HI Biff thanks for the reply, yes did have the batch number, but have had the fault occur with 2 sets from the batch yet others fine. So unless there was a few dodgy sets in the batch I dont know.
When I tested the very first new set with the suspect pump, it ran fine, spot on 2 mL every time until I put a needle on the end to try to simulate the amount of back pressure that a central line might have generated. I put a 20 gauge needle on with gave me a pressure of around 18mmHg in the set. And that is when the first pump/set began playing up immediatly and delivering very small bolus's. But with another pump / set the needle made little difference it just began playing up after about 16 hours, even though it had not infused that much during that time. So yes it is pretty mysterious!!
2 very experienced nurses saw it happen once and in my testing I have seen it occur twice on two different pumps with 2 different (though same batch) sets. A real head scratcher!
