SCOTT SIMON, HOST:
You might have heard doctors and nurses mention pulse oximeters a lot these days. They're small devices about the size of a matchbox that you can clip onto one of your fingertips. They give you a pulse reading and indicate your oxygen saturation levels. It's the second reading doctors know can mean the difference between life and death in patients with COVID-19. That's because COVID victims sometimes do not realize how catastrophically low their oxygen absorption really is until it's too late. Dr. Alon Dagan at Beth Israel Deaconess Medical Center has been studying the use of pulse oximeters with COVID-19 patients and joins us now. Dr. Alon, thanks very much for being with us.
ALON DAGAN: It's a pleasure. Thank you very much for having me.
SIMON: And maybe we should understand first how the virus attacks the lungs.
DAGAN: Sure. It's something that, across the medical field, we are all sort of scrambling to have a better understanding of. One thing that has become apparent is that there seems to be a characteristic progression in terms of the symptoms and how the disease progresses in an individual. For the majority of people, it can be just a very brief viral illness of a few days. But there is a subgroup where they find that at day seven to 10, they have this kind of second effect where the virus seems to attack the lungs. And that's when you get into this trouble with very low oxygen, and that's when these patients will often require critical support and intubation.
SIMON: What can the readings from a pulse oximeter tell you?
DAGAN: The real role for these pulse oximeters is in identifying those subgroup of patients who unfortunately get the lower respiratory symptoms and develop this sort of second phase of illness. What seems to be different about this illness is while these patients come in feeling sick, their oxygen numbers are significantly lower than we would expect based on sort of their work of breathing of the patient and how the patient is presenting clinically.
SIMON: And what has your study revealed about what help the pulse oximeter might be?
DAGAN: We have started enrolling patients out of our emergency department with a protocol where they're provided with a pulse oximeter and structured follow-up calls. And the idea is for patients who are at higher risk, we want to have that reassurance that even though they're OK today, that I'm going to be sending them home with a mechanism so that they can really identify if things are getting worse, and they can come back to the hospital.
SIMON: And because these are being used a lot, when should people get a reading that moves them to call their doctor?
DAGAN: As a general rule, persistent readings below 92% are the cutoff that we're using in our protocol to alert someone to come back to the emergency department.
SIMON: Dr. Dagan, should everybody run out and buy one?
DAGAN: So I would caution against that. I think that the important distinction between what we're doing from our emergency department and having everyone run out and buy a pulse oximeter is that these are patients that have all been screened by an emergency physician, and they're being sent home with instructions to sort of look out for this second phase of illness. I think that the pulse oximeter is a very important tool in identifying this clinical deterioration, but I do not think that this - the pulse oximeter is likely to be an important tool for identifying COVID-19. So I think I would be very hesitant with patients who are otherwise feeling completely well going out, checking their pulse oxygenation every day and sort of looking for a decline.
SIMON: Dr. Alon Dagan of the Beth Israel Deaconess Medical Center in Boston, thanks so much for being with us.
DAGAN: It's my pleasure. Thank you. Transcript provided by NPR, Copyright NPR.