Myocardial insult and arrhythmias after acute hemorrhage in horses.

OBJECTIVE: The objectives of this investigation were to: (1) Determine if acute hemorrhage is associated with increased plasma cardiac troponin I (cTnI) concentration or cardiac arrhythmias, (2) to describe the types of arrhythmias and their clinical course in horses following acute hemorrhage, (3) to determine the ability of clinical or clinicopathological variables to predict an increase in cTnI concentration and the presence of arrhythmias, and (4) to determine the associations of cTnI and cardiac arrhythmias with outcome. DESIGN: Prospective observational study. SETTING: Large animal veterinary teaching hospital. ANIMALS: Eleven client-owned adult horses admitted for treatment of acute hemorrhage (HG) and 4 adult horses undergoing controlled blood collection (BDG). METHODS: Serial cTnI concentrations were measured and continuous ECGs were obtained from the HG and BDG groups. Statistical tests were used to determine associations among acute hemorrhage and plasma cTnI concentrations, the presence of cardiac arrhythmias, clinicopathologic data (heart rate [HR], packed cell volume [PCV], total plasma protein [TPP], plasma lactate, and plasma creatinine concentrations), and outcome. RESULTS: Plasma cTnI concentration and ECG were within reference intervals at all time points in the BDG. All horses in the HG had increased cTnI (ranging from 0.1-29.9 ng/mL). Arrhythmias were detected in 8 of these horses. There was an association between acute hemorrhage and increased cTnI (P = 0.004, ρ = 0.77), and the presence of arrhythmias (P = 0.026, ρ = 0.64). There were associations among plasma cTnI concentration and the presence of arrhythmias (P = 0.005), arrhythmias requiring treatment (P = 0.036), and poor outcome (P = 0.024). CONCLUSIONS: Acute hemorrhage results in myocardial injury that can be detected by measuring cTnI concentration. Arrhythmias were frequent in hospitalized horses following acute hemorrhage.

Coagulopathy of the critically ill equine patient.

OBJECTIVE: To review the hemostasis literature relevant to development of coagulopathy in the critically ill equine patient. DATA SOURCE: Original scientific and review articles. HUMAN DATA SYNTHESIS: Inflammation plays a critical role in the activation and amplification of clot formation, as well as the impairment of physiologic anticoagulant mechanisms, and fibrinolysis. Earlier identification of coagulopathy in patients at risk and restoration of physiologic hemostasis may result in better outcome. Development of scoring systems based on information other than coagulation markers alone may better identify patients with subclinical coagulopathy. VETERINARY DATA SYNTHESIS: Critically ill equine patients commonly at risk for coagulopathy include those with severe gastrointestinal disease, septic foals, and adults subjected to severe systemic inflammatory response syndrome. Publications provide information regarding coagulation markers helpful for identification of hemostatic dysfunction in specific patient populations, as well as information regarding the influence of coagulopathy on outcome. Data regarding clinically relevant information on therapeutic intervention are lacking. CONCLUSIONS: The relationship between inflammation and endotoxemia and development of coagulopathy is better understood in both human patients and the critically ill equine patient. Prospective clinical trials evaluating clinically relevant and financially feasible approaches to treatment are still needed.

Preliminary evaluation of hemostasis in neonatal foals using a viscoelastic coagulation and platelet function analyzer.

OBJECTIVES: To compare coagulation and platelet function parameters measured using a viscoelastic analyzer in 3 groups: foals presenting to a neonatal intensive care unit with presumed sepsis, normal foals, and adult horses. DESIGN: Preliminary prospective trial. SETTING: Veterinary teaching hospital. ANIMALS: Ten clinically healthy foals, 13 clinically healthy adult horses, and 17 foals sequentially admitted for suspected sepsis. Intervention- A single citrated (3.8%) blood sample collected at admission was submitted for coagulation evaluation using a viscoelastic analyzer. MEASUREMENTS AND MAIN RESULTS: Time to initial clot formation (ACT), clot rate (CR), platelet function, and time to peak parameters were collected from the signature generated with the associated software. Peak clot strength was collected manually from signature tracings. Signalment, presenting complaint, blood culture results, clinical progression, and outcome were collected from the medical record. Kruskal-Wallis testing was used to determine differences in coagulation parameters between groups, as well as to identify any associations between coagulation variables, foal variables, and outcome. Normal foals were more likely to have increased platelet function (P=0.04) compared with normal adult horses. Prolonged ACT (P=0.004) and decreased CR (P=0.03) were associated with foals with positive blood culture. There was a trend toward prolonged ACT and increased likelihood of death (P=0.06). CONCLUSIONS: Healthy foals differ in values measured by the viscoelastic coagulation and platelet function analyzer compared with healthy adult horses. ACT and CR abnormalities were more likely to be observed in foals with positive blood cultures. The viscoelastic coagulation and platelet function analyzer may be useful in identifying early hemostasic and platelet dysfunction in critically ill foals, particularly those that are septic.

Comparison of viscoelastic coagulation analysis and standard coagulation profiles in critically ill neonatal foals to outcome.

OBJECTIVE: To determine if changes in viscoelastic variables are associated with abnormalities observed in the standard coagulation profile and patient outcome in foals with suspected septicemia. DESIGN: Prospective clinical trial during 2003 and 2004 foal season. SETTING: Neonatal intensive care unit at a veterinary teaching hospital. ANIMALS: Thirty critically ill foals <72-hour-old admitted sequentially meeting criteria for systemic inflammatory response associated with infection. INTERVENTIONS: Hemostatic evaluation, using standard coagulation testing and viscoelastic analysis, was performed at admission, 24 hours following admission, and 48 hours following admission in critically ill foals. Standard coagulation tests included platelet count, prothrombin time, activated partial thromboplastin time, fibrinogen, fibrin(ogen) degradation products, and antithrombin. Data collected from viscoelastic analysis included time to initial clot formation (ACT), clot rate, and platelet function. Signalment, blood culture results, clinicopathologic data, and outcome were collected from medical records. Equality of populations test was used to determine associations between coagulation tests and blood culture status/outcome, as well as between viscoelastic parameters and coagulopathy, blood culture status, and outcome. Logistic regression was used to quantify associations. A significance level of P<0.05 was used. MEASUREMENTS AND MAIN RESULTS: Foals with decreasing clot rate (CR) over the sample period were more likely to be euthanized or die (P=0.02). Foals with prolonged ACT (P=0.03), and decreased CR at admission (P=0.047), were more commonly coagulopathic. Identification of coagulopathy on admission (P=0.02), or persistence of hemostatic dysfunction 48 hours later (P=0.04), was associated with death. CONCLUSIONS: Viscoelastic coagulation evaluation could be used in a neonatal intensive care unit setting to further characterize coagulopathy, and identify foals at higher risk for poor outcome.