Acute Kidney Injury Flashcards
- 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
- AKI is most common in acute care setting
- CKD more likely in community settings or as a co-existing condition in acute care settings
- Filter wastes & maintain fluid & electrolyte balance, acid-base balance
- Kidneys work together w/many other systems
Assessments: Recognize Cues - Physical Assessment
- Skin, head, & neck
- Respiratory, cardiovascular
- Renal (inc I&O), musculoskeletal
- Abdominal, CNS, psychosocial
Urinalysis
- Color, odor, turbidity
- Specific gravity
- pH
- Glucose
- Ketone bodies, protein
- Leukocyte esterase, nitrites
- Cells, casts, crystals, bacteria
Other Urine
- Urine for C&S
- Composite urine collections
- Creatinine clearance - best indication of overall kidney function !
- Urine electrolytes & osmolarity
Laboratory Assessment
- Serum creatinine, BUN, BUN:serum creatinine ratio
- Blood osmolarity
- Kidney/urinary
! 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
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
What is the BEST indicator of OVERALL kidney function?
creatinine clearance (a measure of GFR)
- Usually done w/a 24 hr urine collection
! CC/GFR is NOT accurate during acute & critical illness
?
Is a urine output <400 mL/day
Oliguria
?
Is the retention & buildup of nitrogenous wastes in the blood
Azotemia
Kidney Failure: Prerenal, Intrarenal, & Postrenal
?
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
Postrenal failure
?
- 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
Intrarenal
?
! 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
Prerenal failure
Prerenal
?
Failure that has a low specific gravity, <1.010
Intrarenal
?
Failure that has a normal specific gravity, 1.000 - 1.010
Postrenal
?
Failure that has a high specific gravity, >1.030
Prerenal
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
Nephrotoxic Substances: Other
- Organic solvents/non-drug chemical agents
- Heavy metals & ions
Comparison of Acute (many systems) vs Chronic (every system)
AKI - Classifications: RIFLE, KDIGO
R - Risk stage
I - Injury stage
F -Failure stage
L - [Outcome] loss
E - [Outcome] end-stage kidney disease
KDIGO - Kidney Disease Improving Global Outcomes
Phases of Acute Renal Failure - (4)
Onset > Oliguric > Diuretic > Recovery
? 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
Recovery
? Phase
- Output between 100-400 mL urine/day
- Elevation of substances usually excreted by kidneys, i.e., urea, creatinine, uric acid, K, Mg
Oliguric
? Phase
- Increase in daily u/o of 1-3 L/day but may be higher
- Kidneys excrete but are unable to concentrate
Diuretic
? Phase
- The time from initial insult until oliguria develops
Onset
Health Promotion & Maintenance
- Severe blood volume depletion can lead to renal failure even in people who have no known kidney problems
- Continual assessment of I&O, blood volume depletion, lab values, use of nephrotoxic substances
! Decreased urine SG indicates a loss of urine-concentrating ability & is the earliest sign of renal tubular damage
- NSAIDs can cause or increase risk for AKI
- Obtain peak & trough levels of abx known to be nephrotoxic (i.e., garamycin, vancomycin)
Assessment: Recognize Cues
- History, physical assessment/clinical manifestations
- Lab assessment
- Imaging/diagnostic tests
> urine, labs, xray, US, CT, Nuc Med, Bx - Drug therapies
- 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)
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
- 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
- Careful observ of I&O, daily weights
- Frequent serum labs
- 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
- When AKI is assoc w/drug or alcohol intoxication, RRT can also remove toxins
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
Interventions: Taking Action cont’d
- Consult a dietitian
- Plan meals w/client
- Provide a pleasant mealtime environment
- Administer rx’s to reduce nausea
> Tailor interventions toward what you find in assessments
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
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
