I’ve been working with emergency medicine for thirty years. In 1994, I invented an imaging system to teach intubation, the procedure for inserting breathing tubes. So, I started doing research on this procedure and, later on, I started teaching courses on airways to doctors around the world in the last two decades.

Then, in late March, when a crowd of covid-19 patients began to overwhelm New York City hospitals, I volunteered to spend ten days at Bellevue, helping the hospital where I graduated. During those days, I realized that we are not detecting the deadly pneumonia that the virus causes early enough and that we could be doing more to prevent patients from needing ventilators – and die.

On the long drive from my New Hampshire home to New York, I called my friend Nick Caputo, an emergency physician in the Bronx, who was already in the eye of the hurricane. I wanted to know what I was going to face, how to ensure my safety and what were his ideas about airway management in this disease. “Rich,” he said, “I have never seen such a thing in my life.”

Was he right. Coronavirus pneumonia has had an impressive impact on the city’s hospital system. Usually, an emergency room serves a range of patients ranging from serious conditions, such as heart attacks, strokes and traumatic injuries, to conditions that pose no risk of death, such as minor injuries, intoxication, orthopedic injuries and migraines.

However, during my recent visit to Bellevue, almost all patients in the emergency room had covid-19 pneumonia. In the first hour of my first shift, I inserted breathing tubes into two patients.

Even patients without respiratory complaints had covid pneumonia. The patient stabbed in the shoulder, whom we radiographed because we feared he had one of his lungs collapsed, actually had covid pneumonia. We also found covid pneumonia in patients who performed CT scans for falls. The same happened with elderly patients who passed out for unknown reasons and several diabetic patients.

Here is what really surprised us: these patients did not report any sensation of respiratory problems, even though the chest X-rays showed diffuse pneumonia and the oxygen was below normal. How could this happen?

We are just beginning to understand that covid pneumonia initially causes a form of oxygen deprivation that we call “silent hypoxia” – silent because it has an insidious and difficult to detect nature.

Pneumonia is an infection of the lungs in which the air sacs fill with liquid or pus. Typically, patients experience chest discomfort, pain in breathing and other breathing problems. But when covid pneumonia strikes, patients do not experience shortness of breath, even when oxygen levels drop. And when they finally find it difficult to breathe, they have alarmingly low levels of oxygen and moderate to severe pneumonia (as seen on chest X-rays). Normal oxygen saturation for most people at sea level is between 94% to 100%; the patients with covid pneumonia that I saw even had oxygen saturations of just 50%.

To my surprise, almost all of the patients I saw said they had been sick for a week, with fever, cough, stomach pain and fatigue, but they only got out of breath on the day they went to the hospital. Clearly, their pneumonia had been installed days before, but by the time they felt they had to go to the hospital, they were already in critical condition.

In emergency departments, we insert breathing tubes into critically ill patients for several reasons. But in my thirty years of experience, most patients in need of emergency intubation were in shock, with altered mental status or difficulty breathing. Patients who need intubation because of acute hypoxia are often unconscious or using all possible muscles to breathe. They are under extreme suffering. Cases of covid pneumonia are quite different.

The vast majority of patients with covid pneumonia that I treated in the hospital had extraordinarily low oxygen saturation during screening – at levels apparently incompatible with life. But they kept messing with their cell phones when we put them on the monitors. Even though they were breathing faster, they seemed to have relatively minimal suffering, despite dangerously low oxygen levels and terrible pneumonia on chest X-rays.

We are just beginning to understand why this happens. The coronavirus attacks the lung cells that produce surfactant. This substance helps to keep the air sacs in the lungs open between breaths and is essential for normal lung function. When inflammation of covid pneumonia begins, it causes the air sacs to collapse and oxygen levels to drop. However, the lungs initially remain “in compliance”, not yet rigid or filled with fluid. This means that patients can still expel carbon dioxide – and, without carbon dioxide build-up, patients do not experience shortness of breath.

Patients make up 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 cause even more inflammation and further collapse of air pockets. Pneumonia worsens and oxygen levels plummet. The truth is that the patient is injuring his own lungs as he breathes harder and harder. Twenty percent of patients with covid pneumonia go on to a second and more deadly phase of lung injury. The fluid builds up and the lungs become rigid. Carbon dioxide increases and patients develop acute respiratory failure.

When patients start having visible breathing difficulties and arrive at the hospital with dangerously low levels of oxygen, many need a ventilator.

The fact that silent hypoxia progresses rapidly to respiratory failure explains the cases of covid-19 patients who die suddenly, without even experiencing shortness of breath. (It appears that the majority of covid-19 patients have relatively mild symptoms and overcome the disease in a week or two without treatment.)

One of the main reasons why this pandemic is affecting our health system is the alarming severity of patients who arrive at the emergency room with lung injuries. Covid-19 ruthlessly kills the lungs. And, as many patients do not visit the hospital until pneumonia is well advanced, many end up needing ventilators, causing a shortage of devices. And even when they are on the fans, many die.

Avoiding the use of a ventilator is a great victory for the patient and the healthcare system. The resources required for ventilator patients are astounding. Ventilated patients need several sedatives so that they do not resist ventilation or accidentally remove breathing tubes; they need intravenous and arterial accesses, intravenous pumps and medications. In addition to the tube in the trachea, they need tubes in the stomach and bladder. It is necessary for the teams to move each patient twice a day, turning him on his back and then on his back, to improve lung function.

There is a way to identify more patients with covid pneumonia earlier and treat them more effectively – without having to wait for a coronavirus test in a hospital or doctor’s office. This is the early detection of silent hypoxia by means of a common medical device, which can be purchased without a prescription at most pharmacies: a pulse oximeter.

Performing pulse oximetry is as simple as using a thermometer. Simply press the button to turn on the device and place it at your fingertip. In a few seconds, the display shows two numbers: oxygen saturation and heart rate. Pulse oximeters are extremely reliable in detecting oxygenation problems and high heart rates.

Pulse oximeters helped save the lives of two emergency physicians I know, by alerting them from the beginning of the need for treatment. When they realized that their oxygen levels were dropping, they both went to the hospital and recovered (one of them needed more time and treatment). Apparently, hypoxia detection, early treatment and careful monitoring also worked for British Prime Minister Boris Johnson.

Widespread pulse oximetry detection for covid pneumonia – with people testing themselves with home devices or going to clinics and doctors’ offices – could establish an early warning system for the types of respiratory problems associated with covid pneumonia.

People using home devices would have to consult their doctors to reduce the number of people who go to hospitals unnecessarily due to a mistake in interpreting the device’s data. There may also be some patients with chronic lung problems not known and with borderline or slightly low oxygen saturation unrelated to covid-19.

All patients who have tested positive for coronavirus should monitor pulse oximetry for two weeks, during which time covid pneumonia usually develops. All people with cough, fatigue and fever should also monitor the pulse oximeter, even if they have not had a virus test or the test has been negative, because these tests are only 70% accurate. The vast majority of Americans who have been exposed to the virus do not know it.

There are other things we can do to avoid using the intubation and ventilator immediately. The patient’s positioning maneuvers (with the patients lying face down and on their sides) open the lower and posterior lungs, the parts most affected by covid pneumonia. Oxygenation and positioning helped patients to breathe more easily and, apparently, prevented the disease from progressing in many cases. According to a preliminary study by Dr. Caputo, this strategy helped to prevent three out of four patients with advanced covid pneumonia from needing a ventilator within the first 24 hours.

To date, covid-19 has killed more than 40,600 people across the country – more than 10,000 in New York state alone. Oximeters are not 100% accurate and are not a panacea. There will be deaths and bad consequences that are not preventable. We still don’t know for sure why certain patients get so sick or why some develop multiple organ failure. Many elderly people, already debilitated by chronic illnesses, and people with underlying lung disease are very ill with covid pneumonia, despite aggressive treatment.

But we can do more to fight the virus. At the moment, many emergency services are being devastated by this disease – or awaiting its impact. We must direct resources to identify and treat the early stage of covid pneumonia earlier, examining silent hypoxia.

It’s time to get ahead of this virus, instead of just running after it. / Translation by Renato Prelorentzou.

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