Effect of limbs' motion on pulse oximetry in preterm infants

Pulse oximetry (PO) is a measurement method used to determine the percentage of blood that is loaded with oxygen (oxygen saturation). It is an easy-to-sue, safe, convenient, inexpensive, painless and noninvasive measurement method for the assessment of oxygen content in the circulatory system and it also allows to measure the pulse frequency (coincident to the heart rate). It is frequently asses in intensive care, in particular in neonatal one and it provides information on the adequacy of cardio/respiratory function. Motion artifacts can largely influence PO measurement performances. The aim of this paper is to compare the PO measurement data obtained (test population: 5 subjects; test duration 2 hours) on fixed limb to the ones obtained in a free-to-move limb conditions, using 2 PO systems applied on the patient limbs. Despite to the manufacturers claimed accuracy data (>2%), we report differences >3.4% on the saturation data between free and fixed limb.