Fig. 1. Patients’ and anesthesiologists‘ estimation of patient discomfort caused by the oxygen mask during preoxygenation on a continuous scale from 1 (no discomfort) to 10 (maximum discomfort). Shown are the median and 5th and 95th percentiles as box-and-whisker plot and outliers as single data points. The anesthesiologists markedly overestimated the discomfort of patients during preoxygenation.