A nurse is caring for a 45-year-old patient with newly diagnosed acute myeloid leukemia receiving chemotherapy. The patient suddenly develops severe shortness of breath, chest pain, and hypotension. Vital signs: BP 85/50 mmHg, HR 125 bpm, RR 32/min, SpO2 88% on room air. The patient appears anxious and restless. Laboratory results show a white blood cell count of 180,000/mm³. What is the nurse's priority action?

The patient's symptoms and high WBC indicate leukostasis, a life-threatening emergency requiring immediate physician notification and emergency interventions like leukapheresis. Other options are supportive but do not address the urgent need to reduce WBC.

Clinical Presentation and Underlying Pathophysiology

This patient is presenting with a classic picture of leukostasis, a life-threatening hematologic emergency. The laboratory value of a white blood cell (WBC) count of 180,000/mm³ confirms severe hyperleukocytosis (HL), most often defined as a WBC count greater than 100,000/μL ^[1]. In acute myeloid leukemia (AML), 5%–20% of newly diagnosed patients present with HL, and it is associated with severe complications, early mortality, and a poor prognosis ^[1].

The pathophysiology of this emergency is twofold. First, the massively elevated number of circulating myeloblasts, which are larger and less deformable than mature leukocytes, increases blood viscosity. This leads to sludging of blood flow within the microvasculature. Second, these blasts are metabolically active and compete with endothelial cells for oxygen, creating a state of localized tissue hypoxia even when the large vessels are patent. The clinical consequences manifest dramatically in the pulmonary and cerebral circulations, producing the symptoms seen here: severe dyspnea, chest pain, hypoxemia (SpO2 88%), and neurological changes such as anxiety and restlessness [2,3]. The resulting right-to-left shunting and ventilation-perfusion mismatch explain the hypoxemia, while the sudden hemodynamic instability (hypotension and tachycardia) signals impending cardiovascular collapse due to profound capillary stasis and myocardial strain.

Analysis of Nursing Actions and Priority Setting

In a hematologic emergency like HL with leukostasis, the nurse must prioritize actions that directly address the immediate threat to life—tissue hypoxia and cardiovascular collapse—by initiating definitive therapy. The core principle, highlighted in the literature, is that prompt initiation of chemotherapy is paramount ^[3]. All supportive measures are temporizing until the disease process itself is reversed.

* Option 1: Administer supplemental oxygen via nasal cannula at 2 L/min. This is an appropriate supportive intervention to address the hypoxemia. However, it does nothing to resolve the underlying cause, which is the mechanical obstruction and oxygen consumption by leukemic blasts. Oxygen administration alone will not prevent the progression of respiratory failure or intracranial hemorrhage. It is a secondary, not primary, priority.

* Option 2: Immediately notify the physician and prepare for emergency interventions. This is the correct priority action. The patient’s condition is a recognized hematologic emergency requiring immediate intervention to reduce the white blood cell count [1,4]. The nurse's role is to recognize the syndrome, communicate the critical findings urgently, and prepare for the definitive treatments the provider will order. These interventions may include emergent leukocytapheresis (LCP), which can rapidly and safely reduce the WBC count as an adjunct to systemic chemotherapy [1,3], or the immediate initiation of induction chemotherapy. Preparing for these interventions involves gathering emergency equipment, ensuring IV access, and preparing for potential transfer to a higher level of care.

* Option 3: Position the patient in high Fowler's position and monitor vital signs. This is a comfort and supportive measure that may ease the work of breathing. However, it does not treat the life-threatening leukostasis. Continuous monitoring is essential, but it is a passive action. In a rapidly deteriorating patient, the nurse must actively initiate the chain of events that leads to definitive treatment, not just observe the decline.

* Option 4: Obtain a chest X-ray to assess for pulmonary complications. While a chest X-ray may be part of the diagnostic workup to rule out other causes like pneumonia or hemorrhage, it is not the immediate priority. The clinical presentation of severe dyspnea, chest pain, and hypoxemia in the setting of a WBC of 180,000/mm³ is highly specific for pulmonary leukostasis. Delaying life-saving treatment to obtain a diagnostic study would be a critical error. The priority is to treat the presumptive diagnosis.

The nurse’s immediate recognition of hyperleukocytosis as a hematologic emergency with high early mortality and the subsequent activation of the healthcare team to deliver rapid cytoreduction are the most critical steps in preventing irreversible end-organ damage and death [2,4].