Pulse Oximetry

Pulse oximetry is a non-invasive method for continuously monitoring arterial oxygen saturation, or SpO2. A probe or sensor is attached to the patient's fingertip, forehead, earlobe, or nose bridge. The sensor detects oxygen saturation levels using light signals generated by the oximeter, which are absorbed and reflected by the pulsing blood beneath the probe.

Average SpO2 values are above 95%, indicating adequate tissue oxygenation. Readings below 90% indicate that tissues are not receiving enough oxygen, necessitating further evaluation. When SpO2 falls below 70%, pulse oximetry readings become less accurate, and blood studies such as blood studies i abg and vbg should be obtained to verify values.

Pulse oximetry is particularly valuable in perioperative and critical care situations where anesthesia, sedation, or decreased consciousness may mask signs of hypoxia. It allows healthcare providers to detect changes in SpO2 swiftly and administer appropriate treatment before tissue damage occurs.

Several factors affect pulse oximetry accuracy, including motion, anemia, cold extremities, bright fluorescent lights, intravascular dyes, acrylic nails, and dark skin color. To ensure accurate readings, nurses should verify correct probe placement and minimize excess motion such as shivering or extremity movement.

The pulse oximetry probe or sensor can be attached to the patient's fingertip, forehead, earlobe, or nose bridge. Correct placement is essential for accurate readings. The nurse should verify proper positioning and ensure the probe maintains contact with the skin to detect pulsing blood effectively.

If the accuracy of SpO2 reading is doubtful or uncertain, an arterial blood gas analysis should be obtained to verify the values. This is especially important when pulse oximetry readings fall below 70% or when factors affecting accuracy cannot be eliminated.

Pulse oximetry is helpful in perioperative and critical care settings because anesthesia, sedation, or decreased consciousness can hide clinical signs of hypoxia. Continuous SpO2 monitoring allows nurses to quickly detect changes in oxygen saturation and provide appropriate intervention before hypoxia becomes severe.