Karl E. Jandrey

Etiology and clinical outcome in dogs with aspiration pneumonia: 88 cases (2004–2006)

OBJECTIVE To evaluate the number and types of underlying disorders detected in dogs with aspiration pneumonia and determine the survival rate among affected dogs. DESIGN Retrospective case series. Animals-88 dogs with aspiration pneumonia. PROCEDURES Medical records were reviewed to identify disease processes that could result in aspiration pneumonia. To assess outcome (ie, survival to discharge from the hospital or nonsurvival), dogs were grouped by the type and number of underlying disease processes. Duration of hospitalization and radiographic severity of disease were evaluated with regard to case outcome. RESULTS As the cause of aspiration pneumonia, a single underlying disorder was identified in 60 of the 88 dogs; 2 or more diseases were identified in the remaining dogs. Esophageal disease (n = 35), vomiting (34), neurologic disorders (24), laryngeal disease (16), and postanesthetic aspiration (12) were identified most commonly. Overall, 68 dogs survived to discharge from the hospital (survival rate, 77%). Survival rates were comparable among dogs regardless of the underlying cause of aspiration pneumonia. Radiographic severity of disease and duration of hospitalization did not influence survival. CONCLUSIONS AND CLINICAL RELEVANCE Among these study dogs, aspiration pneumonia was associated with a high survival rate. The presence of more than 1 underlying disease associated with aspiration pneumonia did not adversely impact survival rate. Interestingly, radiographic severity of disease and duration of hospitalization were not associated with overall survival rate.

The effect of Hetastarch (670/0.75) in vivo on platelet closure time in the dog.

OBJECTIVE To evaluate the effect of 6% hydroxyethyl starch (HES) solution in vivo, with an average molecular weight of 670 kDa and degree of substitution of 0.75, on canine platelet function. DESIGN Prospective, controlled-experimental study. SETTING University of California, Davis, Veterinary Medical Teaching Hospital. ANIMALS Seven healthy employee-owned dogs. INTERVENTIONS Seven dogs were included in the treatment group. Four of these dogs also served as the control group. Platelet closure time (CT) was measured using a platelet function analyzer and collagen/ADP cartridges. Dogs were given 20 mL/kg of either sodium chloride 0.9% (control group, n=4) or HES (treatment group, n=7) IV over 1 hour. CT was measured before the infusion, and at 1, 3, 5, and 24 hours after the start of the infusion. MEASUREMENTS AND MAIN RESULTS There was a significant change over time from 0 to 24 hours (P<0.001), a significant difference between groups across time (P<0.001), and a significant group-by-time interaction (P=0.007). At 3 hours, mean CT for the treatment group was 122.3+/-18.1 seconds, which was significantly different (P<0.001) from the control group (71.0+/-3.5 s). At 5 hours, mean CT for the treatment group was 142.7+/-33.9 seconds, which was significantly different (P=0.001) from the control group (75.0+/-8.6 s). Mean CT at 24 hours was within the reference interval for both the control and treatment group (66.0+/-2.9 and 81.8+/-11.9 s, respectively); however, CT in 3 individual dogs in the treatment group at this time point remained prolonged. CONCLUSIONS A clinically relevant dose of HES 670/0.75 prolongs CT in dogs for up to 24 hours. This may be due to platelet dysfunction in addition to the effects of hemodilution, and therefore, may increase the risk of bleeding.

Clinical, clinicopathologic, and radiographic findings in dogs with aspiration pneumonia: 88 cases (2004-2006).

OBJECTIVE To evaluate clinical, clinicopathologic, and radiographic findings in dogs with aspiration pneumonia. DESIGN Retrospective case series. Animals-88 dogs with aspiration pneumonia. PROCEDURES History, physical examination findings, and clinicopathologic data were obtained from medical records and analyzed for all 88 dogs. Thoracic radiographic findings for all dogs were reviewed to determine the type and location of pulmonary infiltrates. RESULTS Aspiration pneumonia was evident at admission to the hospital in 65 (74%) dogs and developed during hospitalization in 23 (26%) dogs. Less than half of these affected dogs had high values for rectal temperature, heart rate, or respiratory rate; however, most (68%) affected dogs had increased, decreased, or adventitious lung sounds. Neutrophilia with a left shift was a common finding. Hypoalbuminemia was detected in 31 of 58 (53%) dogs. Hypoxemia and a high alveolar-arterial gradient in partial pressure of oxygen were detected in 22 of 28 (79%) dogs and 27 of 28 (96%) dogs, respectively. Among the 88 dogs, thoracic radiography revealed a predominantly alveolar infiltrate in 65 (74%) dogs and an interstitial pattern in 23 (26%) dogs; a single lung lobe was affected in 46 (52%) dogs, most commonly the right middle lung lobe (21/46 [46%] dogs). CONCLUSIONS AND CLINICAL RELEVANCE In dogs, aspiration pneumonia was often associated with abnormalities in pulmonary auscultation in the absence of objective changes in physical examination findings. However, neutrophilia, hypoalbuminemia, and hypoxemia were frequently detected, and radiographic evidence of infiltrates in the right middle lung lobe was common.

Assessment of platelet function

OBJECTIVE To review the current in vivo and in vitro tests of platelet function (PF) currently available and applicable to companion animals. DATA SOURCES Scientific reviews, case reports, original clinical and laboratory research publications, and recent veterinary research conference proceedings. HUMAN DATA SYNTHESIS Disorders of primary hemostasis are very common in human medicine. These include inborn errors of PF and granule storage contents, primary disease mechanisms that alter PF, disorders secondary to surgical interventions, and the effects of anticoagulant medications. Knowledge of PF disorders and the optimal method for assessment must be known to understand the mechanism and to monitor the process or drug therapy. VETERINARY DATA SYNTHESIS Interest in the study and treatment of primary coagulopathies in clinical veterinary patients has resulted in a surge of recent publications and scientific research presentations. A translational approach that uses laboratory and point-of-care tools to uncover the pathophysiologic mechanisms in the patient with defects in primary hemostasis allows the clinician to plan the diagnosis and treatment more effectively. SUMMARY Primary hemostatic disorders are being more commonly recognized in clinical veterinary practice. The diagnosis of platelet dysfunction may be obtained via point-of-care analyzers that use relatively small blood samples and have a quick turnaround time. Recent investigations may lead to a better understanding of the pathophysiology of PF disorders and potentially the optimization, or discovery, of novel treatments. CONCLUSIONS The assessment of PF can be completed through in vivo and in vitro point-of-care techniques as well as by submission of blood samples to more specialized platelet biology laboratories. The information obtained including the physical examination and clinical manifestations of a hemostatic disorder, as well as the benefits of each testing modality, must be known prior to the diagnostic investigation of a patient with a coagulopathy.Objective To review the current in vivo and in vitro tests of platelet function (PF) currently available and applicable to companion animals. Data Sources Scientific reviews, case reports, original clinical and laboratory research publications, and recent veterinary research conference proceedings. Human Data Synthesis Disorders of primary hemostasis are very common in human medicine. These include inborn errors of PF and granule storage contents, primary disease mechanisms that alter PF, disorders secondary to surgical interventions, and the effects of anticoagulant medications. Knowledge of PF disorders and the optimal method for assessment must be known to understand the mechanism and to monitor the process or drug therapy. Veterinary Data Synthesis Interest in the study and treatment of primary coagulopathies in clinical veterinary patients has resulted in a surge of recent publications and scientific research presentations. A translational approach that uses laboratory and point-of-care tools to uncover the pathophysiologic mechanisms in the patient with defects in primary hemostasis allows the clinician to plan the diagnosis and treatment more effectively. Summary Primary hemostatic disorders are being more commonly recognized in clinical veterinary practice. The diagnosis of platelet dysfunction may be obtained via point-of-care analyzers that use relatively small blood samples and have a quick turnaround time. Recent investigations may lead to a better understanding of the pathophysiology of PF disorders and potentially the optimization, or discovery, of novel treatments. Conclusions The assessment of PF can be completed through in vivo and in vitro point-of-care techniques as well as by submission of blood samples to more specialized platelet biology laboratories. The information obtained including the physical examination and clinical manifestations of a hemostatic disorder, as well as the benefits of each testing modality, must be known prior to the diagnostic investigation of a patient with a coagulopathy.

Platelet function in clinically healthy cats and cats with hypertrophic cardiomyopathy: analysis using the Platelet Function Analyzer-100

BACKGROUND There is currently no simple analytical tool for the evaluation of hypercoagulability in cats. The Platelet Function Analyzer-100 (PFA-100; Dade Behring Inc., Deerfield, IL, USA) is a bench-top machine that evaluates platelet function by measuring closure time (CT) in citrated whole blood under high shear conditions. We hypothesized that cats with hypertrophic cardiomyopathy (HCM) have up-regulated platelet function, which shortens their CT and increases their risk for thromboembolic events. OBJECTIVES The goals of this study were to: (1) establish a feline reference interval for CT using the PFA-100, (2) measure CT in blood from cats with HCM, and (3) determine if there is a measurable difference between the CT of healthy cats compared with cats with HCM. METHODS Citrated blood samples from 42 clinically healthy cats and 30 cats with HCM were analyzed according to manufacturers specifications. CT was measured in triplicate and the mean value was used for analysis. Transformed data were compared between clinically healthy cats and cats with HCM using a Students t-test, and among cats with mild, moderate, or severe HCM using ANOVA. RESULTS The median CT of clinically healthy cats was 64 seconds (range 43-176 seconds). The median CT of cats with HCM was 74 seconds (range 48-197 seconds). There was no significant difference in CT between cats with HCM and clinically healthy cats. There also were no significant differences in cats with mild, moderate, or severe HCM. CONCLUSIONS A feline reference interval for PFA-100 CT will be useful in future studies of platelet function in cats. Cats with HCM do not have shorter CTs when compared with clinically healthy cats.

Assessment of a dimethyl sulfoxide-stabilized frozen canine platelet concentrate

OBJECTIVE To assess platelet count, mean platelet volume (MPV), metabolic characteristics, and platelet function in a dimethyl sulfoxide (DMSO)-stabilized canine frozen platelet concentrate (PC). SAMPLE POPULATION 11 units of a commercial frozen PC in 6% DMSO and fresh platelet-rich plasma from 6 healthy control dogs. PROCEDURES PCs were thawed, and the following data were collected: thaw time, platelet count, MPV, pH, PCO2, and PO2 and HCO3-, glucose, and lactate content. Phosphatidylserine translocation was determined by use of flow cytometry. Fresh platelet-rich plasma from healthy dogs served as a source of control platelets for flow cytometric analysis. RESULTS At thaw, the platelet count in the frozen PC ranged from 243,000 to 742,000 platelets/microL. Median platelet count of paired samples was 680,000 platelets/microL and decreased significantly to 509,000 platelets/microL at 2 hours after thaw. Median MPV at thaw was 11.15 femtoliters and was stable after 2 hours. Compared with fresh platelets, frozen PC had increased amounts of phosphatidylserine in the outer leaflet of the platelet membrane in the resting (ie, not treated with thrombin) state (19% vs 99%, respectively) and alterations in cellular morphology, all of which were consistent with platelet activation. CONCLUSIONS AND CLINICAL RELEVANCE Results of this in vitro study indicated that there was a decrease in platelet quantity and function as well as an increase in platelet activation during the freeze-and-thaw process in DMSO-stabilized canine frozen PC. In vivo effects on PC remain to be determined.

Analysis of a commercial dimethyl-sulfoxide-stabilized frozen canine platelet concentrate by turbidimetric aggregometry.

OBJECTIVES To assess platelet function of a commercial dimethyl-sulfoxide (DMSO)-stabilized frozen platelet concentrate (PC) using turbidimetric aggregometry. DESIGN In vitro analysis. SETTING Research laboratory in a school of veterinary medicine. ANIMALS Five units of frozen PC in 6% DMSO were studied. Fresh platelet-rich plasma (PRP), with and without 6% DMSO, from 6 healthy dogs were used as controls. INTERVENTIONS Turbidimetric platelet aggregation was measured after initiation of platelet aggregation by addition of adenosine diphosphate (ADP), collagen, or thrombin at concentrations of 30 μM, 20μg/mL, and 0.5U/mL, respectively. Measures were performed at thaw and repeated 2 hours after thaw for the frozen PC. MEASUREMENTS AND MAIN RESULTS Compared with PRP, the frozen PC showed decreased aggregation in response to thrombin (amplitude of 84% versus 25%, P=0.01), and collagen (amplitude of 13% versus 3%, P=0.05) but not ADP (6.5% versus 18%, P=0.2). Compared with frozen PC at thaw, the frozen PC at 2 hours after thaw showed decreased aggregation in response to thrombin, collagen, and ADP (P<0.05). There was no difference in aggregation between PRP in 6% DMSO and frozen PC. CONCLUSIONS These in vitro data suggest there is a decrease in platelet response to agonists associated with the freeze-thaw process in the commercially available 6% DMSO canine frozen PC.

The Prognostic Utility of Degenerative Left Shifts in Dogs

BACKGROUND A degenerative left shift (DLS) in dogs is reported to be a poor prognostic indicator, but no studies have been reported to verify this claim. HYPOTHESIS/OBJECTIVES To characterize the canine population affected by DLS and to determine if the presence and severity of the DLS are associated with increased risk of euthanasia or death. ANIMALS Three-hundred and nineteen dogs with DLS (cases) and 918 dogs without DLS (controls) presented to the University of California, Davis Veterinary Medical Teaching Hospital between April 1, 1995 and April 1, 2010. METHODS Retrospective case-control study. All cases had a CBC performed within 24 hours of presentation that showed an immature neutrophil count higher than the mature neutrophil count. Controls were matched by year of presentation and primary diagnosis. Survival analysis was used to determine the risk of death or euthanasia associated with DLS and other potential predictors. RESULTS Half of cases versus 76% of controls were alive at discharge. Median in-hospital survival time was 7 days for cases and 13 days for controls. DLS was a significant predictor of death or euthanasia in both univariate and multivariate analysis (hazard ratio, HR, 1.9; 95% CI 1.54-2.34). CONCLUSIONS AND CLINICAL IMPORTANCE DLS in dogs is associated with an increased risk of death or euthanasia. This finding, however, varies with disease diagnosis and should be interpreted in light of the individual patient.

Platelet activation in cats with hypertrophic cardiomyopathy

Background Cats with hypertrophic cardiomyopathy (HCM) are at risk for development of systemic thromboembolic disease. However, the relationship between platelet activation state and cardiovascular parameters associated with HCM is not well described. Objectives To characterize platelet activation by flow cytometric evaluation of platelet P‐selectin and semiquantitative Western blot analysis of soluble platelet‐endothelial cell adhesion molecule‐1 (sPECAM‐1). Animals Eight normal healthy cats (controls) owned by staff and students of the School of Veterinary Medicine and 36 cats from the UC Davis Feline HCM Research Laboratory were studied. Methods Platelet‐rich plasma (PRP) was used for all flow cytometry studies. Platelet surface CD41 and P‐selectin expression were evaluated before and after ADP stimulation. sPECAM‐1 expression was evaluated by Western blot analysis of platelet‐poor plasma that had been stabilized with aprotinin. Standard echocardiographic studies were performed. Results Resting platelets from cats with severe HCM had increased P‐selectin expression compared to controls, and expressed higher surface density of P‐selectin reflected by their increased mean fluorescence intensities (MFI). Stimulation with ADP also resulted in significantly increased P‐selectin MFI of platelets from cats with severe HCM. Increased P‐selectin expression and MFI correlated with the presence of a heart murmur and end‐systolic cavity obliteration (ESCO). sPECAM‐1 expression from cats with moderate and severe HCM was significantly increased above those of control cats. Conclusions and Clinical Importance P‐selectin and sPECAM expression may be useful biomarkers indicating increased platelet activation in cats with HCM.

In vitro mechanical comparison of 2.0 and 2.4 limited-contact dynamic compression plates and 2.0 dynamic compression plates of different thicknesses

OBJECTIVE To compare the bending structural stiffness and bending strength of thick and thin 2.4 mm limited contact dynamic compression plates (2.4 LC-DCP), 2.0 mm LC-DCP (2.0 LC-DCP), and 2.0 dynamic compression plates (2.0 DCP). STUDY DESIGN In vitro mechanical study. METHODS Two thicknesses of 2.4 LC-DCP, 2.0 LC-DCP, and 2.0 DCP stainless-steel plates were tested in 4-point bending. Data were collected during bending until implants plastically deformed. Bending structural stiffness and bending strength were determined from load displacement curves. Mechanical properties were compared between plates and the effects of plate type, size, and thickness on stiffness and strength were assessed using ANOVA. RESULTS The thick 2.4 LC-DCP implant was the stiffest and strongest; the thin 2.0 DCP implant was most compliant and weakest. Larger sized plates, thicker plates, and limited contact design of plates enhanced stiffness and strength. For the plates studied, plate size had a larger effect than plate type or thickness on stiffness and strength. CONCLUSION Increasing the size (width) and thickness of plates increases both the bending structural stiffness and strength. For the plates studied, LC-DCP implants were stiffer and stronger than DCP implants. CLINICAL RELEVANCE Plate bending structural stiffness and strength can be most effectively enhanced by using a larger sized plate, but gains can also be achieved by using a thicker plate and/or an LC-DCP instead of a DCP implant when possible.