An Evaluation of the Nellcor N-10 Portable Pulse Oximeter

The purpose of this study was to evaluate the accuracy of the SaO 2 measured by the Nellcor N-10 portable pulse oximeter, a small, lightweight, battery-operated device. Method: Our study population consisted of 30 normal, healthy Caucasian volunteers. The accuracy of the Nellcor N-10 was evaluated under conditions of normoxemia (SaO 2 > 95%) and hypoxemia (SaO 2 75-95%). Hypoxemia was produced by a rebreathing technique with CO 2 absorbent. After a subject's SaO 2 stabilized at the desired level, an arterial blood sample was obtained and analyzed on an IL282 CO-Oximeter for SaO 2 , carboxyhemoglobin (COHb), and methemoglobin (metHb). The N-10 SaO 2 was recorded when the arterial sample was drawn. Because the N-10 measures the SaO 2 of hemoglobin capable of binding oxygen (normal hemoglobin, norm Hb-SaO 2 ), the IL282 SaO 2 reading, which represents all forms of hemoglobin (total hemoglobin SaO 2 : totHb-SaO 2 ) was converted to IL282 normHb-SaO 2 , ie, IL282 normHb-SaO 2 = (IL282 totHb-SaO 2 ) ò (100 - COHb - metHb) 100. Results: A total of 60 data sets were collected. The Nellcor N-10 SaO 2 range during the study was 77-100%. The mean (± SD) N-10 SaO 2 was 90 ± 6%, the mean IL282 totHb-SaO 2 was 89 ± 6%, and the mean IL282 normHb-SaO 2 was 92 ± 6%. The mean COHb was 1.9 ± 0.4%, and the mean metHb was 0.6 ± 0.2%. The difference between the N-10 SaO 2 and IL282 totHb-SaO 2 and the difference between the N-10 SaO 2 and the IL282 normHb-SaO 2 were statistically significant. There was a 0.96 correlation between the N-10 SaO 2 and the IL282 totHb-SaO 2 and between the N-10 SaO 2 and the IL282 normHb-SaO 2 . Conclusions: Although the differences between the Nellcor N-10 SaO 2 and the IL282 SaO 2 were statistically significant, in most cases the difference was too small to be clinically important. The IL282 SaO 2 and the N-10 SaO 2 correlated well. When COHb and metHb levels are low, as they were in this normal population, the Nellcor N-10 pulse oximeter demonstrates acceptable accuracy in the SaO 2 range of 77-100%.