Antinociceptive, sedative and cardiopulmonary effects of subarachnoid and epidural xylazine-lidocaine in xylazine-sedated calves

ObjectiveTo evaluate the antinociceptive, sedative and cardiopulmonary effects of subarachnoid and epidural administration of xylazine-lidocaine in xylazine-sedated calves.Study designProspective, crossover study.AnimalsSix clinically healthy Holstein calves.MaterialsThe calves were allocated randomly to receive two treatments, subarachnoid or epidural xylazine (0.025 mg kg^?1)–lidocaine (0.1 mg kg^?1) diluted to a total volume of 5 mL with physiological saline. Prior to either epidural or subarachnoid injection, sedation was induced in all calves by intravenous administration of 0.1 mg kg^?1 xylazine. The quality and duration of antinociception and sedation were monitored. Areas of the cranial abdomen, umbilicus, and caudal abdomen were evaluated for antinociception using pinprick tests with a scoring system of 0–3 (0, none; 1, mild; 2, moderate; 3, complete). Sedation was assessed by using a 4-point scale (0, none; 1, mild; 2, moderate; 3, deep). The following cardiopulmonary variables were monitored: heart rate (HR), respiratory rate (f_R), mean arterial pressure (MAP), blood pH, arterial partial pressure of oxygen (PaO₂), partial pressure of carbon dioxide (PaCO₂), bicarbonate (HCO₃), base excess (BE), and oxygen saturation (SaO₂).ResultsXylazine sedation and subarachnoid xylazine-lidocaine resulted in significantly higher nociceptive block than the epidural technique. Moreover, subarachnoid xylazine-lidocaine induced a significantly longer duration of complete antinociception (median [IQR]) in the cranial abdomen (15.0 [15.0–30.0] versus 7.5 [1.3–10.0] minutes; p < 0.05) and umbilicus (45.0 [32.5–57.5] versus 10.0 [6.3–17.5] minutes; p < 0.05) compared with epidural xylazine-lidocaine. There was moderate sedation with both techniques. In both treatments, blood pH, MAP and PaO₂ decreased significantly, and PaCO₂ increased significantly during anaesthesia. No change was evident in HR, f_R, HCO_3, BE, or SaO₂.Conclusion and clinical relevanceThe subarachnoid injection provided better quality and longer duration of antinociception than epidural administration of the same doses of xylazine-lidocaine in xylazine-sedated calves, while cardiopulmonary depressant effects were observed with both regimens.     

Epidural ketamine in the dromedary camel

ObjectiveTo evaluate the clinical and physiological effects of epidural injection of ketamine in camels.Study designRandomized prospective study.AnimalsTen healthy immature male dromedary camels.MethodsKetamine was administered epidurally at doses of 1 and 2 mg kg^?1 (five animals in each treatment). The drug was injected into the first intercoccygeal epidural space. Anti-nociception, sedation, ataxia, and effect on cardiopulmonary, rectal temperature and some selected haematological parameters were recorded at different intervals before (baseline) and after the drug administration. Data were analyzed by anova or U Mann–Whitney tests, as relevant and significance was taken as p < 0.05.ResultsEpidural ketamine at the 2 mg kg^?1 dose produced complete anti-nociception in the tail, anus and perineum, whilst the 1 mg kg^?1 dose produced complete anti-nociception only in the tail. Epidural ketamine resulted in mild to moderate sedation at the 1 mg kg^?1 dose and deep sedation at the 2 mg kg^?1 dose. Ataxia was observed in all test subjects and was severe, resulting in recumbency, in the 2 mg kg^?1 group. Respiratory rate and rectal temperature did not change significantly after injection of either treatment. Following epidural injection of 2 mg kg^?1 of ketamine, heart rate increased significantly from the pre-injection baseline of 55 ± 2 to 76 ± 4 (mean ± SD) beats minute^?1, but after the lower dose changes were not significant. The only significant changes in measured haematologic parameters were decreases in total erythrocyte count at 45 minutes and total leukocyte count from 45–75 minutes, in the 2 mg kg^?1 group.ConclusionEpidural ketamine injection was associated with caudal anti-nociception, sedation and ataxia in the dromedary camels; the intensity and duration of which was dose dependant.Clinical relevanceNeither of the doses of epidural ketamine injection in our study was applicable for standing surgical procedures in dromedary camels.     

不同麻醉方法对胸部手术应激反应的影响

目的:观察不同麻醉方法对胸部手术患者应激激素的影响。方法:42例肺癌手术患者随机分为全麻复合硬膜外腔阻滞(GEA)组和全麻(GA)组,每组21例,分别测定麻醉诱导前、手术2h、术毕、术后1d的血浆去甲肾上腺素、肾上腺素、内皮素、C-反应蛋白、皮质醇的水平。结果:GEA组的血浆去甲肾上腺素、内皮素和血清皮质醇,术中、术后差异无显著性(P>0.05),与GA组比较差异有非常显著性(P<0.01)。两组血浆肾上腺素,术中、术后差异均无显著性(P>0.05)。两组血清C-反应蛋白,术中、术后均显著升高(P<0.01),组间比较差异无显著性。结论:硬膜外腔阻滞可以减轻胸部手术的应激反应。     

SPINAL MAST CELL TUMORS IN DOGS: IMAGING FEATURES AND CLINICAL OUTCOME OF FOUR CASES

Published information regarding canine vertebral column mast cell tumors (MCTs) is limited. The objectives of this study were to report clinical and advanced imaging findings for a group of dogs with confirmed spinal MCT. Inclusion criteria for this retrospective case series were dogs with spinal magnetic resonance imaging (MRI) or computed tomography (CT) scans and a histological diagnosis of spinal MCT. Clinical, imaging, treatment, and outcome data were recorded. Four dogs met inclusion criteria. One dog had primary spinal MCT and three dogs had metastatic spinal MCT. All four dogs presented for paraspinal hyperesthesia and subacute progressive or acute myelopathy. All CT and MRI lesions were extradural. Two cases exhibited distinct masses in the epidural space. In one case, an epidural tumor invaded from the paravertebral musculature. One case exhibited polyostotic lesions indistinguishable from multiple myeloma by MRI. One dog with a primary epidural low‐grade MCT remains clinically normal 4 years postoperatively, following adjunctive lomustine. An epidural high‐grade MCT, metastatic from a cutaneous tumor, recurred within 2 months of surgery despite adjunctive vinblastine. Two high‐grade cases with concurrent visceral involvement were euthanized immediately after imaging. In dogs, MCT should be considered as a differential diagnosis for a progressive painful myelopathy and CT or MRI evidence of an extradural spinal lesion (epidural, paravertebral, or polyostotic). While more often associated with cutaneous or disseminated disease, MCT may also occur as a primary tumor of the epidural space in dogs.     

Comparison of clinical effects of epidural levobupivacaine morphine versus bupivacaine morphine in dogs undergoing elective pelvic limb surgery

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.

Compressive myelopathy caused by epidural haematoma associated with fibrocartilaginous embolism in a horse

Compressive myelopathy caused by an epidural haematoma associated with fibrocartilage embolism was diagnosed in a 2.5‐year‐old Hanoverian gelding. The patient showed severe ataxia with no improvement following medical therapy and a poor prognosis after myelography. An epidural mass located dorsal to the intervertebral disc between C4 and C5 was compressing the spinal cord dorsally to approximately one‐third of its normal height. The epidural tissue was characterised histologically as an organised thrombus, and its major com‐ponents were fibrin and macrophages with intracytoplasmic brown, iron‐rich granules. Positive Alcian blue stain confirmed the presence of cartilage within the thrombus.     

Efficacy of caudal epidural injection of lidocaine,xylazine and xylazine plus hyaluronidase in reducing discomfort produced by electroejaculation in bulls

To test the hypothesis that epidural administration of lidocaine, xylazine or xylazine plus hyaluronidase provides reduced pain and stress during electroejaculation in bulls, eight 30-month-old Nellore bulls received saline solution (control), 2% lidocaine, 2% xylazine or 2% xylazine plus hyaluronidase injected into the first intercoccygeal (Co1–Co2) epidural space in randomized order. Heart rate, respiratory rate, mean arterial pressure, analgesia, animal behavior and motor blockade were evaluated before treatment and at predetermined intervals during and after treatment. Pain and stress were scored subjectively, and semen quality was evaluated. The onset of anesthetic action was significantly faster with lidocaine (3.0 ± 1.2 min) than with xylazine or xylazine plus hyaluronidase (8.9 ± 1.5 and 5.5 ± 2.6 min, P=0.021 and P=0.012, respectively), and the onset of anesthesia with xylazine plus hyaluronidase was significantly faster than that with xylazine alone (P=0.032). Treatment with xylazine or xylazine plus hyaluronidase resulted in less discomfort than treatment with lidocaine, as indicated by animal behavior. Changes in heart rate, respiratory rate and arterial pressure were within acceptable limits. Penile protrusion and semen emission occurred in all animals during all four treatments. Our results suggest that xylazine plus hyaluronidase reduced discomfort during electroejaculation more effectively than xylazine or lidocaine alone. Further experiments are necessary to determine whether electroejaculation with xylazine plus hyaluronidase is feasible for obtaining semen from Nellore bulls unaccustomed to being handled or restrained.     

The volume effect of lidocaine on thoracic epidural anesthesia in conscious Beagle dogs

ObjectiveTo evaluate the volume effect of local anesthetic solution on thoracic epidural analgesia in dogs.Study designProspective, experimental trial.AnimalsFive healthy adult Beagle dogs weighing 9.7 ± 1.3 kg.MethodsA catheter was inserted into the seventh thoracic epidural space using a lumbosacral approach, and secured with suture under total intravenous (IV) anesthesia with propofol. Each dog was administered four volume treatments (0.05, 0.10, 0.15 and 0.20 mL kg⁻¹) of 2% lidocaine via the catheter at 12 hour intervals. In every treatment, dogs were re-anesthetized with propofol (6 mg kg⁻¹, IV) and isoflurane, and received iohexol at each volume to visualize the epidural distribution (ED) through computed tomography. Three hours after epidurography, when dogs had recovered from anesthesia, the appropriate volume of lidocaine was injected through the catheter, and sensory blockade (SB) in dermatomes was evaluated by pinching with a mosquito forceps. Results were presented as median (range), and the volume effect on ED and SB was analyzed with one-way Kruskal–Wallis anova.ResultsIn proportion to volumes (0.05, 0.10, 0.15 and 0.20 mL kg⁻¹), there were significant increases in the extent of ED from 7.4 (5.5–9.0) to 10.4 (8.0–12.0), 13.2 (12.5–13.0), and 15.2 (13.0–18.0) vertebrae, respectively, p < 0.001, and in SB from 2.7 (1.0–5.0) to 6.8 (4.5–10.5), 9.9 (6.5–13.0), and 13.1 (11.0–15.0) dermatomes, respectively, p < 0.001. Unilateral ED and SB were observed in all treatments with various grades, and this distribution was more frequent in the low volume treatments. In the high volume treatments, temporary complications including Horner's syndrome, ataxia, paraplegia, depression, stupor, and intermittent cough occurred often.Conclusions and clinical relevanceThe increase in volume of local anesthetic solution improved SB by resulting in more consistent bilateral dermatome blockade as well as an extended blockade. However, caution should be exerted, as higher volume injections of lidocaine caused side effects in all dogs.     

Epidural spread of iohexol following the use of air or saline in the 'loss of resistance' test

ObjectiveTo compare, using CT epidurography, the cranial distribution of contrast after epidural injection when saline or air is used for the loss of resistance (LOR) technique in identifying the epidural space.Study designProspective, randomized, cross-over experimental study.AnimalsNine healthy adult Beagle dogs.MethodsUnder general anaesthesia, a spinal needle (22-gauge, 70 mm) was inserted through the lumbosacral space, and the position in the epidural space confirmed using the LOR technique employing either 0.3 mL per dog of saline or of air. Epidurography using CT was performed before and 5, 10 and 20 minutes after epidural injection of 0.2 mL kg^?1 of iohexol. The cranial distribution of iohexol was recorded as the number of vertebral segments reached from the seventh lumbar vertebrae.ResultsThe median values in vertebral segments of the cranial distribution at 5, 10 and 20 minutes after epidural injection were 19.5, 20.5 and 21.0 respectively with the saline treatment, and 12.0, 15.0 and 16.0 respectively in the air treatment. At all time points spread of contrast was significantly less with the air treatment. All dogs after air treatment had some air bubbles in the epidural space, and in seven, the spinal cord was moderately compressed by the air. No neurological complications were observed after recovery.Conclusions and clinical relevanceThe use of air for the LOR technique is associated with significantly less spread, uneven cranial distribution of the contrast medium and compression of the spinal cord. It is recommended that saline, and not air, should be used to identify the epidural space by this method.     

Caudal epidural anti‐nociception using lidocaine,bupivacaine or their combination in cows undergoing reproductive procedures

ObjectiveTo evaluate the anti-nociceptive effects of lidocaine, lidocaine-bupivacaine combination or bupivacaine following caudal epidural administration in cows undergoing reproductive procedures.Study designBlinded, randomized experimental study.AnimalsThirty seven healthy Holstein cows (mean weight ± SD, 633 ± 41 kg).MethodsAnimals 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.ResultsMean ± 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 relevanceEpidurally 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.