Selected Podcast

Advanced Lung Disease/ARDs

The Advanced Lung Disease Service at UAB Medicine is one of the busiest ECMO providers in the Nation. Our highly trained physicians work with general practitioners and specialists from other fields to collaborate on the diagnosis and treatment of such lung diseases as cystic fibrosis, acute respiratory distress syndrome (ARDS), and lung cancer.

In this segment, Dr. Vincent G. Valentine, Professor, in the Department of Pulmonology at UAB Medicine, discusses Advanced Lung Disease/ARDs, who might be candidates for lung transplant and when to refer to a specialist.
Advanced Lung Disease/ARDs
Featured Speaker:
Vincent G. Valentine, MD
Vincent G. Valentine, MD is a Professor in the Department of Pulmonology at UAB Medicine.

Learn more about Vincent G. Valentine, MD 

Dr. Valentine has no financial relationships related to the content of this activity to disclose. Also, no other speakers, planners or content reviewers have any relevant financial relationships to disclose.

There is no commercial support for this activity.
Transcription:

Melanie Cole (Host): Patients with acute respiratory distress syndrome (ARDS) may present with severe respiratory flairs that require intensive management. My guest today is Dr. Vincent Valentine. He’s a professor in the Division of Pulmonary, Allergy, and Critical Care Medicine and the Medical Director of Lung Transplantation at UAB Medicine. Welcome to the show Dr. Valentine. Explain a little bit about acute respiratory distress syndrome, what exactly this is.

Dr. Vincent Valentine (Guest): Well as the name implies it is a syndrome with a variety of conditions that could trigger it. Notably infectious, viral infections, infections away from the lung we call it sepsis if there is an intra-abdominal infection or even a bad cellulitis somewhere on the skin, but also patients who suffer with trauma, inhalation exposures, fire exposures can develop sudden respiratory distress where they have difficulty oxygenating their blood and their tissues.

Melanie: What are some complications of acute respiratory distress syndrome if left untreated or undiagnosed?

Dr. Valentine: On one hand patients who have such distress do present to emergency rooms rather quickly and frequently they end up intubated on mechanical ventilation in efforts to improve their gas exchange, to improve oxygen, and to help eliminate carbon dioxide. Again, it’s a syndrome and specifically defined by a consensus conference where the amount of oxygen tension divided by how much oxygen enrichment they’re on is below 300 it’s really acute lung injury, once it’s below 200 it’s acute respiratory syndrome and as it gets lower and lower and the ratio gets below 100 it’s even more severe. SO that’s one, is recognizing that the syndrome in the absence of heart failure or other conditions where they might be fluid overloaded. Some of the complications are really centered around mechanical ventilation and the triggering cause of the ARDS. In the last decade and most recently in the last 8 years related to the influenza epidemic, there’s a strategy to minimize mechanical ventilation which usually requires positive pressure forcing air into the lungs to help gas exchange. A strategy that’s emerged is extracorporeal membrane oxygenation where we can put cannulas in patients usually in the neck and pull blood out and an external source can oxygenate and remove CO2 with less pressure put on the lung or less stress put on the lung if you will as the lungs need to heal and heal and we can externally provide gas exchange for these patients.

Melanie: Are there any early signs and symptoms before ARDS develops?

Dr. Valentine: Usually not. However, there may be patients who have other conditions comorbid conditions that may make them more susceptible to pneumonias for example because any pneumonia presentation can deteriorate or generate into ARDS. Patients may have a variety of inflammatory conditions unrelated to the lungs that can eventually effect the lungs and they can get rather suddenly short of breath, can’t catch their breath, suddenly need oxygen and will present similar to ARDS, again as parameters defined by the oxygen tension in their blood divided by how much oxygen they’re requiring, and again being below 200. So comorbid conditions may actually predispose such patients and again ARDS is really the syndrome that occurs rather suddenly within minutes and sometimes within minutes to exposure to chlorine gas chemical for example to within a day or two, anything taken long than that would not necessarily be ARDS.

Melanie: Are there some valuable prognostic tools to aid in early or quick diagnosis of ARDS and how important are they to improve outcome prediction?

Dr. Valentine: Well indirectly I made a comment about the PFiO2 ratio or arterial oxygen tension divided by the FiO2, again below 300 is acute lung injury and below 200 is ARDS. And what’s been added to this is the Berlin criteria where that ratio falls below 150, falls below 100, and as they get lower and lower in that ratio the more severe and the worse the prognosis thus the interventional strategies have been considered to maybe be using external support. So this Berlin criteria is there. There are all sorts of criteria related to the acuity of illness to the patient, the Apache score, the Sofa score that we really don’t need to get into right now that we do use but tests more in the setting of how acutely ill the patient is these patients invariably need to be in an intensive care unit and in a unit that’s well equipped and experienced in managing such patients.

Melanie: Does sometimes on a chest x-ray for example ARDS look like heart failure? Can they be confused?

Dr. Valentine: Yes, and there are a few publications about that. When the patients again get rather suddenly out of breath they can get suddenly out of breath if they have a BBQ feast if you will or if a large salt load particularly in patients who have underlying heart disease and they can retain a lot of fluid or they can even have an acute heart attack and back up fluid into the lung or a valve problem in their heart. So the x-ray of patients with ARDS and the x-ray with patients who have acute heart failure can be a little similar just a glance at the x-ray the lung fields could be whited out but sometimes if you look more carefully you can see if the blood vessels are a little more plump as they would be in heart failure. And so subtle distinctions described by Vanderbilt in the past that can help delineate what might be ARDS and not ARDS and that’s an important point because heart failure is a mimic of ARDS and we got to make sure that a 60, 65 year old presents rather suddenly out of breath make sure it’s not a cardiac or heart reason and once you eliminate that possibility then you might be dealing with ARDS. Whereas if you have a young patient is less likely to be a heart reason although some of those patients can still have a heart problem for their rather sudden respiratory distress.

Melanie: And depending on the diagnosis Dr. Valentine, assess for us the appropriateness of specific treatments that you would use once you detect what is going on.

Dr. Valentine: Well, again, the underlying trigger of ARDS is most of the time related to some infection. Viruses have fewer treatments than bacteria, you want to treat the potential underlying pneumonia. Again it could be a systemic infection, patients with acute pancreatitis can present with ARDS so we would have to focus our efforts on managing the pancreatitis but on top of that these patients are on mechanical ventilation and we want to make sure we minimize trauma to the lungs related to the positive pressure of the ventilator. There is a study the ARDs Net Trial that showed that minimizing the amount of tidal volume that the patient is requiring to 6 ml per kg of ideal body weight or lower and minimizing the distention pressures the difference between the plateau pressure and a positive end expiratory pressures below 30 preferably lower to minimize any trauma to the lungs. Because the ventilator can impart more trauma or further trauma or trigger worse trauma in patients who are trying to be managed with ARDS. The lungs will need to heel but we can damage them further if we’re not too careful with the mechanical ventilator strategies as we are focusing on the underlying cause.

Melanie: And what are some factors based on what you’re doing with ventilation associated with hospital mortality and maybe one year mortality?

Dr. Valentine: Well I mean most of these studies are really retrospective but mortality for ARDS has improved over the years a little bit. The younger population does better, somebody with isolated lung event you know, and influenza, pneumonia in a 30 year old for example their mortality might be as low as 20% perhaps less. The older the patient the more likely comorbidities are there those patients could have mortalities as high as 60% so age is a huge variable. Comorbid conditions, other chronic illnesses play a role in how well they’re going to recover. And again it’s how the patients are managed with ARDS with the positive pressure ventilation.

Melanie: And what would you want other physicians to know about ARDS and what they should be aware of?

Dr. Valentine: Well one, physicians in the area of UAB should be aware that we’re well equipped to manage their patients who they think have ARDS. And we actually are recommending early referral. We see quite a bit of ARDS here. We’re getting referrals every month to get the patients here you know with a team of physicians and nurses and nurse practitioners and respiratory therapists that are well experienced in managing such patients where one strategy can we get them through just using mechanical ventilator support. Getting them here early gives us an opportunity to see those patients who may actually get worse and may have to go to more drastic measures such as ECMO (extracorporeal membrane oxygenation) which we have good experience here at UAB. And so I think the awareness of the physicians in the area, refer them here because we would love to manage these patients for them instead of them having to decide with their patient they’re managing with ARDS and get worse in their hands and then they’re referring them a little late. I would like to believe we have a well experienced team managing such patients and those managing strategies may include temporary paralysis of the patient. And then in those strategies are not working or if patients are getting acutely worse we can get them set up for ECMO and manage them through ECMO. Just recently we’ve had several patients who were referred for ARDS that we did not even need to have to use ECMO and we actually got them through it. We did have a few others that did get referred here and we had to put them on ECMO and we even got those patients through it. Our success really stems from our team effort of specialized physicians and pulmonary critical care even lung transplantation and the nurse practitioners and the nursing personnel and the ECMO and perfusion personnel for ECMO.

Melanie: And how can a community physician refer a patient to UAB medicine?

Dr. Valentine: They can call our MIST line, our MIST operators. Actually my cell number, they can ask the operator to call Dr. Valentine or Dr. Wille, either one of us are always on call. There’s a Dr. Russinoff and the UAB ICU attending, which has a variety of different people, but Dr. Wille and myself are on call pretty much 24/7 and our numbers are never turned off.

Melanie: And a community physician can refer a patient to UAB medicine by using the MIST line, 1-800-UABMIST (822-6478). And tell us about your team Dr. Valentine, why is UAB so great to work with?

Dr. Valentine: Again, we have a team of experienced personnel if you want to look to the nth degree that would be ECMO again (extracorporeal membrane oxygenation) where they have over 300 patient experiences over the last several years, that’s one of the largest programs in the country with very good success actually. And ARDS is a rewarding condition where these patients can be turned around because we just need to buy the patient and their lungs some time to peel and heal while we don’t impose the damaging effects of positive pressure. We certainly don’t want to put everybody on ECMO but if we had the patient in front of us it’s easier for us to decide whether they need it or not and you know just in the last several months we’re becoming increasingly aware of which patients may not require ECMO. And all of the personnel I mentioned from the bed side nurse of the respiratory therapists to the nurse practitioners and the team approach of physicians, intensivists, pulmonologists and consultants have gained a considerable about of experience just over the last several months and going back to several years. That’s where UAB can make a difference.

Melanie: Thank you so much Dr. Valentine for being with us today. You’re listening to UAB Med Cast and for more information on resources available at UAB Medicine you can go to UABMedicine.org/physician. This is Melanie Cole, thanks so much for listening.