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How I treat hypoxia in adults with hemoglobinopathies and hemolytic disorders

Evans M. Machogu and Roberto F. Machado

Article Figures & Data

Figures

  • Figure 1.

    Pulmonary fibrosis complicating multiple episodes of ACS. Axial image of the chest computed tomography of a patient with SCD. Extensive fibrotic changes with honeycombing are noted anteriorly; reticular opacities are appreciated with an anterior predominance, and mild ground glass opacities are noted within the lungs.

  • Figure 2.

    Proposed algorithm for evaluation of PH related to SCD. 6MWD, 6-minute walk distance; ANA, anti-nuclear antibody; CXR, chest radiograph; EKG, electrocardiogram; LFTs, liver function tests; mPAP, mean pulmonary artery pressure; NT-pro-BNP, N-terminal pro–brain natriuretic peptide; PAWP, pulmonary artery wedge pressure; PVR, pulmonary vascular resistance. 1The use of the term screening refers to mortality risk assessment. Echocardiography should be performed while patients are clinically stable. Patients with an mPAP between 20 and 25 mm Hg need further study, as they may be at increased mortality risk. PH therapy is to be considered on the basis of a weak recommendation and very-low-quality evidence. Reprinted from Klings et al,59 with permission.

  • Figure 3.

    Proposed diagnostic workup algorithm for hypoxemia in patients with SCD. Proposed algorithm for evaluation of hypoxemia in patients with SCD and other hemoglobinopathies. BIPAP, bilevel positive airway pressure; CPAP, continuous positive airway pressure; OPSG, overnight polysomnogram. Echocardiography should be performed while the patient is clinically stable. All or some of the proposed studies may be obtained depending on the patient presentation and clinical suspicion for the underlying cause of hypoxemia.

Tables

  • Table 1.

    Etiology of hypoxia in patients with SCD

    Mechanism of hypoxiaCauses in SCD
    HypoventilationSDB (OSA, upper airway obstruction)
    Thoracic splinting due to chronic pain
    Restrictive pulmonary disease
    Reduced chest excursion due to hepatomegaly
    Central hypoventilation (eg, due to excessive use of narcotics)
    Diffusion impairmentSCD-associated interstitial lung fibrosis
    PH
    Pulmonary vascular disease
    ShuntIntracardiac shunt (eg, ventriculoseptal defect)
    Extracardiac shunt
    Arterial-venous malformations
    Intrapulmonary shunt (eg, due to consolidation or atelectasis resulting in decreased perfusion to affected area)
    Ventilation-perfusion inequalityChronic VTE
    ACS
    Plastic bronchitis
    Obstructive lung disease without asthma
    Chronic airway inflammation due to asthma
    • OSA, obstructive sleep apnea; SDB, sleep-disordered breathing.