Comparison of a pulse oximeter with an ear oximeter and an in-vitro oximeter

A pulse oximeter was compared with an ear oximeter for measurement of arterial hemoglobin saturation within the range of 70 to 100% in 11 healthy volunteer subjects. Two hundred seventy-seven pooled data points were obtained, and analysis was performed by means of linear regression. The accuracy was 3% (95% confidence limits). The pulse oximeter was also compared with an in-vitro oximeter, and accuracy was within 2%. The pulse oximeter was easy to use because, unlike the ear oximeter, it required no time-consuming instrument calibration or site preparation. In addition, the delays involved in taking an invasive sample, transporting it to the blood gas laboratory, and waiting for the results were eliminated. Saturation values were continually available, and placement and use of the pulse oximeter sensor caused no discomfort to the volunteer subjects.