Department of Anesthesiology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Division of Intensive Care Unit, University Hospital, Kyoto Prefectural University of Medicine, Kyoto, Japan.
PeerJ. 2023 Apr 10;11:e15174. doi: 10.7717/peerj.15174. eCollection 2023.
In the treatment of acute hypoxemic respiratory failure (AHRF) due to coronavirus 2019 (COVID-19), physicians choose respiratory management ranging from low-flow oxygen therapy to more invasive methods, depending on the severity of the patient's symptoms. Recently, the ratio of oxygen saturation (ROX) index has been proposed as a clinical indicator to support the decision for either high-flow nasal cannulation (HFNC) or mechanical ventilation (MV). However, the reported cut-off value of the ROX index ranges widely from 2.7 to 5.9. The objective of this study was to identify indices to achieve empirical physician decisions for MV initiation, providing insights to shorten the delay from HFNC to MV. We retrospectively analyzed the ROX index 6 hours after initiating HFNC and lung infiltration volume (LIV) calculated from chest computed tomography (CT) images in COVID-19 patients with AHRF.
We retrospectively analyzed the data for 59 COVID-19 patients with AHRF in our facility to determine the cut-off value of the ROX index for respiratory therapeutic decisions and the significance of radiological evaluation of pneumonia severity. The physicians chose either HFNC or MV, and the outcomes were retrospectively analyzed using the ROX index for initiating HFNC. LIV was calculated using chest CT images at admission.
Among the 59 patients who required high-flow oxygen therapy with HFNC at admission, 24 were later transitioned to MV; the remaining 35 patients recovered. Four of the 24 patients in the MV group died, and the ROX index values of these patients were 9.8, 7.3, 5.4, and 3.0, respectively. These index values indicated that the ROX index of half of the patients who died was higher than the reported cut-off values of the ROX index, which range from 2.7-5.99. The cut-off value of the ROX index 6 hours after the start of HFNC, which was used to classify the management of HFNC or MV as a physician's clinical decision, was approximately 6.1. The LIV cut-off value on chest CT between HFNC and MV was 35.5%. Using both the ROX index and LIV, the cut-off classifying HFNC or MV was obtained using the equation, LIV = 4.26 × (ROX index) + 7.89. The area under the receiver operating characteristic curve, as an evaluation metric of the classification, improved to 0.94 with a sensitivity of 0.79 and specificity of 0.91 using both the ROX index and LIV.
Physicians' empirical decisions associated with the choice of respiratory therapy for HFNC oxygen therapy or MV can be supported by the combination of the ROX index and the LIV index calculated from chest CT images.
在治疗由 2019 年冠状病毒病（COVID-19）引起的急性低氧性呼吸衰竭（AHRF）时，医生根据患者症状的严重程度，选择从低流量氧疗到更具侵入性的方法等呼吸管理措施。最近，氧饱和度（ROX）指数比被提议作为支持高流量鼻导管（HFNC）或机械通气（MV）决策的临床指标。然而，ROX 指数的报告截止值范围很广，为 2.7 至 5.9。本研究的目的是确定用于启动 MV 的经验性医生决策的指标，为缩短从 HFNC 到 MV 的延迟提供依据。我们回顾性分析了我院 59 例 AHRF 的 COVID-19 患者在开始 HFNC 后 6 小时的 ROX 指数和胸部计算机断层扫描（CT）图像计算的肺浸润体积（LIV）。
我们回顾性分析了我院 59 例 AHRF 的 COVID-19 患者的数据，以确定 ROX 指数在呼吸治疗决策中的截止值以及肺炎严重程度放射学评估的意义。医生选择 HFNC 或 MV，使用 ROX 指数对启动 HFNC 的结果进行回顾性分析。LIV 使用入院时的胸部 CT 图像计算。
在入院时需要高流量氧疗的 59 例患者中，有 24 例随后转为 MV；其余 35 例患者康复。MV 组的 24 例患者中有 4 例死亡，这些患者的 ROX 指数分别为 9.8、7.3、5.4 和 3.0，这表明一半死亡患者的 ROX 指数高于报告的 ROX 指数截止值，范围为 2.7-5.99。HFNC 开始后 6 小时的 ROX 指数截止值可用于分类 HFNC 或 MV 的管理，作为医生的临床决策，约为 6.1。HFNC 和 MV 之间胸部 CT 的 LIV 截止值为 35.5%。使用 ROX 指数和 LIV，通过方程，LIV = 4.26×（ROX 指数）+7.89，获得了将 HFNC 或 MV 分类的截止值。分类的接收器工作特征曲线下面积（AUC）作为评估指标，使用 ROX 指数和 LIV 后提高到 0.94，灵敏度为 0.79，特异性为 0.91。
通过将 ROX 指数与胸部 CT 图像计算的 LIV 指数相结合，可支持医生在 HFNC 氧疗或 MV 选择时进行经验性呼吸治疗决策。
