# A nurse is caring for a patient receiving warfarin therapy. Which laboratory value requires the most immediate nursing intervention?

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> subject: Pharmacology

## 문제

A nurse is caring for a patient receiving warfarin therapy. Which laboratory value requires the most immediate nursing intervention?

## 보기

1. PT/INR of 2.5
2. PT/INR of 6.8 **✔ 정답**
3. Platelet count of 180,000/mm³
4. Hemoglobin of 12.5 g/dL

**정답: 2**

## 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.

## 심화 해설

Understanding the Therapeutic Range and Critical Values for Warfarin

Warfarin therapy requires meticulous monitoring because of its narrow therapeutic index, a concept highlighted in the provided literature as a primary challenge in management [1]. The drug’s effectiveness and safety are quantified using the Prothrombin Time (PT) and its standardized derivative, the International Normalized Ratio (INR). For most indications, including atrial fibrillation and mechanical heart valves, the target therapeutic INR range is typically 2.0 to 3.5. A value within this range indicates that the patient is receiving the intended anticoagulation effect to prevent thromboembolism while maintaining a controlled risk of bleeding.

When the INR exceeds this therapeutic window, the risk of major hemorrhage escalates exponentially. An INR of 6.8 is a critically supratherapeutic value that represents a state of profound anticoagulation. At this level, the coagulation cascade is severely inhibited, and the patient is at imminent risk for life-threatening spontaneous bleeding. The provided references underscore this danger, documenting catastrophic events such as warfarin-associated intracerebral hemorrhage (ICH), which carries high mortality and disability [2], and spontaneous hematomas in closed compartments like the iliacus muscle or rectus sheath, which can mimic acute surgical abdomens and lead to significant blood loss and hemodynamic instability [3, 4]. These complications are a direct consequence of the excessive anticoagulant effect reflected by a dangerously elevated INR.

Analysis of the Provided Laboratory Values

A systematic evaluation of each option clarifies why the INR of 6.8 demands the most immediate action:

- **Option 1: PT/INR of 2.5** — This value falls squarely within the standard therapeutic range. It indicates that the warfarin dose is achieving the desired anticoagulant effect without signaling an elevated bleeding risk. No immediate intervention is required beyond routine continued monitoring [1].

- **Option 2: PT/INR of 6.8** — This is a critical value. The risk of a major hemorrhagic event, such as an ICH or a spontaneous retroperitoneal or intramuscular hematoma, is extremely high [2, 3, 4]. This finding necessitates an immediate nursing intervention, which includes holding the warfarin dose, conducting a thorough assessment for signs of active bleeding (e.g., neurological changes, severe abdominal or flank pain, hypotension, guaiac-positive stools), and promptly notifying the healthcare provider to prepare for potential administration of vitamin K or other reversal agents.

- **Option 3: Platelet count of 180,000/mm³** — This platelet count is within the normal range (150,000–400,000/mm³). While warfarin affects the coagulation cascade (secondary hemostasis), a normal platelet count indicates that primary hemostasis is intact. This value does not explain or compound the bleeding risk from an elevated INR.

- **Option 4: Hemoglobin of 12.5 g/dL** — This hemoglobin level is within the normal range for an adult female and low-normal for an adult male. It does not indicate active or severe anemia. While a sudden drop from a previous value would be concerning, a single stable value of 12.5 g/dL does not, in itself, require immediate intervention. The supratherapeutic INR, however, is a direct harbinger of a potential future drop in hemoglobin from acute hemorrhage [4].

Clinical Reasoning and Nursing Priority

The clinical priority is dictated by the immediate threat to the patient's physiological safety. An INR of 6.8 represents a state of severe, uncompensated coagulopathy. The pathophysiological mechanism is clear: warfarin inhibits vitamin K-dependent clotting factors (II, VII, IX, X), and a supratherapeutic INR indicates a near-complete suppression of these factors. This directly precipitates the complications described in the source material, where supratherapeutic anticoagulation was the common etiological factor in patients presenting with spontaneous ICH and rectus sheath hematoma [2, 4]. The nurse's most immediate role is to recognize this critical value, prevent further drug administration, and activate the chain of response to reverse the anticoagulation and assess for occult bleeding, thereby preventing the progression to a potentially fatal hemorrhagic event.

References (research sources)

- [1]AI-WAR: a novel warfarin management software with a bidirectional LSTM dosing model improves time in therapeutic range.Research articleLi Y, Xu N, Song L, Liu Y, Pei Q, Kuang Y, Yang G. (2026) · DOI: 10.3389/fphar.2026.1750503

- [2]Clinical and Radiological Evaluation of Warfarin-Associated Intracerebral Hemorrhage (ICH) in Patients With Mechanical Prosthetic Heart Valves: A Retrospective Observational Study.Research articleKumar A, Bidwaikar A, Panika SD, Raj N. (2026) · DOI: 10.7759/cureus.109377

- [4]Spontaneous Rectus Sheath Hematoma Presenting As Acute Abdomen in an Anticoagulated Patient: A Case Report.Case reportHasan AK, Hasan SK, Alsudairy NM. (2026) · DOI: 10.7759/cureus.109486

## 임상 시나리오

Managing Critical Supratherapeutic INRImmediate intervention for INR >5.0 to prevent life-threatening hemorrhage
An INR of 6.8 is a critical value representing profound anticoagulation. The risk of spontaneous, life-threatening bleeding, such as intracerebral hemorrhage, is exponentially increased.

The first nursing action is to hold the warfarin dose and immediately notify the healthcare provider. Anticipate orders for vitamin K (oral or IV) or prothrombin complex concentrate (PCC) for urgent reversal.

CautionAssess the patient for any signs of active bleeding (e.g., bruising, petechiae, dark stools, altered mental status). Intravenous vitamin K must be administered slowly to mitigate the risk of anaphylaxis.

## 핵심 개념

- **International Normalized Ratio (INR)** — A standardized measure of the extrinsic pathway of coagulation, used to monitor warfarin therapy; therapeutic range is typically 2.0-3.5.
- **Warfarin** — An oral anticoagulant that inhibits vitamin K-dependent clotting factors; has a narrow therapeutic index requiring regular INR monitoring.
- **Supratherapeutic INR** — An INR value above the target therapeutic range, exponentially increasing the risk of major and spontaneous bleeding.
- **Prothrombin Time (PT)** — A blood test that measures how long it takes blood to clot; results are standardized and reported as the INR for patients on warfarin.

## 같은 주제 문제

- [A nurse is caring for a patient receiving warfarin therapy. Which set of laboratory values…](https://mymerci.kr/pages/nclex_q.php?qn_id=543507)

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