Shore-Lesserson L, Ammar T, DePerio M, Vela-Cantos F, Fisher C, Sarier K
Department of Cardiothoracic Anesthesiology, The Mount Sinai Medical Center, New York, New York, USA.
Anesthesiology. 1999 Aug;91(2):362-8. doi: 10.1097/00000542-199908000-00008.
Platelet dysfunction is a major contributor to bleeding after cardiopulmonary bypass (CPB), yet it remains difficult to diagnose. A point-of-care monitor, the platelet-activated clotting time (PACT), measures accelerated shortening of the kaolin-activated clotting time by addition of platelet activating factor. The authors sought to evaluate the clinical utility of the PACT by conducting serial measurements of PACT during cardiac surgery and correlating postoperative measurements with blood loss.
In 50 cardiac surgical patients, blood was sampled at 10 time points to measure PACT. Simultaneously, platelet reactivity was measured by the thrombin receptor agonist peptide-induced expression of P-selectin, using flow cytometry. These tests were temporally analyzed. PACT values, P-selectin expression, and other coagulation tests were analyzed for correlation with postoperative chest tube drainage.
PACT and P-selectin expression were maximally reduced after protamine administration. Changes in PACT did not correlate with changes in P-selectin expression at any time interval. Total 8-h chest tube drainage did not correlate with any coagulation test at any time point except with P-selectin expression after protamine administration (r = -0.4; P = 0.03).
The platelet dysfunction associated with CPB may be a result of depressed platelet reactivity, as shown by thrombin receptor activating peptide-induced P-selectin expression. Changes in PACT did not correlate with blood loss or with changes in P-selectin expression suggesting that PACT is not a specific measure of platelet reactivity.
血小板功能障碍是体外循环（CPB）后出血的主要原因，但仍难以诊断。一种即时检测仪器，即血小板激活凝血时间（PACT），通过添加血小板激活因子来测量高岭土激活凝血时间的加速缩短。作者试图通过在心脏手术期间连续测量PACT，并将术后测量结果与失血量相关联，来评估PACT的临床效用。
对50例心脏手术患者在10个时间点采集血样以测量PACT。同时，使用流式细胞术通过凝血酶受体激动肽诱导的P-选择素表达来测量血小板反应性。对这些测试进行时间分析。分析PACT值、P-选择素表达和其他凝血测试与术后胸管引流的相关性。
给予鱼精蛋白后，PACT和P-选择素表达最大程度降低。在任何时间间隔内，PACT的变化与P-选择素表达的变化均无相关性。除给予鱼精蛋白后的P-选择素表达外（r = -0.4；P = 0.03），8小时胸管总引流量在任何时间点与任何凝血测试均无相关性。
与CPB相关的血小板功能障碍可能是血小板反应性降低的结果，如凝血酶受体激活肽诱导的P-选择素表达所示。PACT的变化与失血量或P-选择素表达的变化均无相关性，这表明PACT不是血小板反应性的特异性指标。
