1. FY1 Teaching Nov 30th 2011 Dr Jack Bond ST5 Nephrology
Acute Kidney Injury
FY1 Teaching
Nov 30th 2011
Dr Jack Bond
ST5 Nephrology

2. Acute Kidney Injury - Objectives
To recognise AKI
To differentiate between pre-renal, renal and post renal causes of AKI
To recognise and manage hypovolemia
To manage hyperkalemia and pulmonary odema
To know indications for emergency dialysis
How to call a nephrologist without getting shouted at

3. 11/21/2011
June 2009

4. NCEPOD Conclusions - Summary
There were systematic failings in AKI care
Failures in:
Recognition and management of AKI
Recognition and management of complications
Referral and support
Failures in recognition of the acutely ill 4

5. AKI Questions Please complete the questionnaire
Anything you want to ask about AKI
Will answer them anonymously during the lecture

6. Managing AKI Is your patient really sick? Get help
Volume assess + fluid challenge
U+Es + blood gas
Urine dip
U/S abdo
Nephrology referral

7. Definition of AKI Rise in serum creatinine >50% from baseline Or
Urine output <0.5ml/kg/hr for 6 hours

8. SIMPLIFIED RIFLE OR AKIN DEFINITION Usually based on Creatinine rise Loss and End stage components of RIFLE now dropped
Creatinine criteria
Urine output criteria
≥ % rise in Cr
Urine output <0.5 ml/kg/hr for 6 hours
(=240 ml at 80 kg)
High
sensitivity
Risk or
AKIN 1
% rise in Cr
Urine output <0.5 ml/kg/hr for 12 hours
(= 480 ml at 80 kg)
Injury
or AKIN 2
Urine output <0.3 ml/kg/hr for 24 hours or anuria 12 hours
>200% rise in Cr
High
specificity
Failure
or AKIN 3
Oliguria

9. Which scenario is AKI? 1. 85 male, D+V, creat 120, usually 80
2. 82 female, D+V, Urea 15.2, Creat 150
3. 60 male, diabetic, creat 250, usual 200
4. 74 male, legionella pneumonia, Na 118, Creat 130, usual creat 70
5. 63 female, diabetic, myocardial infarct, eGFR 25, usual eGFR 35

10. Suspect AKI in a sick patient with a modest rise in their creatinine
Large acute drop in GFR with oligoanuria
GFR falls rapidly to near zero
- only shown by oliguria
Slow rise in Cr until
eventually a new steady state is reached
Only a small early rise in Cr: not easy to recognise as AKI
11/21/2011

11. Effect of AKI on odds of death Chertow GM et al J Am Soc Nephrol 2005
11/21/2011

12. Rise in serum creat > 50% baseline
baseline creatinine of 80 mmol/L
Rises to 120 mmol/L
Significant kidney injury
This is the moment to act – it is too late when the creatinine reaches 400

13. Things that don’t diagnose AKI
Urea – not specific
eGFR – used in Chronic Kidney disease
Electrolytes disturbance
A result of AKI, but not specific

14. Case
66 year old man is admitted to A+E with breathlessness. He has been unwell for a week, coughing up phlegm and having fevers. His past medical history includes diabetes and hypertension. His medication is metformin, aspirin, ramipril, atenolol and simvastatin.
On examination he is unwell. His obs are BP 85/50, HR 115, Sats 92% on air, RR 25, Temp You hear coarse crackles on the right side of his chest. A CXR confirms pneumonia.
His blood results come back which show Na 130, K 4.5, Urea 14.3, Creat 189. The nurse asks you to assess him as he hasn't passed urine since admission.

15. Case Outline the management you would undertake in A+E.
What is the likely cause for his renal failure?
What investigations would you order and why?
What risk factors are evident in this man's case that make him more likely to have renal failure?

16. Managing AKI Is your patient really sick? Get help
Volume assess + fluid challenge
U+Es + blood gas
Urine dip
U/S abdo
Nephrology referral

17. AKI risk factors Most people have > 1 risk factor Age
Drugs (ACEi, diuretics, NSAIDS)
Chronic kidney disease
Hypovolemia/Sepsis
Diabetes

18. AKI: causes
Important to attempt to categorise broadly into one of 3 groups
sepsis/hypovolemia 70%
drug related, acute GN 20%
obstruction 10%
PRE-RENAL
RENAL
POST-RENAL

19. Cause of AKI – 3 tests Fluid/volume assessment PRE Urinalysis RENAL
3 assessments result in a 45% 36 months survival, compared with 15% for 0 assessments
Fluid/volume assessment PRE
Urinalysis RENAL
Ultrasound POST

20. Question Which of these is the most useful indicator of hypovolaemia?:
capillary refill time > 5 seconds
jugular venous pulse not visible at 30º
postural pulse rise > 30 bpm
systolic blood pressure < 95 mm Hg
systolic BP rise with 250 ml saline bolus > 20 mm
11/21/2011

21. Volume assessment - key
MEWS score
Cap refill
BP, HR,
Postural BP
JVP
Auscultate lungs
Peripheral odema
Urine output

22. Volume assessment Is patient fluid depleted, euvolemic or overloaded?
You are the FY1 covering orthopedics. You have been asked to see 74 female post #NOF as she has low urine output
PMH - diabetes, hypertension
Creat 150, baseline 100, urine output 20mls in last hour
CRT 2 secs, BP 110/50, HR 98, JVP ??, chest couple of creps, no edema
Is patient fluid depleted, euvolemic or overloaded?
How much fluid would you prescribe?

23. Volume management Most patients are hypovolemic (70%)
If not grossly overloaded – fluid challenge
- 500ml + recheck
“Normal” BP for 75 year old – 150/70
- a post op BP of 110 is relatively hypotensive

24. Volume assessment Furosemide in ARF – meta-analysis
- Ho et al 2006, BMJ
Does not improve mortality
Does not reduce need for dialysis

25. Urinalysis Ie glomerulonephritis
- this points towards intrinsic renal disease
Ie glomerulonephritis
- blood and proteinuria on dipstick = nephrology referral

26. AKI investigations u/s urinary tract
- suspect obstruction in men with prostatic symptoms
- palpable mass
- intra-abdominal malignancy compress ureters with no bladder palpable females
- where cause not obvious

27. Managing AKI Is your patient really sick? Get help
Volume assess + fluid challenge
U+Es + blood gas
Urine dip
U/S abdo
Nephrology referral

28. AKI QUESTION TIME

29. Hyperkalaemia - True/False
1. Calcium gluconate acts by reducing the serum potassium T/F
2. Insulin/dextrose infusion requires 30mins to shift potassium into cells T/F
3. Insulin/dextrose infusion effects last for 24 hours T/F
4. Salbutamol nebulisers have the same effect as insulin/dextrose infusion T/F
5. IV sodium bicarbonate can reduce potassium T/F
6. to treat hyperkalemia you would prescribe 50 units of actrapid in 50ml 50% dextrose T/F
7. 10ml of 10% Calcium gluconate is the correct prescription for the treatment of hyperkalemia T/F
8. Calcium resonium acts within minutes to reduce serum K T/F

30. Hyperkalemia
K+ >6.5
- 1st – repeat measure on VBG/ABG (takes 5 mins)
- if true – ECG
- if life threatening changes
Calcium gluconate 10ml 10% stat (through big vein – tissue burns)
- thereafter 10 units actrapid in 50mls 50% glucose over 30 mins.

31. Hyperkalemia Insulin/dextrose – lasts 4 hours only
- in meantime correct cause of high K
- Repeat ABG at 4 hours to see if better
If K+ still high – DIALYSIS MAY BE INDICATED

32. Hyperkalemia - caution in cardiac disease
Salbutamol nebs (10-15mg) have same action as insulin/dextrose and may be an option
- caution in cardiac disease
IV sodium bicarbonate 1.26%
- useful in dehydrated patient who is ACIDOTIC
- discuss with senior, but consider if HCO3 <18 and needs ongoing fluid replacement
- worsens pulmonary oedema ++

33. Hyperkalemia Key is to recheck after treatment
Correct underlying cause
Consider dialysis

34. Pulmonary oedema in AKI
ABCDE approach
Oxygen
GTN infusion
Diamorphine
Consider large dose furosemide 250mg IV
CPAP
ITU/ventilation
Correct cause of renal failure (days)

35. Dialysis indications Resistant hyperkalaemia >6.0
Consider haemodialysis/haemofiltration if:
Resistant hyperkalaemia >6.0
Fluid overload and no urine output
Persistent acidosis pH<7.2
Call for senior support in all cases
Nephrology referral for dialysis patients admitted under any other specialty

36. When to call nephrology
Any known dialysis patient admitted
Any known renal transplant patient admitted
Any case of AKI where cause not clear
Worsening AKI
Emergency dialysis indications
Suspect glomerulonephritis

37. What info to have when calling nephrologist
Your (boss') reason for referral
The history and background in your head – dont read the notes to me – check with patient if not clear history
The notes by the phone
The obs chart by the phone (MEWS, Urine output)
A urine dipstick result
Your assessment of the patients fluid status
An up to date venous blood gas (that day)

38. Managing AKI Is your patient really sick? Get help
Volume assess + fluid challenge
U+Es + blood gas
Urine dip
U/S abdo
Nephrology referral

39. AKI: Summary
Small changes in creatinine can have grave clinical consequences
ABCDE assessment and careful management of fluid status is mainstay of treatment
Get help early