Acute Kidney Injury Flashcards
1
Q
What is AKI?
A
rapid reduction of GFR → increased nitrogenous waste products
- +/- Decreased urine output
- 5-7% of hospitalizations results in AKI
- 5-10x as many as community AKI
- critically ill patients may end up with CKD → mortality rate > 50% with AKI
- 5-10x as many as community AKI
2
Q
Staging System for AKI
A
-
Stage 1:
- absolute serum creatinine increase
- ≥ 0.3mg/dL or 150-200% increase from baseline
- Urine Output: less than 0.5ml/kg/hour for 6+ hours
- absolute serum creatinine increase
-
Stage 2:
- absolute serum creatinine increase (unavailable) or 200-300% increase from baseline
- Urine Output: less than 0.5ml/kg/hr for 12+ hours
-
Stage 3:
- absolute serum creatinine increase ≥ 4mg/dL with an acute increase of ≥ 0.5mg/dL or 300% or greater increase from baseline
- Urine Output: urine output less than 0.3ml/kg/hr for 24 hours or anuria for 12 hours
- → need renal replacement therapy
3
Q
RIFLE Criteria and AKI
A
- RIFLE: Risk, Injury, Failure, Loss, ESKD
- GFR criteria
- Risk: increase SCr x 1.5 or GFR decrease greater than 25%
- Injury: increase SCR x 2 or GFR decrease greater than 50%
- Failure: increase SCr x 3 or GFR decrease greater than 75%
- OR SCr greater than 4mg/dL, acute ≥ 0.5mg/dL
- Urine Output Criteria
- Risk: UO <0.5mL/kg/hour x 6 hours
- Injury: UO <0.5 mL/kg/hour x 12 hours
- Failure: UO <0.3mL/kg/hour x 24 hours, or anuria x 12 hours
- LOSS: persistent AKI - complete loss of kidney function > 4 weeks
- ESKD: loss of kidney function > 3 months
4
Q
Cockcroft-Gault Equation For Adults
A
5
Q
Meds that can cause AKI
A
- high risk pts should avoid these meds
- aminoglycosides
- amphotericin B
- radiocontrast Dye
- Cyclosporine and Tacrolimus
- ACE and ARB
- NSAIDs
- MTX etc
6
Q
Diuretics and AKI
A
they may increase urine output but do not decrease mortality
- should only be used for hypervolemic states
- should NOT be used to make oliguric patients nonoliguric in AKI, nor increase urine output when pt is NOT hypervolemic
7
Q
Loop Diuretics and dosage
A
40mg furosemide = 20 mg torsemide = 1 mg bumetanide
- torsemide and bumetanide have a greater bioavailability and duration than furosemide
- 40mg furosemide IV → response in 30min - 1 hour (output ≥ 1mL/kg/hr)
- can double dose if AKI pt with fluid overload is not initially responsive → if still not responsive then add thiazide
8
Q
Dopamine & Fenoldopam and AKI
A
- Dopamine = improves urine output but does not have any clinical benefit
- fenoldopam = low dose reduces SCr but did not improve mortality or lower the need for dialysis
9
Q
Fenoldopam (Corlopam)
A
Stimulates dopamine D1-like and Alpha-2 (mild-mod affinity) receptors → causes rapid vasodilation
- R-isomer = responsible for biological response
-
INDICATIONS: severe HTN
- contrast induced nephropathy (off-label)
-
SEs:
- ≥ 5%: flushing, hypotension, headache, nausea
- <5%: angina, bradycardia,, chestpain, MI, orthostatic hypotension
- anxiety, dizziness
- hyperglycemia, hypokalemia
- abdominal pain, N/V/D Constipation
- UTIs
- bleeding, leukocytosis
- IOP increased
- BUN and creatinine increase
- DDI: antihypertensive meds → increases hypotension
10
Q
Preventing Contrast-Induced Nephropathy
A
-
NS or NAHCO<u>3</u> IV infusion → decreases incidence of nephropathy
- give 1mL/kg/hr NS IV 12 hours before and 12 hours after procedure
- if pt high risk for volume overload: CHF with EF <40% → use 3 amps NaHCO3 + 1L D5W
-
N-acetylcysteine:
-
PO at 1200mg Q12 hours
- for high-risk pts the before contrast and day of procedure
- AVOID: diuretics, NSAIDs, ACEI, Metform 24-48 hours prior
-
PO at 1200mg Q12 hours
-
Statins:
- use before coronary angiography → reduces contrast induced AKI
- high intensity
11
Q
Rule of Thumb for Fluid Replacement in adults
A
30-40mL/kg/day + normal insensible losses (lungs: 400mL/day, Skin 400mL/day, Feces 100mL/day)
12
Q
Drugs that cause HyperK
A
K-sparing diuretics
K-supplements
Abx with K salts
ACE-I
ARBs
NSAIDs
13
Q
Hypokalemia Tx
A
When to tx? <3.5 mEq/L and/or pt is symptomatic
- treatment:
- oral: K-chloride, KPO4, K-acetate, K-citrate, k-gluconate
- IV: if >10 mEq/L should be monitored via telemetry
- other: diuretic induced (spironolactone- K+ sparing diuretic)
- correct hypomagnesemia
- ****low magnesium makes body resistant to K+ replacement, so tx mg deficiency first or concurrently*****
- correct acid-base imbalance
- correct hypomagnesemia
- oral: K-chloride, KPO4, K-acetate, K-citrate, k-gluconate
14
Q
Hyperkalemia Tx
A
-
Symptomatic (urgent/emergent)
- IV calcium to stabilize the heart membrane
- insulin +/- glucose/dextrose to temporarily push K+ back into the cell
- albuterol to also temporarily push K+ back into the cell
- Sodium bicarb to be considered to tx acidosis
- Eliminate Source: IV, total parenteral nutrition (TPN), tube feeds, oral supplements, K sparing diuretics
-
Symptomatic:
- sodium polystyrene sulfonate (Kayexelate) → binds potassium, slower onset, but duration of 4-6 hours (constipation though…)
- Loop diuretics (lasix)
-
Asymptomatic;
- eliminate source
- kayexelate (sodium polystyrene sulfonate) → binds potassium
- loop diuretics
15
Q
Serum and Ionized/Free Calcium Levels
A
- Normal Total Serum Ca2+: 8.5-10.5mg/dL
- >13 or <6 = critical values
- Normal Ionized/Free Ca2+: 1.18-1.30mmol/L
- critical values= <0.9 or >1.6
