A nurse is caring for a patient receiving warfarin therapy. Which laboratory value requires the most immediate nursing intervention?
1PT/INR of 2.5
2PT/INR of 6.8✓ 정답
3Platelet count of 180,000/mm³
4Hemoglobin of 12.5 g/dL
해설
An INR of 6.8 indicates severe anticoagulation with high bleeding risk, requiring immediate intervention like warfarin cessation or vitamin K. Other values (INR 2.5, normal platelet count, normal hemoglobin) are within safe or therapeutic ranges.
Core Nursing ExplanationKey Concept Analysis: This question assesses the critical nursing responsibility of monitoring a patient on warfarin (Coumadin) anticoagulant therapy. The core concept is understanding the therapeutic and toxic ranges of the Prothrombin Time (PT) and International Normalized Ratio (INR). Warfarin works by inhibiting vitamin K-dependent clotting factors (II, VII, IX, X), thereby prolonging the time it takes for blood to clot. The INR standardizes the PT result, making it the primary monitoring tool. The therapeutic range is typically 2.0 to 3.0 for most conditions (e.g., atrial fibrillation, DVT treatment), though it may be higher (2.5-3.5) for mechanical heart valves.
Answer Rationale: Key Point! An INR of 6.8 represents a supratherapeutic level, indicating a dangerously high risk of spontaneous, life-threatening bleeding (e.g., intracranial, gastrointestinal). This requires the most immediate nursing intervention, which includes notifying the provider immediately, holding the next warfarin dose, and being prepared to administer vitamin K (phytonadione) as an antidote per order. The nurse must also perform a focused assessment for signs of bleeding.
Distractor Analysis:
Watch out for confusion! Option 1 (PT/INR of 2.5) is within the standard therapeutic range and represents effective, safe anticoagulation. No immediate action is needed.
Option 3 (Platelet count of 180,000/mm³) is a normal value (normal range 150,000-400,000/mm³). While monitoring platelets is important for overall bleeding risk, it is not the primary monitoring parameter for warfarin. A dangerously low platelet count (
임상 시나리오
Nursing Clinical Practice GuideClinical Scenario: You are the day-shift nurse for Mr. Johnson, a 68-year-old with atrial fibrillation discharged 1 week ago on warfarin 5 mg daily. He presents to the clinic for his first post-discharge INR check. He reports no unusual bleeding but mentions he ate a large spinach salad yesterday.
Nursing Intervention Strategy:
1. Assessment: Before even getting the lab result, perform a focused assessment. Ask about signs of bleeding (gums, nose, stool, urine, bruising). Check skin for petechiae or ecchymosis. Assess for signs of clotting (new pain/swelling in legs, chest pain, shortness of breath).
2. Action Based on Result:
• INR 6.8 (as in the question): This is a critical value. Immediately notify the provider. Hold the scheduled warfarin dose. Instruct the patient to remain in the clinic. Prepare for possible administration of Vitamin K (oral or subcutaneous/IV per order). Initiate frequent vital sign monitoring.
• INR within range (2.0-3.0): Reinforce education on consistent diet and medication adherence. Schedule the next INR check.
• INR subtherapeutic (
핵심 개념
International Normalized Ratio — A standardized calculation of the Prothrombin Time (PT) used to monitor the anticoagulant effect of warfarin. Therapeutic range is typically 2.0-3.0.
Warfarin — A vitamin K antagonist oral anticoagulant that inhibits the synthesis of clotting factors II, VII, IX, and X. Requires regular INR monitoring.
Vitamin K — The antidote for warfarin overdose or toxicity. It reverses warfarin's effect by promoting the synthesis of vitamin K-dependent clotting factors.
Therapeutic Range — The narrow range of drug concentration in the blood that provides the desired clinical effect with minimal toxicity. For warfarin, this is an INR of 2.0-3.0 for most indications.
Supratherapeutic — A drug level or effect that is above the desired therapeutic range, indicating an increased risk of adverse effects (e.g., bleeding for warfarin). An INR >5.0 is considered supratherapeutic.