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

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

11/21/2011 June 2009

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

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

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

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

SIMPLIFIED RIFLE OR AKIN DEFINITION Usually based on Creatinine rise Loss and End stage components of RIFLE now dropped Creatinine criteria Urine output criteria ≥ 50-100% rise in Cr Urine output <0.5 ml/kg/hr for 6 hours (=240 ml at 80 kg) High sensitivity Risk or AKIN 1 101-200% 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

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

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

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

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

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

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 38.3. 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.

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?

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

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

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

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

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

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

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?

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

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

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

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

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

AKI QUESTION TIME

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

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.

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

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 ++

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

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)

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

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

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)

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

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