared with those with complete parasagittal fractures (OR 2.62; 95% CI 1.36-5.07, P = 0.006). No horses with comminuted fractures returned to racing. MAIN LIMITATIONS: Data are relevant only to Thoroughbred racehorses in the UK. CONCLUSIONS: Approximately half of the cases in this series raced following surgical repair. More 2-year-old horses raced following surgery, but this likely reflects horses, specifically older horses, passing out of training from unrelated factors. Fracture configuration affects odds of racing, which is relevant to owners when deciding on treatment.

Peri-anaesthetic complications in an equine referral hospital: Risk factors for post anaesthetic colic.

REASONS FOR PERFORMING STUDY: Peri-anaesthetic complications are relatively common in equine patients and further investigations are warranted to identify manageable risk factors. OBJECTIVES: To report morbidity and mortality rates and identify associated risk factors for horses undergoing general anaesthesia, within a predominantly racing Thoroughbred (TB) population. STUDY DESIGN: Single centre retrospective observational study. METHODS: Anaesthetic and case records of all horses ≥12 months old undergoing general anaesthesia at Newmarket Equine Hospital between August 2010 and April 2012 were analysed, excluding emergency abdominal/dystocia procedures or traumatology cases with cardiovascular compromise. Mortality and morbidity rates were calculated and described. Uni- and multivariable analyses were used to investigate the relationship between the principal complication, post anaesthetic colic (PAC) and risk factors. RESULTS: A total of 1067 anaesthetic records of 1021 horses were included in the study; of these, 702 horses (65.8%) were TB, 169 (15.8%) developed a complication within 7 days of general anaesthesia and 10 (0.94%) died as a result. The most prevalent morbidity was PAC, 111 horses (10.5%) developed colic within 7 days of general anaesthesia. Thoroughbred horses (odds ratio [OR] 2.93, 95% confidence interval [CI] 1.73-4.96) and horses receiving sodium benzylpenicillin (NaBP) (OR 2.77, 95% CI 1.69-4.50) were at increased risk of PAC. CONCLUSIONS: Thoroughbred racehorses were identified as at increased risk of PAC in this study and might benefit from more critical evaluation of post anaesthetic gastrointestinal function. An alternative to the administration of NaBP for prophylactic antimicrobial therapy needs to be further investigated if its role in PAC is confirmed by other studies.

Retrospective clinical evaluation of hypobaric spinal anaesthesia in dogs undergoing pelvic limb orthopaedic surgery.

OBJECTIVE: To evaluate intraoperative effects, complications, postoperative rescue analgesia requirement and presence of postoperative unilateral blockade after hypobaric spinal anaesthesia in dogs. METHODS: Retrospective review of case records of dogs that underwent pelvic limb orthopaedic surgery and received hypobaric spinal anaesthesia. Cases that contained complete information on perioperative analgesia, end tidal anaesthetic agent, arterial blood pressure, postoperative urination, motor function and assessment at the sixth week re-examination were selected. RESULTS: Twenty-four of forty-eight records were sufficiently complete to meet the selection criteria. Local anaesthetic dose and volume of the solution administered were 0 · 22 (±0 · 06) mg/kg and 0 · 16 (±0 · 05) mL/kg, respectively. Fentanyl was administered intraoperatively in seven dogs (29%); mean ± sd end-expired isoflurane was 1 · 09 ± 0 · 17%; hypotension was observed in nine dogs (37 · 5%). Unilateral blockade was documented in 18 dogs (75%); 6 dogs (25%) required methadone postoperatively; urinary retention was not observed. One dog developed steroid responsive meningitis arteritis. CLINICAL SIGNIFICANCE: Hypobaric spinal anaesthesia achieved unilateral postoperative pelvic limb motor blockade in dogs, although bilateral block occurred in a proportion of animals; intraoperative hypotension was not infrequent. Fentanyl and postoperative methadone might be required to control nociception and pain, despite technical success in performing spinal anaesthesia.

Retrospective comparison of two peripheral lumbosacral plexus blocks in dogs undergoing pelvic limb orthopaedic surgery.

OBJECTIVES: To compare the lateral pre-iliac approach to the lumbar plexus combined with lumbar paravertebral sciatic nerve block, and the dorsal paravertebral approach to the lumbar plexus combined with sciatic nerve block in dogs. METHODS: Retrospective examination of case records of dogs that received the blocks and underwent pelvic limb orthopaedic surgery between 2010 and 2012. Success rate (intraoperative fentanyl consumption <2·1 µg/kg/hour), type and dose of local anaesthetic used, multiple of minimum alveolar concentration of volatile anaesthetic agent administered, incidence of intraoperative hypotension, postoperative methadone administration, postoperative contralateral limb paralysis and neurological complication at 6 weeks re-examination were analysed. RESULTS: Ninety-six and 95 records were retrieved in which lateral pre-iliac - lumbar paravertebral sciatic nerve and dorsal paravertebral - sciatic nerve were used, respectively. Success rates were 82·3% in lateral pre-iliac - lumbar paravertebral sciatic nerve and 74·7% in dorsal paravertebral - sciatic nerve groups. Bupivacaine, levobupivacaine and ropivacaine were used. Total local anaesthetic doses, intraoperative hypotension and postoperative methadone administered were similar between groups; minimum alveolar concentration multiple was significantly (P<0·001) lower in lateral pre-iliac - lumbar paravertebral sciatic nerve group. No neurological complications were noted. CLINICAL SIGNIFICANCE: Although success rates and perioperative analgesic requirements were not significantly different, the different exposure to anaesthetic agents suggests that the two techniques may not be equivalent.

Peripheral nerve blocks of the pelvic limb in dogs: a retrospective clinical study.

OBJECTIVE: To evaluate the success rate and complications of lumbar plexus (LP) and femoral nerve (FN) blocks, each combined with a sciatic nerve (SN) block, in dogs undergoing pelvic limb orthopaedic surgery. DESIGN: Retrospective clinical study. PROCEDURE: The intra-operative and postoperative clinical records of dogs that underwent orthopaedic surgery of the pelvic limb were reviewed. Dogs were divided into two groups according to the analgesic technique used during surgery: dogs that received a peripheral nerve block (group PNB) and dogs in which opioid analgesia alone was used (group C). RESULTS: The PNB and C groups included 265 and 31 dogs, respectively. Complete statistical analysis was performed in 115/265 dogs of PNB group. The overall success rate of the PNB performed was 77% (89/115): 76% (72/95) and 85% (17/20) for LP-SN and FN-SN blocks, respectively. In group PNB, the prevalence of intra-operative hypotension was 7.8% (9/115). Only one (out of 95 [1.05%]) LP-SN block manifested transient postoperative bilateral pelvic limb paralysis. None of the 265 dogs in group PNB manifested neurological complications at six weeks postoperatively. CONCLUSION: The success rate and the absence of neurological complications obtained support the use of LP-SN and FN-SN for loco-regional anaesthesia and analgesia in dogs undergoing orthopaedic surgery of the pelvic limb.

The effect of omeprazole on oesophageal pH in dogs during anaesthesia.

OBJECTIVES: Intra-operative, gastro-oesophageal reflux may be associated with post-anaesthestic complications such as oesophagitis and oesophageal stricture in dogs. The aim of this study was to investigate the effect of preoperative administration of omeprazole, a proton pump inhibitor, on oesophageal pH in anaesthetised dogs. METHODS: Forty-seven dogs undergoing elective pelvic limb orthopaedic surgery were enrolled into the study. These were randomly allocated to treatment group (n=22) or control group (n=25). The treatment group received one dose of omeprazole (1 mg/kg po) at least 4 h before anaesthesia. All dogs were anaesthetised by the same standardised protocol. A pH probe was inserted into the distal oesophagus after induction of anaesthesia and oesophageal pH was continuously monitored. RESULTS: In the treatment group, four animals (18 per cent) showed a sudden decrease in oesophageal pH (<4). In the control group the same phenomenon was detected in 13 animals (52 per cent). Gastro-oesophageal reflux occurred more frequently in the control group compared with the omeprazole group (odds ratio 4.7, 95 per cent C.I. 1.1 to 24.7, P=0.032). CLINICAL SIGNIFICANCE: This study suggests that the preoperative administration of omeprazole is effective in reducing the incidence of gastro-oesophageal reflux during anaesthesia in dogs.