Pascual-Guàrdia Sergi, Ferrer Antoni, Díaz Óscar, Caguana Antonio O, Tejedor Elvira, Bellido-Calduch Salomé, Rodríguez-Chiaradia Diego A, Gea Joaquim
Servicio de Neumología, Hospital del Mar-IMIM. DCEXS, Universitat Pompeu Fabra. CIBERES, ISCIII. BRN, Barcelona. España.
Laboratorio de Referencia de Cataluña, El Prat de Llobregat, España.
Arch Bronconeumol (Engl Ed). 2021 Mar 26;57(12):757-63. doi: 10.1016/j.arbres.2021.03.015.
Pulmonary involvement in COVID-19 is frequently associated with alterations in oxygenation. The arterial partial pressure of oxygen (PaO) is the most clinically used variable to assess such oxygenation, since it decisively influences the oxygen transported by hemoglobin (expressed by its percentage of saturation, SaO). However, two recent studies conducted respectively in silico and using omic techniques in red blood cells of COVID-19 patients have suggested that SARS-CoV-2 could decrease the affinity of oxygen for the hemoglobin (which would imply that PaO would overestimate SaO), and also reduce the amount of this carrier molecule.
To evaluate this hypothesis in blood samples from COVID-19 patients.
Blood gases of all COVID-19 patients performed in our laboratory in two months were included, as well as those from two control groups: synchronous patients with negative PCR for SARS-CoV-2 (SCG) and a historical group (HCG). Both SaO and venous saturations (SvO) measured by cooximetry (COX) were compared separately with those calculated using the Kelman (K), Severinghaus (SV) and Siggaard-Andersen (SA) equations in each group.
Measured and calculated SaO and SvO were practically equivalent in all groups. Intraclass correlation coefficients (ICC) for SaO in COVID-19 were 0.993 for COX-K and 0.992 for both COX-SV and COX-SA; being 0.995 for SvO for either COX-K, COX-SV or COX-SA. Hemoglobin and ferritin were slightly higher in COVID-19 compared to SCG and HCG (hemoglobin, p < 0.001 for both; ferritin, p < 0.05 for SCG and p < 0.001 for HCG).
Under clinical conditions SARS-CoV-2 does not have an appreciable influence on the affinity of oxygen for the hemoglobin, nor on the levels of this carrier molecule. Therefore, PaO is a good marker of blood oxygenation also in COVID-19.
新冠病毒肺炎（COVID-19）中的肺部受累常与氧合改变相关。动脉血氧分压（PaO）是临床上评估此类氧合最常用的变量，因为它决定性地影响血红蛋白运输的氧气（以其饱和度百分比SaO表示）。然而，最近分别通过计算机模拟和对COVID-19患者红细胞使用组学技术进行的两项研究表明，严重急性呼吸综合征冠状病毒2（SARS-CoV-2）可能会降低氧气与血红蛋白的亲和力（这意味着PaO会高估SaO），并且还会减少这种载体分子的量。
在COVID-19患者的血样中评估这一假设。
纳入了在两个月内于我们实验室进行检测的所有COVID-19患者的血气样本，以及来自两个对照组的样本：SARS-CoV-2聚合酶链反应（PCR）阴性的同期患者（SCG）和一个历史组（HCG）。将通过共血氧测定法（COX）测量的SaO和静脉饱和度（SvO）分别与每组中使用凯尔曼（K）、西弗林豪斯（SV）和西格gaard-安德森（SA）方程计算得出的值进行比较。
所有组中测量值与计算值的SaO和SvO实际相当。COVID-19组中SaO的组内相关系数（ICC），COX-K法为0.993，COX-SV法和COX-SA法均为0.992；SvO的ICC，COX-K法、COX-SV法或COX-SA法均为0.995。与SCG组和HCG组相比，COVID-19组的血红蛋白和铁蛋白略高（血红蛋白，两组均p<0.001；铁蛋白，SCG组p<0.05，HCG组p<0.001）。
在临床条件下，SARS-CoV-2对氧气与血红蛋白的亲和力以及这种载体分子的水平没有明显影响。因此，PaO也是COVID-19中血液氧合的良好指标。
