Episode 458 – A Case & The Book – Rabih and Reza discuss with Dr. Daniel Kelmenson, a patient with severe hypoxemia

In Episode 458 of The Clinical Problem Solvers, hosts Rabih and Reza welcome Dr. Daniel Kelmenson, a pulmonary and critical care attending at UAB Hospital, to discuss a complex and rare clinical case involving a patient with severe hypoxemia. The case unfolds during a 4 a.m. rapid response call where a 62-year-old man with newly diagnosed acute leukemia and hyperleukocytosis presents with a pulse ox saturation of 80% on BiPAP despite being asymptomatic and having clear lung exam findings. The team meticulously dissects the paradox between objective hypoxemia and subjective well-being, ultimately uncovering a dual diagnostic trap: methemoglobinemia triggered by rasburacase treatment in a patient with undiagnosed G6PD deficiency, and a falsely low PaO2 due to oxygen consumption by leukemic cells in the ABG sample. The episode highlights the critical importance of questioning data, integrating clinical context, and using point-of-care testing to avoid diagnostic errors. The case concludes with the patient’s recovery through supportive care and vitamin C, reinforcing the value of slow, thoughtful clinical reasoning. Key takeaways include: (1) Always question the validity of pulse oximetry and ABG results, especially in complex cases; (2) Methemoglobinemia can cause falsely low SpO2 even with normal or high PaO2; (3) Hyperleukocytosis can artifactually lower PaO2 if ABG is delayed; (4) Methylene blue is contraindicated in G6PD deficiency; (5) Vitamin C is a safe alternative treatment for methemoglobinemia in such patients; (6) The patient’s lack of symptoms despite severe hypoxemia underscores the disconnect between dyspnea and hypoxemia; (7) Rapid, accurate point-of-care testing is essential in acute settings; (8) Clinical intuition and systematic thinking must be balanced with data scrutiny. The episode is celebrated as a masterclass in diagnostic reasoning and a standout case in the podcast’s history.