Brown Samuel M, Duggal Abhijit, Hou Peter C, Tidswell Mark, Khan Akram, Exline Matthew, Park Pauline K, Schoenfeld David A, Liu Ming, Grissom Colin K, Moss Marc, Rice Todd W, Hough Catherine L, Rivers Emanuel, Thompson B Taylor, Brower Roy G
1Pulmonary and Critical Care Medicine, Intermountain Medical Center/University of Utah School of Medicine, Salt Lake City, UT.2Department of Critical Care, Respiratory Institute, Cleveland Clinic, Cleveland, OH.3Division of Emergency Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA.4Division of Pulmonary and Critical Care Medicine, Baystate Medical Center, Springfield, MA.5Oregon Health & Science University, Portland, OR.6Ohio State University Medical Center, Columbus, OH.7Division of Acute Care Surgery, University of Michigan, Ann Arbor, MI.8Biostatistics Center, Massachusetts General Hospital, Boston, MA.9Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado School of Medicine, Aurora, CO.10Division of Allergy, Pulmonary, and Critical Care Medicine, Vanderbilt University School of Medicine, Nashville, TN.11Division of Pulmonary and Critical Care Medicine, Harborview Medical Center, University of Washington, Seattle, WA.12Henry Ford Hospital, Detroit, MI.13Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston, MA.14Pulmonary and Critical Medicine, Johns Hopkins University School of Medicine, Baltimore, MD.
Crit Care Med. 2017 Aug;45(8):1317-1324. doi: 10.1097/CCM.0000000000002514.
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 PaO2/FIO2 from SpO2/FIO2 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 PaO2/FIO2 among mechanically ventilated patients and understand what factors influence the accuracy of imputation.
Simultaneous SpO2, 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 (PaO2/FIO2 ≤ 300) and moderate-severe acute respiratory distress syndrome (PaO2/FIO2 ≤ 150).
Nine hospitals within the Prevention and Early Treatment of Acute Lung Injury network.
We prospectively enrolled 703 mechanically ventilated patients admitted to the emergency departments or ICUs of participating study hospitals.
None.
We studied 1,034 arterial blood gases from 703 patients; 650 arterial blood gases were associated with SpO2 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 PaO2/FIO2 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 (PaO2/FIO2 ≤ 150); nonlinear imputation remained superior (p < 0.001). For PaO2/FIO2 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.
In mechanically ventilated patients, nonlinear imputation of PaO2/FIO2 from SpO2/FIO2 seems accurate, especially for moderate-severe hypoxemia. Linear and log-linear imputations cannot be recommended.
在当代重症监护病房（ICU）中，接受机械通气的患者在相关时间点可能无法进行动脉血气测量。严重程度标准通常取决于动脉血气结果。回顾性研究表明，从脉搏血氧饱和度（SpO2）/吸入氧分数值（FIO2）对动脉血氧分压（PaO2）/FIO2进行非线性插补是准确的，但在接受机械通气的ICU患者中尚未进行前瞻性验证。目的是验证在接受机械通气的患者中PaO2/FIO2非线性插补的优越性，并了解哪些因素会影响插补的准确性。
在进行临床动脉血气检测时，记录同步的SpO2、血氧仪特征、血管加压药的使用情况和皮肤色素沉着。记录急性呼吸窘迫综合征（ARDS）标准。对于每种插补方法，我们计算了符合ARDS标准（PaO2/FIO2≤300）和中重度ARDS标准（PaO2/FIO2≤150）患者的插补误差和曲线下面积。
急性肺损伤预防与早期治疗网络内的9家医院。
我们前瞻性纳入了703例入住参与研究医院急诊科或ICU的接受机械通气的患者。
无。
我们研究了703例患者的1034次动脉血气；650次动脉血气与SpO2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，对于PaO2/FIO2小于或等于300，非线性插补的误差更低（p<0.001），曲线下面积更高（p<0.001）（0.87；95%CI，0.85 - 0.90），优于线性/对数线性插补（0.80；95%CI，0.76 - 0.83）。所有插补方法在识别中重度ARDS（PaO2/FIO2≤150）方面表现更好；非线性插补仍然更优（p<0.001）。对于PaO2/FIO2小于或等于150，非线性插补的敏感性和特异性分别为0.87（95%CI，0.83 - 0.90）和0.91（95%CI，0.88 - 0.93）。皮肤色素沉着和血管加压药的使用与插补准确性无关。
在接受机械通气的患者中，从SpO2/FIO2对PaO2/FIO2进行非线性插补似乎是准确的，尤其是对于中重度低氧血症。不推荐线性和对数线性插补。
