Pulse Oximetry and its Importance in COVID-19

BelluscuraKnowledge

Patients with conditions such as chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, and various cardiac conditions have utilized pulse oximeters as tools in monitoring their supplemental oxygen use. Pulse oximeters have become essential diagnostic tools because of ease of use, portability, and applicability in a wide range of clinical settings. In the face of the current pandemic, pulse oximeters have gained popularity with patients and physicians alike. Could early pulse oximetry monitoring be utilized in COVID-19?

Globally as of today,  09/23/2020, there are now approximately 31,375,325 confirmed cases of COVID-19 according to the World Health Organization (WHO). Since the outbreak, there have been roughly 749,069 cases in Texas with a significant spike in cases just days ago on 09/21 of 9,853. That is the most significant jump in new daily cases since mid-July when cases climbed to 14,916 on 07/17/2020.  While the number of daily new cases is trending down, we should remain cautious and continue to wear masks, social distance, and avoid large gatherings when possible.

When oxygen levels are low, the organs in our body receive less oxygen which can negatively impact their bodily function. Knowing baseline oxygen saturation levels at rest and with activity can help trend changes among various health conditions. In the presence of COVID-19, monitoring pulse oximetry levels can help monitor oxygenation and warn of impending or silent hypoxemia. While only a few independent studies have assessed the performance of pocket oximeters and smartphone-based systems, future studies could be performed to determine their accuracy.

Pulse Oximeter

Pulse Oximeter monitoring SpO2 and heart rate.

Common Questions regarding Pulse Oximeters:

What is a Pulse Oximeter?

A pulse oximeter is a small, battery-powered device that is used to measure how much oxygen your blood is carrying. The blood oxygen level measured with an oximeter is called your oxygen saturation level (SpO2) and is displayed as a percentage. The device works by sending two wavelengths of light into the finger through the nail bed and measures what is absorbed by the blood. It can also calculate your pulse and that is displayed as beats per minute (bpm).

How are Pulse Oximeters used?

A pulse oximeter comes as a small unit with a built-in finger/toe clip. All you must do is place your finger inside the pulse oximeter. The pulse oximeter delivers a calculated value and will display it once the reading stabilizes. It is normal for the value to fluctuate so do not worry if you see it changing constantly. Remember to keep working batteries in your oximeter to limit interruptions in your monitoring.

What is a Normal Oxygen Saturation Level?

The American Thoracic Society (ATS) recommends you ask your health care provider what oxygen saturation level they want you to maintain. ATS suggests most people need an oxygen saturation level of at least 89% to keep their cells healthy. COPD patients are advised to maintain a pulse oximetry level between 88-92%. Normal oxygen saturation levels run between 95% and 100%. Medical professionals should be consulted if a patient with suspected or confirmed COVID-19 has SpO2 ≤90%. Having a pulse oximeter will allow you to monitor your blood oxygen level, know if you are within your recommended range, and whether you need to increase your supplemental oxygen level.

How Accurate is a Pulse Oximeter?

The oxygen level from a pulse oximeter is reasonably accurate. Most oximeters give a reading 2% over or 2% under what your saturation would be if obtained by arterial blood. A pulse oximeter may also be less accurate with very low oxygen saturation levels (below 80%).

Factors affecting accuracy to read include:

  • Dark-colored nail polish
  • Cold fingers or poor circulation
  • Tremor or movement
  • Too much pressure on the probe
  • Low blood pressure

Closing Thoughts

For patients and health professionals alike, it will be imperative to be vigilant in the use of new technology advances, such as the way consumer tech companies are marketing health capabilities and promoting pulse oximetry monitoring among their devices. What they can do and what they can reliably do may in fact be two separate things. The use of these devices could potentially threaten and jeopardize a person’s health if the user relies on its accuracy to dictate when they seek medical care. Recently, Brian Clark, a pulmonologist and professor at the Yale University School of Medicine was featured in an article in the Washington Post speaking on the topic of emerging tech companies diving into the medical space. He commented, “I agree with you that it is a dangerous trend for technology companies to release medical devices that don’t meet FDA standards and claim that they are not medical devices”. Dr. Clark also adds, “But the more concerning and potentially dangerous scenario is when the devices provide false reassurance and people don’t seek health care when they really need it”.

Patients suffering from respiratory health conditions will continue to use pulse oximetry monitoring devices for the unforeseeable future. Hand-held pulse oximeters have become a common assessment tool and according to various studies, have been useful as diagnostic tools for the assessment of COPD. They can be used during both stable phase and exacerbations, as well as confirming the need for oxygen therapy.

Worldwide, people are looking to health monitors for any clue that they may have COVID-19, the illness caused by the novel coronavirus. For regular supplemental oxygen users that notice oxygen levels trending low, it will be important to speak with your healthcare provider or respiratory therapist as to when to increase or decrease your oxygen level based on pulse oximetry readings. Regardless of preexisting conditions, monitoring yourself for COVID-19, or recovering from recent hospital admission, its important to seek immediate medical attention if you notice significant changes in your oxygen levels. If you are caring for a patient with COVID-19 and their SpO2 ≤90%, refer to their primary care provider for further evaluation and possible treatment.

Sources:
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