Pulse oximetry, what it is, and why it is necessary to diagnose COVID-19
When examining those infected with COVID-19 a telltale symptom of the disease have low oxygen levels even when they are feeling well. Low oxygen levels can be a very early warning sign that medical intervention is needed. Pulse oximetry is the method that measures the percentage of hemoglobin carrying oxygen. It can be considered vital to monitor since COVID-19, therefore, is becoming a “vital sign” like blood pressure. The way it works is that a beam of red light is passed through the fingertip. Oxygen levels or saturation is determined by measuring how much light is absorbed as it passes through the fingertip.
What are normal levels, and when I should worry?
Normal SPO2 is usually at least 95%. Some patients with chronic lung disease or sleep apnea can have normal levels of around 90%. Medical professionals should be consulted if a patient with suspected or confirmed COVID-19 has suspected or confirmed COVID-19 with a SpO2 < 90%. Supplemental oxygen or other treatments might be needed if it is at or below the 90% range. If oxygen is available, it should be prioritized for oxygen saturation levels <85%. Levels between 80-90%, and levels that are decreasing over time, often indicate severe disease and the potential for the rapid decline.
If a patient with COVID-19 has SpO2 < 90%, refer for further evaluation and possible treatment.
How do I measure a patient’s oxygen saturation?
Follow manufacturer instructions for cleaning and disinfecting pulse oximeters. Be sure to disinfect the unit with an antiviral wipe before and after using it. Turn the unit on with the power button (make sure to check batteries, if applicable). Place your finger in the unit and wait for the number to display. In addition to SpO2, the unit might display heart rate and the waveform of the pulse. This can be helpful because more distinct pulse waves indicate better measurement quality. Some factors that can make it difficult for the unit to read are dark-colored nail polish, cold fingers (IE poor circulation), tremors, too much pressure on the probe, and low blood pressure.
IMPORTANT, if you are an individual looking to purchase a pulse oximeter for home use please contact your doctor to determine whether or not pulse oximeters are relevant for you. This article does not serve as a substitute for medical advice. We also encourage readers to stay informed on news and recommendations for their own communities by using the CDC, WHO, along with their local health department as resources.