Pulse oximetry is a non-invasive medical device that allows real-time measurement of:
Arterial blood oxygen saturation (SpO₂)
Heart rate (pulse rate)
It operates using two light beams (red and infrared) that pass through the tissue (typically the finger or earlobe). The device analyzes light absorption by oxygenated and deoxygenated hemoglobin.
Main Technical Characteristics
Feature
Detail
SpO₂ Range
0 to 100% (most reliable zone is typically between 70% and 100%)
SpO₂ Accuracy
± 2 to 3% within the 70–100% range
SpO₂ Resolution
1%
Heart Rate Range
25 to 250 beats/min
Heart Rate Accuracy
± 2 to 3 bpm
Power Supply
AAA batteries or rechargeable battery depending on the model
Display
LED or OLED screen, numerical values, and sometimes plethysmography waveforms
Dimensions / Weight
Compact, portable device, generally < 100 g
Connectivity (model dependent)
USB, Bluetooth, or wireless for data transfer
Advantages
Fast, non-invasive, and completely painless measurement.
Allows for continuous or spot-check monitoring of oxygen saturation and pulse.
Compact, easy to carry, and simple to use in medical settings or at home.
Highly useful in anesthesia, intensive care, sports medicine, and for monitoring respiratory or cardiac pathologies.
Limitations
Sensitivity to movement artifacts and poor peripheral perfusion conditions (e.g., cold hands, low blood pressure).
Potential measurement errors in the presence of nail polish, artificial nails, or very dark skin pigmentation.
Less reliable when oxygen saturation drops below 80%.
Requires maintenance and regular battery replacement or recharging.