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Glomerular Filtration
the movement of fluid and solutes from teh vascular system to the tubular system of the nephron
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Glomerular Filtration Rate
the volume of plasma that can be cleared of a substance within a set time frame
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Functions of the kidney
- Maintain fluid and electrolyte balance
- Maintains acid-base balance
- Excretes nitrogeneous end products of protein
- Activates vitamin D
- Secretes erythropoietin
- ESRD pts: chronically anemic bc kidneys and bone marrow can't make more RBCs
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2 types of vitamin D
- 25, OH (supplements): inactive, used by kidneys; unusable by body
- 125, OH: active and usable for cells
- Conversion takes place in kidneys
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AKI results in...
(characteristics)
- azotemia: retention of BUN and Cr
- imbalances in fluids and electrolytes
- acid-base disorders
- decreased urine output
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Prerenal failure
- a decrease in effective renal perfusion resulting in a decreased GFR and kidney function
- MAP >70-75 mmHg should be maintained to perfuse kidneys
- Urine output of at least 25-30ml/hr
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Prerenal failure causes
- Excessive fluid loss: hemorrhage, burns, vomiting, diarrhea, acities
- Decreased renal perfusion: HF, decreased CO, MI, shock, tumor, vascular obstruction; kidneys one of last organs to get perfusion in emergencies
- Glomerular arteriole vasodilation or constriction: ACE-inhibitors, NSAIDS, cyclosporine
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Intrinsic (intrarenal) renal failure cause
- Most common: ATN: from ischemia, sepsis, drugs (big)
- Renal tubular ischemia
- Nephrotoxicity: from contrast dye (big), antibiotics, NSAIDS, chemicals
- Rhabdomyolysis: muscle breakdown w/ myoglobin release (urine is dark red, toxic to kidneys)
- Intratubular obstruction
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End result of Intrarenal failure
- Permanent injury
- Only thing can do is fix cause and keep from getting worse
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Postrenal failure causes
- Calculi
- Clots
- Prostatic hypertrophy
- Strictures
- Edema
- Tumors
- Obstructed catheter (kinks/clots)
- Diabetic neuropathy
- Pregnancy
- Drugs (narcotics, PCA)
- Spinal cord injury
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Systemic complications of AKI
- Neuro: decreased alertness (buildup of nitrogeneous wastes, ph issues), drowsiness, seizures (f/e imbalances), coma
- Cardiac: HTN, dysrythmias, edema
- Pulmonary: decreased cough reflex (decreased LOC, RR), crackles, infiltrates
- GI: weight loss (will stop eating bc vomiting), anorexia, N/V, constipation (phosphorus imbalances), diarrhea
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Systemic complications of AKI cont.
- Hematopoietic: anemia (decreased erythropoietin production), fatigue, weakness, platelet function impaired (presence of uremic toxins)
- Skin: pale, dry, dull, yellow skin, bruising (impaired platelets), pruritis, thin hair, brittle nails
- Skeletal: disorders r/t decreased calcium absorption, fractures
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2 Principle features of AKI
Azotemia Oliguria/AnuriaCould be compensatory mechanisms to decreased intravascular blood flow
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Lab Trends: BUN
Increased
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Lab Trends: Chloride
Increased
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Lab Trends: Phosphorus
Increased
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Lab Trends: Albumin
Decreased
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Lab Trends: Protein
Increased
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Lab Trends: Creatinine/Urea Clearence
Decreased
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AKI Managment: FVE
- Diuretic therapy
- Dialysis
- Fluid restriction (may allow 1L/day)
- Monitor for: imbalanced I&O, edema, pulmonary crackles, HTN, weight gain
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AKI Management: Catabolic process
- Protien, Na, K+, and fluid restircted diet
- High carb, fat, and amino acid diet
- Dialysis to decrease BUN & Cr
- Monitor for: weight gain, neuro changes, GI dysfunction, decreased serum protein levels
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AKI Management: Electrolyte Imbalance (elevated K+)
- Administer Kayexylate via oral, gastric, or rectal routes (if doesn't have BM in 4-6hrs, K+ will not be removed)
- Administer IV sodium bicarb, insulin followed by D5 (prevent hypoglycemia), then hypertonic glucose to move K+ into cells
- Hemodialysis
- ECG changes: prolonged QRS, tall, peaked T waves
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AKI Management: Electrolyte Imbalance (Met. Acidosis)
- Sodium bicarb (severe cases)
- IV or dialysate additive
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AKI Management: Electrolyte Imbalance (Na)
- Limit oral and IV Na
- Diuretics for hypernatremia (use cautiously)
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AKI Management: Infection
- Strict medical asepsis w/ all invasive lines
- Antibiotics
- Monitor for: elecated WBC, fever, positive blood cultures
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Intermittent Hemodialysis
- Filter toxins and excess water from blood
- Toxins removed by diffusion
- Fluid removed by ultrafiltration by pressure gradient across semipermeable membrane
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When is IHD used?
- Pts w/ renal failure who were on peritoneal dialysis and got an infection
- When PD cannot adequately remove wastes
- More efficient in clearing blood, but more destabilizing
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IHD Indications
- BUN >100
- Cr >10
- Hyperkalemia, drug toxicity, met. acidosis, fluid overload, pulmonary edema
- S/S of uremia: pericarditis, GI bleeding, encephalopathy
- Contraindications to other forms of dialysis
- Transfusion rx
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Contraindications for IHD
- Hemodynamic instability (biggest)
- Coagulopathies
- Lack of access to circulation
- Age extremes (children and elderly)
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Temporary vascular access
Dual lumen subclavian or femoral vein catheter (Udall, Quinton, or Tesio)
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Permanent vascular access
Internal arteriovenous (AV) fistula
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Continuous Renal therapy indications
- Need for fluid volume removal in a hemodynacially unstable pt
- Hypervolemia unresponsive to diuretics
- MODS
- Coagulapathies
- Ease of fluid management
- PD/HD contraindications
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Continuous Renal therapy contraindications
- Hct >45%
- Lack of arterial/venous access
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Continuous Arteriovenous Hemofiltration (CAVH)
- Venous and arterial access obtained, fluid and moderate solute removal
- Driven by pt's BP
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Continous Arteriovenous Hemofiltration (CAVH-D)
- Venous and arterial access obtained
- Allows for fluid removal plus maximum solute removal
- Driven by pt's BP
- Dialysate bag used
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Continous Venovenous Hemofiltration (CVVH)
- Double lumen catheter placed in vein
- Blood pumped through filter
- Removes solutes and fluid
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Continous Venovenous Hemofiltration Dialysis (CVVH-D)
- Double lumen catheter placed in vien
- Blood pumped though a filter
- Removes solutes and fluid
- Dialysate bag used
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Graft AV fistula
- Used when surgeon blieves standard AV fistula will not work
- An artery and vein are joined w/ an artificial substance (bovine graft) or w/ the saphenous or umbilical veins
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IHD Nursing Care
- Monitor of increased risk for bleeding 6hr post HD (on heparin and anticoags)
- BP q 5-15min
- HR q 5-15min
- PCWP q 1-2hrs
- Respiratory pattern q 1hr
- Neuro status q 1hr
- Continous cardiac monitoring
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IHD Complications
- Hypotension: lower HOB, raise feet, slow rate of ultrafiltration, IV volume expanders, vasopressors, blood products
- Dysrythmias
- Bleeding
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PD Nursing Care
- Dialyste instilled at body temp
- Weight pt before 1st and after last exhange
- Document I&O
- Restrict fluid intake
- Monitor, assess, and report changes in VS, LOC
- Watch and prevent peritonitis
- Drain if SOB occurs
- Small feedings to prevent nausea
- Skin care
- Tenchoff catheter care: sterile dressing
- Prevent infection
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Peritonitis
- Rebound tenderness
- Severe abdominal pain
- Guarding
- Distention
- Cloudy drainage
- Fever
- Leukocytosis
- Change in LOC
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