5. Acute Kidney Injury Flashcards
What is the clinical definition of Acute Kidney Injury?
Rapid reduction in Kidney function (hours to days) characterised by High Creatinine and/or Low Urine output
- Rise in Serum Creatinine of > 26 umol/L in 48 hours
OR
- 1.5-1.9 x Increase in Serum Creatinine known to have happened in the last 7 days
OR
- 6 hours of Oliguria (Urine Output of <0.5 ml/kg/hour)
What patients are at risk of getting AKI?
- Elderly
- CKD (eGFR < 60ml/min/1.73 m^2)
- Cardiac Disease
- Liver Disease
- Diabetes
- Vascular Disease
- Nephrotoxic Medication
What is the Main Acronym to manage AKI?
Sepsis: Find the infection (if there is one) and treat it
Toxicity: Avoid medications that harm the Kidneys
Optimising BP
Parenchymal Disease
What are the 4Ms to prevent AKI?
- Monitor (BP/Fluids/Blood)
- Maintain circulation (Hydration/Resus/Oxygenation)
- Minimise Renal Insults
- Nephrotoxic meds
- Iodinated Contrast
- HAIs - Manage acute illnesses appropriately
How do we maintain fluids in AKI?
Assess the volume status (Standing/Supine)
- HR
- JVP
- Cap Refill
- Conscious Level
- Lactate
- Weight
If they are HypoVol, give bolus fluids (250-500 ml) and review
If 2+ Litres are given and underperfused, give circulatory support
Why is too much fluid harmful in AKI?
Pulmonary oedema
Delayed recovery
For a euvolemic patient with AKI, how should you manage them?
Give maintenance fluids: Estimated Daily output + 500 mL
What fluids are best suited for AKI patients?
Isotonic Fluids (Plasmalyte/Hartmann’s): Containing Potassium (5 mmol/L)
0.9% Saline: But can worsen Metabolic Acidosis if large volumes used
Colloids: High molecular weight starches (HES)
- Dextran can worsen AKI
How do we monitor and Manage AKI?
- Urinary Catheter + Hourly input/output
- U+Es, Bone Profile, Venous Bicarbonate
- Blood Gases
- Lactate
- Regular Fluid assessment
- Daily weights
How do we investigate AKI?
- Urine Dip (PCR if protein is present)
- US Scan < 24 hours
- 6 hours if Pyonephrosis is suspected - Inflam Markers (CK/LFTs)
- Blood Film/LDH/Reticulocyte count
- HUS/TTP/Acc HTN with MAHA
- If Platelets are low
What 8 things can be investigated in AKI in the blood?
- Serum protein electrophoresis/Bence Jones Protein (Myeloma)
- Blood and Protein +++ on dip
- HIV/HCV/IgG/HepB
- ANCA
- Anti-GMB
- Complements
- Rheumatoid Factor
- ANA/ENAs
What does the Bence Jones Protein indicate in the urine?
Multiple Myeloma
If there is blood and protein +++ on dip, what can be suspected?
Acute Glomerulonephritis
What do we do whilst supporting AKI recovery?
- Treat Sepsis
- Maintains Perfusion
- Stop NSAIDs, ACE, ARB, Metformin, PSD/Adjust drug doses
- Stop antihypertensives if hypotensive
- Minimise iodinated contrast
Why is Calcium gluconate given to AKI patients?
If their ECG changes and to reduce the risk of Myocardial Arrhythmias
Why is IV Insulin or Dextrose given to AKI patients?
10 Units Insulin or 50 mL of 50% Dextrose can promote Potassium shift into ICS
- Given if Potassium is above 6.5 mmol/L
- Sometimes Na2CO3 is given
Why do we given 1.26% bicarbonate IV 500 ml 1-4 hours to AKI patients?
If their Bicarbonate is below 22 mmol/L
If an AKI patient has their whole body potassium lowered, what do they need?
Kidney recovery of function
Renal Replacement therapy
- Haemodialysis
- Filtration
How can we manage Pulmonary Oedema as a result of AKI?
- Sit them up and give O2
- GTN Infusion
- Furosemide
- >80 mg bolus (then further)
- 10mg/hr infusion
How can we manage Acidosis as a result of AKI?
- Ensure it is renal in origin
- Recovery of renal function
- Critical Care referral if pH drops below 7.15
- Renal Replacement Therapy maybe
How can we confirm if acidosis is renal in origin?
- Raised Anion gap
- Gases
- Lactate
- Ketones
How do we refer AKI patients with an Obstruction?
Urology/Interventional Radiology for Nephrostomy +/- Stenting
How do we refer AKI patients with blood/protein on dip/Autoimmune diseases
Renal (Local or Regional)
How do we refer AKI patients progression into Stage 3 (Creatinine 3x above baseline and rise of 354 umol/L, 12 hours of Anuria?)
Local Renal for HD
Regional if they are safe to transfer
How do we refer AKI patients if they have 1 organ failure/unstable/acute HD unavailable and they are unsafe to travel?
ICU for CVVHF
What does CVVHF stand for?
Continuous Veno-venous Haemofiltration