Whole blood platelet impedance aggregometry with the ROTEM platelet device: comparison of 2 anticoagulants and storage times for the establishment of canine reference intervals

Abstract

The ROTEM platelet device, a point-of-care whole blood platelet impedance aggregometer, is an add-on to the rotational thromboelastometry ROTEM delta device. The latter has been validated in dogs. We examined whether canine whole blood is suited for analysis with the ROTEM platelet device using adenosine-5′-diphosphate (ADP) and arachidonic acid (ARA) as agonists for platelet activation, and if there are significant differences between sample storage times and anticoagulants used. Subsequently, we determined canine reference intervals (RIs) for the ROTEM platelet device for ADP and ARA. In a pilot study, we examined whole blood from 7 dogs after 15-min and 60-min storage of lithium-heparinized samples and 40-min and 80-min storage of hirudinized samples. Statistical analysis showed no significant differences between ROTEM platelet device results for both ADP and ARA in lithium-heparin and hirudin anticoagulated canine whole blood. Lithium-heparinized blood samples analyzed after 15-min storage had the lowest coefficient of variation. RIs were determined for heparinized whole blood samples from 49 dogs after 15 min of storage.

Evaluation of the Effect of Induced Endotoxemia on ROTEM S® and Platelet Parameters in Beagle Dogs Anaesthetized with Sevoflurane

“…For the observed changes in ROTEM platelet variables, the different resting times were therefore not deemed important. In a pilot study in seven healthy dogs, lithium-heparin sample ARA-tem and ADP-tem AUC values had a tendency to increase slightly between 10 and 60 min resting time [16], which is in contrast to ROTEM delta variables that became more hypocoaguable over time in a recent study [31].…”

“…It is therefore possible that single measurement errors went undetected. However, the changes in results of the ARA-tem and ADP-tem were similar among individuals over all timepoints, and all evaluated samples at baseline were within reference ranges [16]. For ROTEM delta, all curves were controlled for artifacts and unusual appearance and repeated if deemed necessary.…”

“…The database was manually checked for errors, and descriptive statistics were performed. All data are presented together with reference intervals [16,18] as median and range (min-max) due to the low number of dogs examined. For the following variables, percent change from baseline was calculated: platelet count, AUC ARA-tem, AUC ADP-tem, MCF Ex-tem, MCF In-tem, MCF Fib-tem, MCF Ap-tem, d-dimers as follows: (Xactual − Xbaseline)/Xbaseline.…”

“…For the ROTEM platelet analysis (TEM innovations GmbH, Munich, Germany), the lithium-heparin blood samples were held at room temperature for at least 15 min. Analysis was performed as described previously [16] with the two different agonists arachidonic acid (ARA-tem) and Adenosindiphosphat (ADP-tem) as reagents for platelet activation. Briefly, diluent (0.9% sodium chloride with preservatives; TEM innovations GmbH) was warmed to 37 • C in the designated heating area prior to analysis.…”

“…Broad reference intervals for ARA and ADP-tem AUC are reported and may cause problems in defining what is considered normal [16]. Individual baseline values and evaluation of changes over time have been suggested in order to increase the sensitivity of detecting abnormal values in dogs [25,26].…”