Udeh Chiedozie I, Hadder Brent, Udeh Belinda L
1 Cardiovascular Intensive Care Unit, Department of Cardiothoracic Anesthesiology, and.
2 Department of Anesthesia, University of Iowa Hospitals and Clinics, Iowa City, Iowa.
Ann Am Thorac Soc. 2015 Dec;12(12):1845-51. doi: 10.1513/AnnalsATS.201504-200OC.
Prognostic models can inform management decisions for patients requiring prolonged mechanical ventilation. The Prolonged Mechanical Ventilation Prognostic model (ProVent) score was developed to predict 1-year mortality in these patients. External evaluation of such models is needed before they are adopted for routine use.
The goal was to perform an independent external validation of the modified ProVent score and assess for spectrum extension at 14 days of mechanical ventilation.
This was a retrospective cohort analysis of patients who received prolonged mechanical ventilation at the University of Iowa Hospitals. Patients who received 14 or more days of mechanical ventilation were identified from a database. Manual review of their medical records was performed to abstract relevant data including the four model variables at Days 14 and 21 of mechanical ventilation. Vital status at 1 year was checked in the medical records or the social security death index. Logistic regressions examined the associations between the different variables and mortality. Model performance at 14 to 20 days and 21+ days was assessed for discrimination by calculating the area under the receiver operating characteristic curve, and calibration was assessed using the Hosmer-Lemeshow goodness-of-fit test.
A total of 180 patients (21+ d) and 218 patients (14-20 d) were included. Overall, 75% were surgical patients. One-year mortality was 51% for 21+ days and 32% for 14 to 20 days of mechanical ventilation. Age greater than 65 years was the strongest predictor of mortality at 1 year in all cohorts. There was no significant difference between predicted and observed mortality rates for patients stratified by ProVent score. There was near-perfect specificity for mortality in the groups with higher ProVent scores. Areas under the curve were 0.69 and 0.75 for the 21+ days and the 14 to 20 days cohorts respectively. P values for the Hosmer-Lemeshow statistics were 0.24 for 21+ days and 0.22 for 14 to 20 days.
The modified ProVent model was accurate in our cohort. This supports its geographic and temporal generalizability. It can also accurately identify patients at risk of 1-year mortality at Day 14 of mechanical ventilation, but additional confirmation is required. Further studies should explore the implications of adopting the model into routine use.
预后模型可为需要长期机械通气的患者的管理决策提供依据。长期机械通气预后模型（ProVent）评分旨在预测这些患者的1年死亡率。在这些模型被常规应用之前，需要进行外部评估。
对改良后的ProVent评分进行独立的外部验证，并评估机械通气14天时的谱扩展情况。
这是一项对爱荷华大学医院接受长期机械通气患者的回顾性队列分析。从数据库中识别出接受机械通气14天或更长时间的患者。对他们的病历进行人工查阅，以提取相关数据，包括机械通气第14天和第21天的四个模型变量。在病历或社会保障死亡指数中检查1年时的生命状态。逻辑回归分析了不同变量与死亡率之间的关联。通过计算受试者工作特征曲线下面积评估14至20天和21天及以上时间段模型的鉴别能力，并使用Hosmer-Lemeshow拟合优度检验评估校准情况。
共纳入180例患者（21天及以上）和218例患者（14至20天）。总体而言，75%为外科手术患者。机械通气21天及以上患者的1年死亡率为51%，14至20天患者的1年死亡率为32%。在所有队列中，年龄大于65岁是1年死亡率最强的预测因素。按ProVent评分分层的患者预测死亡率与观察死亡率之间无显著差异。ProVent评分较高的组中死亡率的特异性接近完美。21天及以上队列和14至20天队列的曲线下面积分别为0.69和0.75。21天及以上时间段的Hosmer-Lemeshow统计量P值为0.24，14至20天时间段的P值为0.22。
改良后的ProVent模型在我们的队列中是准确的。这支持了其在地理和时间上的普遍性。它还可以在机械通气第14天时准确识别有1年死亡风险的患者，但需要进一步证实。进一步的研究应探讨将该模型应用于常规使用的意义。
