Ferraris V A, Gildengorin V
Department of Surgery, Letterman Army Medical Center, Presidio of San Francisco, Calif. 94129-6700.
J Thorac Cardiovasc Surg. 1989 Oct;98(4):492-7.
One hundred fifty-nine consecutive patients who underwent coronary artery bypass grafting were studied to determine clinical and laboratory predictors of excessive postoperative packed red blood cell transfusion. Consideration of the distribution of packed red blood cells administered revealed that the patients could be divided into two groups: those patients who received 5 units of red blood cells or less (group I, n = 139) and those patients who received more than 5 units of packed red blood cells (group II, n = 20). The Mann-Whitney test or Fisher's exact test was used whenever appropriate to test differences between these two groups with respect to twelve patient variables. Patients in group II were found to have a significantly longer preoperative template bleeding time and decreased preoperative packed red blood cell volume (p less than 0.0008 for both variables). In addition, group II patients were significantly older (p = 0.026), were more likely to have had preoperative heparin therapy (p = 0.049), and contained a greater proportion of women (p = 0.0048). Of interest, variables that did not achieve statistical significance between groups were partial thromboplastin time, prothrombin time, platelet count, preoperative hematocrit level, urgency of operation, recent ingestion of aspirin, and recent heparin administration. All of the measured variables were used in a stepwise logistic regression analysis to identify the best predictors of the need for more than 5 units of packed red blood cells after operation. Of the variables examined, bleeding time (p less than 0.001; chi 2 improvement = 15.1) and red blood cell volume (p = 0.009; chi 2 improvement = 6.8) were the best predictors of excessive postoperative packed red blood cell use. On the basis of a 50% logistic probability level, the specificity and sensitivity of these two variables in predicting greater than a 5-unit transfusion requirement were 85% and 99%, respectively. A clinically useful nomogram based on this logistic model is presented. This nomogram suggests that a ratio of bleeding time to red blood cell volume of 0.0071 or greater is associated with a greater than 70% chance of requiring more than 5 units of packed red blood cells. We conclude that preoperative bleeding time and red blood cell volume are useful predictors of excessive postoperative blood transfusion. These results suggest that factors other than aspirin therapy may be associated with bleeding time prolongation leading to excessive postoperative transfusion.
对159例连续接受冠状动脉搭桥术的患者进行研究，以确定术后红细胞输注过多的临床和实验室预测因素。考虑所输注红细胞的分布情况，这些患者可分为两组：接受5单位或更少红细胞的患者（I组，n = 139）和接受超过5单位红细胞的患者（II组，n = 20）。在适当时使用Mann-Whitney检验或Fisher精确检验来检测这两组在12个患者变量方面的差异。发现II组患者术前模板出血时间显著延长，术前红细胞体积降低（两个变量的p值均小于0.0008）。此外，II组患者年龄显著更大（p = 0.026），更可能接受过术前肝素治疗（p = 0.049），且女性比例更高（p = 0.0048）。有趣的是，两组之间未达到统计学显著性的变量有部分凝血活酶时间、凝血酶原时间、血小板计数、术前血细胞比容水平、手术紧迫性、近期阿司匹林摄入情况以及近期肝素使用情况。所有测量变量都用于逐步逻辑回归分析，以确定术后需要超过5单位红细胞的最佳预测因素。在所检查的变量中，出血时间（p小于0.001；卡方改善 = 15.1）和红细胞体积（p = 0.009；卡方改善 = 6.8）是术后红细胞输注过多的最佳预测因素。基于50%的逻辑概率水平，这两个变量预测超过5单位输血需求的特异性和敏感性分别为85%和99%。给出了基于该逻辑模型的临床实用列线图。该列线图表明，出血时间与红细胞体积之比为0.0071或更高时，需要超过5单位红细胞的可能性大于70%。我们得出结论，术前出血时间和红细胞体积是术后输血过多的有用预测因素。这些结果表明，除阿司匹林治疗外的其他因素可能与出血时间延长导致术后输血过多有关。
