The disclosure relates to a nasal cannula comprising a port configured for delivery of a medicament into a flow of a fluid being delivered by the nasal cannula to a user and/or configured for interfacing with a medicament delivery device or an instrument. The disclosure also relates to a nasal cannula comprising an asymmetric profile to reduce an amount of occlusion of one nare of a user to provide access for an instrument to the nare with the nasal cannula in use.