Pht- 1.5.2 Pressure Holding Test (Pht) Theory - Fresenius Medical Care 2008K2 Troubleshooting Manual

PHT- 1.5.2 PRESSURE HOLDING TEST (PHT) THEORY

DO NOT START THE TESTS TILL INSTRUCTED!
A)
B) Understanding Pressure Holding Test (PHT) theory (steps 1 – 5 below) aids troubleshooting. If already
familiar with PHT theory see procedure number
C) Call debug screen 1 to locate ATMP AND FILACT.
1) The Pressure Tests begin with "Remove Air". This is a sixteen (16)
second Filling Program to purge air from the hydraulics. During this
time FILACT = 1 then should go to and remain = 0.
2) During "Get Neg TMP" the UF Pump strokes, every eight (8) seconds, to achieve
NEGATIVE PRESSURE. ATMP (Figure right) should increase to its TARGET of
more than negative 250 which causes the UF Pump to stop.
NOTE: All ATMP readings (in mmHg) are from Dialysate
Pressure Transducer #9
3) When "Neg Flow On" appears a thirty (30) second STABILIZATION period begins followed
immediately by a thirty (30) second HOLD period. During STABILIZATION ATMP should settle
between negative 250 and 450. During the HOLD period ATMP should not change more than
+/- 20!
IMPORTANT NOTE: If ATMP DOES NOT STABILIZE or HOLD the tests automatically return to
step #1
4) During the very brief "Get Pos TMP" the fresh side balancing chamber valves
momentarily open to achieve POSITIVE PRESSURE then all eight (8) balancing
chamber valves close (i.e. Flow Off)! ATMP should go to about positive (+)350.
5) When "Pos Flow Off" appears a twenty (20) second STABILIZATION period begins followed by a
thirty (30) second HOLD period. During STABILIZATION ATMP is initially unstable but should settle
between +180 and +350. During the HOLD period ATMP should not change more than +/- 30!
IMPORTANT NOTE: FILACT should NOT = 1 during the Positive Tests!
D) See procedure number
PHT- 2.0.0
PHT- 2.0.0 (page 478).
2008K/K2 Troubleshooting Guide
P/N 507298 Rev. H
(page 478)
Page 477