Thank you for "Monitoring Your Adult Patient with Bedside Pulse Oximetry" (Photo Guide, September 2008).* Although pulse oximeters have become commonplace, they have limitations. Even with correct sensor placement, the reading may be inaccurate.
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Pulse oximeters merely measure the arterial saturation of available hemoglobin. If the hemoglobin is saturated with carbon monoxide, the reading will be falsely high, despite poor oxygenation. Similarly, a patient could have a very low level of hemoglobin, but if the available hemoglobin is saturated with oxygen, the reading will again be misleadingly high. In either case, the patient may not have adequate tissue perfusion despite acceptable pulse oximetry readings. Thank you for reminding nurses to use equipment properly and to use their clinical knowledge to correctly interpret results.
Bridget Parsh, RN, CNS, MSN