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in Journal of the American Veterinary Medical Association

Abstract

Objectives

To establish intracranial pressure (ICP) measurements in healthy cats under isoflurane anesthesia, using a fiberoptic monitoring system; to assess brain lesions associated with such monitoring; and to determine whether decompressive intracranial surgery decreases ICP in healthy cats.

Animals

6 healthy cats.

Procedure

Craniectomy and durotomy were performed, and the effect of these procedures on ICP was determined. ICP was monitored by use of a fiberoptic monitoring system. Gross and microscopic evaluations of brain tissues were performed after data collection.

Results

ICP decreased significantly after craniotomy and durotomy. After wound closure, ICP remained significantly reduced relative to initial pressures. However, postsurgical pressures were significantly increased, compared with those associated with ICP after durotomy. Gross and histologic abnormalities associated with placement of the ICP monitoring cable included mild focal acute hemorrhage and mechanical cortical disruption.

Conclusions

Craniectomy and durotomy significantly decreased ICP in healthy cats. ICP increased after wound closure, but remained significantly lower than initial pressures.

Clinical Relevance

Craniectomy and durotomy may be used to decrease ICP in cats. (Am J Vet Res 1996;57:1659–1661)

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine the minimal ultrasonic aspirator pressure necessary to damage the cerebral cortex of healthy dogs.

Animals—9 mixed-breed dogs.

Procedure—The study comprised 2 parts. In part A, 6 dogs were euthanatized immediately prior to the experiment. In part B, 3 dogs were anesthetized for recording of physiologic variables. In both parts, craniectomy and durotomy were performed to bilaterally expose the lateral aspect of the cerebral cortex. An ultrasonic aspirator was placed in contact with various areas of the cerebral cortex, and aspirator power was altered (10, 20, 30, and 40%). Duration of contact at each power was 5 and 10 seconds. Subsequently, gross morphologic and histologic damage was assessed in the cortex.

Results—Gross observations for all dogs were similar. At 10% power, visible or histologic damage was not evident in the cortex. At 20% power, the cortex was slightly indented from contact with the hand piece; however, cortical disruption was not evident. Cortical disruption was initially detectable at 30% power in some dogs and was consistently evident at 40% power in both sets of dogs.

Conclusions and Clinical Relevance—Ultrasonic aspirator power of < 20% created minimal acute morphologic damage to the cortex. Power settings between 20 and 30% may superficially damage the cerebral cortex in healthy dogs, whereas 40% power consistently damages the cerebral cortex. Knowledge of the degree of damage to cerebral cortex caused by various amounts of power for ultrasonic aspirators will allow surgeons to avoid damaging normal brain tissues during surgery. (Am J Vet Res 2001;62: 248–251)

Full access
in American Journal of Veterinary Research

Objective—

To evaluate chronic obstructive pulmonary disease of horses in Louisiana by assessing the signalment, history, environmental factors, clinical signs, and treatment of such horses.

Design—

Epidemiologic mail survey.

Sample Population—

83 of 240 veterinarians contacted by mail agreed to take part in the survey. Veterinarians contacted were listed as mixed-animal or equine practitioners in the 1991/1992 directory of the Louisiana Veterinary Medical Association or had submitted a specimen from a horse to the Louisiana Veterinary Medical Diagnostic Laboratory within the past 2 years.

Procedure—

The survey contained 47 questions designed to elicit information from owners and veterinarians about horses reported to have chronic obstructive pulmonary disease (COPD). Questions were included to evaluate age, breed, sex, vaccination history, respiratory disease history, environment of primary activity, level of exercise, primary residence (pasture or stall), condition of pasture or barn, type and condition of feed, clinical signs, concurrent conditions, and treatment regimen prescribed. Information from the returned forms was analyzed by using a microcomputer program designed for epidemiologic data.

Results—

Of the 83 veterinarians who agreed to participate, 31 returned 71 completed questionnaires for horses affected with COPD. Most affected horses were mature in age, kept on pasture, and had developed clinical signs during the summer months. The most consistent clinical signs were dry coughing, slight serous nasal discharge, labored expiratory effort, and flaring nostrils.

Clinical Implications—

Summer pasture-associated obstructive pulmonary disease appears to be precipitated by factors different than those associated with the traditionally diagnosed form of COPD and, thus, successful management measures may also vary. (J Am Vet Med Assoc 1996;208:248-251)

Free access
in Journal of the American Veterinary Medical Association

Objective

To determine the prevalence of various clinical signs in dogs with brain tumors.

Design

Retrospective study.

Animals

97 dogs with brain tumors.

Procedure

Medical records were reviewed for signalment, tumor type and location, and clinical signs.

Results

33 breeds were represented; Golden Retrievers were most commonly affected. Most dogs were older (median age, 9 years); 95% of dogs were ≥ 5 years old. Seventy-six percent of dogs had tumors in the supratentorial region. Seizures were the most common clinical sign at initial examination, with lower prevalence for circling, ataxia, and head tilt. Meningioma was the most common tumor.

Conclusions and Clinical Relevance

Brain tumors develop most often in dogs ≥ 5 years old and are uncommon in dogs < 5 years old. Seizures are a common clinical sign, and a brain tumor should be considered in dogs that have their first seizure after they are 4 years old. (J Am Vet Med Assoc 1999;215:818–819)

Free access
in Journal of the American Veterinary Medical Association

SUMMARY

During 2 separate studies, intracranial pressure (icp) was measured in 13 healthy dogs (group A, n = 7; group B, n = 6), using a fiberoptic monitoring system implanted surgically in the right superficial cerebral cortex. Average icp was measured for 15 minutes after a 15-minute post-implantation period of equilibration. Intracranial pressure was measured in group-A dogs at 2.0 and 1.3% end-tidal isoflurane concentrations. Mean ± 1 sd icp in group-A dogs at 2.0 and 1.3% end-tidal isoflurane concentrations was 11 ± 2 and 11 ± 3 mm of Hg, respectively. Dogs of group A were euthanatized immediately after measurements were obtained. Mean icp ± 1 sd in group-B dogs was 11 ± 3 mm of Hg. After monitoring, but prior to euthanasia, group-B dogs underwent callosotomy, and were maintained for 30 days after surgery. The brain was removed from all dogs, formalin fixed, and examined grossly and microscopically for lesions associated with fiberoptic cable implantation. Variable degrees of hemorrhage and mechanical brain damage were seen focally around the catheter site in all brains from group-A dogs, especially when the cable entered through a sulcus. In 1 dog, local vacuolation was seen in the brain immediately adjacent to the tract associated with implantation of the fiberoptic catheter. In all other dogs, the additional cortex was histologically normal. Histologic lesions associated with cable implantation were not observed in group-B dogs.

Free access
in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association

Abstract

Objective

To determine the effect of craniectomy and durotomy on intracranial pressure (ICP) in clinically normal dogs.

Design

Two-part study (experiments A and B) involving craniectomy and durotomy, with and without treatments to lower ICP.

Animals

Six (experiment A) and 7 (experiment B) healthy dogs.

Procedure

In experiment A, craniectomy was performed in combination with durotomy, diuretic administration, methylprednisolone sodium succinate administration, and hyperventilation, and effect of these manipulations on ICP was determined. In experiment B, dogs had only craniectomy and durotomy without associated ICP-lowering treatments. During both experiments, ICP was monitored throughout the surgical procedure with a fiber optic ICP monitoring device.

Results

Intracranial pressure decreased after the combination of craniectomy, durotomy, and other ICP-lowering treatments in dogs of experiment A. Similar magnitude of decrease in ICP was observed in dogs of experiment B after craniectomy and durotomy.

Conclusions

Comparison of these experiments indicate that surgical removal of overlying skull and incision of the dura mater can significantly decrease ICP in clinically normal dogs.

Clinical Relevance

Craniectomy and durotomy may be useful as an adjunct treatment for increased ICP. (Am J Vet Res 1996;57:116-119)

Free access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To compare serum cardiac troponin I (cTnI) concentrations between sea otters with and without cardiomyopathy and describe 2 cases of cardiomyopathy with different etiologies.

ANIMALS

25 free-ranging southern sea otters (Enhydra lutris nereis) with (n = 14; cases) and without (11; controls) cardiomyopathy and 17 healthy managed southern sea otters from aquariums or rehabilitation centers (controls).

PROCEDURES

Serum cTnI concentration was measured in live sea otters. Histopathologic and gross necropsy findings were used to classify cardiomyopathy status in free-ranging otters; physical examination and echocardiography were used to assess health status of managed otters. Two otters received extensive medical evaluations under managed care, including diagnostic imaging, serial cTnI concentration measurement, and necropsy.

RESULTS

A significant difference in cTnI concentrations was observed between cases and both control groups, with median values of 0.279 ng/mL for cases and < 0.006 ng/mL for free-ranging and managed controls. A cutoff value of ≥ 0.037 ng/mL yielded respective sensitivity and specificity estimates for detection of cardiomyopathy of 64.3% and 90.9% for free-ranging cases versus free-ranging controls and 64.3% and 94.1% for free-ranging cases versus managed controls.

CONCLUSIONS AND CLINICAL RELEVANCE

Cardiomyopathy is a common cause of sea otter death that has been associated with domoic acid exposure and protozoal infection. Antemortem diagnostic tests are needed to identify cardiac damage. Results suggested that serum cTnI concentration has promise as a biomarker for detection of cardiomyopathy in sea otters. Serial cTnI concentration measurements and diagnostic imaging are recommended to improve heart disease diagnosis in managed care settings.

Full access
in American Journal of Veterinary Research