Cardiovascular, colloid osmotic pressure, and hemostatic effects of 2 formulations of hydroxyethyl starch in healthy horses

BACKGROUND

Lower molecular weight and molar substitution formulations of hydroxyethyl starch (HES) solutions might maximize cardiovascular function and colloid osmotic pressure (COP) and minimize adverse effects on coagulation.

HYPOTHESIS/OBJECTIVES

To compare effects of 1 low and 1 high molecular weight and molar substitution HES solution on cardiovascular variables, COP, and hemostasis in normal horses.

ANIMALS

Eight healthy adult horses.

METHODS

Randomized, crossover designed study: 10 mL/kg bolus of 6% HES (600/0.75) (hetastarch) (HS), 6% HES (130/0.4) tetrastarch (TS), and 0.9% NaCl (NS). Variables recorded included central venous pressure (CVP), noninvasive arterial blood pressure, packed cell volume (PCV), COP, and automated platelet analysis (CT).

RESULTS

Central venous pressure was increased for 8 hours after all treatment (baseline = 8.4 ± 3.8; 8 hours = 10.3 ± 3.5 cm H2 O; P < .001). HS and TS produced an increase in systolic arterial pressure (HS = 109.1 ± 11.9; TS = 109.5 ± 10.9 mmHg) and mean arterial pressure (HS = 80.4 ± 13.0; TS = 82.3 ± 10.1 mmHg) compared to NS (SAP = 103.2 ± 13.2 [P = .023]; MAP = 74.2 ± 11.4 mmHg [P = .048]). PCV decreased transiently with HS (baseline = 37.1 ± 4.4%; 1.5 hours = 31.6 ± 3.9%) and TS (baseline = 38.4 ± 3.9%; 1.5 hours = 32.2 ± 3.3%), but not NS (P = .007). COP was greater with HS (1 hour; 24.0 ± 2.1 mmHg) and TS (8 hours; 25.9 ± 2.1 mmHg) than NS (1 hour = 20.8 ± 2.6; 8 hours = 22.9 ± 3.1 mmHg; P < .001). CT was greater at 8 (HS = 178.6 ± 36.9; TS = 121.9 ± 33.3; NS = 108.3 ± 23.6 seconds) and 24 hours (HS = 174.2 ± 41.7; TS = 100.8 ± 26.0; NS = 118.7 ± 38.7 seconds; P < .001) in horses receiving HS than TS or NS.

CONCLUSION AND CLINICAL IMPORTANCE

Both TS and HS resulted in more effective volume expansion and arterial pressure support than NS. TS produced a more sustained effect on COP with shorter duration of adverse effects on platelet function than HS.

Thrombelastography in horses with acute gastrointestinal disease

BACKGROUND

Coagulopathies in horses with gastrointestinal disease are frequently identified and associated with morbidity and fatality.

OBJECTIVE

Determine if thrombelastography (TEG) identifies abnormalities associated with lesion type, presence of systemic inflammatory response syndrome (SIRS), morbidity, and fatality more consistently than traditional coagulation testing.

ANIMALS

One-hundred and one horses examined for gastrointestinal disease and 20 healthy horses.

METHODS

TEG, tissue factor (TF)-TEG, and traditional coagulation panels parameters and percentages of horses with coagulopathies were compared for lesion type, presence of SIRS, complications, and survival.

RESULTS

Changes in individual parameters and increased incidence of coagulopathies were associated with fatality (R, P= .007; k-value [K], P= .004; clot lysis [CL]30, P= .037; CL60, P= .050; angle [Ang], P= .0003; maximum amplitude [MA], P= .006; lysis [Ly]30, P= .042; Ly60, P= .027; CI, P= .0004; ≥ 2 TEG coagulopathies, P= .013; ≥ 3 TEG coagulopathies, P= .038; TF-R, P= .037; TF-K, P= .004; TF-CL30, P < .0001; TF-CL60, P < .0001; TF-Ang, P= .005; TF-Ly30, P= .0002; TF-Ly60, P < .0001; TF-CI, P= .043; ≥ 1 TF-TEG coagulopathies, P= .003; ≥ 2 TF-TEG coagulopathies, P= .0004; prothrombin tme [PT], P < .0001; activated partial throboplastin time [aPTT], P= .021), inflammatory lesions (MA, P= .013; TF-CL30, P= .033; TF-CL60, P= .010; TF-Ly60, P= .011; ≥ 1 TF-TEG coagulopathy, P= .036; ≥ 2 TF-TEG coagulopathy, P= .0007; PT, P= .0005; fibrinogen, P= .019), SIRS (MA, P= .004; TF-CL30, P= .019; TF-CL60, P= .013; TF-Ly30, P= .020; TF-Ly60, P= .010; PT, P < .0001; aPTT, P= .032; disseminated intravascular coagulation, P= .005), and complications (ileus: aPTT, P= .020; diarrhea: TF-CL30, P= .040; TF-Ly30, P= .041; thrombophlebitis: ≥ 1 TF-TEG coagulopathy, P= .018; laminitis: MA, P= .004; CL60, P= .045; CI, P= .036; TF-MA, P= .019; TF-TEG CI, P= .019). Abnormalities in TEG and TF-TEG parameters were indicative of hypocoagulation and hypofibrinolysis.

CONCLUSIONS AND CLINICAL IMPORTANCE

TEG identifies changes in coagulation and fibrinolysis associated with lesion type, SIRS, morbidity, and fatality in horses with gastrointestinal disease.

Results of plate fixation of type 5 olecranon fractures in 20 horses

REASONS FOR PERFORMING STUDY

Previous olecranon fracture reports contain a small proportion of type 5 fractures, mostly treated with conservative therapy.

OBJECTIVES

To evaluate the clinical details and outcome of type 5 olecranon fractures in a large group of horses treated by tension band plate fixation and to compare results with other treatment methods.

METHODS

Medical records of 97 cases, including 32 (33%) classified as type 5, were reviewed. Subject details, history, radiographic findings, treatment and follow-up results (2-146 months post operatively) were recorded.

RESULTS

Treatment included open reduction and internal fixation using a narrow or broad dynamic compression plate (n = 20), conservative therapy (n = 7) and euthanasia (n = 5). Long-term follow-up was available in 15 cases treated surgically, of which 2 were sound and in training, 11 sound and performing athletically and 2 unsound. Distal semilunar notch involvement, comminution or open status did not appear to affect prognosis.

CONCLUSIONS

Internal plate fixation provides an excellent prognosis for an animal to be capable of athletic performance.

POTENTIAL RELEVANCE

Describing tension band plate fixation and results offers a method of fracture repair that should improve treatment and prognosis for type 5 olecranon fractures.