Intrapulmonary shunting is a key contributor to hypoxia in COVID-19: an update on the pathophysiology

Data from every patient over 18 years old admitted to the two centres for clinically and/or laboratory-confirmed COVID-19 was recorded. Patients were only included if they were hypoxic on admission and required supplemental oxygen. Patients were excluded if they were pregnant, self-discharged against medical advice before treatment completion, or if there was no documentation of oxygen saturations on admission. Oxygen saturations measured using fingertip pulse oximetry by the ambulance crew and emergency departments were collected. Oxygen flow (litres/min) was converted to FiO2 according to predetermined conversion charts. Baseline saturations on air followed by saturations after administration of oxygen were collected and used to construct the oxygen dissociation curve (ODC). The calculation has been previously described in detail. Intrapulmonary shunt and VA/Q mismatch were estimated using software based on the algorithm developed by Lockwood et al which produces ODCs using a two-compartment model. Epidemiological, clinical, laboratory, and radiological characteristics were collected in addition to treatments and outcome (discharge or death).

本数据集收录了两家医疗中心内所有因临床确诊或实验室确诊新型冠状病毒肺炎（COVID-19）收治的18岁及以上患者的相关数据。仅纳入入院时存在低氧血症且需补充氧疗的患者。排除标准包括：妊娠、治疗未完成即自行出院，或入院时无血氧饱和度记录的患者。收集了急救人员与急诊科室采用指尖脉搏血氧饱和度仪测得的血氧饱和度数据。根据预设转换表，将氧流量（单位：升/分钟）转换为吸入氧浓度（FiO2）。收集空气呼吸状态下的基础血氧饱和度以及氧疗后的血氧饱和度数据，用于构建氧解离曲线（ODC）。该计算方法此前已在文献中详细阐述。基于Lockwood等人开发的双室模型氧解离曲线算法，使用专用软件估算肺内分流与通气/灌注（VA/Q）不匹配程度。此外，还收集了患者的流行病学、临床、实验室及影像学特征，以及治疗方案与转归（出院或死亡）情况。