Pulse oximetry: Advantages and pitfalls

Pulse oximetry has the advantage of being a noninvasive and cost- effective method of providing continuous measurements of arterial oxygen saturation. It is particularly useful in assessing dyspnea and tachypnea, monitoring patients who are being weaned from supplemental oxygen, evaluating the need for supplemental oxygen during emergency transport of patients, and monitoring patients during conscious sedation. However, pulse oximetry does not measure arterial carbon dioxide tension or pH; it is not a reliable indicator of hyperoxemia; and it can be unreliable in certain patients, such as those with dyshemoglobinemia or sickle cell anemia. Remember that the accuracy of pulse oximetry varies among the different devices, and a signal loss may occur with slight hypothermia, hypotension, or infusion of vasoconstrictive drugs.