‘Bending the curve’: A pulmonologist’s perspective on COVID-19
On March 11, WHO officially designated the current COVID-19 outbreak as a pandemic. As the disease spread worldwide, physicians in the United States began bracing themselves for when it would inevitably land in North America.
As of March 25, there have been 54,453 confirmed or presumptive positive cases of COVID-19 and 737 deaths related to the disease reported in 50 states, the District of Columbia and three U.S. territories, according to the CDC.
Amid these rising numbers as well as concerns about their effect on the health care system, Clayton Cowl, MD, MS, chair of the division of preventive, occupational and aerospace medicine with a joint appointment in the pulmonary and critical care division at Mayo Clinic in Rochester, Minnesota, and immediate past-president of CHEST, spoke with Healio Pulmonology about working as a pulmonary specialist during the COVID-19 pandemic.
What are your thoughts right now as a physician working during a global pandemic?
Cowl: First from a pandemic perspective, we’ve seen COVID-19 start in Asia, transform Europe into the greatest hot spot for cases and then make its way toward North America. This underscores the fact that we are a transportation society and that transportation has made us so mobile that pandemics can move faster than they ever have.
Second, when we look at epidemics and pandemics, the first portion of a prevalence curve is relatively flat and starts to pick up slowly. Then, at some point, there’s a spike where transmission, as they say, goes “ballistic.” The idea of all this social isolationism — closing venues, shutting down countries and stopping transportation points — is all part of an effort to bend this curve so that we see less of a spike and rather, turn it into more of a lightly sloping hill. We know there are going to be more cases. We know there is community transmission in all 50 states and the District of Columbia. The key at this point is keeping as many new cases as possible to a minimum and mild as opposed to moderate or severe cases. If we can do that, we will be able to maintain the services that we need for those who are most affected by COVID-19, such as patients with severe respiratory disease, and we will have enough personal protective equipment to keep the health care providers who are caring for the most seriously affected patients from becoming ill as well.
Also, when we talk about the importance of having enough ventilators, masks and hospital and medical equipment or supplies, we are trying to minimize the potential firehose of cases and keep it more to a trickle in order to preserve those services downstream. When someone asks if we have enough ventilators, the answer is: “It depends.” If there’s unbridled community transmission of a virus with no intervention, the answer will be “no.” But that’s the whole purpose of the public health measures that have been going into effect. We are trying to preserve those precious resources for those who are the most ill.
What are you seeing at your institution?
Cowl: Mayo Clinic has set up a hospital incident command enter, which is not unique. It’s done in many disaster management planning scenarios in the United States, and much like many medical centers around the country, Mayo Clinic has been preparing for this since early January. The good news is that there are or have been a lot of people and resources mobilized to focus on how to respond to a situation such as this. The bad news, of course, is in no point in any of our lifetimes have we seen the kind of response that is required and the level of social isolationism that has been needed to try to bend the proverbial prevalence curve of new cases. There have been countless hours spent in preparation, communication, logistics and supply chain management, but the challenge with any of these types of responses is that the ground rules change on a daily, if not hourly, basis. In other words, travel quarantines were initially one strategy. However, what happens when your own geography — in this case, the United States — becomes a zone 3 area? Everyone has the same risk at that point when we talk about travel. So, the rules about travel quarantine get thrown out and other strategies need to be considered. Currently, it’s about trying to understand and define what constitutes a “case” — meaning what are the symptoms — and keeping people with symptoms away from areas that have congregations of sick people and letting those with mild disease isolate themselves in a home environment and get through it — because we currently know that 85% or more of individuals who contract the virus will have a relatively mild, self-limited disease similar to influenza. Within 48 to 72 hours, individuals become relatively asymptomatic, although in others, it can drag on for a little longer. There has been some individual variation within those cases.
Is your institution seeing many patients with COVID-19?
Cowl: Yes, we have patients right now in our facility who have COVID-19. Our health care providers are aware of them and have been provided appropriate personal protective equipment to handle those patients who are being cared for on specialized, predesignated units. Most, if not all, have negative pressure rooms and patients are receiving supportive care within those environments.
We have also been getting an incredible volume of questions and spent a lot of time discussing how to address positive cases. For example, if we have an employee who’s positive, our process is to identify concentric circles of the people with whom they were in contact and attempt to stratify their risk for contracting the disease as low, moderate or high. Additionally, we’re working tremendously hard to try to avoid having people who think they may have COVID-19 from even getting through the doors. This means triaging remotely using phone calls, telehealth, video consulting or other methods. Most recently, our institution instituted a fairly rigid visitor policy and all patients who come in the door are screened for fever and other symptoms and the number of visitors with them limited.
Testing capacity appears to be a concern for many physicians. How is your institution doing with testing?
Cowl: All institutions are having issues with testing capacity. Fortunately, our Mayo Clinic Medical Laboratories has developed its own COVID-19 test, so we are in a unique situation. We have been able to ramp up the volume of tests that can be processed daily and that volume increases each day as more and more kits are developed or produced. Our community, like many other communities, have developed a strategy of drive-through nasopharyngeal swabbing in which people first go through a triage process via phone and we then direct them to a certain drive-through area for testing. However, a person cannot just drive up and decide to get checked. To conserve the number of kits, the pretest probability with this triage algorithm has to be relatively high in order for someone to get tested.
Overall, though, testing is one of the limiting variables in this pandemic. These tests require certain reagents and many places have to send samples to larger labs before they get results. This is not a common test. However, it’s becoming more available as there is now more commercial production of the test itself.
As a pulmonary specialist, do you have specific concerns for patients with existing respiratory conditions such as asthma, COPD or interstitial lung disease?
Cowl: Any patient with a known chronic pulmonary condition, be it significant airway disease such as COPD — particularly those with a significant emphysemous component — partially controlled or uncontrolled asthma or pulmonary fibrosis, is at a particular risk because this is a virus that has a predilection for the respiratory tract and the respiratory system. Anyone with a compromised immune system, due to either an underlying condition or medications that they’re taking, is also at greater risk than the general population for developing a viral-associated pneumonia.
Nevertheless, we must not forget that influenza A is still circulating in the community. Coronavirus, not the one that causes COVID-19, but rather the common cold, is also still out there causing sniffly noses, watery eyes and congestion. So, it’s important to remember that not all that sniffles or coughs is COVID-19.
When do you view cough as a potential symptom of COVID-19 vs. another illness?
Cowl: Unfortunately, without specific viral testing we don’t have a magic way to know precisely whether or not a patient has COVID-19 — and even more frustrating is that the individual with a positive test is often asymptomatic and shedding virus before they even realize they may have the disease. Therefore, much like with any other condition, we try to ask specific questions when attempting to make a diagnosis. COVID-19 is usually characterized by a sensation of myalgias and total body aches, fatigue and fever — many people look ill — as well as cough and shortness of breath. Basically, patients usually experience multiple symptoms as opposed to just a cough. Could COVID-19 present with fewer symptoms? Yes, and this occasionally has been reported in those with positive tests.
Although it’s still early, have you heard about any lasting effects of COVID-19 on the lungs?
Cowl: First, it should be noted that X-ray and CT scanning are not appropriate methods for screening for COVID-19, and chest radiography in particular has not been very helpful at all in those whom we know have the disease, as confirmed by nasopharyngeal swab testing and culture. There have been a few studies from China published in open-access journals showing digital images of somewhat nodular-like densities that are most prominent in the lateral aspects of the lungs. I saw one particular case in which this was bilateral, but my guess is that they can present in multiple ways. However, at this point, we do not know precisely the long-term effects of COVID-19 on the lungs because the virus has only been known since approximately December.
What is your advice for physicians at this time?
Cowl: In terms of protection, it comes down to hygiene and social isolation because the virus can spread through contact. Wash your hands frequently. Don’t touch your face or mouth or rub your nose. Take a few extra seconds to wipe down shared surfaces, such as community keyboards, touch screens or phones, with a disinfectant wipe before using. Wash your hands and wipe down other fomites like your stethoscope between patients. Make sure you always carry hand sanitizer and use it as necessary. Don’t share your cellphone with others unless you wipe it down after. Little things like that during a pandemic will go a long way toward keeping you healthy.
Use of appropriate personal protective equipment is also essential. This includes gowns, which can be worn over normal clothes, gloves and eye protection, as the virus can spread through conjunctival contact, and a mask. It’s important to bear in mind that the risk for contracting COVID-19 lies in aerosolized respiratory droplet exposure. Therefore, a surgical mask is adequate and a powered air-purifying respirator (PAPR) or N95 respirator is not always necessary. However, for those performing aerosol-generating procedures, such as bronchoscopy, we recommend that those individuals use PAPRs to protect them from aerosols that can arise during the procedure. Several national organizations have recommended temporarily shutting down pulmonary function labs completely. Amazingly, I have heard of some medical facilities continuing to allow elective procedures and physicians taking trips to global “hot spots” for COVID-19. We have to take this disease seriously and everyone plays a part. – by Melissa Foster
Disclosure: Cowl reports no relevant financial disclosures.