Nice video. You can actually turn the handle of sampling stopcock (with a blue valve) to flushing position (the handle lever facing downwards, the opposite to what is shown in the in the video) and flush all the "dead space" with the residues of the blood that is trapped in the side branch underneath the valve.
I'm sorry that raised so many questions for me. Perhaps I need to go and find out what a pressurised bag is , where the lines went to, where was the flush being drawn from, is that red fluid meant to be arterial blood ? would it look like that or a richer colour? why was first extraction clear - then pale red, is that a two way tap, .
The saline is used to prime the tubing that you're hooking to the arterial line. It is placed into a bag that you pump up to keep pressure to keep the patient from pumping blood into your saline bag. In the first example he is withdrawing a "waste" sample that is used to clear the line of saline (to prevent a diluted sample). What you are seeing is him drawing back on the syring to bring blood back into the tubing so you can get an accurate sample. And no, blood does not look like that. It's probably water with food coloring.
