The effect of pulsating arteries on reflectance pulse oximetry: Measurements in adults and neonates

Objective. The objective of our study was to describe the results from human experiments during normoxia that demonstrate the effect of pulsating arteries on the measured arterial oxygen saturation (Spo₂) using a reflectance pulse oximeter sensor.Methods. In 6 healthy adults and 7 healthy neonates, a Nellcor reflection sensor (FS-10 oxisensor, Nellcor, Inc., Pleasanton, CA) was placed in three different positions: (1) on the forehead, (2) on the temporal area, with the photodiode placed over the superficial temporal artery, and (3) on the temporal area, with the light-emitting diodes (LEDs) placed over the superficial temporal artery.Results. Placement of the sensor in position 2 resulted in a significantly lower Spo₂ reading, compared to sensor position 1: 5.8% (p<0.01) lower for adults and 7.5% (p<0.01) lower for neonates. Placement of the sensor in position 3 resulted in significantly larger plethysmographic signals, compared to sensor position 1; but, the Spo₂ readings were alike.Conclusions. Pulsating arteries can affect the reliability of reflection pulse oximetry. Depending on the position of the sensor, a falsely low Spo₂ value can be observed.