1. From the Departments of Anesthesiology and Critical Care Medicine (X.-H.W., F.C., Z.-T.M., D.-X.W.), Respiratory Disease and Critical Care Medicine (C.Z., J.M., G.-F.W.), and Biostatistics (S.-N.Z.), Peking University First Hospital, Beijing, China; and Section of Anaesthetics, Pain Management and Intensive Care, Department of Surgery and Cancer, Imperial College London, Chelsea and Westminster H