The Science Journal of the American Association for Respiratory Care

1998 OPEN FORUM Abstracts

A COMPARISON OF THE NONIN ONYX 9500 PULSE OXIMETER TO THE CRITICARE SYSTEMS 503 PULSE OXIMETER AND THE CORNING 482 CO-OXIMETER.

Lilianna Rajtak, BS, RRT, Asthildur Gudmundsdottir, BS, RRT and David C. Shelledy, PhD, RRT. The University of Texas Health Science Center at San Antonio, Texas.

BACKGROUND: Pulse oximetry was introduced into routine clinical use in 1984. Pulse oximeters provide a fast, accurate and non-invasive method to assess patients' arterial oxygen levels. Pulse oximetry utilizes two wavelengths of light which pass through a fingertip or earlobe to determine oxy-hemoglobin saturation (SpO_{2}). Prior to routine clinical use of pulse oximetry, an arterial blood sample was required to determine oxyhemoglobin saturation. The Nonin Onyx 9500 pulse oximeter (Nonin Medical Inc., Plymouth, MN) is a miniature device used to measure SpO_{2} at the bedside. We compared the Nonin Onyx system to a larger and less portable Criticare Systems Inc. 503 (Criticare Systems Inc., Milwaukee, WI) conventional pulse oximeter and to the results of arterial blood co-oximetry using the Corning 482 Co-oximeter (Ciba Corning Diagnostics Corp., Norwick, MA). METHOD: Following informed consent, 56 hospitalized patients had simultaneous measurements of SpO_{2} using the Nonin Onyx 9500 and Criticare Systems Inc. 503 (CSI 503). Of the 56 measures, 26 patients also had concurrent arterial blood samples drawn and analyzed using the Corning 482 Co-oximeter. Mean SpO_{2} and SaO_{2} values were compared using the t-test for dependent samples to determine if there were significant differences (p < .05) between the Nonin Onyx SpO_{2} values and those obtained via the CSI 503 or Corning 482. Pearson-product moment correlations were calculated to determine if there were significant correlations (p < .05) between instruments. Results: Means and standard deviations for the three instruments were as follows:

Nonin Onyx 9500 CSI 503 Corning 482

Oxygen Saturation 96.4 (3.1) 95.0 (3.5) 95.0 (3.1)

There was no significant difference between the Nonin system and the Corning 482 values (t=-.21; p=.83; n=26). There was also no significant difference between SpO_{2} as measured by the CSI 503 and values obtained using the Corning 482 (t=1.32; p=.20; n=26). There was a significant difference between the SpO_{2} obtained by the Nonin Onyx 9500 and the CSI 503 (t=6.17; p < .0001; n=56). There were significant correlations between the Nonin Onyx 9500, the CSI 503 (r=.86; p < .0001) and the Corning 482 (r=.74; p=.00002).

Regression equations were:

Nonin Onyx SpO_{2} = 3.7106 + .96217 x Corning SaO_{2}

Nonin Onyx SpO_{2} = 24.187 + .76086 x CSI 503 SpO_{2}

Conclusions: There was no significant difference between SpO_{2} as measured by the Nonin Onyx 9500 pulse oximeter and the results of arterial blood co-oximetry using the Corning 482. There were significant differences between the SpO_{2} as measured by the Nonin Onyx 9500 and the CSI 503, however, these differences were probably not clinically important.

The 44th International Respiratory Congress Abstracts-On-DiskĀ®, November 7 - 10, 1998, Atlanta, Georgia.

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