Nonlinear Imputation of Pao2/Fio2 From Spo2/Fio2 Among Mechanically Ventilated Patients in the ICU: A Prospective, Observational Study
Nonlinear Imputation of Pao2/Fio2 From Spo2/Fio2 Among Mechanically Ventilated Patients in the ICU: A Prospective, Observational Study
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DOI：
10.1097/ccm.0000000000002514
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发表时间：
2017-08-01
影响因子：
8.8
通讯作者：
Brower, Roy G.
中科院分区：
文献类型：
--
作者：
Brown, Samuel M.;Duggal, Abhijit;Brower, Roy G.
目的：在当代ICU中，机械通气患者可能无法在相关时间点进行动脉血气测量。严重程度标准通常取决于动脉血气结果。回顾性研究表明，根据Spo（2）/Fio（2）对Pao（2）/Fio（2）进行非线性插补是准确的，但尚未在机械通气ICU患者中建立前瞻性插补。目的是验证Pao（2）/Fio（2）在机械通气患者中的非线性插补的优越性，并了解影响插补准确性的因素。设计：在临床动脉血气分析时同时记录Spo（2）、血氧仪特征、血管加压药的接受和皮肤色素沉着。记录急性呼吸窘迫综合征标准。对于每种插补方法，我们计算了符合急性呼吸窘迫综合征（Pao（2）/Fio（2）= 300）和中重度急性呼吸窘迫综合征（Pao（2）/Fio（2）= 150）标准的患者的插补误差和曲线下面积。我们前瞻性地纳入了703例在参与研究医院的急诊科或ICU住院的机械通气患者。干预措施：无。测量和主要结果：我们研究了703例患者的1,034例动脉血气; 650例动脉血气与Spo（2）小于或等于96%相关。非线性插补的误差始终低于其他技术。在所有患者中，Pao（2）/Fio（2）小于或等于300时，非线性插补的误差（p <0.001）和曲线下面积（0.87; 95% CI，0.85-0.90）低于线性/对数线性插补（0.80; 95% CI，0.76-0.83）。所有插补方法均能更好地识别中重度急性呼吸窘迫综合征（Pao（2）/Fio（2）= 150）;非线性插补仍具有上级优势（p < 0.001）。Pao（2）/Fio（2）小于或等于150时，非线性插补的灵敏度和特异性分别为0.87（95% CI，0.83-0.90）和0.91（95% CI，0.88-0.93）。结论：在机械通气患者中，根据Spo（2）/Fio（2）对Pao（2）/Fio（2）进行非线性插补似乎是准确的，特别是对于中重度低氧血症。不推荐线性和对数线性插补。
Objectives: In the contemporary ICU, mechanically ventilated patients may not have arterial blood gas measurements available at relevant timepoints. Severity criteria often depend on arterial blood gas results. Retrospective studies suggest that nonlinear imputation of Pao(2)/Fio(2) from Spo(2)/Fio(2) is accurate, but this has not been established prospectively among mechanically ventilated ICU patients. The objective was to validate the superiority of nonlinear imputation of Pao(2)/Fio(2) among mechanically ventilated patients and understand what factors influence the accuracy of imputation.Design: Simultaneous Spo(2), oximeter characteristics, receipt of vasopressors, and skin pigmentation were recorded at the time of a clinical arterial blood gas. Acute respiratory distress syndrome criteria were recorded. For each imputation method, we calculated both imputation error and the area under the curve for patients meeting criteria for acute respiratory distress syndrome (Pao(2)/Fio(2) = 300) and moderate-severe acute respiratory distress syndrome (Pao(2)/Fio(2) = 150).Setting: Nine hospitals within the Prevention and Early Treatment of Acute Lung Injury network.Patients: We prospectively enrolled 703 mechanically ventilated patients admitted to the emergency departments or ICUs of participating study hospitals.Interventions: None.Measurements and Main Results: We studied 1,034 arterial blood gases from 703 patients; 650 arterial blood gases were associated with Spo(2) less than or equal to 96%. Nonlinear imputation had consistently lower error than other techniques. Among all patients, nonlinear had a lower error (p < 0.001) and higher (p < 0.001) area under the curve (0.87; 95% CI, 0.85-0.90) for Pao(2)/Fio(2) less than or equal to 300 than linear/log-linear (0.80; 95% CI, 0.76-0.83) imputation. All imputation methods better identified moderate-severe acute respiratory distress syndrome (Pao(2)/Fio(2) = 150); nonlinear imputation remained superior (p < 0.001). For Pao(2)/Fio(2) less than or equal to 150, the sensitivity and specificity for nonlinear imputation were 0.87 (95% CI, 0.83-0.90) and 0.91 (95% CI, 0.88-0.93), respectively. Skin pigmentation and receipt of vasopressors were not associated with imputation accuracy.Conclusions: In mechanically ventilated patients, nonlinear imputation of Pao(2)/Fio(2) from Spo(2)/Fio(2) seems accurate, especially for moderate-severe hypoxemia. Linear and log-linear imputations cannot be recommended.