A nurse is caring for a 60-year-old patient with non-Hodgkin… | 마이메르시 MyMerci
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문제

A nurse is caring for a 60-year-old patient with non-Hodgkin lymphoma who develops tumor lysis syndrome after starting rituximab. Which nursing intervention should be the highest priority?

해설
The highest priority is aggressive IV hydration with normal saline to maintain urine output and prevent acute kidney injury from uric acid and phosphate crystallization in tumor lysis syndrome. Other interventions (hemodialysis, calcium gluconate, allopurinol) may be needed but are not the immediate priority.

심화 해설

Core Nursing Explanation Key Concept Analysis: This question tests the priority nursing intervention for Tumor Lysis Syndrome (TLS), a life-threatening oncologic emergency. TLS occurs when cancer cells (like in non-Hodgkin lymphoma) are rapidly destroyed by chemotherapy (e.g., rituximab), releasing large amounts of intracellular contents (potassium, phosphate, uric acid) into the bloodstream. This leads to hyperkalemia, hyperphosphatemia, hyperuricemia, and hypocalcemia. The primary threat is Key Point! Acute Kidney Injury (AKI) caused by the precipitation of uric acid and calcium phosphate crystals in the renal tubules, leading to obstruction and renal failure.

Answer Rationale: The highest priority intervention is Aggressive Intravenous Hydration. Administering IV normal saline (option 1) dilutes the serum concentration of the toxic metabolites, increases renal blood flow, and promotes a high urine output to flush the crystals out of the renal tubules. Close monitoring of urine output is critical to assess renal function and the effectiveness of hydration. This intervention addresses the root cause of the most immediate life threat—preventing AKI.

Distractor Analysis:
  • Option 2 (Prepare for hemodialysis): Hemodialysis is a corrective treatment for severe, established TLS with refractory electrolyte imbalances or anuria, not the preventive first priority. It is indicated when conservative management fails.
  • Option 3 (Administer calcium gluconate): Calcium gluconate is given for symptomatic hypocalcemia (e.g., tetany, cardiac arrhythmias). While hypocalcemia is a component of TLS, it is often a consequence of hyperphosphatemia. Treating the symptom (hypocalcemia) without addressing the cause (crystal precipitation from hyperuricemia/hyperphosphatemia) and without aggressive hydration is not the priority. Furthermore, giving calcium can worsen calcium phosphate precipitation in the kidneys if hyperphosphatemia is not controlled.
  • Option 4 (Give allopurinol): Allopurinol is a xanthine oxidase inhibitor that prevents the formation of uric acid. It is a prophylactic and adjunctive therapy, often started before chemotherapy in high-risk patients. In an acute TLS setting, hydration to manage the existing uric acid load takes precedence over administering a preventive medication.
Related Concepts: The nursing process prioritization follows the ABCs (Airway, Breathing, Circulation) and Maslow's Hierarchy of Needs. Preventing renal failure supports circulation (fluid volume) and elimination, which are physiological priorities. In TLS, think "Flush the Kidneys First."

Concept Summary
ComponentMechanism in TLSPrimary Threat
HyperkalemiaCell lysis releases intracellular K+.Cardiac arrhythmias, cardiac arrest.
HyperphosphatemiaCell lysis releases phosphate.Binds with calcium, causing hypocalcemia and renal crystal precipitation.
HyperuricemiaPurine breakdown from nucleic acids.Uric acid crystal precipitation in kidneys → AKI.
HypocalcemiaPrecipitation with phosphate.Neuromuscular irritability (tetany), arrhythmias.

Side-by-Side Comparison!
InterventionPurpose/Role in TLSPriority Timing
IV Hydration (NS)Preventative & First-line: Dilutes solutes, promotes diuresis to prevent crystal formation.HIGHEST PRIORITY - Initiate immediately upon risk or diagnosis.
Allopurinol / RasburicaseUric Acid Control: Prevents (allopurinol) or breaks down (rasburicase) uric acid.Prophylactic (pre-chemo) or early adjunctive therapy.
Electrolyte Correction (e.g., Kayexalate, Insulin/Glucose, Calcium)Symptomatic Management: Treats life-threatening electrolyte levels (e.g., severe hyperkalemia).As needed based on lab values and symptoms. Treats effects, not the root cause of AKI.
Renal Replacement Therapy (Hemodialysis)Rescue Therapy: Removes toxins when medical management fails and renal function is severely compromised.Last resort for refractory cases or anuria.

Anatomy, Physiology & Pharmacology Points
  • Pathophysiology: Rapid cell death → Nucleic acid (purine) breakdown → Uric acid ↑. Cell membrane breakdown → Intracellular K+ and phosphate flood into blood → Hyperkalemia & Hyperphosphatemia → Phosphate binds serum calcium → Hypocalcemia.
  • Renal Physiology: Uric acid and calcium phosphate are poorly soluble. High concentrations in acidic, low-flow urine lead to crystal formation in renal tubules, causing obstruction and AKI.
  • Pharmacology: Rituximab is a monoclonal antibody (anti-CD20) that targets B-cells in non-Hodgkin lymphoma, causing cell lysis. Allopurinol inhibits xanthine oxidase. Rasburicase (recombinant urate oxidase) converts uric acid to allantoin (more soluble).

Memory Tips
  • Acronym "CHOP" for TLS Labs: Calcium (Low), High Potassium, High Phosphate, High Uric acid. (Note: Calcium is low, others are high).
  • Priority Rule: "FLUSH before you FIX." First, FLUSH the kidneys with IV fluids. Then, FIX the electrolytes and give specific medications.
  • High-Risk Cancers: Think "BALL" - Burkitt's lymphoma, Acute leukemias (especially ALL), Lymphomas (high-grade), Large tumor burden.

High-Frequency NCLEX Topics Tumor Lysis Syndrome is a classic NCLEX priority question. The exam tests:
  1. Recognizing TLS as an oncologic emergency.
  2. Knowing the four hallmark lab abnormalities.
  3. Applying nursing process prioritization: Preventing acute kidney injury through hydration is almost always the #1 priority.
  4. Identifying high-risk patients (lymphomas, leukemias with high tumor burden starting chemo).

Watch Out for Question Variations!
  • Shift from "Priority Intervention" to "Expected Finding": "The nurse identifies which finding as an early sign of TLS?" (Answer: Elevated serum uric acid or Decreased urine output).
  • Shift to "Patient Education": "Which instruction is most important for a patient at risk for TLS?" (Answer: "Increase your fluid intake to 2-3 liters per day unless contraindicated.").
  • Shift to "Medication Administration": "The nurse is preparing to administer rasburicase. Which action is essential?" (Answer: Do not shake the vial; administer IV over 30 minutes; handle blood samples for uric acid on ice to prevent false-low readings).

임상 시나리오

Nursing Clinical Practice Guide Clinical Scenario: You are the nurse on an oncology unit. Mr. Johnson, 60, was admitted with aggressive non-Hodgkin lymphoma. He received his first dose of R-CHOP chemotherapy (which includes rituximab) 24 hours ago. This morning, he reports fatigue, nausea, and vague muscle cramps. His vital signs are stable, but you note his urine output over the last 8 hours has decreased from 60 mL/hr to 25 mL/hr.

Nursing Intervention Strategy:
  1. Assessment (Immediate):
    • Vital Signs & I&O: Strict intake and output monitoring. Weigh daily.
    • Labs: STAT basic metabolic panel (BMP), calcium, phosphate, uric acid, LDH. Key Point! Look for the "CHOP" pattern.
    • Physical Exam: Assess for edema, lung sounds (for fluid overload), cardiac rhythm (hyperkalemia risk), neuromuscular status (tetany from hypocalcemia).
  2. Planning & Implementation (Priority Actions):
    • Initiate/Increase IV Hydration: Collaborate with the provider to order IV normal saline at 150-200 mL/hr (or per protocol) unless the patient shows signs of fluid overload. The goal is a urine output >100 mL/hr or >3L/day.
    • Monitor Response: Closely track urine output hourly. If output remains low despite hydration, notify the provider immediately.
    • Administer Adjunct Medications: As ordered, give allopurinol or rasburicase. Administer electrolyte correction agents (e.g., kayexalate for hyperkalemia, calcium gluconate for symptomatic hypocalcemia) only after addressing hydration and based on specific, severe lab values/symptoms.
    • Alkalization of Urine: This is controversial and less common now. Historically, sodium bicarbonate was added to IV fluids to alkalinize urine and increase uric acid solubility. However, this can promote calcium phosphate precipitation. Current guidelines often recommend hydration with normal saline alone. Follow your institution's protocol.
  3. Evaluation:
    • Is urine output improving and maintained >0.5 mL/kg/hr?
    • Are serum electrolyte levels (K+, Phos, Uric acid) stabilizing or decreasing?
    • Is the patient free from complications like pulmonary edema, cardiac arrhythmias, or seizures?
Patient Safety and Precautions:
  • Contraindication for Aggressive Hydration: Congestive Heart Failure (CHF), renal failure with anuria. In these cases, the risk of pulmonary edema must be balanced, and early dialysis may be necessary.
  • Medication Caution: Rasburicase is contraindicated in patients with G6PD deficiency (can cause hemolytic anemia). Calcium gluconate must be given slowly IV and through a central line if possible to avoid tissue necrosis.
  • Key Monitoring: Continuous cardiac monitoring for hyperkalemia (peaked T waves, widened QRS). Frequent lab draws (every 4-6 hours initially).

Nursing Procedure & Medication Flow Managing IV Hydration for TLS:
  1. Obtain order for IV normal saline infusion.
  2. Calculate drip rate: Total mL ordered ÷ total minutes × drop factor (gtt/mL) = gtt/min.
  3. Use an IV pump for precise control.
  4. Place a Foley catheter if strict, accurate hourly urine output measurement is required.
  5. Assess for signs of fluid overload (crackles, dyspnea, increased JVD) every 1-2 hours.
Administering Rasburicase (Example):
  1. Reconstitute as per manufacturer instructions. DO NOT SHAKE—gently swirl to mix.
  2. Administer IV over 30 minutes.
  3. Critical Lab Draw Note: Inform the lab that the patient is on rasburicase. Blood samples for uric acid must be collected in pre-chilled tubes, placed on ice, and assayed within 4 hours. If not, the drug will break down uric acid in the sample tube, giving a falsely low reading.

A Word from Your Senior Nurse "Tumor Lysis Syndrome is a perfect example of why we say 'nurses save kidneys!' Your vigilant monitoring of I&O and early recognition of decreased urine output after chemotherapy can trigger the life-saving intervention of aggressive hydration before labs even come back critically abnormal. In oncology nursing, you're not just giving chemo; you're managing the body's dramatic reaction to it. Always think one step ahead: 'This patient got cell-killing drugs today. What are the cells releasing, and where is it going to cause trouble?' That clinical foresight is what makes an extraordinary nurse. On the NCLEX, they want to see that you know the foundational principle: prevent the kidney damage first. Carry that same priority mindset to the bedside."

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