hi old and new timers. i am following the procedure in the 4000 hr/annual maintenance guide for the k's to check the blood pump. it says to rig up some tubing with a pressure gauge and if your highest pressure when you clamp the line isn't between 25 and 35 psi you should change the springs. well even when i try this procedure on 2 week old k's i can't get the pressure up over 24 psi. nothing is leaking in my set up. can these parameters be wrong. any ideas. thanks
Make sure you are using 37C water in the line, or as close as you can get, and not just air. If you use cold water, it will make the blood line too stiff and the pump rotor springs cannot occlude it enough to acheive the pressure.
Posts: 130 | Location: Eastern PA | Registered: 24 January 2005
Ya, that test is lame, very lame. used 37C straight from the machine, even put a brand new rotor, still got the same press around 18 to 20. i just check 100,200,300, and so on with fluid into a bucket per minute.
I have no problem doing the same exact test on the 2008H. ( I'm guessing its the same based on what's already been posted.) And yes, I have found weak springs or missing spacers this way. Then again, most of my machines are over 30K hours.
Have the same problem also and my blood pumps are only a year and a half old. As an experiment I loosened up the screws about a half turn each. Did the same calibration again and reached the minimum 25 psi. So to see if I could get a higher psi I backed them off a little more. It improved about 1 psi but then reached a point where it would not fit into the blood pump. So I tightened the screws until it caused no interference and did the calibration again. I have the minimum psi of 25 but you would think they would provide a stronger spring.
Since this is a measure of blood line occlusion, it could be a quality problem related to the blood pump segment of the blood line that you use. If you are having continual problems with many machines or rotors try a couple of different blood lines and see what happens.
