Final answer:
The interpretation of an abnormal decrease in SpO2 depends on the clinical context and patient characteristics, as various factors like altitude and health condition affect oxygen saturation readings.
Step-by-step explanation:
An absolute decrease in arterial oxygen saturation (SpO2) is often monitored using a device called a pulse oximeter. The normal range for a pulse oximeter reading is 95-100%. A decrease of more than 2% can indeed be considered abnormal, but the correct interpretation of such a change in SpO2 depends heavily on specific patient characteristics and clinical context. For instance, individuals at high altitudes may normally have lower SpO2 due to the reduced atmospheric pressure and partial pressure of oxygen, making it harder to achieve the same level of oxygen saturation as at sea level. Therefore, the most accurate answer to the question would be that an absolute decrease in SpO2 of more than 2% is considered abnormal depending on the clinical setting and patient characteristics, as different factors like altitude, hemoglobin levels, patient age, and overall health condition can influence oxygen saturation.