* Assistant Professor, † Statistician, § Resident, ** Associate Professor, †† Professor, Dipartimento di Anestesiologia e Rianimazione, Università di Torino, Ospedale S. Giovanni Battista-Molinette, Torino, Italy. ‡ Professor, Keenan Research Center at the Li Ka Shing Knowledge Institute of St. Michael's Hospital; Department of Medicine and Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada. ‖ Assistant Professor, # Statistician, Sezione di Anestesiologia e Rianimazione, Dipartimento dell'Emergenza e dei Trapianti d'Organo, Università di Bari, Bari, Italy.
Anesthesiology. 2013 Oct;119(4):880-9. doi: 10.1097/ALN.0b013e3182a05bb8.
Guidelines suggest a plateau pressure (PPLAT) of 30 cm H(2)O or less for patients with acute respiratory distress syndrome, but ventilation may still be injurious despite adhering to this guideline. The shape of the curve plotting airway pressure versus time (STRESS INDEX) may identify injurious ventilation. The authors assessed accuracy of PPLAT and STRESS INDEX to identify morphological indexes of injurious ventilation.
Indexes of lung aeration (computerized tomography) associated with injurious ventilation were used as a "reference standard." Threshold values of PPLAT and STRESS INDEX were determined assessing the receiver-operating characteristics ("training set," N = 30). Accuracy of these values was assessed in a second group of patients ("validation set," N = 20). PPLAT and STRESS INDEX were partitioned between respiratory system (Pplat,Rs and STRESS INDEX,RS) and lung (PPLAT,L and STRESS INDEX,L; esophageal pressure; "physiological set," N = 50).
Sensitivity and specificity of PPLAT of greater than 30 cm H(2)O were 0.06 (95% CI, 0.002-0.30) and 1.0 (95% CI, 0.87-1.00). PPLAT of greater than 25 cm H(2)O and a STRESS INDEX of greater than 1.05 best identified morphological markers of injurious ventilation. Sensitivity and specificity of these values were 0.75 (95% CI, 0.35-0.97) and 0.75 (95% CI, 0.43-0.95) for PPLAT greater than 25 cm H(2)O versus 0.88 (95% CI, 0.47-1.00) and 0.50 (95% CI, 0.21-0.79) for STRESS INDEX greater than 1.05. Pplat,Rs did not correlate with PPLAT,L (R(2) = 0.0099); STRESS INDEX,RS and STRESS INDEX,L were correlated (R(2) = 0.762).
The best threshold values for discriminating morphological indexes associated with injurious ventilation were Pplat,Rs greater than 25 cm H(2)O and STRESS INDEX,RS greater than 1.05. Although a substantial discrepancy between Pplat,Rs and PPLAT,L occurs, STRESS INDEX,RS reflects STRESS INDEX,L.
指南建议急性呼吸窘迫综合征患者的平台压（PPLAT）应低于或等于 30cmH₂O，但即使遵循这一指南，通气仍可能造成损伤。气道压力与时间的关系曲线（STRESS INDEX）的形态可能识别出损伤性通气。作者评估了 PPLAT 和 STRESS INDEX 识别损伤性通气的形态学指标的准确性。
将与损伤性通气相关的肺充气指数（计算机断层扫描）作为“参考标准”。通过评估接收者操作特性（“训练集”，N=30）确定 PPLAT 和 STRESS INDEX 的临界值。在第二组患者（“验证集”，N=20）中评估这些值的准确性。将 PPLAT 和 STRESS INDEX 分配到呼吸系统（Pplat,Rs 和 STRESS INDEX,RS）和肺（PPLAT,L 和 STRESS INDEX,L；食管压力；“生理集”，N=50）。
PPLAT 大于 30cmH₂O 的敏感性和特异性分别为 0.06（95%CI，0.002-0.30）和 1.0（95%CI，0.87-1.00）。PPLAT 大于 25cmH₂O 和 STRESS INDEX 大于 1.05 最佳识别损伤性通气的形态学标志物。这些值的敏感性和特异性分别为 0.75（95%CI，0.35-0.97）和 0.75（95%CI，0.43-0.95）用于 PPLAT 大于 25cmH₂O，0.88（95%CI，0.47-1.00）和 0.50（95%CI，0.21-0.79）用于 STRESS INDEX 大于 1.05。Pplat,Rs 与 PPLAT,L 无相关性（R²=0.0099）；STRESS INDEX,RS 和 STRESS INDEX,L 有相关性（R²=0.762）。
用于区分与损伤性通气相关的形态学指标的最佳临界值为 Pplat,Rs 大于 25cmH₂O 和 STRESS INDEX,RS 大于 1.05。尽管 Pplat,Rs 和 PPLAT,L 之间存在显著差异，但 STRESS INDEX,RS 反映了 STRESS INDEX,L。
