CRRT

Question 1

Function of the kidneys

Answer 1

Sodium and water regulation
Excretion of waste products
Electrolyte regulation
Acid/base balance - bicarbonate buffer system
BP control - RAAS system
Stimulation of RBC production (erythropoietin)
Activation of vitamin D

Question 2

Transmembrane pressure

Answer 2

Pressure across the filter membrane

TMP= (filter pressure + return pressure)/2 - effluent pressure

Normal TMP = 0 to 350

Question 3

Renal indications for CRRT

Answer 3

ARF with oliguria or anuria
Azotemia
Fluid overload in response to diuretics
Sepsis
Cerebral edema

Question 4

Non renal indications for CRRT

Answer 4

Drug overdose
Metabolic disorders
Crush injuries (haemolysis)
Sever burns
ECMO

Question 5

Diffusion

Answer 5

Movement of solute from an area of high concentration to an area of low concentration

Rate of diffusion depends on:
Filter surface area
Molecule size

Diffusion removes small molecules effectively

Question 6

Convection

Answer 6

The movement of solutes with a water flow “solvent drag”

Used to remove middle and large size molecules
The greater the amount of fluid that moves, the greater the solute loss

Question 7

Osmosis

Answer 7

The tendency of a fluid to move across a semi permeable membrane into an area of high concentration, thus equalising the concentrations on both sides of the membrane

Question 8

Ultrafiltration

Answer 8

Movement of fluid across a pressure gradient

Uses a pressure gradient, whereas diffusion uses a concentration gradient

Question 9

Adsorption

Answer 9

Where molecules that are too large to migrate through the membrane adhere to the membrane itself

Can eventually block the filter and crash the set

Question 10

SCUF

Answer 10

Slow continuous ultrafiltration

Purely fluid removal through a semi permeable membrane
No dialysate and no replacement fluid

Question 11

CVVH

Answer 11

Continuous veno-venous haemofiltraton

Convective dialysis
Uses convection and ultrafiltration
No dialysate
For mid and large sized molecules

Question 12

CVVHD

Answer 12

Continuous veno-venous haemodialysis

Diffusive dialysis
Chemical dialysis, no pressure used
Uses dialysate with a counter That current
No fluid is removed because there is no ultrafiltration

Question 13

CVVHDF

Answer 13

Continuous veno-venous haemodiafiltration

Combines CVVH and CVVHD
Solute removal is achieved by diffusion and convection

Question 14

TPE

Answer 14

Therapeutic plasma exchange

Used in auto immune diseases where plasma exchange is required
Uses a plasma filter instead of a haemofilter

Question 15

SLED

Answer 15

Sustained low efficiency dialysis

Hybrid therapy (between IRT and CRRT)
Same as IRT but with reduced blood flow rates
Called low efficiency but it’s actually higher efficiency than CRRT

Question 16

Contents of a multibic bag

Answer 16

Mmol/L

Na 140
K 0
Ca 1.5
Mag 0.5
Cl 109
HCO3 35
Glucose 5.55

pH is approx 7.2

Question 17

Access pressure

Answer 17

-50 to -150mmHg

Can be positive is using ECMO or a fistula
Can also be positive when starting at low rate

Question 18

Filter pressure

Answer 18

+100 to +250mmHg

Question 19

Effluent pressure

Answer 19

-150 to +150mmHg

Negative or positive depending on the life of the filter (eg. Adsorption makes pump work harder so more negative)

Question 20

Return pressure

Answer 20

+50 to +150mmHg

Same as access pressure but positive

Question 21

Blood leak detector

Answer 21

Detects blood in effluent line

Question 22

Air detector

Answer 22

Detects air in return line
Clamp will clamp down if air is detected

Need to monitor level in de-airation chamber and adjust as required

Question 23

Green

Answer 23

All clear, continue

Question 24

Yellow

Answer 24

All pumps stop except blood pump eg. Change bag

Question 25

Red alarm

Answer 25

All pumps stop including blood pump eg. Filter clotted

Question 26

Blood flow rate

Answer 26

Start at 50mls/hr Increase to 200ml/hr as haemodynamically tolerated

Question 27

Dialysate rate

Answer 27

Run at 20ml/kg/hr

Question 28

Pre blood pump

Answer 28

Run at 10ml/kg/hr

Question 29

Post filter replacement

Answer 29

Run at 200ml/hr (set rate)

Question 30

Heparin

Answer 30

Drawn up 12,500units in 50ml | Run at 4ml hour = 1000units/ hour

Question 31

Protamine

Answer 31

Drawn up 100mg in 100ml 1mg reverses 100units of heparin Therefore run protamine at 10mls/hour Protamine runs on seperate pump via 3 way tap or on seperate vascath lumen

Question 32

Equipment for connecting filter

Answer 32

``` Dressing trolley Dressing pack Sterile gauze Chlorhex Sterile gloves 2 10ml syringes 2 5ml syringes 2 saline ampules Gogglese Surgical mask ```

Question 33

Equipment for disconnecting filter

Answer 33

``` Dressing trolley Dressing pack Sterile gauze Chlorhex Sterile gloves 2 10ml syringes 2 5ml syringes 2 saline ampules Goggles Surgical mask Heparin for heparin lock 2 3 ml syringes for heparin lock ```

Question 34

Extreme negative access pressure

Answer 34

Negative pressure measured by access pump More than -250mmHg Could be caused by linking, vascath on vessel wall, vascath is occluded, severe hypovolaemia

Question 35

Positive access pressure

Answer 35

May be positive when filter first set up and blood pump is only at 50mls May also be positive with ECMO or filter access

Question 36

Extreme positive return pressure

Answer 36

Pressure messed by return pump is more than 300mmHg Causes Linking, blocked vascath, vascath against the vessel wall, vascath is dislodged and emptying into haematoma, vascath in artery

Question 37

Extreme positive filter pressure And High TMP

Answer 37

Alarms when difference between filter and return pressure is more than 250mmHg Causes Natural filter degradation eg adsorption Embolus or clot in filter Pre blood replacement is set too high High TMP with normal return pressure = problem with filter High TMP with high return pressure = problem with filter AND/OR return line Advisory TMP alarm when TMP is 300 Filter clotted alarm occurs when TMP 450

Question 38

Blood leak detected

Answer 38

Look for blood Test with dip stick If positive, filter may have ruptured Need new set If not positive normalise BLD to recalibrate

Question 39

Air in return line

Answer 39

Check for air Level is too low in de airation chamber If possible, aspirate air Otherwise need new set

Question 40

Excessive/inaccurate fluid removal

Answer 40

Check correct weight | Check scales for interference

Question 41

Indications for ceasing RRT

Answer 41

``` Indication for initiating is resolved eg. Drug toxicity resolved Renal recovery Fluid state normalised Electrolyte state normalised Transfer to comfort/palliative care ```

Question 42

What if the filter clots

Answer 42

If possible, stop spike start before filter clots | If filter already clotted, need to prime new set

Question 43

What if therapy is to be ceased

Answer 43

Blood is returned using saline bag | Connect saline bag to access and press start return

Question 44

What if therapy is to be temporarily ceased

Answer 44

Recirculation ``` Press recirculation option Connect saline bag to access line Return the blood by pressure start return Disconnect patient from return line Filter can recirculate for 120 mins ```

Question 45

Normal clotting values

Answer 45

INR 1.1-1.3 (2.0-3.0 for warf) APTT 30-40 seconds Fibrinogen 1.5-4

Question 46

Molecule sizes

Answer 46

``` Small Urea Creatinine Na K ``` Medium Vitamin B12 Glucose Large Insulin Albumin

Question 47

Lactate buffer solution is not suitable in which patients?

Answer 47

Liver failure Severe metabolic acidosis In these cases use bicarbonate buffer solution

Question 48

Pinch valves

Answer 48

Can close valves to use pre/post filter replacement or not depending on filter mode

Question 49

How to get rid of static electricity

Answer 49

Electrostatic discharger ring