AKI Flashcards Preview

662 > AKI > Flashcards

Flashcards in AKI Deck (43):
1

Drug dosing in AKI

  • Decision to dose adjust medications should be a clinical decision based on CrCl, UO, and suggested dosing guidelines
  • Calculate CrCl and review UO daily
  • Dose reduce based on suggested guidelines
  • Consider serum drug concentrations
  • Dose adjust back up when renal function recovers

2

AKI pt evaluation steps

  1. Discontinue nephrotoxic medications
  2. Identify cause of AKI
  3. Treat AKI
  4. Renally dose adjust medications 

3

Post renal AKI diagnosis

  • Renal imaging
  • UA: Hematuria, crystals
  • BUN:SCr <15:1
  • FeNa > 1%
  • No daily change in SCr
  • Anuria 

4

Be able to identify and treat different types of AKI

 

Know how to calculate a CrCl and UO

Be familiar with prevention strategies

Know common medication nephrotoxins

Dose adjust medications in AKI 

5

Urinary Analysis

 

  • Hydration
    • Color
      • Dark yello=dehydrated
    • Specific gravity
    • >1.020 = dehydration
  • Infection
    • WBC
      • >50= infection
    • Leucocyte esterase
      • Production of neutrophils 
      • 1+,2+, 3+ = infection
    • Nitrites
      • made by bacteria
      • Positive= infection
  • Kidney Function
    • Protein, 1+,2+,3+ = intrinsic renal failure
    • RBC,  Positive = Traumatic catheterization, tumor, nephrolithiasis
  • Casts 
    • Different types (hyaline, granular)
    • Positive = intrinsic renal failure
  • Crystals
    • Different types (uric acid, calcium oxalate)
    • Positive = tumor lysis syndrome or nephrolithiasis

6

Types of Acute Kidney Injury

Prerenal

Intrinsic

Postrenal

7

Prerenal AKI

  • Occurs prior to the kidney 
  • Reduction in blood volume
  • Reduction in bloodflow to the kidney 
    • Hypotension
    • Sepsis
    • Heart or liver failure
    • Bleeding
    • Renal thrombosis

8

AKI definition

Decline in?

Increase?

Increase?

 

  • Abrupt reduction in kidney function
    • Decline in urine output
    • Increase SCr
    • Increase BUN

9

Post renal failure tx

  • Remove obstruction
    • Nephrolithiasis- lithotripsy
    • Tumore= Surgery
    • Stricture = urinary stent
    • BPH = doxazosin, tamulosin, finasteride
  • Hydronephrosis
    • Nephrostomy tube

10

Prerenal Failure Tx

  • Restore blood volume
    • IV fluids- aggresive rehydration with normal saline or balance solution
    • Discontinue diuretics
  • Restore blood flow 
    • Blood - indicated in bleeding situations 
    • Treat the underlying cause conditions (heart failure, sepsis)
  • Discontinue and limit nephrotoxins 

 

11

Types of intrinsic AKI

ATN and AIN

12

CRRT

  • Indicated when blood pressure too low to tolerate HD
  • Continual removal of fluids and solutes so more resembles actual kidney function
  • Differ in way the solute is removed

13

Diagnosing prerenal AKI

  • Pt hx, N/V, diarrhea
  • Dry mucous membranes, decrease jugular venous distension
  • UA: Dark yello, high specific gravity
  • BUN:SCr > 20:1
  • Urinary Na < 10
  • FeNa < 1%
  • Oliguria
  • Rapid change in SCr with tx 

14

AKI symptoms

  • Fluid overload
    • SOB
    • Peripheral edema
    • wt gain
  • Urinary Changes
    • Decreased or painful urination
    • Change in color or odor
  • Uremia
    • N/V
    • Itching
    • Fatigue
    • Confusion
  • Situation
    • Flank pain
    • HA
    • Arthralgia

15

AKI complications

  • Fluid overload
    • Pulmonary and peripheral edema
    • IV bolus loopd diuretics --> Continuous infusion loop diuretics ---> hemodialysis
  • Electrolyte abnormalities
    • Increase K, Phosphorus, magnesium
    • Hyperkalemia most common and concerning
  • Blood glucose irregularities
    • Hyperglycemia common due to impaired glucose homeostasis and metabolic stress
    • Insulin eliminated by the kidneys so may result in hypoglycemia

16

Drug dosing in AKI 

HD 

and 

CRRT

  • Assume little to no UO
  • Drug elimination dependent on filter type, flow rate, amount of time on HD and drug characteristics
    • Molecule size, protein binding, ionized form
  • Dosing different for each medication
    • Bolus dosing daily or 3 times/week after HD

 

CRRT

  • Dependent on flow rate but usually assume normal renal function with no drug adjustment 

17

ATN - 

Nephrotoxic meds

  • ACEs
  • ARBs
  • NSAIDs
  • Amnoglycosides
  • Vancomycin
  • Amphotericin B

18

ATN- Rhabdomyolysis

Rhabdomyolysis

  • breakdown of muscle cells releases damaging proteins into systemic circulation
  • Seen by an increase in CPK and myoglobin
  • Myoglobin specifically damages kidneys 
  • Serum myoglobin level useful in diagnosis
  • Treat with fluids such as normal saline or sodium bicarbonate 

19

Risk factors for AKI

  • Male
  • AA
  • Advanced Age
  • CKD
  • DM
  • Heart or Liver Disease
  • Surgery
  • Sepsis
  • Hypotension
  • Volume depletion
    • Diarrhea
    • Vomiting
    • Dehydration
  • Medications

20

AKI monitoring

  • Daily wts
  • Fluid intake and UO
  • Daily serum creatinine
  • daily serum electrolytes
  • Vital signs 
  • Symptoms (edema) 

21

Post Renal AKI

  • Occurs after kidney 
  • Caused by an obstruction between kidney and urethra
    • Nephrolithiasis
    • Uric acid crystals
    • Tumor 
    • Stricture
    • BPH

22

Type of renal replacemen

Hemodialysis

Rapid removal of fluids and solute

Performed daily in acute setting or 3 x 

common complication hypotension

23

AKI treatment goals

  • Restore renal function to baseline
  • Identify the cause
  • Reverse the cause
  • Limit damage
  • treat symptoms
  • Manage complications

 

24

Modification of Diet in Renal Disease (MDRD)

 

  • Calculate an eGFR
  • Better estimates renal function
  • Utilized to stage renal failure

25

Indications for renal replacement therapy

AEIOU

  • Acidosis
  • Electrolytes 
  • Intoxication
  • Overload
  • Uremia

26

ATN

Contrast Induced Nephropathy

  • Dye causes free radical formation which is directly toxic to the kidneys 
  • SCr increase 2-5 days after contrast exposure
  • Prevention is key
    • Normal saline or sodium bicarb infusion
    • N-Acetylcysteine

27

SCr

 

  • Must know pts baseline
  • Trend in SCr more important than acutal level
  • Lag in SCr change by 1-2 days from original insult
  • Use of GFR equations limited as these assume stable renal function 

28

Urine Output

  • Most acute marker of change in renal function
  • Conern when <0.5 mL/kg/hr
  • Complicated by volume status, diuretic use and obstruction
  • Nomentclature
    • Nonoliguric is > 500 ml/day 
    • Oliguric <500 ml/day
    • Anuric <50 mL/day

29

Acute Interstitial Nephritis AIN

  • Delayed hypersensitivty rxn
  • Tubular and Interstitial inflammation 
  • Symptom triad, Fever, Rash, Urine Eosinophils 
  • Medications most common cause
    • beta lactam antibiotics
    • NSAIDs 
    • Trimethoprim/ sulfamethoxazole 

30

Review 

  • Normal kidney function markers
  • Definite, detect and classify AKI
  • Types of AKI
    • Diagnosis and tx
    • Prerenal, intrinsic and postrenal
  • Renal replacement therapy
  • Complications of AKI
  • Drug dosing in AKI
  • AKI prevention 

31

Fractional Excretion of Sodium

 

  • Reflection of ability of kidney to concentrate urine
  • Not accurate if recent diuretic use

32

AKI Markers and lab testing

 

  • SCr
  • UO
  • Urinary Analysis
  • Urine Electrolytes
  • Renal imaging 

33

Urine output criteria

Risk 

injury

Failure

Loss ESRD

  • UO < 0.5 ml/kg
  • UO < 0.5 ml/kg x 12 hours
  • UO < 0.3 ml/kg x 24 hours or anuria x 12 (oliguria)
  • Persistent ARF = complete loss of renal function > 4 weeks 
  • ESRD

34

Kidney Function Markers

Urine Output

Normal Output?

How to calculate?

  •  Best marker of urine function
  • Normal urine output = 0.7-1 ml/kg/hr
  • To calculate determine amount of urine output and divide by the pts weight and time period

35

Kidney Function Markers

Serum Creatinine

SCr < 1 

Affected by age, gender, muscle mass, diet and hydration status

Some medications may increase

36

Intrinsic AKI

 

  • Direct damage can be due to the glomerulus or tubules 
  • Kidney injury a result of 
    • Ischemia
    • Toxins
      • Medications
      • Contrast dye
      • Proteins (myoglobin)

37

AKI classifications

Staging Criteria

Types of Staging systems

  • Staging 
    • SCr change for baseline
    • GFR change from baseline
    • Urine output over specified time period
  • Systems
    • Risk, Injury Failure, Loss of Function and ESKD (RIFLE)
    • Acute Kidney Injury Network (AKIN)
    • Kidney Disease: Improving global Outcumes (KDIGO)
       

38

glomerular filtration rate

equation

(140-age) x wt (kg)

72 x SCr

 

if female x by 0.85

39

GFR Criteria

Risk

Injury

Failure

Loss

ESRD

  • Increased creatinine x 1.5 or GFR decrease > 25%
  • Increased creatinine x 2 or decrease >50%
  • Increased creatinine x 3 or >75% decrease or creatinine > 4 mg per 100 mL
  • Persistent ARF = Complete loss of renal function > 4 wks 
  • ESRD

40

Renal imaging

Renal ultrasounds

Abdominal CT scan

41

Intrinsic renal failure treatment 

  • Discontinue offending agent 
  • IV-fluids- normal saline or balanced solutions
  • Limit nephrotoxins

42

Normal Renal Function 

A WET BED

  • A- Acid/base balance
  • W-Water balance
  • Electrolyte balance
  • Toxin Removal
  • Blood pressure control (Renin)
  • Erythropoietin production
  • Vitamin D activation

43

Intrinsic AKI diagnosis

  • UA: Protein, granular casts, eosinophils
  • BUN:SCr < 15:1
  • FeNa > 1%
  • Slow change in SCr with tx