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Andrew Pollack-Gray

Nursing Notes

Measuring Oxygen Saturation

3 min read

When & Why?

Use pulse oximetry to estimate arterial oxygen saturation (SpO₂) and recognize changes that may require reporting.

SpO₂: Estimated percentage of hemoglobin carrying oxygen.

Pulse oximetry does not directly measure ventilation, carbon dioxide, or the underlying cause of respiratory distress.

Before You Start

  • Review the care plan and prescribed reporting thresholds.
  • Explain the procedure and obtain permission.
  • Perform hand hygiene.
  • Select an appropriate pulse oximeter and sensor.
  • Ensure the sensor is clean and functioning.
  • Check for factors that may interfere with the reading.

Steps

  1. Position the resident comfortably.
  2. Select an appropriate measurement site, usually a finger.
  3. Apply the sensor according to manufacturer instructions.
  4. Ask the resident to remain still when possible.
  5. Allow the reading to stabilize.
  6. Observe the SpO₂ value and displayed pulse rate.
  7. Check the signal quality or other reliability indicators provided by the device.
  8. Record the reading, time, and relevant details according to facility policy.
  9. Report abnormal values or concerning symptoms promptly.
  10. Clean and disinfect reusable equipment as required.

Safety & Observations

Factors Affecting Accuracy:

  • Poor peripheral circulation.
  • Cold extremities.
  • Movement.
  • Nail polish or artificial nails.
  • Incorrect sensor placement.
  • Skin pigmentation and differences in device performance.

Important: A pulse oximeter can produce an inaccurate reading. Do not rely on SpO₂ alone to determine whether a resident is experiencing respiratory distress.

Reporting & Escalation

  • Report readings outside prescribed parameters.
  • Report unexpected changes from baseline.
  • A reading below 90% generally warrants urgent clinical attention, but follow the resident’s individualized targets and facility escalation policy.
  • Activate emergency response for severe breathing difficulty, cyanosis, sudden deterioration, or other critical symptoms, regardless of the displayed number.
  • Do not independently change oxygen flow rates or prescribed treatment.

What Should I Remember?

  • A commonly taught adult SpO₂ reference range is 95–100% at sea level.
  • Some residents have individualized oxygen saturation targets.
  • A normal-appearing reading does not exclude respiratory distress.
  • Poor signal quality can make measurements unreliable.
  • Follow the care plan and report symptoms alongside measurements.

Practice

  • Studied
  • Observed
  • Practiced
  • Passed checkoff

Sources

Flashcards

What does SpO₂ estimate?01-foundations / clinical-skills
Answer

The percentage of hemoglobin saturated with oxygen.

Does normal SpO₂ rule out respiratory distress?03-application / clinical-skills
Answer

No. Symptoms and clinical condition must also be considered.

What factors can affect pulse oximeter accuracy?02-mechanisms / clinical-skills
Answer

Movement, poor circulation, sensor placement, nail polish, and skin pigmentation.

May a CNA independently increase oxygen flow because SpO₂ is low?03-application / clinical-skills
Answer

No. Report the finding and follow authorized emergency procedures.

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