Renal ICM Teaching 23/10/14QUIZ

J Plumb

1

1. What are the 4 main modes used for RRT within intensive care? (2 marks for all 4)

ANSWER: CVVH, CVVHD, CVVHDF, SCUF

Vascular access 2&3

2. How long should a femoral VASCATH be?

• ANSWER: at least 20cm, usually 25cm lines to the hilt to aim for the tip to sit at the IVC-atrial junction

3. Why is the subclavian route least preferred? (max 3 marks)

• ANSWER: Bleeding risk, worse flows, risk of stenosis is highest, important if long term RRT required

4

4. What is the overall size (surface area) of the haemofilter? (Clue it is in m2)

• ANSWER: The filter size is described in terms of ‘square metres’ (about 0.6-1.5m2).

5. You are asked to see a 76 year old man in ED who has CKD stage 3 (Not yet referred to renal services; GP managed), he has come in drowsy and confused, the electrolytes are as follows:

• Na+ 131, K+ 6.7, Ur 38, Cr 568

• After initial treatment to lower K+

• What mode of RRT would you instigate? What ‘dose’ would you prescribe? And why?

• ANSWER: CVVH 25mls/kg/hr

6

6. Why?

ANSWER: To avoid disequilibrium syndrome

• I’ll probably get slated for these answers

7. Approximately what will the GFR have fallen to (I’m after a %) when you start to see a rise in serum creatinine?

ANSWER: 50%

7

8&9

8. Why then do we not measure GFR at the bedside on ICU?

ANSWER: It is completely impractical to do this, for anyone who didn’t know there are a number of ways to actually do this (Radioisotope or iothalamate methods require multiple blood samples and, if renal function is reduced, the duration of sampling may be up to 24 hours)

9. How then do we estimate it?

ANSWER: These include the MDRD formula and the Cockcroft and Gault formula. (limitations, both have Cr!)

10

10. Can anyone name any of the new biomarkers that may well soon be available to better detect AKI?

ANSWER: kidney injury molecule-1 (KIMI-1), neutrophil gelatinase associated lipocalin(NGAL), interleukin 18 and urine cystatin C

11

11. Can anyone define AKI? (clue 4 things!)

• Well “Kidney disease: Improving global outcomes” (KDIGO) state: Any of the following:

• An increase in serum creatinine by ≥ 26.5 μmol/l within 48 hours

• An increase in serum creatinine by ≥1.5 times baseline which is known or presumed to

• have occurred within the past 7 days

• Urine volume ≤ 0.5 ml/kg/hour for 6 hours

12

12. Can we grade AKI? (I am thinking scoring systems)

ANSWER: RIFLE then AKIN and in 2012 KDIGO combined the 2

• GRADED 1-3

RIFLE and AKIN criteria for AKI

13. Can you distinguish these 2 causes of AKI?

A BUrine sodium < 20 mmol/l > 40 mmol/l

Urine : plasma urea ratio

> 20 < 10

Urine : plasma creatinine ratio

> 40 < 10-20

Urine : plasma osmolality

> 1.5 < 1.1-1.2

Urine osmolality > 500 < 300-500

Fractional excretion of Na 1

< 1% >1%

ANSWER

• A = Pre-renal

• B = Intrinsic ATN

14&15

14. What is a normal Intra-abdomial pressure? (IAP)?

ANSWER: 7 mmHg

15 When do you see renal compromise with raised IAP?

ANSWER: Renal compromise starts to occur when the IAP is over 20-24 mmHg

16&17

16 A patient is very uraemic but requires an urgent laparotomy. There is not time to start RRT.

• What drug could be considered to help prevent bleeding?

ANSWER: DDAVP

17. How does it work?

ANSWER: It (possibly) acts by increasing the release of factor VIII and enhancing the expression of von Willebrand factor.

18

• A patient presents with fast AF and hyperkalaemia of unknown cause, the K+ is 6.8 and they have a worrying looking ECG.

• PMH- HTN, AF, CCF, MI (2010), DM, Obesity• DH- Aspirin, Simvastatin, Amlodipine, Ramipril,

Furosemide, Digoxin, Spironolactone• You want to urgently treat the hyperkalaemia so

you start to draw up some insulin/dextrose but firstly you decide to give some calcium

• How do you do this?

Single best answer

A- 10 mls of 10% calcium gluconate via a central line STAT

B- 10 mls of 10% calcium gluconate via a large cannula over 3 mins

C- 10 mls 10% calcium gluconate diluted in 100 mls 5% glucose over 20 minutes

D- 10 mls of calcium chloride via a central line over 2 mins

E- 10mls of calcium chloride via a large cannula over 3 mins

Answer

• C- 10 mls 10% calcium gluconate diluted in 100 mls 5% glucose over 20 minutes

• WHY?

• Because (rapid calcium administration can precipitate myocardial digoxin toxicity).

19

• Name 3 drugs that can be removed via CRRT on ICU?

• Lithium

• Barbituates

• Salicylates

• Theophyline

• Ethylne glycol

• Methanol

20

You are asked to review a patient who has been established on CVVH for AKI secondary to sepsis for the last 6 hours, however things haven’t been straight forward. There have been line ‘issues’ and the nurse at the bedside isn’t very experienced with running the filter. The TPM has gone up and the filter appears to be: ‘it’s just not working doc’

Single best answerA- Check APTR, consider switching to a different method of anticoagulation, give a fluid challenge, increase the blood flow.

B- Switch the replacement fluid to a pre/post ratio of 20/80 to ensure that more replacement is given post dilution.

C- Accept that the filter is not working and set up a new filter. This time give a heparin bolus prior to restarting the filter. Give 1000mls of NaCl.

D- Check that the patient has been adequately anti-coagulated, check the pre-dilution/post-dilution ratio for the replacement fluid and ensure that intravascular volume is adequate.

E- Assess the patients general filling status, ensure adequate anticoagultion (Check APTR), increase the amount of pre-dilution replacement fluid and switch the mode to CVVHDF.

F- Ask the nurse to give a fluid bolus of 500mls of NaCl, switch the replacement ratio to 50/50, check the latest APTR, suggest that you think changing the mode to SLED is likely to help.

Answer

D- Check that the patient has been adequately anti-coagulated, check the pre-dilution/post-dilution ratio for the replacement fluid and ensure that intravascular volume is adequate.

21

A 19 year old cerebral palsy patient weighing 28kgs was admitted 5 hours ago with AKI thought to be secondary to profound dehydration. After fluid resuscitation (50mls/kg) she remains anuric her pH is 7.13 and her BE= -16 with a lactate of 6.2. Vascular access looks extremely challenging due to contractures.

Ur 23

Cr 412

SBAA- Assess volume status, check Hb, consider ECHO/CO monitor, if non responsive to fluid and remains anuric insert a VASCATH and filter CVVHDF at 35mmls/kg/hr.

B- Get an ECHO, assess volume status with CO monitor + ECHO, start CVVHDF with an overall exchange of 50mls/kg/hr.

C- Continue to give fluid/blood, use a non-invasive cardiac output monitor, if remains anuric insert a VASCATH and filter CVVHDF with an effluent dose of 70mls/kg/hr.

D- Insert a VASCATH and start CVVH at 25mls/kg/hr paying close attention to the urea level.

E- Speak to PICU, Give 10mls/kg blood, Insert a VASCATH and start SCUF.

F- Insert a VASCATH and start CVVH as per protocol at 35mls/kg/hr with standard anticoagulation and a standard pre/post ratio.

Answer

A- Assess volume status, check Hb, consider ECHO/CO monitor, if non responsive to fluid and remains anuric insert a VASCATH and filter CVVHDF at 35mmls/kg/hr.

22

You have a patient who has recently gone onto CVVH who is very unwell with severe sepsis and MOF secondary to HAP. He has not tolerated going onto the filter very well and keeps dropping his blood pressure with escalating inotrope requirements. You have been asked to review.

SBAA- Stop the filter as he is clearly not tolerating it, aim to improve hemodynamics first then re-start.

B- Assess volume status, check electrolytes, rule out arrhythmias, consider fluid challenge, ensure that the filter prescription is correct.

C- Decrease the blood flow/minute to see if that helps.

D- Ensure that fluid is not being removed on the filter, slow down the blood flow, give a fluid challenge.

E- Check electrolytes, give 250mls NaCl, slow down the exchange, change to pre/post ratio and slow down the blood flow rate.

F- Look for the cause, check electrolytes, consider fluid challenge after assessing volume status, check to filter membrane being used.

Answer

B- Assess volume status, check electrolytes, rule out arrhythmias, consider fluid challenge, ensure that the filter prescription is correct.

THE END

• TOTAL MARKS POSSIBLE = 49

• SBA questions 4 marks for correct answer 0 marls for any other answer!

• Sorry if I have caused SBArage (this is a well described clinical syndrome amongst modern medical trainees)