A 50-year-old woman with severe resting hypoxia not amendable to high-flow oxygen supplementation

Authors

• Razi Even-dar Pulmonology Unit, Rambam Health Care Campus, Haifa, Israel
• Reem Mhamid Pulmonology Unit, Rambam Health Care Campus, Haifa, Israel
• Karwan Badarni General Intensive Care Unit, Rambam Health Care Campus, Haifa, Israel
• Evelyne Shabad Hemoglobinopathy Clinic, Rambam Health Care Campus, Haifa, Israel
• Yaron Bar-lavie General Intensive Care Unit, Rambam Health Care Campus, Haifa, Israel; Technion – Israel Institute of Technology, Haifa, Israel
• Yaniv Dotan Pulmonology Unit, Rambam Health Care Campus, Haifa, Israel; Technion – Israel Institute of Technology, Haifa, Israel

razieven@gmail.com

Keywords

Abstract

Introduction: Pulse oximetry is a widely used non-invasive method to measure arterial oxygen saturation (SpO₂). However, haemoglobinopathies, including rare low-oxygen-affinity variants such as haemoglobin (Hb) Lansing can result in falsely low SpO₂ readings due to alterations in the Hb oxygen dissociation curve and spectral properties. Recognising these conditions is crucial to avoid misdiagnosis and unnecessary interventions.
Case description: A 50-year-old female with a history of chronic obstructive pulmonary disease (COPD), hypertension and compensated cirrhosis presented for pre-operative evaluation. Persistent hypoxia (SpO₂ 84%), unresponsive to oxygen supplementation, was noted during routine assessment. Diagnostic investigations excluded pulmonary or cardiac shunts, hepatopulmonary syndrome and common causes of methaemoglobinaemia or carboxyhaemoglobinemia. Arterial blood gas analysis using a CO-oximeter revealed a true oxygen saturation of 90%, highlighting a discrepancy with pulse oximetry. Hb electrophoresis demonstrated an abnormal haemoglobin fraction, and subsequent genetic testing identified a heterozygous mutation (HBA1: c.264C>G), confirming Hb Lansing. The patient was asymptomatic apart from mild exertional dyspnoea attributed to underlying COPD and safely underwent planned surgery.
Discussion: Hb Lansing is a rare haemoglobinopathy characterised by low oxygen affinity and high p50, leading to falsely low SpO₂ readings and minimal response to supplemental oxygen. Diagnosis relies on CO-oximetry, Hb electrophoresis and genetic analysis. No specific treatment is required for low-affinity haemoglobinopathies, which generally have a benign clinical course.
Conclusion: Haemoglobinopathies should be considered in the differential diagnosis of unexplained hypoxia. Utilisation of targeted diagnostic tools enables clinicians to ensure accurate diagnosis and appropriate management.

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