Muckart D J, Bhagwanjee S, Gouws E
Department of Surgery, University of Natal Medical School, Congella, Republic of South Africa.
J Trauma. 1997 Dec;43(6):934-8; discussion 938-9. doi: 10.1097/00005373-199712000-00011.
The Acute Physiology and Chronic Health Evaluation (APACHE) II system is inaccurate in predicting the risk of death in trauma patients, especially those without head injury. Using multivariate analysis of the APACHE II system in a development set, a new predictive equation was modeled. The four variables that were independently associated with mortality were PaO2/FiO2 ratio, mean arterial pressure, temperature, and the need for inotropic support. This model was tested prospectively in an independent validation set of 300 patients.
Risk of death was calculated using the APACHE II system with the diagnostic category of multiple trauma and weighting for operative intervention as required. The new model was similarly assessed using the four predictor variables and their beta-coefficients for each mechanism of injury and the entire group. The predicted risk of death derived by both models was compared with the observed mortality rate. Discrimination was calculated using a 2 x 2 decision matrix with a decision threshold of r = 0.5 and receiver operating characteristic curves. Calibration was assessed graphically and by statistical correlation.
The observed mortality rate was 28.3% and the predicted mortality risk was 27.4% for the model and 6.26% for APACHE II. The sensitivity and specificity of the model were 58.8 and 90.7%, and the sensitivity and specificity of APACHE II were 1.2 and 100%. The areas under the receiver operating characteristic curves were 0.84 and 0.78 for the model and the APACHE II system, respectively. Calibration of the model was superior within all deciles of risk (model, R2 = 0.93, p < 0.001; APACHE II, R2 = 0.82, p = 0.02).
The model accurately predicted the risk of death for the entire group. It is superior to the APACHE II system and is the highest reported sensitivity for 24-hour intensive care unit predictive models that have been applied to the critically injured.
急性生理学与慢性健康状况评估（APACHE）II系统在预测创伤患者的死亡风险方面并不准确，尤其是对于那些没有头部损伤的患者。在一个开发集中对APACHE II系统进行多变量分析后，建立了一个新的预测方程。与死亡率独立相关的四个变量是氧合指数（PaO2/FiO2）、平均动脉压、体温以及使用血管活性药物支持的必要性。该模型在一个由300名患者组成的独立验证集中进行了前瞻性测试。
使用APACHE II系统计算死亡风险，并根据需要对多发伤的诊断类别和手术干预进行加权。使用四个预测变量及其针对每种损伤机制和整个组的β系数对新模型进行类似评估。将两个模型得出的预测死亡风险与观察到的死亡率进行比较。使用2×2决策矩阵（决策阈值r = 0.5）和受试者工作特征曲线计算区分度。通过图形和统计相关性评估校准情况。
观察到的死亡率为28.3%，该模型预测的死亡风险为27.4%，而APACHE II系统预测的死亡风险为6.26%。该模型的敏感性和特异性分别为58.8%和90.7%，APACHE II系统的敏感性和特异性分别为1.2%和100%。该模型和APACHE II系统的受试者工作特征曲线下面积分别为0.84和0.78。在所有风险十分位数范围内，该模型的校准情况更佳（模型，R2 = 0.93，p < 0.001；APACHE II，R2 = 0.82，p = 0.02）。
该模型准确预测了整个组的死亡风险。它优于APACHE II系统，并且是已应用于重伤患者的24小时重症监护病房预测模型中报道的最高敏感性。
