Effects of motion, ambient light, and hypoperfusion on pulse oximeter function

Area of Science:

• Biomedical Engineering
• Clinical Monitoring

Background:

• Pulse oximetry is a critical tool for monitoring oxygen saturation (SpO2) and heart rate (HR).
• Device performance can be compromised by various physiological and environmental factors.

Purpose of the Study:

• To compare the performance of five different pulse oximeters.
• To evaluate oximeter accuracy under simulated conditions of hypoperfusion, probe motion, and ambient light interference.

Main Methods:

• A prospective laboratory study was conducted using eight healthy volunteers.
• Five common pulse oximeters were tested against simulated hypoperfusion, hand motion (2 Hz and 4 Hz), and operating room light interference.
• Electrocardiography (ECG) and arterial blood gas (SaO2) values served as gold standards for HR and SpO2, respectively.

Main Results:

• Significant differences in accuracy were observed among pulse oximeters under nonideal conditions.
• Ambient light interference caused high failure rates for Ohmeda and Nellcor N200 devices.
• Nellcor N200 models showed better SpO2 accuracy during motion, but all devices failed dramatically in HR measurement during 4 Hz motion.
• In hypoperfusion, Nellcor N200 devices performed significantly better, while Criticare failed completely.

Conclusions:

• Commercially available pulse oximeters exhibit variable accuracy during challenging clinical scenarios.
• Failure rates ranged from 5% to 50% depending on the oximeter and interference type.
• No single pulse oximeter demonstrated superior performance across all tested adverse conditions.