AKI Flashcards
Overview
- Managment of AKI (4 main goals of thearpy)
- identify the reason for the acute kidney injury & treat the underlying disease process
- supportive therapy: electrolyte balance & decide if you need diuretics v. fluids
- Avoiding nephrotoxic agents
- adjust medications and monitor the dosages (due to the renal elimination)
how do you decide if your pt. needs diuretics v fluids to assess the AKI
assess their fluid status
Edematous state v Volume Depleted
Edematous:
- have they been making and able to make urine from the beginning : diuretics then can be used in this case
- if they havent been making urine (anuric) : assess the need for renal replacement thearpy (dialysis)
Volume Depleted:
- give fluids
Loop Diuretics in the setting of an AKI
- what loops are used (names)
- MOA
- most commonly used
- eGFR status
Loop Diuretics
MOA: work to BLOCK sodium, Cl and water reabsorbtion within the thick acending loop of henle
these will not affect the renal recovery process or the survival of the pt. –> only to help fluid offload
When are we using?
- for those pts. who are volume overloaded & edematous
- this will NOT be used in those who have pre-exisitng anuria
Names
- Furosemide (lasixs)
- Bumetanide (HF pts.)
- Torsemide (HF pts.)
- ethacrynic acid (rarely used)
CAN be used with a GFR < 30 = which is comonly our pts. with an AKI
Specifics about the Loop Diuretics
- when can you use ethacrynic acid
- when should you use the others (furosemide, etc.)
the others (Furosemide, bumetanide, torsemide) are all sulfonamide containing diuretics – thuse those who are allergic to sulfonaimide cannot use these
- those who have a mild reaction to sulfa drugs (hives, rash, etc.) can still use these
for those who have a severe reaction to loop diuretics…
- ethacrynic acid can be used: no sulfonamide containing ingredients
note on the dosage for loop diuretics
- they have equipotent dosages which vary depending on the type of the loop & the delivery (PO or IV)
- example: furosemide is poorly bioavalible
your pt. is in AKI and has volumer overload
- what is the treatemetn
- furosemide IV x 1 dose - assess and adjust their response to the SINGLE dose prior to delivering another
do not just give lasix PRN = need to assess their kidney function as it is delivered
how can you tell when your loop diuretic is working in your pt. with AKI
- assess edematous state: easy breathing, cest xray showing less fluid, decreased edema on PE
- increase urine output: aiming to see > 1ml/kg/hr
- weight: daily weights to see how they drop the fluid
Toxicities of the Loop Diuretics
over diueresis
- dehydration
- prerenal AKI (hypoperfusion to the kidney due to the decrease in volume futher injuries the kidneys)
- orthostatic hypotension: due to the decrease in volume
electrolyte abnormalities
- hypokalemia
- hypomagnesia
- hyponatrimia
- hypocalcemia
- INCREASED uric acid, glucose
ototoxicity
- mostly with ethycrynic acid
- seen in the others less (not torsemide)
- seen in furosimide with a dose-dependent course
how to combat resistance to loop diuretics
- double the dose: most commonly what is done in practice
- dose more frequently
- administer via IV continuous
- add a thiazide 30 mins. prior to loop (to impact different areas of the nephron)
HCTZ: can be used at crcl > 30
metolazone: can be used for crcl < 20
how to approach a pt. with a prerenal AKI : who is volume depleted
prerenal AKI: due to sepsis, shock, where the fluid is pulled out to the extracellular spaces (hypoalbuminemia –> push fluid to 3rd spaces)
if moderately volume deplented: give oral fluids
if hypotensive: MAP < 70
- volume repleate 500-1000ml NaCl IV 15-30 minutes
(using isotonic fluids: normal saline, lactate ringers, plasmolyte to maintain the dynamic of the fluid to solute ratio)
- using approx. 1-2L (unless severe sepsis, shock or hyperglycemic emergencies; they will need more)
do NOT use hypotonic solution: this will push water into the cells and not stay within the plasma
only add dextrose if they are also hypoglycemic (< 70)
in what population of pt. do you need to slow the rate of volume repletion in an AKI
these pts. are predisposed to edema: easy to volumer overload them quickly
- heart failure
- pullmonary insufficiency
- stage 4 or 5 CKD
- pre-exisitnig anuria or dialysis dependent pt.
consider a slower rate of fluic repleteion: 250 mL at 30 mins
adverse effects of IV fluids
- acute
- longer term
acute
- pulmonary edema
- peripheral edema
longer term
- hypernatremia
- hyperchloremia
- a non-gap metabolic acidosis : since youre altering the cl
when replacing fluids in an AKI pt.
what are the three parameter you want to assess
- goal measurements
- blood pressure: want a MAP > 65
- heart rate: 60-100 bpm
- urine output: at least 0.5ml/kg/hr
drugs to avoid due to nephrotoxicity in an AKI pt.
Aminoglycoside antibiotics
Amphotericin B
ACE inhibitors
ARBs
(temporarily stop ACE/ARB during an AKI)
Ccontrast : IV radiocontrast dye
NSAIDS
Vvancomycin
… and many others
how to determine drug dosing in those with an AKI
GFR estimations are inacurate in an AKI
- based on SCr
- will see a decrease in urine output prior to an increase in the SCr (takes 1-2 days to see changes in teh SCr)
use clinical reasoning
- assesstheir volume status : is the larger VD due to overlaod or volumer or due to the fluids
- if thye’re not uriniation: assume their SCr level is 0
- risk/benefit of the drug in the pt.
- can monitor drug levels via pulling levels!
