Rationale and key points Measurement of peripheral oxygen saturation (SpO2) is used to identify early hypoxia in patients and evaluate the effectiveness of oxygen therapy. Nurses should be aware of the procedure for using a pulse oximeter to measure SpO2 levels and the normal range for SpO2 readings. » A pulse oximeter is used to measure SpO2 levels, and involves placing a probe on the patient's finger, toe or ear lobe. » A SpO2 level of less than 90% is a clinical emergency. If the SpO2 level is below 94%, the nurse should assume the patient is hypoxic until proven otherwise, and therefore they may require supplemental oxygen administration. » Nurses should be aware of the factors that might affect SpO2 readings, including anaemia, peripheral vasoconstriction, dark skin tone and skin discolouration.
Keywords: hypoxia; oxygen saturation; oxygen therapy; pulse oximetry; respiratory assessment.