Key result
The Hewlett-Packard 47201A ear oximeter measures arterial O2 saturation within +/- 4% when saturation is >65%, but underestimates at lower levels and overestimates with carboxyhemoglobin.
Why the study?
How accurate is the Hewlett-Packard 47201A ear oximeter in measuring arterial O2 saturation?
Observational
How accurate is the Hewlett-Packard 47201A ear oximeter in measuring arterial O2 saturation?
The Hewlett-Packard 47201A ear oximeter provides accurate O2 saturation readings above 65% but is confounded by lower saturations and elevated carboxyhemoglobin levels.
Answers are grounded in this paper and cite their sources.
Caution advised for ear oximeter use below 65% saturation or with carboxyhemoglobin; leaves open modern device performance in these scenarios.
We have shown that the Hewlett-Packard 47201A ear oximeter measures arterial O2 saturation within 95 per cent confidence limits of +/- 4 per cent when arterial blood saturation is more than 65 per cent, but at lower saturations the oximeter consistently provides a reading that is too low. The oximeter is sensitive to carboxyhemoglobin, progressively overestimating arterial saturation as carboxyhemoglobin concentration increases from 0 to 18 per cent. The time response is exponential, with a normal time constant of 3 sec, but this is halved in the fast mode or operation.
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Douglas et al. (1979) conducted an observational in Arterial O2 saturation measurement. Hewlett-Packard 47201A ear oximeter was evaluated on Accuracy of arterial O2 saturation measurement (95% CI +/- 4%). The Hewlett-Packard 47201A ear oximeter measures arterial O2 saturation within +/- 4% when saturation is >65%, but underestimates at lower levels and overestimates with carboxyhemoglobin.
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