Assessing COVID‐19 pneumonia—Clinical extension and risk with point‐of‐care ultrasound: A multicenter, prospective, observational study gan Arthur W. E. Lieveld, Bram Kok, Kaoutar Azijli, Frederik H. Schuit, Peter M. van deVen, Chris L. deKorte, Robin Nijveldt, Frederik M. A. vanden Heuvel, Bernd P. Teunissen, Wouter Hoefsloot, Prabath W. B. Nanayakkara, Frank H. Bosch