Figure 4
Continuous insufflation of either CO 2 or air after administration of capsaicin. Pain ratings on a numerical rating scale from 0 to 10 before and during nasal insufflation of CO2 (black dots) with a flow of 1 l/min or compressed air (grey boxes) for 19 minutes after intranasal application of capsaicin. The time is given in minutes. Error bars are given as standard error of the mean.