Equine Internal Medicine Resident University of Illinois Urbana, Illinois, United States
Abstract: Background- Coagulopathy is common in equine critical disease with early recognition crucial for patient management and prognosis. Increased red blood cell mass (RCM) creates viscoelastic (VE) hypocoagulable profiles in dogs and horses. While small animal studies show in vitro VE hypercoagulability with decreased RCM, there are no data in horses to date.
Hypothesis/Objectives- Acepromazine induced splenic volume increase is associated with decreased RCM and altered VE profiles.
Animals- Eight healthy adult horses from the University of Illinois research herd.
Methods- Non-randomized, controlled experimental study. Acepromazine (0.1 mg/kg) IV. CBC, fibrinogen, PT, PTT, PCV, TP and VE testing with VCM Vet™ performed stallside: pre-acepromazine administration(T0), 1h post(T1) and 12h post(T2). Splenic volumes determined ultrasonographically. One-way repeated measures ANOVA was performed to determine the effect of time (sample) on the VCM Vet™ and CBC parameters, as well as spleen volume. Where a significant effect was identified (p< 0.05), pair-wise comparisons between groups were performed by Tukeys HSD.
Results- PCV decreased ~13% following acepromazine administration, p< 0.001(T1-T0 p< 0.001; T2-T0 p< 0.001; T2-T1 p< 0.001). MCF (maximal clot firmness) increased p=0.04(T0-T1 p=0.03), WBC decreased p< 0.001(T1-T0 p< 0.001;T2-T1 p=0.006), and splenic volume increased p=0.045(T1-T0 p=0.04). No other examined variables were significantly altered.
Conclusions and clinical importance- This normovolemic non-inflammatory acute model of equine anemia demonstrated both VE hypercoagulability -increased MCF- and splenic volume increase. A normovolemic subacute RCM removal anemia model in dogs, using native uncitrated blood, demonstrated in vitro VE hypercoagulability as decreased CFT (clot formation time), with increased alpha and MCF, potentially artefactual. Horse blood may be similar.
