Fig. 5

The spread of tracer gas from the patient's mouth a) case 1: high intensity-LED surgical lamp; b) case 2: low intensity-LED surgical lamp; and case 3: high intensity-LED surgical lamp with a curtain
The spread of tracer gas from the patient's mouth a) case 1: high intensity-LED surgical lamp; b) case 2: low intensity-LED surgical lamp; and case 3: high intensity-LED surgical lamp with a curtain