Video 2.
Download video file (629.4KB, mp4)
DOI: 10.1136/bcr-2018-228896.video02
Repeat ECHO.
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.