hemodialysis machine key feature

1. DIALYSIS MACHINES KEY FEATURES
Yousaf Khan
Renal Dialysis Lecturer
IPMS-KMU

2. DIALYSIS MACHINES KEY FEATURES
 Blood pump
 Dialysate delivery system
 Safety monitors
 Options
 System disinfection

3. BLOOD PUMP
 Circulate the blood through the dialyzer back to the patient.
 Peristaltic roller pumps which works by progressive
compressing special segments of the blood tubing are used.
 Pump occlusion: occlusion means that the roller compress the
tubing segments against the semicircular housing sufficiently
to close the lumen completely at that point.
 Overocclusion may crack tubing and rupture
 Occlusion incomplete – back flow

4. DIALYSATE DELIVERY SYSTEM
 Appropriate blending of concentrate and water for preparation
of final dialysate.
 To monitor dialysate for temperature, composition and blood
leak.
 To control dialysate pressure or ultrafiltration rate.
 To regulate the dialysate flow rate through the dialyzer.
 Deareation of water
 Provide protective mechanisms to isolate the blood circuit and
the patient from unsafe dialysis.
 System for disinfection and cleaning.

5. SAFETY MONITORS
 Monitors for blood circuit
Arterial pressure monitor
 Proximal to the blood pump
 Reads the arterial pressure at the segment between the pts
needle site and proximal to the blood pump which represent
the negative pressure created by roller pump.
 How much suction is being placed on the arterial wall and
guard against excessive suction on the vascular access.
 Resistance within the needle
 It provide an index of vascular access blood supply relative to
the flow demand by the blood pump.

6. ARTERIAL PRESSURE MONITOR
 A guide to appropriateness of needle placement or kink or
obstruction in the blood segment between the pts and monitor.
Mechanism:
 The pressure is monitored by mechanical or electronic
manometers ( pressure transducer). Electronic transducer is
more sensitive and have rapid response.

7. VENOUS PRESSURE MONITOR
 Just distal to the dialyzer usually attached to the top of the
venous air trap.
 Reads the venous pressure at the segment b/w the point after
the dialyzer and before the blood return to the pts body.
 Represent resistance of the blood returning to the patient via
the venous needle.
 It may indicate venous stenosis proximal to the needle site.
 Mechanism: as in arterial pressure monitor

8. VENOUS AIR TRAP AND AIR DETECTOR
 Just distal to venous pressure monitor.
 Often second air trap on the arterial line is also used.
 To prevent air entry into pt or the dialyzer.
 Mechanism: air bubble enter- sensor reacted through
ultrasonic transducer or light beam by stopping blood pump,
clamping the venous line and activation audiovisual alarms.

9. MONITORS FOR DIALYSIS SOLUTION
CIRCUIT
Conductivity:
 Before dialysate reaches to dialyzer
 To guard against excessive diluted or concentrated dialysis solution.
 Conductivity meter detects high or low conductivity the machine
automatically sounds an alarm and puts the dialysate into bypass
mode so that no dialysate flow to the dialyzer.
 Exposure of the blood to hyperosmolar dialysate can lead to
hypernatremia and other electrolyte disturbances.
 Exposure of the blood to hypo osmolar dialysate can lead result in
hyponatremia and rapid hemolysis.

10. Temperature:
 Before the dialyzer
 To avoid high temperature
 Mechanism: through a temperature sensor, high temperature activate
an audiovisual alarm simultaneously with bypass mechanism.
Dialysate pressure or transmembranouse monitor:
 To monitor the ultrafiltration with an upper limits avoids excessive
level (the usual preset range 0-500 mmHg). Excessive TMP may
lead to rupture of the dialyzer and secondary deareation ( cause air
accumulation).
 Mechanism: the monitor may have automatic or manually set limits
so that extrusion outside the limits trigger an audiovisual alarm.

11. Blood leak detector:
 In the effluent dialysate line
 It guards against undetected blood loss during dialysis.
 A beam of light is directed through a column of dialysate onto a
photoelectric cell. A change in translucence and light scatter in
dialysate reduces the light received by the photocell, stopping blood
pump and activating audiovisual alarms.
Bypass valve or mechanism:
 If the conductivity or temperature found to be out of limits a bypass
valve is activated to divert dialysate around the dialyzer directly to
the drain.

12. OPTION IN HEMODIALYSIS MACHINE
 Heparin pump
 Bicarbonate
 Variable sodium
 Controlled ultrafiltration
 Programable ultrafiltration
 Dialysate urea sensor (online kt/v monitor)
 Single blood pathway

13. SYSTEM DISINFECTION
 All dialysis unit must have written policies the deal with the dialysis
fluid pathway and dialysis machine.
 Disinfection procedure should be done on regular base according to
manufacturer's instruction.
Target:
 To control bacterial contamination. HIV, HCV and HBV viruses are
known to be inactivated by common household bleach.
Methods:
 Heat disinfection requires temperature greater than 85-90 C.
 Chemical disinfection such as formaldehyde, sodium hydrochloride
and acetic acid.

14. DIALYSIS MACHINE: PATIENT MONITOR
B.p:
 Some machine monitor arterial pressure automatically.
ECG:
 Can be monitored by the machine
Blood volume monitors:
 Hct or protein conc. In the arterial blood line by optical or
ultrasonic sensors as surrogate for blood volume (as water is
removed from the blood, blood volume falls, and red blood cell
and protein conc. increase) they can measure relative blood
volume reliably and reproducibly and allow automatic
feedback.

15. DIALYSIS MACHINE: PATIENT MONITOR
Monitoring fluid balance:
 Blood volume monitor can analyze the effects of a short period of rapid
UF on blood volume to determine the hydration status of a patient.
 The rate of refilling of the vascular compartment can give a measure of
extravascular fluid.
Access recirculation:
 Can be measure temperature in the arterial blood line after reducing or
increasing the dialysate temperature for a few minutes.
Access blood flow:
 Can be measure by saline injection techniques during Hct monitoring or
change in Hct due to a short period of UF.
Delivered Kt/V
 Online measurement of urea removal or change in dialysate conductivity

16. ALARM DURING HEMODIALYSIS
PROBLEM SOLVING GUIDE LINES
 When an alarm is activated during dialysis do the
following
 Identify which alarm has been activated
 Identify the cause
 Correct the cause
 Resume dialysis if safe to do so

17. Power:
 Turn the system off and on: if still no power check the power cord
make sure power is available.
 Check the fuse.
Arterial and Venous Pressure:
 Check to see that blood pump is running and connected properly
 Check to see if blood flow rate has changed
 Determine if patient has coughed or moved
 Check to see if the monitor line is leaking
 Check the blood line for kinks or leaks
 Ensure the monitoring lines are connected to proper drip chambers

18. High venous pressure:
 Manipulate the needle and or the line. If access is small a tourniquet
must be used, being certain the blood pump is off, recantation with
new needle if needed.
 Adjust the blood flow rate, proper heparnization, treat access
problem and proper needle and needling.
 Extreme care must be exercised when dialyzing a patient with high
venous pressure
 This increase the baseline TMP and obligatory ultrafiltration will
occur.
 Single needle device is occasionally impossible to use, because with
high venous pressure, venous return will be impaired and blood
recirculation will be high.

19. High negative pressure:
 Manipulation of the arterial needle is similar to that of venous needle.
In most cases the needle may have to be replaced with the same
precaution as with venous needle.
 Treat the cause
 Proper needling
 Asses the access
High positive dialysate pressure alarm:
 Check to see if drain is occluded or kinked
 Check to see if dialysate hoses are leaking
Low negative dialysate pressure alarm:
 Check to see if dialysate hoses are kinked

20. Air Detector alarm:
 Check for air leaks around tubing joints
 Excessive undetected negative pressure
 Check for unattended intravenous solution administration.
Management of air embolism if present.
 Clamp the venous line and stop the blood pump.
 Place the patient in trendelenberg position on the left side with the chest
and head tilted downward to trap the air at the apex of right ventricle away
from the outflow tract.
 Cardiorespiratory support oxygen 100%.
 Occasionally percutaneous aspiration of the air foam from the heart may
be necessary.

21. High temperature alarm:
 Determine temperature of dialysate in the line actually high
 Check to ensure incoming water temperature is below 90 F.
Low Temperature alarm:
 Determine temperature of dialysate to dialyzer in the line is actually
low.
 Turn the mode selector switch to dialyzer
 Allow adequate time for the system to stabilize and come to proper
temperature range.
 Check to ensure incoming water temperature is above 40 F.
High Conductivity alarm:
 Check to see if water is flowing too slowly or turn off.
 Check for kink in the concentrate out line.
 Make sure that the system has had time to stabilize
 Analyze the dialysate to confirm high conductivity at the to dialyzer line
connection:

22. a. If normal there is malfunction in the machine itself (change it)
b. If high again concentrate before resuming dialysis.
c. Be certain that the dialysate flow rate is proper.
Low conductivity alarm:
 Turn the mode selector switch to dialyze.
 Connect the concentrate line to the system
 Drop the concentrate line into the concentrate container
 Check for kinks in the concentrate in line
 Make sure the filter on the concentrate in is clean
 Allow adequate time for the system to stabilize
 Change the concentrate container if it is dry
 If the concentrate container has not run dry a sample of dialysate
should sent to the laboratory for sodium and chloride.
 Analyze the dialysate to conform low conductivity at drain
 If low conductivity is conformed change the concentrate bottle.

23.  If the conductivity still low after changing the concentrate a different
machine should be tried.
 Be certain that the dialysate flow rate is proper.
Blood leak alarm:
 make sure the blood leak detector is clean
 Check the effluent for traces of blood
 Exclude
 Bilirubin in dialysate in jaundiced patient, Air bubbles in dialysate, Dirty
sensor
 If leak confirmed and you can not mange the cause
 Reduce dialysate compartment pressure to -50 mmHg to avoid bacterial
entry to the blood
 Dicontinoue dialysis

24. Thank You