Prediction of Bleeding Diathesis in Patients Undergoing Cardiopulmonary Bypass during Cardiac Surgery: Viscoelastic Measures Versus Routine Coagulation Test

Background: Severe hemorrhagic tendency often complicates cardiopulmonary bypass (CPB) in cardiac surgery. In this study, we compared the effectiveness of thromboelastography (TEG), Sonoclot (SCT), and routine coagulation test (RCT) in the prediction of coagulation defects. Methods: Forty-three patients undergoing cardiac surgery with CPB were included. Blood for RCT, TEG, and SCT profiles was sampled before systemic heparinization and after protamine administration. Clinically significant bleeding was defined as chest tube drainage in excess of 100 ml/h for 3 consecutive hours or 300 ml/h in 1 h. All coagulation parameters obtained before and after CPB were compared. The sensitivity, specificity, accuracy, false positive, and false negative rate were also calculated and compared. Results: All coagulation tests were within normal range except higher partial thromboplastin time. Variables which were significantly different from those before CPB included platelet count, fibrinogen level, prothrombin time, and thrombin time in RCT, α angle and maximum amplitude in TEG, and R_2 and peak time in SCT. In the TEG tracing, all variables had high sensitivity, specificity, and accuracy (average 85.4%, 83%, and 83.5% respectively) and low false positive and negative rate (12.5% and 5% respectively). Although SCT had high sensitivity (76.3%) and low false negative rate (6.5%), its specificity and accuracy were all under 50%. Conclusions: Our data demonstrated that the TEG monitoring is a useful tool for detecting post-CPB bleeding diathesis and can provide much predictive information. RCT and SCT are of limited value because of higher rate of unreliable results.

關鍵字

Blood coagulation tests: thromboelastography, Sonoclot ； Surgery, cardiovascular

並列摘要

背景：體外循環後的大量出血是心臟手術患者常見的併發症之一，如何使用有效的儀器及方法來預測凝血功能的異常，並給予適當的處理和治療，即為本研究探討的主題。方法：本研究選擇四十三位接受心臟手術之患者，在體外循環肝精給予前以及體外循環結束魚精蛋白給予後，均採血接受血液黏滯之測定與傳統凝血之檢驗，以評估凝血功能有無異常並比較其差別。術後異常的出血定義為胸管引流每小時超過100 ml，連續3小時以上，或單一小時出血超過300 ml。各項檢測均計算敏感度，特殊性，準確度，偽陽率以及偽陰率，並比較不同檢查之差異。結果：手術前後有意義差別的項目包括：傳統凝血檢驗中的血小板數、纖維蛋白原值、前凝血酵素時間、凝血酵素時間，thromboelastography中的α角度、最大幅度值，以及Sonoclot中的R_2值、最高幅度時間。在thromboelastography圖形中，所有項目均有較高的敏感度、特殊性和準確度（分別為85.4%、83%、83.5%）以及較低的偽陽率和偽陰率（分別為12.5%、5%）。雖然Sonoclot具有高敏感度（76.3%）和低偽陰率（6.5%），但它的特殊性和準確度均不及50%。結論：本實驗數據顯示，thromboelastography能夠有效的監測凝血功能，不但可以預測體外循環後的出血傾向，還能提供有價值的數據分析，作為輸血治療的參考。而傳統的凝血檢驗方法，以及另一種亦以血液黏滯度改變為原理的檢測儀器Sonoclot，由於臨床上的誤差率過高，在凝血功能的監測上，使用的價值有限。

並列關鍵字

血液凝結檢驗：thromboelastography, Sonoclot ；手術：心臟血管

國際替代計量

Prediction of Bleeding Diathesis in Patients Undergoing Cardiopulmonary Bypass during Cardiac Surgery: Viscoelastic Measures Versus Routine Coagulation Test

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