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fluid therapy and avoid rapid shifts in osmolality, which may result in life-threatening complications such as cerebral edema. 5 – 7 The sodium correction factor describes the expected relationship between plasma sodium and glucose concentrations. In

Open access
in Journal of the American Veterinary Medical Association

functions; therefore, polynomial correction factors are generally recognized as being more accurate. The mean overestimation in the present study was 12.48% and ranged from 5.79% to 29.27%, with the error increasing with increasing filtration function

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether pharmacokinetic analysis of data derived from a single IV dose of iohexol could be used to predict creatinine clearance and evaluate simplified methods for predicting serum clearance of iohexol with data derived from 2 or 3 blood samples in clinically normal foals.

Animals—10 healthy foals.

Procedure—Serum disposition of iohexol and exogenous creatinine clearance was determined simultaneously in each foal (5 males and 5 females). A 3-compartment model of iohexol serum disposition was selected via standard methods. Iohexol clearance calculated from the model was compared with creatinine clearance. Separate limited-sample models were created with various combinations of sample times from the terminal slope of the plasma versus time profile for iohexol. Correction factors were determined for the limited-sample models, and iohexol clearance calculated via each method was compared with exogenous creatinine clearance by use of method comparison techniques.

Results—Mean exogenous creatinine clearance was 2.17 mL/min/kg. The disposition of iohexol was best described by a 3-compartment open model. Mean clearance value for iohexol was 2.15 mL/min/kg and was not significantly different from mean creatinine clearance. A method for predicting serum iohexol clearance based on a 2-sample protocol (3- and 4-hour samples) was developed.

Conclusions and Clinical Relevance—Iohexol clearance can be used to predict exogenous creatinine clearance and can be determined from 2 blood samples taken after IV injection of iohexol. Appropriate correction factors for adult horses and horses with abnormal glomerular filtration rate need to be determined. (Am J Vet Res 2003;64:1486–1490)

Full access
in American Journal of Veterinary Research

Abstract

Objectives—To evaluate computed tomography (CT) densitometry as a technique for quantifying contrast enhancement of compressive soft tissues in the canine lumbosacral vertebral canal and to determine whether the degree of contrast enhancement can be used to help predict tissue type or histopathologic characteristics.

Animals—29 large breed dogs with lumbosacral stenosis.

Procedure—Contrast-enhanced CT of L5-S3 was performed by use of a previously described protocol. At each disk level, CT densities of a water-filled syringe, epaxial muscles, and 4 vertebral canal locations were measured. Mean tissue enhancement was calculated by vertebral canal location, using water-filled syringe enhancement as a correction factor. Corrected CT enhancement was compared with tissue type, degree of tissue inflammation, and degree of tissue activity.

Results—Intravenous contrast administration of contrast medium significantly increased CT densities of water-filled syringes and epaxial muscles. Corrected CT enhancement of vertebral canal soft tissues at stenotic sites was greater than at nonstenotic sites. There was no association between enhancement and tissue type for any vertebral canal location. There was no correlation between enhancement and degree of tissue inflammation. There was a correlation between enhancement and tissue activity in the dorsal vertebral canal only.

Conclusions and Clinical Relevance—A water-filled syringe is a useful calibration tool for CT density measurements. The degree of tissue contrast enhancement, measured by CT densitometry, can be helpful for predicting the location of compressive soft tissues in dogs with lumbosacral stenosis. However, it is of limited value for predicting compressive soft-tissue types or histopathologic characteristics. (Am J Vet Res 2002;63:733–737)

Full access
in American Journal of Veterinary Research

Summary

Cerebrospinal fluid and serum were obtained from 16 clinically normal adult cows (11 dairy, 5 beef). Sodium, potassium, magnesium, total protein, and albumin concentrations, osmolality, and lactate dehydrogenase and creatine kinase activities, were quantified in csf and serum. Total and differential cell counting, protein electrophoresis, and IgG quantification were performed on csf. Statistical analyses of these variables, including mean, sem, range, and 95% confidence intervals, were performed. Effects of blood contamination were evaluated, and were found to be negligible for all measured constituents. Correction factors for csf creatine kinase and lactate dehydrogenase activities accounting for cellular contamination were developed.

Total nucleated cell count was similar to counts in csf of other species, but higher than values in healthy people. Differential leukocyte count in csf was similar to that reported in csf of other domestic animals: mostly lymphocytes, fewer monocytoid cells, and scant neutrophils.

Cerebrospinal fluid protein concentration was higher than concentration reported for dogs, goats, and people, but was similar to values reported for horses. Beef cows had higher csf total protein concentration than did dairy cows; also, beef cows had higher csf γ-globulin concentration.

The concentration of sodium in csf was slightly higher than the value in serum, and potassium concentration was lower than the value in serum. In contrast to studies of human beings, csf osmolality was generally less than serum osmolality in the cows studied. Reference values for csf electrolyte concentrations and osmolality are useful for diagnosis of salt poisoning and for assessment of the effects of fluid therapy. Magnesium concentration was lower in csf, compared with serum. Reference values may be useful for diagnosis of grass tetany.

Glucose concentration in csf was variable, compared with serum concentration; sometimes, it was similar, lower, or even higher than serum glucose concentration. This variation reflects a more complete equilibration of glucose between csf and blood, owing to the lower and more stable blood glucose concentration in cows.

Creatine kinase activity in csf was markedly less than, and was not correlated with, serum creatine kinase activity. Cerebrospinal fluid lactate dehydrogenase activity was markedly lower than serum lactate dehydrogenase activity. Compared with lactate dehydrogenase, creatine kinase activity had a wider range in these healthy cows; therefore, the former enzyme has higher specificity and sensitivity for diagnosis of diseases affecting the cns.

Free access
in American Journal of Veterinary Research

without the application of quantitative correction factors adjusting for the abnormalities of serum protein concentrations that are commonly present in dogs with blastomycosis. 4,5,6 Calcium is present in blood in 3 fractions. Approximately 56% is iCa

Full access
in Journal of the American Veterinary Medical Association

solution from the H50 of the control solution. This difference was divided by the nonsucrose effective osmoles known to be added to each solution (ie, 50mM NaCl = 100 mOsM) to establish a correction factor for the assay by use of the following equation

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in American Journal of Veterinary Research

), concordance coefficient, and accuracy (bias correction factor) calculations revealed consistently higher values for the VAP versus invasive telemetry comparison, compared with the noninvasive oscillometry versus invasive telemetry comparison ( Table 3 ). The

Full access
in American Journal of Veterinary Research

postulate that with a correction factor or appropriate reference range, the infrared thermometer can be used in a clinical setting. Measurements at the eye and perineum were both moderately positively correlated with rectal temperatures and were highly

Full access
in Journal of the American Veterinary Medical Association

, bilirubin, and hemoglobin in the urine. Therefore, the presence of those molecules might necessitate specific correction factors for urine osmolality. Materials and Methods Animals —Dogs evaluated by the internal medicine section at the Louisiana State

Full access
in American Journal of Veterinary Research