Why does blood not clot when itís in a surgical drain?
We put this to Professor Adrian Newland:
Adrian - It may eventually clot but at the operation site blood gets activated so the clotting factorís actually get stimulated and removed so the blood is able to clot and it will build up around the wound and cause damage and prevent healing. Itís sucked out.
Chris - When you say clotting factors, Adrian, what actually are they?
Adrian - Theyíre little cells called platelets but also chemicals within the blood called clotting factors.
Chris - How do they work?
Adrian - They work by becoming activated by raw tissue and they form a little spiderís web that brings the blood together.
Chris - And it grabs blood cells, presumably? It forms this meshwork and you donít bleed any more. If youíve got oozing through that just plasma and things what Thomas might have been seeing in his drain was just plasma minus these things that have already been removed?
Adrian - Yes. It might have been exudate that oozed out and was being sucked away.