Renal day 2 Flashcards
Urine Output
Standards
Daily output averages 1000 – 2400 ml / day
Normal adult approximately 1500 mL/day
Acute Care Setting: 30 ml / hour (720 ml / day)
Oliguria: 100 – 400 ml / day
Aging kidney’s lose ability to concentrate
Older adults may be oliguric with volumes of 600 – 700 / day
Anuria: < 100 ml / day
Acute Renal Failure: Causes
Primary causes in Acute Care:
Hypotension
Hypovolemia
Pre-Renal
Intra-Renal
Post-Renal
Pre-Renal Causes
Issues that interfere with renal perfusion
Circulatory volume depletion
Volume shifts
“3rd Spacing”
Decreased cardiac output
Decreased PVR
Vascular Obstruction
General Symptoms
High specific gravity & osmolarity
Normal sediment
May have Hyaline/Granular casts
BUN / Cr significantly elevated (10:1 – 40:1)
Proteinuria & sodium excretion not significant
Intra-Renal Causes
Parenchymal changes caused by disease or nephrotoxins
Acute tubular necrosis (75%)
Muddy brown granular casts
Glomerulonephritis
Hematuria
RBC & Hemoglobin casts
Vascular lesions
Cortical necrosis (Prolonged vasospasm)
Tissue damage - Elevated
Serum creatinine
Phosphokinase
K+
General Symptoms:
Fixed specific gravity
Edema
Weight gain
Hemoptysis
Elevated LV EDP
Weakness (Anemia)
Hypertension
High urine sodium
Proteinuria
Post-Renal Causes
Issues that cause obstruction of urinary tract
BPH
Calculi
Tumor
Surgical accident
Spinal cord injury
Neurogenic bladder with retention (decreased bladder emptying)
“Functional” obstruction
General Symptoms
Fixed specific gravity
Elevated urine sodium
Little or no proteinuria
Sediment normal
Indications of obstruction
Anuria / Polyuria: Intermittent?
Acute Kidney Injury: Elderly Considerations
Decreased GFR with aging
More susceptible to AKI & decreased ability to recover
Dehydration
Polypharmacy (Diuretics, laxatives)
Illness
Immobility
Hypotension, diuretic therapy, aminoglycoside therapy, obstructive disorders, surgery, infection, & contrast medium
Renal Replacement Therapies (RRT) still an option
Acute Kidney Injury: Oliguric Phase
U.O. < 400 ml / day
Occurs: 1 – 7 days of injury (24 - hours ischemia)
Duration: 10 – 14 days to months
Longer phase = poorer prognosis
50% patients non-oliguric; > 400 mL urine/day
Urinalysis; Casts, RBCs, WBCs, Protein
Specific gravity 1.010 (Fixed)
Osmolality 300 mOsm/kg
Acute Kidney Injury: Oliguric Phase cont
Hypovolemia may exacerbate AKI
Decreased urine output leads to fluid retention
Neck veins distended
Bounding pulse
Edema
Hypertension
Fluid overload can lead to:
CHF
Pulmonary edema
Pericardial or pleural effusions
Leukocytosis: Infection may be fatal
Urinary & respiratory
Waste product accumulation; Increased BUN & Cr
Neurologic disorders
Fatigue
Difficulty concentrating
Seizures, stupor, coma
Metabolic acidosis
Kidneys cannot excrete Hydrogen or acid products of metabolism
Serum bicarbonate production decreased; Reabsorption & regeneration defective
Severe acidosis develops; Kussmaul respirations (increase exhaled CO2)
Results from
Impaired ability of kidneys to excrete excess acid
Defective reabsorption & regeneration of bicarbonate
Plasma bicarbonate level usually falls to approximately 16 to 20 mEq/L (16 to 20 mmol/L)
Hyponatremia
Increased excretion of Na+ d/t damaged tubules
Can lead to cerebral edema
Hyperkalemia
Impaired ability to excrete K+
Usually asymptomatic; Peaked T waves, Wide QRS, ST depression
Increased risk with massive tissue trauma
Weakness, cardiac arrhythmias
EKG Monitoring / Remote Telemetry
Treatment:
K+ restriction
Potassium removal
Dialysis
Kayexalate
Acute Kidney Injury: Diuretic Phase
Lasts 1 – 3 weeks
Daily U.O. 1 - 3 Liters (up to 5 Liters)
Osmotic diuresis from high urea
Low specific gravity; Nearly iso-osmolar
Kidneys able to excrete waste, but not concentrate urine
Patients who develope oliguria will have greater diuresis than those who do not
Monitor for:
Hypovolemia,
Hypotension
Hyponatremia
Hypokalemia
Dehydration
Acute Kidney Injury: Recovery Phase
Begins when GFR increases
Allows BUN & Cr to plateau & then decrease
Major improvements occur in first 1 – 2 weeks
May take up to 12-months to stabilize
AKI: Diagnostics
Thorough history
Serum BUN / Cr
Serum electrolytes
Urinalysis
Renal ultrasound
Renal CT scan
Renal biopsy
Contraindications: Contrast
MRI or MRA with Gadolinium (May be fatal)
Contrast-induced nephropathy
Metformin: Hold 48-hours before & after use of contrast; Risk for lactic acidosis
If contrast needed for high-risk patients - Use low-dose & ensure optimal hydration
AKI: Interprofessional Care
Goals of Care:
Eliminate cause
Manage signs/symptoms
Prevent complications
Ensure adequate intravascular volume & cardiac output
Loop diuretics: Furosemide (Lasix)
Osmotic diuretics: Mannitol
Closely monitor fluid intake during Oliguric phase
Fluid restriction: All fluid losses for previous 24 hours + 600 mL
Expected outcomes:
Regain & maintain normal fluid & electrolyte balance
Adhere to treatment regimen
No complications
Complete recovery
Electrolytes
K+ (3.5 – 5.0 mEq/L)
Na+ (136 – 145 mEq/L)
Mg+ (1.3 – 2.1 mEq/L)
Phosphorous (3.0 – 4.5 mg/dL)
Ca+ (Parathyroid function)
Total 9.0 – 10.5 mg/dL
Ionized 4.5 – 5.6 mg/dL
Exchange Resins
Kayexalate & Sorbitol
Questions re: efficacy versus risks
Contra-indicated with ileus (Intestinal necrosis)
Patiromer (Veltassa)
Powder for oral suspension in water
Taken daily; Delayed action - Not for emergency use
Indications for Renal Replacement Therapy (RRT)
Volume overload
Hyperkalemia
Metabolic acidosis
BUN > 120 mg/dL
Significant change in mental status
Pericarditis, pericardial effusion, or cardiac tamponade
Clinical status of patient
Hemodialysis (HD): Emergent therapy
Peritoneal dialysis (PD)
ICU Setting Only:
Continuous Renal Replacement Therapy (CRRT)
Continuous cannulation (24-hours) of artery & vein
AKI: Nutritional Therapy
Maintain adequate caloric intake
Primarily carbohydrates, increased fats, adequate protein to prevent breakdown
Restrict Na+, K+, Phosphate
Calcium supplements or phosphate-binding agents
Enteral / parenteral nutrition
Acute Care
Accurate I & O
Daily weights
Assess for hypervolemia or hypovolemia
Assess for K+ & Na+ disturbances
Meticulous aseptic technique
Careful use of nephrotoxic drugs
Skin care measures
Oral care
Patient Teaching for Post-Acute Ambulatory Care
Monitor kidney function
Regulate protein & potassium intake
Follow-up care
Teaching
Appropriate referrals
Chronic Kidney Disease (CKD)
Progressive, irreversible loss of kidney function
Low glomerular filtration rate (GFR); <60 mL/min/1.73m2 for longer than 3 months
More than 26 million American adults have CKD
Increased prevalence: Aging population, increased obesity, increased diabetes & HTN
Increased incidence: Blacks, Native Americans, & Latinos
Underdiagnoses & untreated; Many with CKD are asymptomatic; Approximately 70% aware
Uremia
Syndrome; Kidney function declines to point that symptoms occur in multiple body systems
Often occurs when GFR is less than or equal to 15mL/min
Manifestations vary depending on cause, co-morbidities, age, & adherence to medical regimen
Diagnostic Studies
H & P
Dipstick evaluation of protein; Albuminuria
Urinalysis
Renal ultrasound, scan, CT scan, biopsy
Albumin-to-creatinine ratio (1st AM void)
Serum BUN, creatinine, creatinine clearance, electrolytes, lipids, hemoglobin, hematocrit
GFR
Stages of Chronic Kidney Disease
1
≥ 90
Diagnosis and treatment; CVD risk reduction; slow progression
2
60–89
Estimation of progression
3a
45–59
Evaluation and treatment of complications
3b
30–44
More aggressive treatment of complications
4
15–29
Preparation for RRT (dialysis or transplant)
5
Less than 15 or dialysis
RRT if uremia present and patient desires treatment; necessary to maintain life
CKD: Sodium / Magnesium
HYPOnatremia (Dilutional)
Confusion, seizures, coma
Fluid restriction for self-correction
HYPERmagnesemia
Decreased reflexes, mental status, B/P, respiratory failure
Avoid:
Dark green veggies
Grains, seeds, nuts
Legumes
Antacids with Mg+
Osmotic laxatives (Milk of Magnesia, Magnesium Citrate)
CKD: Calcium / Phosphorous
HYPOcalcemia
Decreased intestinal Ca+ absorption
Synthesis of 1,25 dihydroxyycholecalciferol
HYPERphosphatemia furthers low Ca+
Increased parathyroid hormone excretion leads to bone resorption
Osteomalacia
Osteitis fibrosa
Osteosclerosis
HYPERphosphatemia
Hypocalcemia
Increased risk for fractures, CKD-MBD
Avoid:
Dairy products & foods containing dairy products
Milk
Ice cream
Cheese
Yogurt
Pudding
Protein sources contain Phosphate
Phosphate binders
As Glomerular Filtration Rate (GFR) Falls
Parathyroid hormone levels increase
Activated form of Vitamin D falls
Old thinking: This was just decreased production of 1,25(OH)2D
New understanding: Degradative pathways are up-regulated (some induced by FGF-23)
Fall in 1,25(OH)2D is physiological with CKD
Makes sense because you do not want a lot of 1,25(OH)2D around to cause more calcium & phosphorus absorption when you cannot excrete these ions
