https://www.nytimes.com/2020/04/20/opinion/coronavirus-testing-pneumonia.html

Quote:

---

A vast majority of Covid pneumonia patients I met had remarkably low oxygen saturations at triage seemingly incompatible with life but they were using their cellphones as we put them on monitors. Although breathing fast, they had relatively minimal apparent distress, despite dangerously low oxygen levels and terrible pneumonia on chest X-rays.

We are only just beginning to understand why this is so. The coronavirus attacks lung cells that make surfactant. This substance helps keep the air sacs in the lungs stay open between breaths and is critical to normal lung function. As the inflammation from Covid pneumonia starts, it causes the air sacs to collapse, and oxygen levels fall. Yet the lungs initially remain "compliant," not yet stiff or heavy with fluid. This means patients can still expel carbon dioxide and without a buildup of carbon dioxide, patients do not feel short of breath.

Patients compensate for the low oxygen in their blood by breathing faster and deeper and this happens without their realizing it. This silent hypoxia, and the patient's physiological response to it, causes even more inflammation and more air sacs to collapse, and the pneumonia worsens until their oxygen levels plummet. In effect, the patient is injuring their own lungs by breathing harder and harder. Twenty percent of Covid pneumonia patients then go on to a second and deadlier phase of lung injury. Fluid builds up and the lungs become stiff, carbon dioxide rises, and patients develop acute respiratory failure.

By the time patients have noticeable trouble breathing and present to the hospital with dangerously low oxygen levels, many will ultimately require a ventilator.

Silent hypoxia progressing rapidly to respiratory failure explains cases of Covid-19 patients dying suddenly after not feeling short of breath. (It appears that most Covid-19 patients experience relatively mild symptoms and get over the illness in a week or two without treatment.)

A major reason this pandemic is straining our health system is the alarming severity of lung injury patients have when they arrive in emergency rooms. Covid-19 overwhelmingly kills through the lungs. And because so many patients are not going to the hospital until their pneumonia is already well advanced, many wind up on ventilators, causing shortages of the machines. And once on ventilators, many die.

Avoiding the use of a ventilator is a huge win for both patient and the health care system. The resources needed for patients on ventilators are staggering. Vented patients require multiple sedatives so that they don't buck the vent or accidentally remove their breathing tubes; they need intravenous and arterial lines, IV medicines and IV pumps. In addition to a tube in the trachea, they have tubes in their stomach and bladder. Teams of people are required to move each patient, turning them on their stomach and then their back, twice a day to improve lung function.

There is a way we could identify more patients who have Covid pneumonia sooner and treat them more effectively and it would not require waiting for a coronavirus test at a hospital or doctor's office. It requires detecting silent hypoxia early through a common medical device that can be purchased without a prescription at most pharmacies: a pulse oximeter.

Pulse oximetry is no more complicated than using a thermometer. These small devices turn on with one button and are placed on a fingertip. In a few seconds, two numbers are displayed: oxygen saturation and pulse rate. Pulse oximeters are extremely reliable in detecting oxygenation problems and elevated heart rates.

Pulse oximeters helped save the lives of two emergency physicians I know, alerting them early on to the need for treatment. When they noticed their oxygen levels declining, both went to the hospital and recovered (though one waited longer and required more treatment). Detection of hypoxia, early treatment and close monitoring apparently also worked for Boris Johnson, the British prime minister.

Widespread pulse oximetry screening for Covid pneumonia whether people check themselves on home devices or go to clinics or doctors' offices could provide an early warning system for the kinds of breathing problems associated with Covid pneumonia.

People using the devices at home would want to consult with their doctors to reduce the number of people who come to the E.R. unnecessarily because they misinterpret their device. There also may be some patients who have unrecognized chronic lung problems and have borderline or slightly low oxygen saturations unrelated to Covid-19.

All patients who have tested positive for the coronavirus should have pulse oximetry monitoring for two weeks, the period during which Covid pneumonia typically develops. All persons with cough, fatigue and fevers should also have pulse oximeter monitoring even if they have not had virus testing, or even if their swab test was negative, because those tests are only about 70 percent accurate. A vast majority of Americans who have been exposed to the virus don't know it.

---

i found this extremely hopeful - insofar as what people infected can do on their own while they are home monitoring symptoms (even prior to a positive test).

furthermore, what if the real answer to treatment (for the non-immunocomprised) is just O2 (and lots of it and early)? is a hospital bed needed for non-intensive O2 therapy (during the early showings of hypoxia)? the difference between you going on a vent and walking out with a relatively mild case (a least in how you felt - not whether or not you got pneumonia) might be early O2 intervention. if you avoid / mitigate the initial hypoxia (while your immune system fights the virus), the disease doesn't progress to the ICU required stage?

of course, this means you were still sick, but the relatively healthcare resource required to get you into recovery was much less. that seems to be the point of everything - how can we refine monitoring and treatment to optimize healthcare resources - not just vents but just human resource and time.

if you get a positive test, can you be given a pulse ox immediately, told to monitor at home and also be given a number to request a basic O2 therapy kit just in case?

all the billion dollar pharmaceutical moonshots might not be as useful in the short term with a brute force O2 therapy approach

FYI your Samsung galaxy phone has this capability.

Interesting topic.

Sustained under 93% is cause for concern. Make sure the instrument is getting a good accurate pulse though as poor pulse detection will cause a false low level.

Home O2 was something I was thinking about when this started back in January. I think the major obstacle to this treatment is malpractice suit potential. If I prescribe home O2 for a sick patient with COVID and they develop respiratory distress then failure overnight guess who is at fault for not hospitalizing the patient. Unless the government comes out and says a doc cannot be sued for this it is not going to be widespread due to physician fear factor.