Wen Han, Kanth Shreya, Carrera Julio Huapaya, Sun Junfeng, Do Michael, Chen Marcus Y, Malayeri Ashkan A, Suffredini Anthony F
National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA.
medRxiv. 2022 Sep 15:2022.09.13.22279543. doi: 10.1101/2022.09.13.22279543.
Impairment of the diffusion capacity of the lung for carbon monoxide (DLco) is commonly reported in convalescent and recovered COVID-19 patients, although the cause is not fully understood especially in patients with no radiological sequelae. In a group of 47 patients at 7 - 51 weeks post infection with either none or minimal scarring or atelectasis on chest CT scans (total < 0.1% of lung volume), dispersions in DLco-adj % and total lung capacity (TLC) % of predicted were observed, with median(quartiles) of 87(78, 99)% and 84(78, 92)%, respectively. Thirteen(27.1%) patients had DLco-adj% < 80%. Although the DLco-adj% did not significantly correlate with the severity of the illness in the acute phase, time since the onset of symptoms, the volume of residual lesions on CT, age or sex, DLco-adj/alveolar volume (Kco-adj) % predicted was correlated with the measurements of small blood vessel volume fraction (diameter <= 5mm) and parenchyma density on CT. Multivariate analysis revealed that these two CT metrics significantly contributed to the variance in DLco-adj% independent of TLC%. Comparing to between-subject variability of DLco-adj in healthy individuals, patients in this cohort with DLco-adj% < 80% were likely abnormal with a degree of disease not visually detectable on CT. However, it is not clear whether the associated variance of parenchyma density and small vessel volume fraction were a consequence of the COVID-19 disease or a pre-existing background variance.
新冠康复患者中普遍存在肺一氧化碳弥散能力（DLco）受损的情况，尽管其原因尚未完全明确，尤其是在没有放射学后遗症的患者中。在一组47例感染后7至51周的患者中，胸部CT扫描显示无瘢痕或仅有轻微瘢痕或肺不张（总计<肺容积的0.1%），观察到预测的DLco校正百分比和肺总量（TLC）百分比存在离散，中位数（四分位数）分别为87（78，99）%和84（78，92）%。13例（27.1%）患者的DLco校正百分比<80%。尽管DLco校正百分比与急性期疾病严重程度、症状出现后的时间、CT上残留病变的体积、年龄或性别无显著相关性，但预测的DLco校正/肺泡容积（Kco校正）百分比与CT上小血管容积分数（直径<=5mm）和实质密度的测量值相关。多变量分析显示，这两个CT指标对独立于TLC百分比的DLco校正百分比的方差有显著贡献。与健康个体中DLco校正的个体间变异性相比，该队列中DLco校正百分比<80%的患者可能存在异常，且疾病程度在CT上无法直观检测到。然而，尚不清楚实质密度和小血管容积分数的相关方差是新冠疾病的结果还是先前存在的背景方差。
