Figure 3: Consort flowchart of study participants. (a) Intubation with Macintosh laryngoscope without COVID barrier box group, (b) Intubation with Macintosh laryngoscope with COVID barrier box group, (c) Intubation with KVVL without COVID barrier box, (d) Intubation with KVVL with COVID barrier box group. COVID-19: Coronavirus disease 2019, KVVL: King Vision video laryngoscope