Measuring Oxygen Saturation with Pulse Oximetry
Key Points
- Pulse oximetry provides a noninvasive estimate of arterial oxygen saturation.
- Cold extremities, poor perfusion, nail products, and probe misplacement can create falsely low values.
- Abnormal readings should be validated with repositioning, site change, and clinical correlation.
Equipment
- Pulse oximeter with appropriate sensor/probe
- Optional alternate-site sensor (earlobe or forehead)
- Hand hygiene supplies
Procedure Steps
- Complete routine pre-procedure actions: knock, identify resident, explain procedure, provide privacy, and perform hand hygiene.
- Select a warm, well-perfused site; remove nail polish/artificial nail barrier when finger sensor is used.
- Apply probe correctly and ensure patient minimizes motion.
- Wait for stable waveform/reading according to device guidance before recording value.
- If value is unexpectedly low, reassess for artifact causes (cold limb, poor placement, motion, low perfusion) and repeat.
- If needed, switch to alternate site (earlobe or forehead) and compare trend.
- Correlate reading with respiratory effort, pulse, and overall clinical appearance.
- Restore comfort/safety, perform hand hygiene, and document SpO2 with site and any validation steps used.
Common Errors
- Recording before signal stabilizes → unreliable SpO2 value.
- Ignoring nail product/perfusion artifacts → false low interpretation.
- Treating isolated number without clinical context → inappropriate escalation or delay.
Related
- measuring-respirations - Respiratory quality and rate contextualize SpO2 interpretation.
- vital-sign-indicators-of-physiologic-functioning-and-homeostasis - Integrates oxygen saturation into overall stability analysis.