Evaluation of Hypoxia

Last updated: April 8, 2026, 1:27 PM Pacific Time (PDT)

Symptom-first framework for new or worsening hypoxemia. Stabilize first, then separate alveolar/parenchymal disease, cardiogenic pulmonary edema, pulmonary embolism, obstructive physiology, atelectasis or mucus plugging, and hypoventilation or upper-airway causes.

All Immediate stabilization Parenchymal / shunt Cardiac / volume Vascular Back to Main Page

Interactive diagnostic assistant

Activate the assistant to re-rank likely hypoxia causes from partial clinical data.
Presentation
Parenchymal clues
Cardiopulmonary clues
Airway / ventilation clues
Danger context

Likely diagnoses from entered data

Recommended next labs, imaging, and diagnostics

Flowchart

First pass
Hypoxia is a physiology problem before it is a diagnosis
Start with oxygenation, work of breathing, and hemodynamics. Immediate threats include airway compromise, severe shunt physiology, pulmonary edema, PE, pneumothorax, mucus plugging, and hypoventilation.
↓
Immediate stabilization
Escalate support before the differential gets elegant
Rapidly rising oxygen needs, fatigue, shock, or altered mentation should move ahead of detailed categorization.
Parenchymal / shunt
Fever + cough
Pneumonia / aspiration / ARDS-type process
Think infection, aspiration, diffuse inflammatory lung injury, or focal consolidation.
Post-op / secretion burden
Atelectasis / mucus plugging
Common when the hypoxia is abrupt, post-op, or paired with poor airway clearance.
Cardiac / volume
Orthopnea + edema
Cardiogenic pulmonary edema
Volume overload clues and heart failure history push here quickly.
Wheeze / CO2
Obstructive disease with V/Q mismatch
Asthma/COPD can present as hypoxemia even before hypercarbia is confirmed.
Vascular / other
Pleuritic + risk
Pulmonary embolism
Acute hypoxia with pleuritic pain, tachycardia, or VTE context belongs here.
Somnolence / opioids
Hypoventilation or upper-airway process
Hypoxemia plus somnolence, opioid exposure, obesity hypoventilation, or stridor needs a ventilation-focused lens.
Always consider
Mixed physiology
More than one thing can be true
HF plus pneumonia, COPD plus aspiration, or PE plus underlying lung disease are common inpatient mixes.

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