NLE Renal & Urinary Nursing — Renal & Urinary Assessment & DiagnosticsDetailed Explanation

Review of Renal Structure and Function

Each kidney contains approximately one million nephrons — the basic functional unit. The nephron has a glomerulus (filtering unit) and tubules (reabsorption and secretion). Blood enters the glomerulus under pressure, and a filtrate is formed. Useful substances (glucose, amino acids, water, electrolytes) are reabsorbed back into the blood along the tubules. Waste products and excess substances remain in the filtrate and become urine. The kidneys perform five critical functions that you must connect to clinical signs: 1. EXCRETION OF METABOLIC WASTE: Urea (from protein breakdown) and creatinine (from muscle metabolism) are excreted. When kidneys fail, BUN and creatinine RISE — this is uremia. 2. FLUID AND ELECTROLYTE BALANCE: The kidney regulates sodium, potassium, water, and acid-base balance. It excretes hydrogen ions and reabsorbs bicarbonate. Renal failure → metabolic acidosis and electrolyte imbalances (especially hyperkalemia). 3. BLOOD PRESSURE CONTROL via the Renin-Angiotensin-Aldosterone System (RAAS): When renal perfusion drops (e.g., hypovolemia), the kidney releases renin → angiotensin II → vasoconstriction AND → aldosterone → sodium and water retention → blood pressure rises. This is why renal disease is closely linked to hypertension. 4. ERYTHROPOIETIN PRODUCTION: The kidney secretes erythropoietin to stimulate red blood cell (RBC) production in the bone marrow. Kidney failure → no erythropoietin → anemia. This anemia does NOT respond to iron alone — it needs erythropoietin injections (e.g., epoetin alfa). 5. ACTIVATION OF VITAMIN D: The kidney converts inactive vitamin D (from the diet/sun) into its active form (calcitriol), which promotes calcium absorption from the gut. Kidney failure → no active vitamin D → hypocalcemia → renal osteodystrophy (weak, brittle bones). Key urine output values every nurse must memorize: - Normal output: 1–2 mL/kg/hr (roughly 1,500 mL/day for adults) - Adequate perfusion minimum: 30 mL/hr (or 0.5 mL/kg/hr) - Oliguria: less than 400 mL/day (or less than 0.5 mL/kg/hr) — signals renal compromise - Anuria: less than 100 mL/day — severe renal failure - Polyuria: excessive output — seen in diabetes insipidus, recovering AKI, or uncontrolled DM

Nursing History and Physical Assessment of the Renal/Urinary System

Systematic assessment follows the nursing process and is the starting point of clinical reasoning. In renal nursing, assessment findings directly guide nursing diagnoses and priorities. HISTORY TAKING — Key areas to assess: 1. VOIDING PATTERNS (changes = most common presenting complaint) - Frequency: How many times per day? Normal is about 6–8 times. - Urgency: Sudden, uncontrollable urge to void (UTI, overactive bladder) - Dysuria: Painful or burning urination (UTI, urethritis) - Hesitancy: Difficulty starting urination (BPH in men, stricture) - Nocturia: Waking at night to urinate more than once (early CKD, heart failure, BPH) - Incontinence: Involuntary urine leakage - Retention: Inability to empty the bladder 2. URINE CHARACTERISTICS - Color: Normal = pale yellow to amber. Tea/cola = blood or myoglobin. Cloudy = infection. Frothy = proteinuria. - Odor: Strong ammonia odor = UTI or concentrated urine - Hematuria: Blood in urine — gross (visible) or microscopic 3. PAIN: Flank pain (costovertebral angle area) = kidney origin (pyelonephritis, stones). Suprapubic pain = bladder origin (UTI, retention). 4. FLUID INTAKE: Assess daily fluid intake habits — both inadequate intake (dehydration) and excessive intake patterns. 5. WEIGHT CHANGES AND EDEMA: Sudden weight gain with edema = fluid retention (nephrotic syndrome, renal failure). Weight loss = catabolic state. 6. DRUG HISTORY — NEPHROTOXIC DRUGS TO KNOW: - Aminoglycoside antibiotics (gentamicin, tobramycin) - NSAIDs (ibuprofen, mefenamic acid — commonly used in the Philippines) - IV contrast dye (used in CT scans, IVP) - Some antibiotics (amphotericin B, vancomycin) - ACE inhibitors in certain conditions 7. RELEVANT MEDICAL HISTORY: Hypertension (leading cause of CKD), diabetes mellitus (leading cause of CKD worldwide), recurrent UTIs, renal calculi (kidney stones), autoimmune diseases. PHYSICAL EXAMINATION: 1. DAILY WEIGHT — THE MOST RELIABLE FLUID STATUS INDICATOR - Same time (morning, after first void, before breakfast) - Same scale - Same clothing - 1 kg weight gain = approximately 1 liter of fluid retained - This is more accurate than I&O records because it accounts for insensible loss 2. EDEMA ASSESSMENT - Periorbital (around eyes) — characteristic of nephrotic syndrome, especially in children - Dependent edema (feet, ankles, sacrum in bedridden patients) - Pitting vs. non-pitting: press with finger for 5 seconds; if an indentation remains = pitting edema (fluid overload) 3. LUNG ASSESSMENT: Crackles (rales) at lung bases = pulmonary edema from fluid overload. This is a sign of SEVERE fluid excess. 4. BLOOD PRESSURE: Hypertension is both a cause and effect of renal disease. 5. SKIN ASSESSMENT - Pallor = anemia (loss of EPO) - Dry, itchy skin (pruritus) = uremic toxins depositing in skin - Uremic frost = white crystalline deposits on skin (late-stage uremia — rare, indicates critical uremia) 6. ABDOMEN AND FLANK - COSTOVERTEBRAL ANGLE (CVA) TENDERNESS: The CVA is the angle formed between the 12th rib and the spine. Tenderness here (assessed by firm fist percussion) indicates kidney inflammation — pyelonephritis, renal calculi. This is a classic NLE assessment point. - BLADDER DISTENSION: A very full bladder is palpable and percussable above the pubic symphysis (suprapubic area). Percussion note changes from tympanic to dull when bladder is full.

Laboratory Tests: BUN, Creatinine, GFR, and Electrolytes

Laboratory values are the backbone of NLE renal questions. Memorize the normal values and understand what each test measures and its limitations. BLOOD UREA NITROGEN (BUN) - Normal: 10–20 mg/dL - BUN measures the amount of urea nitrogen (a waste product from protein breakdown) in the blood - When kidneys fail, they cannot excrete urea, so BUN RISES - IMPORTANT: BUN is NON-SPECIFIC — it rises in many conditions BESIDES kidney disease: • Dehydration / hypovolemia (less water = more concentrated blood) • High protein intake (more protein breakdown = more urea produced) • GI bleeding (blood in the gut is digested as protein = more urea) • Fever, burns, catabolism (increased tissue breakdown) • Corticosteroid therapy - So a high BUN alone does NOT confirm kidney disease. You need more information. SERUM CREATININE - Normal: 0.6–1.2 mg/dL (slightly lower in females and elderly due to less muscle mass) - Creatinine is a waste product of muscle metabolism, produced at a relatively CONSTANT rate - It is excreted ALMOST ENTIRELY by the kidneys through filtration - CREATININE IS THE MOST SPECIFIC AND RELIABLE INDICATOR OF RENAL FUNCTION because: • Production rate is constant (not affected by diet) • Not reabsorbed by tubules • Affected by little else other than kidney function - A DOUBLING of serum creatinine = approximately 50% LOSS of kidney function BUN-TO-CREATININE RATIO - Normal ratio: 10:1 to 20:1 - Formula: BUN ÷ Creatinine = ratio - CLINICAL MEANING: • Ratio >20:1 WITH normal or near-normal creatinine → PRERENAL cause (dehydration, hypovolemia, heart failure — less blood reaching the kidneys, so less creatinine is filtered but urea rises more because it is also reabsorbed when flow is slow) • Ratio stays near normal (10:1–20:1) BUT BOTH BUN and creatinine are elevated → INTRINSIC RENAL disease (actual kidney damage) • Ratio <10:1 → liver disease (less urea produced), malnutrition, or low protein intake EXAMPLE: BUN = 60 mg/dL, Creatinine = 2.0 mg/dL → Ratio = 30:1 → PRERENAL (if patient is dehydrated) EXAMPLE: BUN = 80 mg/dL, Creatinine = 6.5 mg/dL → Ratio = 12:1 → INTRINSIC renal disease GLOMERULAR FILTRATION RATE (GFR) - GFR is the BEST OVERALL MEASURE of kidney function - It measures how much plasma is filtered by the glomeruli per minute - Normal GFR: 90–120 mL/min/1.73 m² - Estimated GFR (eGFR) is calculated from serum creatinine, age, sex, and race using formulas (CKD-EPI or MDRD) - GFR defines the FIVE STAGES OF CHRONIC KIDNEY DISEASE: • Stage 1: GFR ≥90 (normal GFR but with kidney damage markers — e.g., proteinuria) • Stage 2: GFR 60–89 (mildly decreased) • Stage 3: GFR 30–59 (moderately decreased) • Stage 4: GFR 15–29 (severely decreased) • Stage 5 — ESRD (End-Stage Renal Disease): GFR <15 → dialysis usually required CREATININE CLEARANCE (24-HOUR URINE) - The timed, measured version of GFR - Requires a 24-hour urine collection PLUS a serum creatinine drawn mid-collection - NURSING RESPONSIBILITIES FOR 24-HOUR URINE COLLECTION: 1. DISCARD the first voiding of the day (this urine has been accumulating since the previous day) 2. Record the exact START time after discarding the first void 3. Collect ALL urine for the next 24 hours — every drop matters 4. Keep the collection container on ICE or refrigerated throughout 5. The LAST specimen is the first void of the NEXT morning 6. Missing even ONE void INVALIDATES the entire test — must restart 7. Inform the patient to void into a separate container first, then pour into the collection jug — never directly into the jug in case one sample is missed KEY ELECTROLYTES IN RENAL DISEASE: - Potassium: Normal 3.5–5.0 mEq/L. Renal failure → HYPERKALEMIA (the most dangerous and potentially FATAL complication of renal failure; causes lethal cardiac arrhythmias) - Sodium: Normal 135–145 mEq/L. May be diluted (hyponatremia) in fluid overload - Calcium: Normal 8.5–10.5 mg/dL. HYPOCALCEMIA in CKD (no active vitamin D) - Phosphate: HYPERPHOSPHATEMIA in CKD - Bicarbonate: Normal 22–26 mEq/L. LOW bicarbonate = METABOLIC ACIDOSIS (kidneys cannot excrete H+ or reabsorb HCO3-) ALWAYS CONNECT HYPERKALEMIA TO ECG CHANGES: - Early: tall peaked T waves - Later: widened QRS - Critical: sine wave pattern, ventricular fibrillation → cardiac arrest

Urinalysis: Interpretation of Normal and Abnormal Findings

Urinalysis (UA) is the most useful, lowest-cost, and most accessible renal test. It is ordered for almost every patient admitted with a urinary or renal complaint. The NLE frequently tests interpretation of UA results. HOW TO COLLECT A PROPER URINE SPECIMEN: - CLEAN-CATCH MIDSTREAM SPECIMEN: Standard for routine urinalysis and culture • Female: Clean the urethral meatus with antiseptic wipes using FRONT-TO-BACK strokes (prevents contamination from fecal bacteria); do NOT touch the inside of the collection cup • Male: Retract foreskin, clean the glans penis • Discard the FIRST stream (washes contaminants from urethra), collect the MIDDLE stream in the sterile cup, discard the final stream - FIRST MORNING SPECIMEN: Most concentrated; best for routine analysis, cytology, and protein/glucose detection (more concentrated = easier to detect abnormalities) - Culture and Sensitivity (C&S): Must be obtained BEFORE starting antibiotics; delay in collection after starting antibiotics may yield false-negative cultures NORMAL URINALYSIS VALUES AND THEIR CLINICAL MEANING: 1. COLOR - Normal: Pale yellow to amber (from urochrome pigment) - Colorless/very pale: Very dilute urine, excessive hydration, or diabetes insipidus - Dark amber/concentrated: Dehydration - Tea/cola/brown: Hematuria (blood), myoglobinuria (muscle breakdown — rhabdomyolysis), or bilirubinuria - Cloudy/turbid: Infection (pus, bacteria), phosphate crystals - Pink/red: Hematuria or some foods/drugs (beets, rifampin) - Frothy/foamy: Significant proteinuria (glomerular damage) 2. pH - Normal: 4.5–8.0 (average approximately 6 — slightly acidic) - Acidic urine (<6): High protein diet, acidosis, dehydration - Alkaline urine (>7): Vegetarian diet, UTI with urea-splitting organisms (Proteus), alkalosis 3. SPECIFIC GRAVITY - Normal: 1.005–1.030 - Measures the kidney's ability to concentrate or dilute urine - HIGH specific gravity (>1.020–1.030): Concentrated urine; dehydration, syndrome of inappropriate ADH (SIADH) - LOW specific gravity (<1.005): Very dilute urine; diabetes insipidus, overhydration - FIXED specific gravity (~1.010): The kidney cannot concentrate OR dilute — this is ISOSTHENURIA and is a hallmark of RENAL FAILURE. The kidney is so damaged it can only produce urine at the same concentration as plasma (1.010) 4. PROTEIN - Normal: Negative or trace only - PROTEINURIA = ABNORMAL; signals glomerular damage (the filtration barrier is broken) - Seen in: Nephrotic syndrome, diabetic nephropathy, glomerulonephritis, pre-eclampsia - Persistent proteinuria with a normal GFR = CKD Stage 1 (kidney damage is present even though GFR appears normal) 5. GLUCOSE - Normal: Negative - Glucosuria appears when blood glucose EXCEEDS the renal threshold (~180 mg/dL) - Not diagnostic of diabetes alone — some people have a low renal threshold for glucose (renal glycosuria) 6. KETONES - Normal: Negative - Positive in: Diabetic ketoacidosis (DKA), starvation, very low-carbohydrate diets 7. BLOOD / RED BLOOD CELLS (RBCs) - Normal: Negative or 0–2 RBCs per high-power field (HPF) - HEMATURIA = blood in urine - Causes: Kidney stones (very common in the Philippines), UTI, glomerulonephritis, tumor, trauma, renal biopsy complications 8. WHITE BLOOD CELLS (WBCs) / LEUKOCYTE ESTERASE / NITRITES - Normal: 0–5 WBCs per HPF; leukocyte esterase = negative; nitrites = negative - ABNORMAL: WBCs in urine = PYURIA → STRONGLY SUGGESTS UTI - Leukocyte esterase: enzyme released by WBCs → positive = WBCs present (UTI marker) - Nitrites: Certain bacteria (gram-negative like E. coli) convert urinary nitrates to nitrites → POSITIVE = bacterial infection likely - ALWAYS obtain culture and sensitivity to confirm and guide antibiotic treatment 9. CASTS — CRITICAL NLE KNOWLEDGE - Casts are cylindrical molds formed in the tubules from proteins/cells - HYALINE CASTS: Normal in small numbers; concentrated urine - RBC CASTS: Pathological — indicate GLOMERULONEPHRITIS (blood leaking from damaged glomeruli) - WBC CASTS: Pathological — indicate PYELONEPHRITIS or interstitial nephritis (infection/inflammation in kidney tubules) - Granular casts: CKD, tubular damage - Fatty casts: Nephrotic syndrome - The NLE commonly asks: 'RBC casts in UA → glomerulonephritis' and 'WBC casts → pyelonephritis' 10. BACTERIA AND CULTURE - Routine UA may show bacteria, but CULTURE AND SENSITIVITY (C&S) is the definitive test for UTI - Significant bacteriuria: ≥100,000 colony-forming units (CFU/mL) in a clean-catch specimen - ALWAYS collect BEFORE starting antibiotics

Diagnostic Procedures: Imaging, IVP, Cystoscopy, and Renal Biopsy

Beyond laboratory tests, several diagnostic procedures are used to visualize kidney structure, function, and pathology. The NLE tests the NURSING RESPONSIBILITIES before, during, and after each procedure. IMAGING STUDIES OVERVIEW: 1. KUB X-RAY (Kidney-Ureter-Bladder X-ray) - Simple abdominal X-ray; no contrast, no prep, no radiation risk - Can show kidney SIZE and POSITION, and detect RADIO-OPAQUE kidney stones (calcium stones) - Does NOT show soft tissue detail or radiolucent stones (uric acid stones) 2. RENAL ULTRASOUND - BEST FOR FIRST-LINE STRUCTURAL ASSESSMENT — no radiation, no contrast dye, NO PREP required - Identifies kidney size, shape, masses, cysts, hydronephrosis (obstruction), and bladder fullness - Can detect obstructive uropathy (blocked ureter) - Can guide needle placement for renal biopsy - NURSING: No fasting or special prep needed; may need a full bladder for bladder assessment 3. CT SCAN / MRI - More detailed anatomical information - CT with contrast: Same precautions as IVP (see below) - MRI: No radiation; useful for soft tissue detail; avoid in patients with metal implants INTRAVENOUS PYELOGRAM (IVP) / INTRAVENOUS UROGRAPHY - Contrast dye is injected IV; as the kidneys excrete the dye, serial X-rays show the entire urinary tract (kidneys, ureters, bladder) - Shows STRUCTURE AND FUNCTION of the urinary tract (can see if a kidney is excreting dye — if not, function is impaired) - Diagnoses: obstructions, strictures, kidney stones, tumors, congenital anomalies PRE-PROCEDURE NURSING RESPONSIBILITIES FOR IVP (and ANY contrast study): 1. ASSESS FOR ALLERGIES: Iodine allergy, shellfish/seafood allergy (contains iodine), or prior contrast reaction — these are CONTRAINDICATIONS or require premedication (antihistamine + steroid) 2. CHECK RENAL FUNCTION: Obtain BUN and creatinine BEFORE the procedure. Contrast dye is NEPHROTOXIC — if kidneys are already impaired, contrast can cause Contrast-Induced Nephropathy (CIN). Creatinine should be below institution threshold (often <1.5 mg/dL) 3. HOLD METFORMIN: Stop metformin (Glucophage) 24–48 hours before and 48 hours AFTER contrast administration — risk of lactic acidosis because impaired kidneys cannot clear metformin if contrast causes nephropathy 4. ENSURE ADEQUATE HYDRATION: IV fluids before and after the procedure to dilute and flush the contrast dye through the kidneys 5. BOWEL PREP: Some institutions require laxatives/enemas the night before to clear bowel gas for better visualization 6. NPO: Usually nothing by mouth 4–8 hours before the procedure 7. INFORMED CONSENT POST-PROCEDURE: Push oral or IV fluids to flush the contrast dye; monitor for contrast reaction (urticaria, dyspnea, hypotension); monitor urine output and creatinine. CYSTOSCOPY - Direct visualization of the BLADDER and URETHRA using a flexible or rigid scope inserted through the urethra - Diagnoses: bladder tumors, stones, strictures, bleeding sources; can take biopsies and remove stones - Requires sterile technique; usually performed under local or general anesthesia POST-CYSTOSCOPY NURSING CARE: EXPECTED findings (normal and should be explained to the patient BEFORE the procedure): - Pink-tinged urine for 24–48 hours (small amount of bleeding from the scope) - Mild burning or discomfort on urination for 1–2 days - Bladder spasms - Feelings of urgency or frequency REPORT IMMEDIATELY (abnormal signs to document and escalate): - BRIGHT RED URINE or BLOOD CLOTS (excessive bleeding) - Inability to void for more than 8 hours after the procedure - FEVER or chills (infection/sepsis) - Severe pain (bladder perforation) Nursing interventions: Encourage oral fluids (flushes the bladder, reduces infection risk); warm sitz baths for perineal discomfort; monitor vital signs for infection; warm blankets for chilling. RENAL BIOPSY - Percutaneous (through the skin) needle biopsy of the kidney under ultrasound guidance - DEFINITIVE DIAGNOSIS for many glomerular diseases: glomerulonephritis, lupus nephritis, IgA nephropathy - Usually performed with the patient PRONE (lying face-down) for posterior kidney access PRE-BIOPSY: - Informed consent - Check coagulation studies (PT, PTT, platelet count) — bleeding is the biggest risk - NPO before the procedure - Two IV lines (one for fluids, one for emergency medications) - Baseline vital signs - Type and crossmatch blood (in case transfusion needed) POST-BIOPSY NURSING CARE (PRIORITY: MONITORING FOR BLEEDING — the kidney is HIGHLY VASCULAR): 1. BED REST for 6–24 hours (minimize movement to prevent further bleeding) 2. Monitor VITAL SIGNS frequently (every 15 minutes initially, then hourly) — falling BP and rising pulse = hemorrhage 3. Monitor for HEMATURIA: Expect pink-tinged urine initially; report gross hematuria or increasing blood 4. Assess for FLANK PAIN (may indicate hematoma or ongoing bleeding) 5. Monitor COMPLETE BLOOD COUNT (CBC) for hemoglobin/hematocrit drop 6. Apply PRESSURE/DRESSING to the biopsy site 7. AVOID strenuous activity, heavy lifting, contact sports for AT LEAST 2 WEEKS 8. Encourage fluid intake to flush blood from kidney 9. Instruct patient to report any frank blood, clots, decreased urine output, or fever Key NLE point: After renal biopsy, the PRIORITY nursing diagnosis is RISK FOR HEMORRHAGE related to the highly vascular nature of the kidney. Vital signs and urine color are the primary monitoring parameters.

Urinary Catheterization: Principles, Technique, and CAUTI Prevention

Urinary catheterization is a fundamental nursing procedure tested heavily in the NLE. The nurse must know the TYPES, INDICATIONS, TECHNIQUE, and CAUTI (Catheter-Associated Urinary Tract Infection) prevention strategies. TYPES OF URINARY CATHETERS: 1. INTERMITTENT (STRAIGHT/ROBINSON) CATHETER: Inserted, bladder drained, then removed. Used for: acute urinary retention relief, specimen collection, bladder instillation. Lowest infection risk. 2. INDWELLING (FOLEY) CATHETER: Retained in bladder with an inflated balloon (usually 5–10 mL water). Used for: continuous drainage, accurate I&O in critically ill patients, urological surgery, urinary incontinence in skin breakdown cases, obstruction. Highest infection risk. 3. SUPRAPUBIC CATHETER: Inserted through the abdominal wall into the bladder surgically. Used when urethral catheterization is contraindicated (urethral trauma, prostate surgery). INDICATIONS FOR CATHETERIZATION: - Acute urinary retention (cannot void despite urge) - Accurate hourly urine output monitoring (ICU, surgical patients) - Urological surgeries - Prolonged immobility with severe incontinence causing skin breakdown - Bladder irrigation (continuous) - NOT an indication: Routine incontinence management (promotes dependency and CAUTI) INSERTION TECHNIQUE — CRITICAL POINTS: - STERILE (ASEPTIC) TECHNIQUE throughout — this is NON-NEGOTIABLE - Set up sterile field BEFORE opening the catheter - Use appropriate catheter size: Adults 14–18 French; smaller for urethra, larger for clots - MALES: Hold the penis perpendicular (90°) to the body during insertion to straighten the urethra - FEMALES: Cleanse the meatus using front-to-back strokes (prevents fecal contamination) - Insert until URINE FLOWS, then advance 2–3 cm more before inflating balloon - NEVER force the catheter — resistance may indicate a stricture or, in males, an enlarged prostate. Stop and notify the physician. - Inflate balloon only after urine is confirmed flowing (inflating in the urethra would cause injury) - After insertion, tape or secure catheter to inner thigh (female) or upper thigh/abdomen (male) to prevent traction DRAINAGE SYSTEM MANAGEMENT: 1. KEEP DRAINAGE BAG BELOW THE LEVEL OF THE BLADDER — always. This uses gravity to drain urine. Raising the bag above the bladder causes urine to BACKFLOW into the bladder = direct cause of infection. 2. CLOSED DRAINAGE SYSTEM — never disconnect tubing unnecessarily. Each disconnection breaks sterility. 3. PREVENT DEPENDENT LOOPS — kinks or loops in the tubing hold pooled urine that acts as a reservoir for bacteria. Keep tubing free of kinks. 4. DO NOT REST THE BAG ON THE FLOOR — contamination risk. 5. Empty the drainage bag every 8 hours or when 2/3 full using a clean technique; use a separate, clean container for each patient; avoid touching the drain spout to the container. CATHETER CARE: - Provide perineal care at least TWICE DAILY with soap and water or per institutional policy - Clean the catheter from the meatus outward (away from the body) — prevents pushing bacteria toward the bladder - Do NOT apply antimicrobial ointment routinely to the catheter-meatus junction (not proven to reduce CAUTI) - Ensure adequate fluid intake (at least 2,000 mL/day unless contraindicated) to maintain urine flow CAUTI PREVENTION — CORE BUNDLE: CAUTI is the most common healthcare-associated infection. Key prevention strategies: 1. INSERT ONLY WHEN NECESSARY — have a clear medical indication 2. REMOVE AS EARLY AS POSSIBLE — duration of catheterization is the #1 risk factor for CAUTI 3. MAINTAIN ASEPTIC INSERTION TECHNIQUE 4. MAINTAIN CLOSED DRAINAGE SYSTEM 5. KEEP DRAINAGE BAG BELOW BLADDER LEVEL 6. PRACTICE HAND HYGIENE before and after catheter care 7. Assess the need for the catheter DAILY and document (in many Philippine hospitals, daily catheter review is a quality indicator) POST-CATHETER REMOVAL CARE: - Encourage fluid intake after removal - Assess for ability to void within 4–6 hours after removal - First void should be documented (time, amount, character) - Expect mild burning on first urination - Bladder Decompression for very full bladder: When a patient with chronic severe urinary retention (bladder very distended) is catheterized, drain GRADUALLY — many institutions cap initial drainage at 300–500 mL, then clamp 15–30 minutes, then drain more. RATIONALE: Rapid decompression of a severely distended bladder can cause sudden vasodilation → hypotension; and the sudden removal of pressure on blood vessels in the bladder wall → bleeding (decompression hematuria). NEVER rapidly drain a chronically distended bladder.

Principles of Dialysis: Hemodialysis and Peritoneal Dialysis

Dialysis is a life-sustaining therapy for patients whose kidneys can no longer maintain homeostasis. The NLE tests the PRINCIPLES of dialysis, the differences between hemodialysis (HD) and peritoneal dialysis (PD), and the nursing responsibilities for each. WHEN IS DIALYSIS NEEDED? Dialysis is initiated when conservative management fails — typically at: - GFR <15 mL/min (Stage 5 CKD/ESRD) - OR earlier for any of these LIFE-THREATENING indications (remember with the mnemonic AEIOU): • A — Acidosis (metabolic, unresponsive to treatment) • E — Electrolyte imbalance (hyperkalemia — lethal, unresponsive to medications) • I — Intoxication (certain drug overdoses — lithium, methanol, ethylene glycol) • O — Overload (fluid — pulmonary edema unresponsive to diuretics) • U — Uremia (symptomatic — pericarditis, encephalopathy, bleeding) PHYSICAL PRINCIPLES OF DIALYSIS (THE CORE CONCEPT): Two physical processes move substances across a SEMIPERMEABLE MEMBRANE: 1. DIFFUSION: Solutes (dissolved substances) move from an area of HIGH CONCENTRATION to LOW CONCENTRATION. In dialysis, the patient's blood contains HIGH levels of waste products (urea, creatinine, potassium, excess acids). The dialysate (dialysis fluid) contains NONE or VERY LOW levels of these substances. So the wastes DIFFUSE from blood across the membrane into the dialysate and are removed. 2. OSMOSIS / ULTRAFILTRATION: Water is removed by creating a pressure or osmotic gradient across the membrane: - In hemodialysis: mechanical pressure (transmembrane pressure) forces water across - In peritoneal dialysis: a high-dextrose dialysate creates an OSMOTIC gradient that pulls water from the blood across the peritoneal membrane into the dialysate THE DIALYSATE: - A carefully formulated balanced electrolyte solution - WARMED to body temperature (35–37°C) — cold dialysate causes vasoconstriction and hypotension - Contains NO urea, NO creatinine (concentration = zero, so wastes diffuse out) - Contains NO potassium (or very low potassium) — so excess potassium diffuses from blood to dialysate - Contains normal levels of sodium, bicarbonate (to correct acidosis), and calcium HEMODIALYSIS (HD): - Blood is removed from the patient, circulated through an ARTIFICIAL KIDNEY (dialyzer/filter) outside the body, and returned - The dialyzer has thousands of small semipermeable hollow fiber membranes - Typical session: 3–5 hours, 3 times per week - Requires VASCULAR ACCESS: • ARTERIOVENOUS (AV) FISTULA: Surgical connection between an artery and vein (usually in the forearm) — PREFERRED ACCESS because it has the lowest infection risk and longest survival rate. Allow 4–6 weeks for maturation before use. The fistula should have a PALPABLE THRILL (vibration felt by touch) and an AUDIBLE BRUIT (whooshing sound heard by stethoscope). Absence = OCCLUSION → EMERGENCY. • AV GRAFT: Synthetic tube connecting artery to vein — used when veins are inadequate for fistula; higher infection risk than fistula. • CENTRAL VENOUS CATHETER (TUNNELED): Temporary or permanent central line (e.g., permacath in the internal jugular or subclavian vein) — highest infection risk; used when fistula/graft is not yet ready. NURSING CARE OF AV FISTULA/GRAFT: - DO NOT take blood pressure in the fistula arm - DO NOT draw blood or start IV in the fistula arm - DO NOT apply constrictive clothing or jewelry - Assess for thrill (palpation) and bruit (auscultation) EVERY SHIFT - Teach patient to protect the arm from injury, pressure, and prolonged compression COMPLICATIONS DURING HD: - HYPOTENSION: Most common complication. From rapid fluid removal. Interventions: slow the rate, lower the patient's head, give IV saline bolus. - MUSCLE CRAMPS: From rapid electrolyte shifts. Give hypertonic saline or reduce ultrafiltration rate. - DIALYSIS DISEQUILIBRIUM SYNDROME: Brain edema from too-rapid removal of urea in the FIRST dialysis session (urea pulls water into brain). Prevent by using shorter initial sessions. - INFECTION: At the access site; strict asepsis. - CLOTTING: AV fistula can thrombose. PERITONEAL DIALYSIS (PD): - Uses the PERITONEUM (the membrane lining the abdominal cavity) as the semipermeable membrane - A PERITONEAL CATHETER (Tenckhoff catheter) is surgically placed through the abdominal wall - DIALYSATE (dextrose solution) is instilled INTO the peritoneal cavity, dwells for a set time, then DRAINED OUT - This cycle is called an EXCHANGE: FILL → DWELL → DRAIN - Dextrose concentration varies: higher dextrose = more fluid removed (stronger osmotic gradient) TYPES OF PD: - CAPD (Continuous Ambulatory PD): Patient performs 4–5 exchanges per day manually while ambulatory - CCPD (Continuous Cycling PD): A machine (cycler) performs exchanges at night while the patient sleeps COMPLICATIONS OF PD: - PERITONITIS: Most serious complication — infection of the peritoneal cavity. Signs: cloudy dialysate effluent (drained fluid), abdominal pain, fever, nausea. The nurse must inspect the drained fluid — CLOUDY EFFLUENT = PERITONITIS UNTIL PROVEN OTHERWISE → notify physician, send effluent for culture. - CATHETER LEAKAGE OR OBSTRUCTION - HYPERGLYCEMIA: Dextrose in dialysate is absorbed → monitor blood glucose, especially in diabetic patients - INADEQUATE DRAINAGE: Ensure patient is upright or repositioned to facilitate drainage COMPARISON: HD vs PD - HD removes wastes FASTER; PD is slower but more GENTLE (better for cardiovascular instability) - HD requires 3x/week hospital visits; PD can be done at HOME - HD access: AV fistula/graft/catheter; PD access: Tenckhoff catheter - PD primary risk: peritonitis; HD primary complication: hypotension during session WHAT DIALYSIS DOES NOT DO: - Does NOT produce erythropoietin → patients still develop anemia → need erythropoietin injections - Does NOT activate vitamin D → patients still develop hypocalcemia/bone disease → need calcitriol and phosphate binders - Does NOT regulate blood pressure in the long-term → antihypertensives still needed DIET DURING DIALYSIS: - PROTEIN: INCREASED (1.2–1.5 g/kg/day) — dialysis removes amino acids so protein needs increase - POTASSIUM: RESTRICTED between dialysis sessions (reduced excretion) - SODIUM and FLUID: RESTRICTED (based on residual urine output + interdialytic weight gain) - PHOSPHATE: RESTRICTED + phosphate binders with meals - CALORIES: Adequate to prevent catabolism

Renal Diet Principles and Age/Cultural Considerations

Dietary management is a cornerstone of renal nursing and is tested repeatedly in the NLE. The renal diet directly reflects the kidneys' lost functions. THE RENAL DIET: UNDERSTANDING THE RATIONALE Each dietary restriction in renal disease has a SPECIFIC REASON tied to the lost renal function: 1. SODIUM RESTRICTION (usually 2,000–3,000 mg/day or as prescribed) - Reason: Failing kidneys cannot excrete sodium normally → sodium and water retention → edema, hypertension, fluid overload - Foods to AVOID: Canned goods, preserved meats (tocino, tapa, longganisa — very common in the Philippines), salted fish (daing, tinapa, tuyo), soy sauce (toyo), fish sauce (patis), MSG-heavy seasonings, chips - IMPORTANT: Salt substitutes (KCl) contain POTASSIUM — AVOID in renal failure 2. POTASSIUM RESTRICTION (usually 2,000–3,000 mg/day) - Reason: Kidneys cannot excrete potassium → HYPERKALEMIA → lethal arrhythmias - Foods HIGH in potassium to LIMIT: • Bananas, oranges, mangoes, avocado, melons • Potatoes, tomatoes, squash • Legumes (beans, mongo) • Dark leafy vegetables • Salt substitutes (KCl) - COOKING TIP: Boiling vegetables and discarding the water ('leaching') reduces their potassium content by 30–50% — teach patients this technique 3. PHOSPHATE RESTRICTION + PHOSPHATE BINDERS - Reason: Kidneys cannot excrete phosphate → hyperphosphatemia → worsens hypocalcemia → renal bone disease (osteodystrophy) - Foods HIGH in phosphate to LIMIT: Dairy products (milk, cheese, ice cream), processed foods (with phosphate additives), beans, nuts, cola drinks, whole grains - PHOSPHATE BINDERS (e.g., calcium carbonate, sevelamer, lanthanum carbonate): Must be taken WITH MEALS (not after) to bind phosphate in the food before absorption. If taken on an empty stomach, they bind nothing. 4. PROTEIN MANAGEMENT - PRE-DIALYSIS (CKD Stages 1–4): RESTRICTED protein (0.6–0.8 g/kg/day) to reduce urea production and slow CKD progression - ON DIALYSIS: INCREASED protein (1.2–1.5 g/kg/day) to replace losses from the dialysis procedure - This is a common exam question — know the reversal based on dialysis status 5. FLUID RESTRICTION - Reason: Anuria or oliguria → fluid accumulates - Amount: Usually residual urine output + 500 mL (insensible loss) per day - Include in fluid calculation: All liquids (water, soups, juice, coffee, tea, ice cream, gelatin/jello, ice) - Teach strategies for thirst management: ice chips (count as fluid — 30 mL of ice = ~15 mL of water), mouth rinses, hard candy, cold moist cloth CALORIES: - Adequate caloric intake prevents the body from breaking down its own protein for energy (catabolism worsens uremia) - Carbohydrates and fats provide calories without adding to the nitrogen load AGE CONSIDERATIONS: - OLDER ADULTS have a normal physiological decline in GFR with aging (approximately 1 mL/min/year after age 40) - Older adults DEHYDRATE EASILY: decreased thirst sensation, decreased concentrating ability - RENALLY CLEARED MEDICATIONS are more likely to accumulate in the elderly — ALWAYS check renal dosing guidelines for renally excreted drugs (e.g., metformin, digoxin, aminoglycosides, NSAIDs, antibiotics) - Muscle mass decreases with age, so creatinine may appear FALSELY NORMAL in elderly even with significant renal impairment — GFR calculation is more reliable CULTURAL CONSIDERATIONS IN THE PHILIPPINE CONTEXT: - Traditional Filipino diet is HIGH in SODIUM (preserved meats, fermented condiments, fish sauce, soy sauce, MSG) — dietary counseling must be culturally sensitive and practical - Herbal and traditional remedies (e.g., tawas, pangontra-diabetis herbal teas, 'natural' kidney teas) — some are NEPHROTOXIC; always ask about herbal use - Filipino patients may use SALT SUBSTITUTES (KCl) thinking it is healthier — must EDUCATE that salt substitutes are dangerous for renal patients (high potassium) - Religious/cultural fasting may affect medication timing and food intake — assess and plan accordingly - Family-centered care is important in Filipino culture — include family in dietary teaching sessions

This case integrates multiple assessment concepts. The BUN:Cr ratio of 12.4:1 tells us both kidneys' function is impaired (not just a dehydration problem). The fixed specific gravity of 1.010 confirms the kidneys have lost concentrating ability — isosthenuria. RBC casts confirm glomerular bleeding, pointing to glomerulonephritis as the etiology. Priority is always determined using Maslow's hierarchy: physiological needs first — hyperkalemia can cause cardiac arrest within minutes if not treated. Priority actions: attach cardiac monitor (ECG for peaked T waves), notify physician immediately, prepare for hyperkalemia treatment (calcium gluconate, sodium bicarbonate, dextrose with insulin, sodium polystyrene sulfonate, or dialysis), restrict potassium intake, and prepare for possible emergency dialysis given the severity of the presentation.

This problem tests pre-procedure nursing preparation for contrast studies — one of the highest-yield NLE topics. The nurse's role is to IDENTIFY and COMMUNICATE risks BEFORE the procedure — not to cancel it unilaterally (that is the physician's decision). The nurse should document the allergy, ensure informed consent includes allergy risk discussion, confirm premedication orders (diphenhydramine and methylprednisolone), hold metformin, and ensure IV access for hydration. Post-procedure hydration is crucial: contrast dye is directly nephrotoxic, but adequate hydration dilutes it and reduces contact time with renal tubules.

Peritonitis in PD patients is a nursing emergency even before fever develops. The absence of fever does not rule it out — early peritonitis may present with only cloudy effluent and mild discomfort. The nursing principle here parallels UTI culture — always collect the specimen BEFORE antibiotics. The sequence is: observe → collect specimen → notify physician → administer ordered antibiotics. Patient education is also essential: teach CAPD patients to inspect every drained bag of effluent for clarity before disposing of it, to maintain strict aseptic technique during exchanges, and to report any cloudiness IMMEDIATELY.

The 24-hour urine collection is a commonly tested nursing procedure. The key error students make is SAVING the first void — that first void contains urine produced before the collection period and would invalidate the test by including old urine. The second critical error is missing a void — even one missed specimen invalidates the 24 hours. Refrigeration is essential: at room temperature, urine begins to break down and bacterial growth can falsify results. The serum creatinine drawn during the collection is used WITH the 24-hour urine creatinine to calculate the creatinine clearance (actual GFR measurement). This test is ordered when an estimated GFR may not be accurate enough (e.g., extremes of muscle mass, pregnancy, malnutrition).

This scenario reflects the highest-priority post-renal biopsy complication and tests the nurse's ability to recognize deterioration and respond using the nursing process and professional communication tools (SBAR). Maslow's hierarchy applies: physiological survival (stopping hemorrhage) is the top priority. The nurse must NOT wait to call because the trend is clearly toward hemodynamic instability. RA 9173 (Philippine Nursing Act of 2002) mandates that the registered nurse provides safe, quality nursing care — early recognition and reporting of deteriorating vital signs is a core professional responsibility.