Objective—To determine whether blood lactate values determined in dogs with 4 commercially available point-of-care meters were in agreement with values determined with a critical care laboratory blood analyzer.
Animals—50 dogs evaluated for emergency treatment.
Procedures—Blood samples were collected at initial evaluation and processed on 4 point-of-care meters and on a critical care laboratory blood analyzer.
Results—All 4 point-of-care lactate meters generated measurements that were in agreement with the hospital's critical care analyzer. Values for agreement (bias) between the 4 point-of-care meters and the critical care analyzer were −0.652 (limits of agreement [LA], −1.958 to 0.654]), −0.670 (LA, −2.110 to 0.769), −0.096 (LA, −2.071 to 1.879), and −0.498 (LA, −2.616 to 1.620), respectively.
Conclusions and Clinical Relevance—Despite its prognostic and therapeutic relevance, blood lactate measurement in dogs has been hampered by the inability to perform the test in a timely fashion. Results of the present study indicated that several handheld point-of-care lactate meters provided results that were in agreement with a laboratory critical care blood analyzer.
Objective—To compare prothrombin time (PT), activated partial thromboplastin time (APTT), and fibrinogen concentration in canine blood samples collected via an indwelling IV catheter and direct venipuncture.
Animals—35 dogs admitted to an intensive care unit that required placement of an IV catheter for treatment.
Procedures—Blood samples were collected via IV catheter and direct venipuncture at the time of catheter placement and 24 hours after catheter placement. Prothrombin time, APTT, and fibrinogen concentration were measured.
Results—5 dogs were excluded from the study; results were obtained for the remaining 30 dogs. Agreement (bias) for PT was −0.327 seconds (limits of agreement, −1.350 to 0.696 seconds) and 0.003 seconds (limits of agreement, −1.120 to 1.127 seconds) for the 0- and 24-hour time points, respectively. Agreement for APTT was −0.423 seconds (limits of agreement, −3.123 to 2.276 seconds) and 0.677 seconds (limits of agreement, −3.854 to 5.207 seconds) for the 0- and 24-hour time points, respectively. Agreement for fibrinogen concentration was −2.333 mg/dL (limits of agreement, −80.639 to 75.973 mg/dL) and −1.767 mg/dL (limits of agreement, −50.056 to 46.523 mg/dL) for the 0- and 24-hour time points, respectively.
Conclusions and Clinical Relevance—Agreement between the 2 techniques for sample collection was clinically acceptable for PT, APTT, and fibrinogen concentration at time 0 and 24 hours. It is often difficult or undesirable to perform multiple direct venipunctures in critically ill patients. Use of samples collected via an IV catheter to monitor PT and APTT can eliminate additional venous trauma and patient discomfort and reduce the volume of blood collected from these compromised patients.
Objective—To determine the association between urine osmolality and specific gravity (USG) in dogs and to evaluate the effect of commonly measured urine solutes on that association.
Animals—60 dogs evaluated by an internal medicine service.
Procedures—From each dog, urine was obtained by cystocentesis and USG was determined with a refractometer. The sample was divided, and one aliquot was sent to a diagnostic laboratory for urinalysis and the other was frozen at −80°C until osmolality was determined. Urine samples were thawed and osmolality was measured in duplicate with a freezing-point depression osmometer. The correlation between mean urine osmolality and USG was determined; the effect of pH, proteinuria, glucosuria, ketonuria, bilirubinuria, and hemoglobinuria on this relationship was investigated with multiple regression analysis.
Results—The Pearson correlation coefficient between urine osmolality and USG was 0.87. The final multivariable regression model for urine osmolality included USG and the presence of ketones; ketonuria had a small negative association with urine osmolality.
Conclusions and Clinical Relevance—Results indicated a strong linear correlation between osmolality and USG in urine samples obtained from dogs with various pathological conditions, and ketonuria had a small negative effect on that correlation.
Objective—To determine whether there are increased concentrations of 25-hydroxyvitaminn D3 in red-eared slider turtles (Trachemys scripta elegans) after exposure to UV radiation.
Animals—12 yearling turtles recently removed from aestivation.
Procedures—Turtles were randomly allocated to 2 groups (6 turtles/group). An initial blood sample was collected from all turtles for measurement of 25-hydroxyvitamin D3 concentrations. Turtles of 1 group were then provided no supplemental lighting, whereas turtles of the other group were exposed to full-spectrum coil bulbs at a distance of 22.86 cm. The UV-A and UV-B radiation generated by the supplemental lighting was measured by use of a radiometer-photometer at weekly intervals. Measurements were collected 2.54 and 22.86 cm from the bulb surface. The study was continued for a 4-week period. At the end of the study, a second blood sample was collected from all turtles for measurement of 25-hydroxyvitamin D3.
Results—Mean ± SD 25-hydroxyvitamin D3 concentrations differed significantly between turtles provided supplemental UV radiation (71.7 ± 46.9 nmol/L) and those not provided UV radiation (31.4 ± 13.2 nmol/L).
Conclusions and Clinical Relevance—Appropriate husbandry recommendations for raising and maintaining red-eared slider turtles should include use of sunlight that is unobstructed by UV-B filtering material or provision of an artificial source of UV-B radiation.
Objective—To determine whether veterinary-specific oscillometric blood pressure units yield measurements that are in good agreement with directly measured blood pressures in cats.
Animals—21 cats undergoing routine spaying or neutering.
Procedures—A 24-gauge catheter was inserted in a dorsal pedal artery, and systolic, diastolic, and mean arterial pressures were directly measured with a validated pressure measurement system. Values were compared with indirect blood pressure measurements obtained with 3 veterinary-specific oscillometric blood pressure units.
Results—There was poor agreement between indirectly and directly measured blood pressures. For unit 1, bias between indirectly and directly measured values was −14.9 mm Hg (95% limits of agreement [LOA], −52.2 to 22.4 mm Hg), 4.4 mm Hg (95% LOA, −26.0 to 34.8 mm Hg), and −1.3 mm Hg (95% LOA, −26.7 to 24.1 mm Hg) for systolic, diastolic, and mean arterial pressures, respectively. For unit 2, bias was −10.3 mm Hg (95% LOA, −52.9 to 32.2 mm Hg), 13.0 mm Hg (95% LOA, −32.1 to 58.0 mm Hg), and 9.1 mm Hg (95% LOA, −32.9 to 51.2 mm Hg) for systolic, diastolic, and mean arterial pressures, respectively. For unit 3, bias was −13.4 mm Hg (95% LOA, −51.8 to 25.1 mm Hg), 8.0 mm Hg (95% LOA, −25.5 to 41.6 mm Hg), and −3.6 mm Hg (95% LOA, −31.6 to 24.5 mm Hg) for systolic, diastolic, and mean arterial pressures, respectively.
Conclusions and Clinical Relevance—Results suggested that none of the 3 veterinary-specific oscillometric blood pressure units could be recommended for indirect measurement of blood pressure in cats.
OBJECTIVE To examine the effect of 24 hours of refrigeration on urine samples collected from dogs with signs of urinary tract infection (UTI).
DESIGN Prospective cross-sectional study.
ANIMALS 104 dogs with signs consistent with UTI that had a urine sample collected via cystocentesis as part of their diagnostic workup.
PROCEDURES A 1-mL aliquot of each urine sample was refrigerated at 5°C for 24 hours in a plain glass tube, then processed for quantitative bacterial culture (QBC). A 0.5-mL aliquot was added to 3 mL of tryptic soy broth (TSB) and refrigerated at 5°C for 24 hours, then processed for QBC. The remaining portion was immediately processed for QBC, with results reported as numbers of bacterial colony–forming units (CFUs). Sensitivity of the QBC for detection of bacteria (and therefore UTI) was determined for sample refrigeration in the 2 conditions, compared with immediate processing (reference standard).
RESULTS Bacterial growth was identified in 35.6% (n = 37), 33.7% (35), and 31.7% (33) of the immediately processed, refrigerated, and refrigerated-in-TSB urine samples, respectively. Sample refrigeration without TSB resulted in no significant difference in CFU counts relative to immediate processing; however, the sensitivity of this method was 95% (35/37). Sample refrigeration with TSB resulted in significantly lower CFU counts, and sensitivity was only 89% (33/37).
CONCLUSIONS AND CLINICAL RELEVANCE Canine urine samples collected for bacterial culture should be immediately submitted for testing. Although CFU counts for refrigerated and immediately processed samples were statistically similar in this study, sample refrigeration in enrichment broth resulted in imperfect sensitivity for UTI detection and is not recommended.
CASE DESCRIPTION A 9-year-old 8.3-kg (18.3-lb) neutered male Miniature Schnauzer was referred for diagnosis and treatment of a sudden onset of lethargy, anorexia, vomiting, and pallor.
CLINICAL FINDINGS On physical examination, the dog was lethargic with pale mucous membranes and a capillary refill time ≥ 2 seconds. Skin and sclera were mildly icteric. Signs of pain were elicited during abdominal palpation, and an enlarged spleen was noted. Results of agglutination testing and cytologic findings were consistent with immune-mediated hemolytic anemia (IMHA). No contributing factors for development of IMHA were identified.
TREATMENT AND OUTCOME Initial treatment included management with immunosuppressant medications. Three packed RBC transfusions were administered, but clinical signs continued to progress. Therefore, therapeutic plasma exchange (TPE) was performed 5 and 9 days after admission. Following each TPE procedure, the dog had an appreciable clinical improvement and decrease in RBC autoagglutination, and the Hct stabilized. Serum IgG and IgM concentrations were measured during and after both TPE procedures. Despite anticoagulative treatment, the dog developed a thrombus in the splenic vein, necessitating a splenectomy.
CLINICAL RELEVANCE The decrease and rebound in serum IgG and IgM concentrations following TPE provided evidence that TPE may have the same immunomodulatory effects in dogs as have been proposed to occur in people. Further, findings suggested that TPE may be a useful alternative in dogs with refractory IMHA when traditional treatments fail.
Procedures—A blood sample (0.5 mL) was collected from the right jugular vein of each parrot and placed into a lithium heparin microtainer tube. Samples were centrifuged, and plasma was harvested and frozen at −30°C. Samples were thawed, and plasma osmolality was measured in duplicate with a freezing-point depression osmometer. The mean value was calculated for the 2 osmolality measurements.
Results—Plasma osmolality values were normally distributed, with a mean ± SD of 326.0 ± 6.878 mOsm/kg. The equations (2 × [Na+ + K+]) + (glucose/18), which resulted in bias of 2.3333 mOsm/kg and limits of agreement of −7.0940 to 11.7606 mOsm/kg, and (2 × [Na+ + K+]) + (uric acid concentration/16.8) + (glucose concentration/18), which resulted in bias of 5.8117 mOsm/kg and limits of agreement of −14.6640 to 3.0406 mOsm/kg, yielded calculated values that were in good agreement with the measured osmolality.
Conclusions and Clinical Relevance—IV administration of large amounts of hypotonic fluids can have catastrophic consequences. Osmolality of the plasma from parrots in this study was significantly higher than that of commercially available prepackaged fluids. Therefore, such fluids should be used with caution in Hispaniolan Amazon parrots as well as other psittacines. Additional studies are needed to determine whether the estimation of osmolality has the same clinical value in psittacines as it does in other animals.
Objective—To determine the degree of agreement between 3 commercially available point-of-care blood glucose meters and a laboratory analyzer for measurement of blood glucose concentrations in Hispaniolan Amazon parrots (Amazona ventralis).
Procedures—A 26-gauge needle and 3-mL syringe were used to obtain a blood sample (approx 0.5 mL) from a jugular vein of each parrot. Small volumes of blood (0.6 to 1.5 μL) were used to operate each of the blood glucose meters, and the remainder was placed into lithium heparin microtubes and centrifuged. Plasma was harvested and frozen at −30°C. Within 5 days after collection, plasma samples were thawed and plasma glucose concen-trations were measured by means of the laboratory analyzer. Agreement between pairs of blood glucose meters and between each blood glucose meter and the laboratory analyzer was evaluated by means of the Bland-Altman method, and limits of agreement (LOA) were calculated.
Results—None of the results of the 3 blood glucose meters agreed with results of the laboratory analyzer. Each point-of-care blood glucose meter underestimated the blood glucose concentration, and the degree of negative bias was not consistent (meter A bias, −94.9 mg/dL [LOA, −148.0 to −41.7 mg/dL]; meter B bias, −52 mg/dL [LOA, −107.5 to 3.5 mg/dL]; and meter C bias, −78.9 mg/dL [LOA, −137.2 to −20.6 mg/dL]).
Conclusions and Clinical Relevance—On the basis of these results, use of handheld blood glucose meters in the diagnosis or treatment of Hispaniolan Amazon parrots and other psittacines cannot be recommended.