Use of plasma for arterial blood gas analysis in leukemia

Overcoming the problem of pseudohypoxemia in myeloproliferative disorders: Another trick in the bag

Pseudohypoxaemia or spurious hypoxaemia is a recurrent problem faced on arterial blood gas analysis in patients with hyperleucocytosis leading to management dilemmas and unnecessary respiratory interventions. Various methods have been suggested to reduce the magnitude of this problem. We report a case of pseudohypoxaemia due to blast crisis in a patient of chronic myeloid leukaemia where arterial blood gas analysed from precooled syringe helped us resolve the problem and hastened our weaning from oxygen therapy.

Factitious biochemical measurements resulting from hematologic conditions

Factitious laboratory results often lead to unnecessary testing or treatment. This brief review of factitious biochemical results due to preexisting hematologic conditions focuses on the mechanisms underlying the factitious results and suggests ways to prevent them. An observant pathologist identifies these errors, intervenes in a timely fashion, investigates the sources of error diligently, and institutes measures to prevent their recurrence.

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.