Spurious hypoxemia

Objective: To discuss the pathophysiology and clinical implications of spurious hypoxemia in the setting of hyperleukocytosis. Design: Case report and review of the literature. Setting: A 22-bed, adult neurosciences critical care unit at a tertiary care hospital. Patient: A 49-yr-old male with chronic myelogenous leukemia. Interventions: Administration of hydroxyurea and imatinib mesylate. Measurements and Main Results: The patient was admitted to the neurosciences critical care unit with an acute nontraumatic subdural hematoma that required emergent surgical evacuation. His clinical course was notable for neurologic deterioration, sepsis, hyperleukocytosis, severe hypoxemia, and prolonged mechanical ventilation. An inverse relationship was observed between arterial oxygen tension and the magnitude of hyperleukocytosis. Hypoxemia resolved after the institution of chemotherapy and normalization of white cell count. Pulse oximeter saturation was normal throughout. Conclusions: Patients with hyperleukocytosis are at risk for severe hypoxemia, which may be real or spurious. Failure to recognize spurious hypoxemia can lead to unnecessary diagnostic tests and therapeutic interventions, exposing patients to avoidable risk. A diagnostic algorithm is proposed.