Up to this day there is still little know about expirated/expectorated bloodstains.  There are some features that are characteristic for expirated bloodstain patterns, these features include air bubbles in/on the bloodstains, the colour is less red because of the interaction with saliva in the mouth. Although there are a lot of characteristics none of these have to be present, this is a problem and makes it difficult to define a bloodstain as expirated blood.  We make use of the hot wire method and high speed imaging to define the air speed expirated mechanisms can achieve, what diameter the droplets have and if it is possible to link a pattern to a certain mechanisms.