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Possible causes of low oxygen saturation (SpO2) detection on pulse oximetry.[41]
| Falsely low readings | True hypoxaemia |
|---|---|
| Abnormal haemoglobin variants | Hypoxia (e.g. carbon monoxide poisoning) |
|
| |
| Methemoglobinaemia | Hypoventilation |
|
| |
| Nail polish | Right-to-left shunting (e.g. ventricular septal defect) |
|
| |
| Movement artefacts | Ventilation and perfusion mismatch (e.g. decompensated heart failure, asthma) |
|
| |
| Vasoconstriction/peripheral hypoperfusion | Diffusion defects |
