Where We Stand with ARDS (Part 3)

By George Barnes, Dr. James Coyle, and Kelsey Day

Now that we have addressed what ARDS is and why it should be our real focus in the COVID pandemic, it’s time to focus on where we as SLPs stand with it at all. There is a lot we can do for our patients with ARDS because managing aspiration risk is so critical for them. But timing is everything. There are days we’ll want to jump in head first and then there are days when doing nothing is the best choice. Patience is a virtue and being patient with patients is everything. Still, even in the waiting game, we can add tremendous value to the IDT through informed questions and feedback during critical care. The journey can be long and the risk of PO intake can be high, but the value of safely eating and drinking again after weeks, if not months, will be priceless.

Staying alive

In order to understand where we stand with ARDS, we must understand how the disease process is managed. First things first, breathing comes first (yes, even before swallowing). The most important goal for a patient is to maintain stability (keep the patient alive). Sounds straightforward enough right? But it’s not. Treating ARDS is tough. It takes a dedicated team of detail-oriented practitioners to manage the many moving parts of this complex condition. One of the few effective options for patients with ARDS is mechanical ventilation. While the vent can keep you alive, it can cause further damage to the lung in many ways that may increase dependence even further.

Venting about Ventilation

The vent. It’s a great invention. Life changing. Life saving even. But like many miracle cures, it comes in a Pandora’s box. For example, the tidal volume and inflation pressure needed to ventilate a patient with ARDS will stretch out the lungs, alveoli, and blood vessels. Remember that fragile blood-gas barrier that becomes permeable with ARDS? Yeah, the vent can make that worse (Don’t remember? See part two to jog your memory) (Lopez-Martinez et al., 2018). High air volume and pressure may also damage the body’s ability to participate in mucociliary clearance (Matthay et al., 2012; Yamashita & Veldhuizen, 2011). Due to a combination of the reduced mucociliary clearance and reduced upper airflow (with cuff inflation), the patient’s ability to cough/mobilize foreign contents, or “stuff” as I like to call it (e.g., aspirate, secretions, viral/bacterial and immune contents, etc.), will be extremely limited (Paju & Scannapieco, 2007). To make matters worse, the driving force of the inflation pressure may also push it down deeper into the lungs where it is even less likely to be cleared (Bassi et al., 2015). With all this “stuff” hanging around, we are going to have copious, thick mucus in the lungs, which can inhibit ventilation and create a risk of further infection (see prior post on mucus for more details on this). 

The last resort for clearing out this material becomes tracheal suctioning, which introduces its own set of risks, including hypoxia, loss of lung volume, atelectasis, and damage to the mucosal membrane (Yazdannik et al., 2018). This is all not to mention the myriad of negative effects the endotracheal tube has on the larynx, which we are all too familiar with (Mota et al., 2012). Ok, so the vent is like drying your hair with a blow torch, but what can we do to help?

Lung protective ventilation is one way to reduce the changes to the blood-gas barrier. This method incorporates lower levels of tidal volume and pressure in order to reduce the stretching effect on the alveoli (Bassi et al., 2015; Matthay et al., 2012). This allows the patient with ARDS to receive the benefits of mechanical ventilation without as much of a drawback. However, severe cases may require higher volumes and pressures to maintain adequate ventilation for gas exchange despite the side effects. The next best thing (or the least bad thing) is to avoid the vent entirely if possible. And we have many options available to do this (thank you, medical technology). 

Pushing back against vent dependence

There are several forms of respiratory support that can be used to prevent respiratory failure and vent dependence. Many of these devices (e.g. BiPAP, high-flow nasal cannula (HFNC), non-rebreather, venti-mask) were once only occasionally seen by the SLP, but in the era of COVID have become more of the norm. In a previous post titled, “Taking a Deep Breath with Dysphagia” I discuss how we should be approaching patients with various levels of support. Other than a few exceptions (e.g. oral intubation and BiPAP), many of these patients can still tolerate PO intake. However, we need to follow their trajectory towards recovery (or clinical decline) to decide if and when the patient is stable enough for PO intake (or not).

Forecasting the storm 

The SLP is tasked with determining if and when PO is indicated. No small feat. In order to do this effectively, we need to understand the indicators for the slippery slope that leads to a possible precipitous downturn in ARDS. These include changes in white blood cell (WBC) count, hemoglobin, platelet count, and overall medical stability (Matthay et al., 2012). These indicators can be read in the form of changes in lab values and vital signs, the trends of which can be closely monitored by the SLP. This will allow us to get a sense of the patient’s current (and possibly future) respiratory status, medical stability, susceptibility to infection, and candidacy for PO intake. For example, you are considering PO intake for a patient with an increased WBC and variable blood pressure. An initial instrumental study may be in order before blind bedside trials as we want to avoid the possibility of introducing aspiration into this patient’s lungs, while they are possibly fighting something else.

It takes a village

To fully understand all of these factors takes life-long learning (even Dr. Coyle admits to daily studying), but here’s a helpful life hack: Talk to your team. The interdisciplinary team (IDT) has more knowledge than you (or anybody) could ever achieve in a lifetime. And you have direct access to them (literally), as they’re often within 6 ft of you (but no more!). You can stand on the shoulders of giants to take a bird’s eye view of the whole clinical picture by using this endless source of knowledge.

Out with the bad: Recovery

ARDS is a tough disease. It has a 40% mortality rate and for those who do recover, many have life-long impairments (Villar et al., 2019). Recovery will look different for every person depending on a number of patient factors. One recent study that looked at COVID-19 recovery found specific indicators for poor recovery, including age, the severity of the disease, time in the ICU and on the vent, as well as a history of smoking and alcoholism (Ojo et al., 2020). These factors may increase the risk of pulmonary fibrosis (disordered lung healing leading to stiffness) which will cause life-long breathing issues (Ojo et al., 2020; Villar et al., 2019). Understanding the recovery process and recognizing a patient who is on track to fully recover vs. those who may have chronic difficulty will help determine if and when full PO intake is clinically indicated. 

ARDS resolves with the resolution of edema, decreased inflammation, and restoration of the blood-gas barrier. In order to do this, the lungs must be able to absorb or clear out all that “stuff” we talked about in order to reestablish the pressure homeostasis that allows for the blood-gas barrier to function again (Matthay et al., 2012). More aspiration during this process is not going to help. In fact, it will only add to the “stuff” that’s already down there; worsening inflammation and edema, and further compromising gas exchange (Matthay et al., 2019). The faster the alveoli are able to reverse this condition, the more competent the immune response will be, and the faster they can be liberated from respiratory support.

Knowing this, it’s best to be conservative when introducing PO intake in patients with suspected dysphagia, as both the risk for and the effects of aspiration will be high. Even in an aspiration event with what would generally be considered innocuous content, such as clean water, the introduction of extra fluid can be life-threatening if it is a sufficient amount (Matthay et al., 2012). This is on top of the pulmonary threat of aspirating bacteria in the form of oropharyngeal secretions; which patients on mechanical ventilation are already at high risk for due to reduced sensation and upper airflow (Paju & Scannapieco, 2007).

In with the good: PO intake

Given that the stakes are so high, an instrumental study should be completed on all patients with or at risk for ARDS and dysphagia. Their respiratory status is simply too fragile to play a guessing game at the bedside. Stricter management of confirmed dysphagia is also preferred in order to manage the risk of respiratory decline and improve the chances for a faster recovery (that trace aspiration you may have brushed off with a healthier patient? Might need to be addressed here). Knowing the patient’s risk of aspiration and the risk factors that would allow that aspiration to lead to infection and/or respiratory changes is essential (see part two for more on this.) Not only will it allow the SLP to manage dysphagia effectively, but it will allow the clinician to allocate time and resources away from the lower-risk patients and towards those who need it the most.

When to begin PO intake is the million-dollar question. And the answer of course is... complicated. The level of respiratory support can be a good indicator of the patient’s overall status, but making hard-and-fast rules on who we can or can’t see is a slippery slope. For example, it’s easy to get excited the second a patient comes off of the vent and think, “They’re ready!” But the fact that mechanical ventilation via tracheostomy improves the outcomes of patients with ARDS tells us that a patient’s stability should be in question during initial trials off of the vent (Matthay et al., 2012). Without the extra ventilation support, the patient may be more likely to succumb to the vicious cycle of infectious and immune system processes, which may lead to hyperventilation, further aspiration, and further decline. 

A better approach is to look at the clinical trends. What’s been happening for the past week or two? Having trouble weaning from the vent? Showing signs that they may need intubation? Or have they been stable on HFNC with no signs of distress? How about on non-rebreather, but for three days in a row has tolerated nasal cannula for five hours straight? There are countless clinical scenarios, but tracking the trends will give you a sense of where the patient is and, more importantly, where they are going. 

Don’t forget your bedside clinical skills. They still apply. For example, if a patient is not showing any dysphagia risk factors other than from the disease process and the vent itself, then doing an instrumental study while they are still on the vent shouldn’t be out of the question. In fact, you can argue that a patient stable on pressure support with an in-line speaking valve may be a better candidate for initial PO intake than somebody just coming off of it for the first time (Kind of like walking with a walker vs sprinting a mile after a leg injury). Just keep in mind the level of vent support they are on and the increased risks involved with a higher level of support (i.e assist control) when the patient has less control of breathing (the vent doesn’t know or care when you’re about to swallow; it will send a breath regardless). 

There is no one-size-fits-all approach. Remember that bird’s eye view we get with our IDT? We need it at every step of the patient’s care so that we can seamlessly assess the risks and benefits of advancing a patient’s PO intake on an ongoing basis. It takes a village and thankfully in the hospital setting, that’s exactly what we have.  

The takeaway 

We have focused on several aspects of this complex syndrome, but there is MUCH more to learn that has not been presented here. The big takeaway is that we need 6 more blogs to discuss this extremely important topic. And maybe we will do just that. It all depends on how deep down the rabbit hole we (and you) want to go. ARDS isn’t new. There is a ton of research out there we can dive into. COVID just made it all rise to the surface. Our role is still evolving with this population, but there’s no doubt that we have a lot of value to add. And that value may come in the form of providing clinical insight to the IDT (i.e., educating on risk factors and weighing costs/benefits of PO intake), monitoring the trends (i.e., labs and imaging), and waiting for the right time to jump in (staying patient for the patient). Other times, it can be to provide an instrumental assessment early and see if we can get things moving (even if it’s only ice chips or saliva swallows). We may live to eat, but first, we need to breathe to live. The good news is that there’s always a place for us to help in that process.

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Bios:
Dr. Coyle PhD, CCC-SLP, BCS-S is a Professor of Communication Science and Disorders and Otolaryngology at the University of Pittsburgh where he teaches undergraduate, Master’s and doctoral SLP students both in the classrooms and clinics and has an active clinical caseload in the University of Pittsburgh Medical Center.  His current research focuses on development of noninvasive sensor-based dysphagia screening and diagnostic systems for dysphagia screening and automated diagnostic annotations.  He teaches nationally and internationally about the medical aspects of our profession.  He is a Board Certified Specialist in Swallowing Disorders, and an ASHA Fellow.

Affiliations: Department of Communication Science and Disorders, Department of Otolaryngology, University of Pittsburgh.

Kelsey Day, M.S., CCC-SLP is an acute care Speech-Language Pathologist (SLP) who specializes in dysphagia management for the medically complex, critically ill, and tracheostomy dependent populations. She now serves as the Lead SLP at California Hospital Medical Center, a trauma and stroke center in downtown Los Angeles, where she supervises a team of nine SLPs. Kelsey demonstrates her commitment to the education of new medical SLPs through her mentorship for the Medical SLP Collective and supervision of graduate student clinicians and Clinical Fellows in the acute care setting. She is a guest lecturer at several graduate level SLP programs, invited keynote speaker at national and international conferences, course creator and presenter of “Clinical Writing for Dysphagia Diagnostics”, and special guest on the “Swallow Your Pride” and “Speech Uncensored” podcasts.

Affiliations: Department of Rehabilitation, California Hospital Medical Center