Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Acknowledgements
We would like to thank all our team members for their efforts in developing the plan. They are Dr. Zhongwei Zhang, Xiaodong Jin, Xiaoqi Xie, Wanhong Yin, Wei Lai, Yao Chen, Xi Zhong, Hao Yang from Department of Critical Care Medicine, West China Hospital. Head nurse Pro.Yongming Tian, Ai Ping Du and Lin Cai from Department of Critical Care Medicine, West China Hospital; Infection control expert Shichao Zhu from Department of Infectious Disease; Respiratory therapist Yiyi Yang, Meiling Dong and Aijia Ma from Department of Critical Care Medicine, West China Hospital.

Funding
Funding was provided by National Natural Science Foundation of China (Grant no. 81701880) and National Natural Science Foundation of China (Grant no. 81873929).

Compliance with ethical standards

Conflicts of interest
On behalf of all authors, the corresponding author states that there is no conflict of interest.