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收治的全部18周岁及以上经临床或实验室确诊为新型冠状病毒肺炎（COVID-19）的患者相关数据。仅纳入入院时存在低氧血症且需接受辅助氧疗的患者；排除妊娠患者、治疗未完成即自行出院的患者，以及入院时无血氧饱和度记录的患者。收集由急救人员及急诊科室通过指尖脉搏血氧仪测得的血氧饱和度数据。将氧流量（单位：升/分钟）依据预设转换表格换算为吸入氧浓度（FiO2）。采集空气呼吸状态下的基础血氧饱和度及吸氧后的血氧饱和度数据，用于构建氧解离曲线（ODC），其计算方法此前已有详细阐述。基于Lockwood等人开发的双室模型算法，通过专用软件估算肺内分流与通气血流（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）。