IDENTIFICATION OF MOVEMENT ARTIFACT BY THE NELLCOR N-200 AND N-3000 PULSE OXIMETERS

Objectives. The Nellcor N-3000 pulse oximeter is designed to be able t o identify signal artefact related to movement of the body pan, to whi ch the probe is attached. It may therefore provide a reliable means of monitoring arterial oxyhemoglobin saturation (SpO(2)) in awake, movin g patients. This study compared the Nellcor N-3000 and N-200 pulse oxi meters in terms of their ability to identify readings associated with movement, in a group of volunteers making standardized movements. Meth ods. Thirty-six volunteers were studied. Volunteers breathed room air throughout the study. SpO(2) of each volunteer was monitored by both a Nellcor N-200 and a Nellcor N-3000 simultaneously on both hands. Volu nteers made a series of five standardized movements, each lasting one minute, with each hand during the monitoring session, while SpO(2) and oximeter status were recorded from ail four oximeters. The mean SpO(2 ) reading was calculated during each movement. SpO(2) readings which t he oximeter identified as being associated with movement, pulse search not locked, sensor not attached, or break in communications were excl uded from analysis. Results. The N-3000 rejected from 17 to 78% of rea dings taken during movement, compared to 0 to 2% with the N-200. Altho ugh the remaining readings of both types of oximeters were subject to some movement artefact, which led to spuriously low SpO(2), this was s ignificantly less with the N-3000. Conclusions. The Nellcor N-3000 pul se oximeter is able, to some extent, to identify movement artefact. It should offer an advantage over the N-200 when monitoring moving patie nts.