Renal Nursing
Master AKI, CKD, dialysis, urinary disorders, fluid management, and renal diet for NCLEX.
Renal Nursing
The renal system plays a vital role in maintaining fluid balance, electrolyte homeostasis, acid-base regulation, and waste elimination. Renal disorders are heavily tested on the NCLEX, requiring nurses to understand acute kidney injury, chronic kidney disease, dialysis modalities, and associated nursing care. For the full scope of physiological topics, see the Physiological Integrity study guide.
Acute Kidney Injury (AKI)
AKI is a sudden decline in renal function characterized by rising BUN and creatinine levels, oliguria (less than 400 mL/day), and electrolyte imbalances. AKI is classified by etiology:
| Type | Cause | Examples | Key Feature |
|---|---|---|---|
| Prerenal | Decreased blood flow to kidneys | Hypovolemia, heart failure, sepsis, hemorrhage, dehydration | BUN:creatinine ratio greater than 20:1; responds to fluid resuscitation |
| Intrarenal (Intrinsic) | Direct damage to kidney tissue | Acute tubular necrosis (ATN), glomerulonephritis, nephrotoxic drugs (aminoglycosides, contrast dye, NSAIDs) | Muddy brown casts in urine; BUN:creatinine ratio approximately 10:1 |
| Postrenal | Obstruction of urine outflow | Kidney stones, BPH, tumors, strictures | Hydronephrosis on imaging; relief of obstruction restores function |
Phases of AKI:
- Onset phase: From the initial insult to the first signs of renal compromise
- Oliguric phase: Urine output drops below 400 mL/day. Risk of hyperkalemia, fluid overload, metabolic acidosis, and uremia. Lasts 1-3 weeks
- Diuretic phase: Urine output increases dramatically (up to 3-5 L/day). Risk of dehydration and electrolyte depletion. Monitor closely and replace fluids and electrolytes
- Recovery phase: Gradual return of renal function over months. GFR may not fully recover
Chronic Kidney Disease (CKD)
CKD is a progressive, irreversible loss of kidney function over months to years. The two leading causes are diabetes mellitus and hypertension. CKD is staged by GFR:
| Stage | GFR (mL/min) | Description |
|---|---|---|
| 1 | 90 or greater | Kidney damage with normal GFR |
| 2 | 60-89 | Mild decrease |
| 3a/3b | 30-59 | Moderate decrease |
| 4 | 15-29 | Severe decrease; prepare for renal replacement |
| 5 | Less than 15 | End-stage renal disease (ESRD); dialysis or transplant needed |
Complications of CKD:
- Fluid overload: Edema, hypertension, heart failure
- Electrolyte imbalances: Hyperkalemia, hyperphosphatemia, hypocalcemia
- Metabolic acidosis: Inability to excrete hydrogen ions and regenerate bicarbonate
- Anemia: Decreased erythropoietin production; treat with epoetin alfa (Epogen)
- Renal osteodystrophy: Calcium and phosphorus imbalance leads to bone disease; administer phosphate binders (calcium acetate, sevelamer) with meals
- Uremia: Buildup of waste products causing fatigue, nausea, pruritus, pericarditis, and neurological changes
BUN and Creatinine Interpretation
BUN (Blood Urea Nitrogen): Normal 10-20 mg/dL. Elevated in dehydration, high-protein diet, GI bleeding, and renal failure. Less specific than creatinine.
Serum Creatinine: Normal 0.6-1.2 mg/dL. More specific indicator of renal function. Even small increases can indicate significant loss of nephron function. A doubling of creatinine suggests a 50% decrease in GFR.
Hemodialysis
Hemodialysis filters blood through an external machine and dialyzer to remove waste products, excess fluid, and correct electrolyte imbalances. Vascular access types include:
- Arteriovenous (AV) fistula: Preferred long-term access. Surgically created anastomosis between an artery and vein. Requires 2-4 months to mature. Assess for a thrill (palpable vibration) and bruit (audible swooshing sound). Best patency and lowest infection rate
- AV graft: Synthetic tube connecting artery and vein. Can be used within 2-4 weeks. Higher infection and clotting risk than fistula
- Central venous catheter: Temporary access for acute situations. Highest infection risk
AV fistula/graft care:
- Never take blood pressure, draw blood, or start an IV in the access arm
- Assess the thrill and bruit every shift; absence indicates clotting
- Avoid constrictive clothing, jewelry, or carrying heavy items on the access arm
- Do not sleep on the access arm
- Teach patient to check the thrill daily at home
Pre-dialysis nursing care: Obtain baseline weight and vital signs. Assess access site. Hold antihypertensives and medications removed by dialysis (check with pharmacy). No blood draws from the access.
Post-dialysis nursing care: Monitor for hypotension (most common complication), assess access site for bleeding, obtain post-weight, and monitor for disequilibrium syndrome (headache, nausea, confusion from rapid fluid/solute shifts).
Complications of hemodialysis: Hypotension, muscle cramps, air embolism (clamp tubing, position on left side in Trendelenburg), infection, and disequilibrium syndrome.
Peritoneal Dialysis
Peritoneal dialysis uses the peritoneal membrane as the dialyzer. Dialysate is infused into the peritoneal cavity, dwells for a prescribed time, and is then drained.
Procedure phases: Infusion (10-15 minutes), dwell (as prescribed, typically 20-40 minutes for manual exchanges), and drain (15-30 minutes). The effluent should be clear and pale yellow. Cloudy effluent indicates peritonitis, the most serious complication.
Nursing considerations:
- Use strict aseptic technique at all times
- Warm dialysate to body temperature before infusion
- Monitor for peritonitis: cloudy effluent, abdominal pain, fever, rebound tenderness
- If outflow is slow, reposition the patient, check tubing for kinks
- Document inflow, dwell time, and outflow volumes accurately
- Monitor blood glucose (dextrose in dialysate can cause hyperglycemia)
Urinary Tract Infections
UTIs are among the most common infections in healthcare settings. Risk factors include female sex, urinary catheterization, urinary stasis, and diabetes. Lower UTIs (cystitis) present with dysuria, urgency, frequency, and suprapubic pain. Upper UTIs (pyelonephritis) present with flank pain, fever, chills, and costovertebral angle tenderness. Prevention includes adequate fluid intake, proper perineal hygiene, voiding after intercourse, and avoiding unnecessary catheterization.
Nephrotic vs. Nephritic Syndrome
| Feature | Nephrotic Syndrome | Nephritic Syndrome |
|---|---|---|
| Proteinuria | Massive (greater than 3.5 g/day) | Moderate |
| Edema | Severe, generalized (anasarca) | Mild, periorbital |
| Hematuria | Minimal | Significant (cola-colored urine) |
| Serum albumin | Severely decreased | Normal or mildly decreased |
| Blood pressure | May be normal | Hypertension common |
| Lipids | Hyperlipidemia | Usually normal |
Renal Diet
Patients with CKD require dietary modifications based on their stage and dialysis status:
- Potassium restriction: Avoid bananas, oranges, potatoes, tomatoes, avocados, dried fruits
- Phosphorus restriction: Avoid dairy products, colas, processed meats, nuts
- Sodium restriction: Limit to 2 g/day to manage fluid retention and hypertension
- Protein: Restricted in pre-dialysis CKD to reduce uremia; increased in dialysis patients to compensate for protein losses
- Fluid restriction: Often 500-1000 mL plus previous day's urine output
NCLEX Renal Focus Points
- Never use the AV fistula arm for blood pressure, blood draws, or IV access
- Cloudy peritoneal dialysis effluent signals peritonitis
- Hyperkalemia is the most life-threatening electrolyte imbalance in renal failure
- Weigh patients daily before breakfast for fluid status assessment
- Prerenal AKI responds to volume replacement; intrarenal does not
Consolidate your renal knowledge with the Renal Nursing Cheat Sheet and practice with Physiological Integrity flashcards. For key terminology review, see the Physiological Integrity Glossary.