Acute Kidney Injury

Question 1

• Loss of kidney function affects ability to maintain normal processes of urinary elimination, fluid & electrolyte balance, & acid-base balance
• Loss also interrupts activity of every organ system, esp immune, endocrine, skeletal, & cardiovascular

Answer 1

• AKI is most common in acute care setting
• CKD more likely in community settings or as a co-existing condition in acute care settings

Question 2

• Filter wastes & maintain fluid & electrolyte balance, acid-base balance

Answer 2

• Kidneys work together w/many other systems

Question 3

Assessments: Recognize Cues - Physical Assessment

• Skin, head, & neck
• Respiratory, cardiovascular
• Renal (inc I&O), musculoskeletal
• Abdominal, CNS, psychosocial

Answer 3

Urinalysis

• Color, odor, turbidity
• Specific gravity
• pH
• Glucose
• Ketone bodies, protein
• Leukocyte esterase, nitrites
• Cells, casts, crystals, bacteria

Question 4

Other Urine

• Urine for C&S
• Composite urine collections
• Creatinine clearance - best indication of overall kidney function !
• Urine electrolytes & osmolarity

Answer 4

Laboratory Assessment

• Serum creatinine, BUN, BUN:serum creatinine ratio
• Blood osmolarity
• Kidney/urinary

Question 5

! BUN is not always the best indicator of kidney function because it’s not ALWAYS elevated

No common pathologic condition other than kidney disease increases the serum creatinine level

Answer 5

Serum creatinine level doesn’t increase until @ least 50% of kidney function is lost, & therefore any elevation of serum creatinine values is important & should be further assessed

! Creatinine is excreted by the kidneys

Question 6

What is the BEST indicator of OVERALL kidney function?

Answer 6

creatinine clearance (a measure of GFR)

• Usually done w/a 24 hr urine collection
  ! CC/GFR is NOT accurate during acute & critical illness

Question 7

?

Is a urine output <400 mL/day

Answer 7

Oliguria

Question 8

?

Is the retention & buildup of nitrogenous wastes in the blood

Answer 8

Azotemia

Question 9

Kidney Failure: Prerenal, Intrarenal, & Postrenal

Question 10

?

Involves cancers such as bladder, cervical, colon, prostate, prostate hypertrophy, obstruction (kidney stones), spinal cord injury/nerve damage/neurogenic bladder, pelvic trauma, blood clots in urinary tract

Answer 10

Postrenal failure

Question 11

?

• Kidney damage - acute tubular necrosis, renal trauma, severe muscle exertion, genetic conditions, infectious diseases/sepsis, metabolic disorders, glomerulonephritis, renal artery lesions
• Abx, contrast imaging dyes, ischemia from cardiac/resp arrest

Answer 11

Intrarenal

Question 12

?

! Perfusion reduction - shock, circulating volume depletions, volume shifts, decreased CO, decreased PVR, renal artery obstruction

___ azotemia - renal failure c/b poor blood flow to the kidneys

Most commonly c/b hypovolemic shock & HF, liver failure, NSAID use, burns, dehydration, stenosis

Answer 12

Prerenal failure

Prerenal

Question 13

?

Failure that has a low specific gravity, <1.010

Answer 13

Intrarenal

Question 14

?

Failure that has a normal specific gravity, 1.000 - 1.010

Answer 14

Postrenal

Question 15

?

Failure that has a high specific gravity, >1.030

Answer 15

Prerenal

Question 16

Nephrotoxic Substances: Rx’s

• Antibiotics/antimicrobials
• Drugs (NSAIDs)/other drugs
  ! Metformin - If pts get contrast dye while taking this rx they can go into renal failure

Answer 16

Nephrotoxic Substances: Other

• Organic solvents/non-drug chemical agents
• Heavy metals & ions

Question 17

Comparison of Acute (many systems) vs Chronic (every system)

Question 18

AKI - Classifications: RIFLE, KDIGO

R - Risk stage
I - Injury stage
F -Failure stage
L - [Outcome] loss
E - [Outcome] end-stage kidney disease

Answer 18

KDIGO - Kidney Disease Improving Global Outcomes

Question 19

Phases of Acute Renal Failure - (4)

Answer 19

Onset > Oliguric > Diuretic > Recovery

Question 20

? Phase

• GFR increases
• BUN/creatinine plateau & then decrease
• Improvement may occur in 1-2 weeks but may take up to 12 mos to stabilize
• Labs return to baseline

Answer 20

Recovery

Question 21

? Phase

• Output between 100-400 mL urine/day
• Elevation of substances usually excreted by kidneys, i.e., urea, creatinine, uric acid, K, Mg

Answer 21

Oliguric

Question 22

? Phase

• Increase in daily u/o of 1-3 L/day but may be higher
• Kidneys excrete but are unable to concentrate

Answer 22

Diuretic

Question 23

? Phase

• The time from initial insult until oliguria develops

Answer 23

Onset

Question 24

Health Promotion & Maintenance

• Severe blood volume depletion can lead to renal failure even in people who have no known kidney problems

Answer 24

• Continual assessment of I&O, blood volume depletion, lab values, use of nephrotoxic substances

Question 25

! Decreased urine SG indicates a loss of urine-concentrating ability & is the earliest sign of renal tubular damage

Answer 25

* NSAIDs can cause or increase risk for AKI * Obtain peak & trough levels of abx known to be nephrotoxic (i.e., garamycin, vancomycin)

Question 26

Assessment: Recognize Cues * History, physical assessment/clinical manifestations * Lab assessment * Imaging/diagnostic tests > urine, labs, xray, US, CT, Nuc Med, Bx * Drug therapies

Answer 26

* MAP of 65 mmHg maintained to promote kidney perfusion * A clinically significant inc in creatinine, esp if it's over a few hrs or a few days, is a concern & needs to be reported immediately (may then order 24 hr urine for CC)

Question 27

ARF: Taking Action > Therapies * Fluid challenge > Prerenal azotemia - fluid challenges & diuretics used to promote renal blood flow (bolus 500-1000 NS over 1 hr) If not FVE. It it's oliguric RF, fluid challenges & diuretics are d/c'd * Diuretic therapy cautiously

Answer 27

* Calcium channel blockers > Used to treat AKI resulting from nephrotoxins > They prevent movement of calcium into kidney cells, maintain kidney cell integrity, & improve kidney blood flow > Are stopped if they don't improve GFR as est by CC

Question 28

* Careful observ of I&O, daily weights * Frequent serum labs

Answer 28

* Nutrition/diet control, PPN, TPN > Specialty tube feedings for kidney pts are lower in Na, K, & P & higher in calories than are standard feedings * Dialysis (or RRT) Indications - > Symptomatic uremia (pericarditis, neuropathy, unexplained decline in cognition) > Persistent or rapidly rising high K lvls (>6.5 mEq/L) > Severe metabolic acidosis (<7.1) > Fluid overload that compromises tissue perfusion

Question 29

* When AKI is assoc w/drug or alcohol intoxication, RRT can also remove toxins

Answer 29

Interventions: Taking Action > Monitor trends of I&O > Assess VS, daily weights > Evaluate skin turgor, mucous membranes > Monitor lab values, frequent oral care, restrict fluids

Question 30

Interventions: Taking Action cont'd * Consult a dietitian * Plan meals w/client * Provide a pleasant mealtime environment * Administer rx's to reduce nausea

Answer 30

> Tailor interventions toward what you find in assessments

Question 31

Gerontologic Considerations: ARF - Older adults more susceptible r/t function of nephrons dec w/age > Dehydration > Hypotension > Diuretic therapy > Aminoglycoside therapy > Obstructive disorders (prostatic hyperplasia) > Surgery, infection, contrast agents

Answer 31

Review - goals for care * Prevention * Find & remove cause of failure * Correct fluid, electrolyte, & acid-base imbalances * Dialysis may be needed to remove metabolic wastes until kidneys heal * Prevent infection * Maintain nutritional status