Title: Quantitative Videofluoroscopic Analysis of Swallowing Physiology and Function in Individuals With Chronic Obstructive Pulmonary Disease
Authors: Mancopes, Peladaeu-Pideon, Barrett, Guran, Smaoui, Pasqualoto, Steele,
Journal: Journal of Speech-Language & Hearing Research
Year of Publication: 2020
Design Type: Cohort
Purpose: “The aim of this study was to analyze swallowing physiology in patients with stable COPD across the range from thin to extremely thick liquids in comparison to available reference data for healthy adults”
Population: adults from pulmonology/physiotherapy outpatient clinic in Brazil
Inclusion criteria: 40+ years; confirmed COPD diagnosis; medically stable (without exacerbation for a month)
Exclusion criteria: individuals dependent on O2; already receiving dysphagia treatment; pregnant women; history of stroke/brain injury/other neurological diseases, HNC, other lung diseases; history of prior oral and/or laryngopharyngeal surgery; use of medications that can alter awareness
In the spirit of the holidays, there’s a lot to be thankful for this year.🙏❤️ This article made me incredibly grateful for all the clear, specific, and comprehensive information the authors provided throughout this 🤩MUST-READ🤩 article on the COPD population.
Whether you’re a #newbie figuring out what to do, or a #seasonedSLP curious of why you’re seeing what you’re seeing, from the spot-on background on COPD, to the detailed descriptions and colorfully-created graphs that give you a clear picture of what’s it all about, this article will make you appreciate what you know, what you don’t, and everything you’ll learn after reading!🥰
In case you’ve wondered why you might see so many patients with COPD in any setting, or if you’re wanting to know more about this population, the article lays the foundation for you:
“COPD is characterized by persistent airflow obstruction with an inflammatory response and systemic manifestations. Peripheral muscle dysfunction and dynamic respiratory hyperinflation lead to restrictions in activities of daily living.” p.1
Some other quick factoids on COPD:
- 4th most common cause of mortality worldwide😬
- expected to become the 3rd most common cause of mortality by the end of 2020😳
So some lungs are obstructed, what does that have to do with how they swallow?
“dysphagia-related aspiration (i.e., entry of foreign material into the lower airway) can be a trigger for exacerbations of COPD…Aspiration during swallowing in patients with COPD is attributed to altered thoracic and abdominal respiratory biomechanics, pulmonary hyperinflation, and discoordination between breathing and swallowing (Steidl et al., 2015).” p.1-2
Sure, but why do we have to care about a patient’s respiratory system when we’re working on their swallowing?🤷♀️
“Instead of the typical exhalation–swallow–exhalation pattern, in which swallowing occurs partway through the expiratory phase of breathing (Martin-Harris et al., 2003), these individuals showed higher frequencies of inhalation preceding or immediately following the respiratory pause associated with swallowing.” p.2
Okay so they breathe differently, what does that matter?🤨
“Post swallow inspiration is thought to increase the risk of aspiration, particularly during the middle of serial ingestion cycles or in situations where residual material is present in the pharynx near the entrance to the airway (Butler et al., 2007).” p.2
Hmmm🤔….what else do we happen to know about COPD and its impact on swallowing?
“Chronic recruitment of the accessory muscles of respiration in pulmonary hyperinflation may serve as an antagonist factor that restricts hyolaryngeal movement. This may contribute to poor LVC, reduced upper esophageal sphincter (UES) opening, and pharyngeal residue, all of which increase the risk of penetration and aspiration. In addition, reduced laryngopharyngeal sensitivity has been shown in people with COPD.” p.2
In case all of that hasn’t blown your mind enough🤯, previous research by Garand et al (2018) also showed that there was also higher maximum scores on the Pen-Asp Scale compared to healthy controls, among additional swallow physiological impairments.🤯🤯🤯
Previous research has also shown differences in respiratory-swallow coordination for those with COPD (Chaves; Cassiani; Clayton; Macri; Cassart; Cvejic; Park) including:
- prolonged pharyngeal transit time
- prolonged laryngeal vestibule closure
- prolonged duration of hyoid bone movement
And yet these authors were still more curious and wanted to know more specifically about the swallowing pathophysiology for COPD. They also wanted to identify what may be considered ‘at-risk‘ factors for this population, which would be suuper helpful so us clinicians can implement the best, most evidence-based treatment plan for our patients.
After giving that great groundwork for the COPD population and how much of a big deal the intertwining of breathing+swallowing functions are, believe-it-or-not the authors give us more details on exactly who and what they are looking at and how, which takes a lot of the guesswork out and let’s us just sit back, breathe in, and start sipping our glasses as we read on! 🤓🍷☕️
- 28 adults (18 men/10 women)
- average age: 65 (range 41-79)
- COPD confirmed with spirometer with no reported exacerbations previous 3 months
- severity confirmed by GOLD staging method (Stage 1 mild — Stage 4 very severe)
“The majority of the COPD cohort was classified as having disease severity at GOLD Level 3, which corresponds to severe airflow limitation with forced expiratory volume measures between 30% and 50% of predicted values” p.8
- data was collected from a previous study (Steele et al., 2019) and specifically looked at reference data for healthy adults 60 years or younger
- 38 healthy participants (10 men/19 women)
- average age: 34 (range: 21-58)
- because the above original referenced study had a lot of data and trial tasks, in order to keep things fair and equal, these data only used the first bolus of each task from the healthy adults
(If you need a quick refresher for what a cohort even is and why it’s important, just Subscribe to SLP R&R to download your own🔥Freebie Reseach Design Cheat Sheet🔥)
So what were they going to be looking at?
Videofluoroscopic Swallow Study is the name of the game, with IDDSI flow testing as a top player.🤩🤩
Yep, they used continuous fluoro mode (sounds like an SLP-transformer😅🤖) at 36 frames per second to watch the COPD group swallow 2 boluses from each of the following liquid consistencies:
- thin liquid
And for those of you (like me) always curious just what the investigators tell participants, “The instructions were to swallow naturally, without waiting for a cue from the investigator.” Yaaayyyy🙆♀️😍🥳🤩!!!! (See Daniels, et al., 2007 for how a lil ‘ol cue can make a big difference). While the researchers still used a spoon for all liquids and now have this data for the future, only the cup sips for all consistencies and the first spoon trial of extremely thick liquid were actually compared to the control (healthy) group to keep things fair and equal.😉⚖️
With some bippity-boppity-boo math-magic, they were also able to figure out how to measure timing aspects to the second, milliseconds to be exact (27.7 ms/frame). More magic happened after stripping everything from each recording in order to have randomized blinding to rate all the following parameters using the Analysis of Swallowing Physiology: Events, Kinematics, and Timing (ASPEKT) method (Steele, et al., 2019):
- # swallows per bolus (PAS)
Anyone else have the ASPEKT method or any of these measures on your SLP Wish List????🎀📜
My nerdy lil SLP heart is going crazy again because, did you see those descriptions?! I can’t tell you how many research articles I’ve read that have had vague definitions or descriptions, or using a term but not really describing what they meant or how they came up with that definition. So I am very grateful to the generous authors for giving a to-the-point list that helps #bridgethegap for the reader and avoids wondering just what they heck their reading!!!🤩😍🙆♀️
Before we forget, since the data for the control group was already known, they really just had to reference the new data to compare to this COPD group, after that and some interrater reliability consensus it’s really just using fancy-schmancy statistics!🤓
I don’t know about you, but all of that was a LOT to unpack (try re-reading it all to break it down for everyone!😅🥴), so let’s review some key big questions that are trying to be answered here:
- “How frequently is ‘X group’ at risk for [insert a measure from above] for ____consistency?”
- “How more frequent are those in the COPD group at-risk for [insert measure from above] for ____consistency compared to a healthy normal control group?”
I for one am not that much of a big gambler, but I am all in for the authors’ idea on giving us an odds ratio to easily think what the odds are of these things happening:
“An odds ratio (OR) is a measure of association between an exposure and an outcome. The OR represents the odds that an outcome will occur given a particular exposure, compared to the odds of the outcome occurring in the absence of that exposure.” (Szumilas, 2010)
Let’s keep this stuff in mind as we truck on for some Results. . .
_____ Safety first _____
When talking about safety, remember we’re talking about the results for the Penetration-Aspiration Scale:
“PAS scores of 3 or higher turned out to be rare in the COPD cohort, and frequencies did not differ significantly from those seen in the healthy cohort…None of the participants in the COPD cohort aspirated material below the level of the vocal folds (i.e., PAS ≥ 6)..” p.5, 9
Was anyone else surprised by this?!
🚨🛑PUMP THE BREAKS🛑🚨
The authors eased my worries and discuss how since this doesn’t exactly match what other studies have found with this population, some likely reasons could be because
- a) the COPD patients in this study were found to have stable COPD versus in exacerbation or severely impaired
- b) other studies (Garand et al., 2018) used not only different scoring but also tested each consistency with a “large-volume sequential drinking task” versus single sips or spoonfuls used in this study
So, based on these small but likely consequential differences and what we know about how larger volumes are more likely to elicit penetration-aspiration, this one sticks with the evidence👍.
__ Timing really is everything __
Now could be the perfect time to re-orient yourself to the list of parameters and their definitions above (just hover over the ° 😉), because this was a doozy even for me to let sink all in one sitting.
Better yet, after that I also highly recommend taking the opportunity with this wonderfully written article to actually try to interpret the pretty-colored IDDSI graphs the authors were so careful to include! Sometimes the devil really is in the details, and these graphs are not as complicated as most (embarrassingly the bright colors really do help my tired eyes🧐, #researchertips).
I’ll admit I am not a numbers nor chart kind of gal (except a pizza pie graph🍕😉)
but after I invested a few extra minutes trying to figure out just what I was looking at and what the heck it meant, I was able to walk away a bit less scared and a bit more confident in this skill, which for this busy clinician,is an accomplishment I’ll happily pat myself on the back for today.😁
Enough of the words of encouragement:
“Despite the absence of penetration–aspiration, the COPD cohort in our study demonstrated significantly higher frequencies of at-risk values for all three parameters measuring aspects of LVC.” p.9
Those three parameters for LVC were:
- incomplete LVC ( for thin, mildly, & moderately thick liquids)
- long time-to-LVC /aka LVC reaction time (for moderately thick liquids)
- short LVC duration (for mildly, moderately, and extremely thick liquids)
Short ‘n sweet: the COPD cohort had less complete LVC, took longer to close, and stayed close for less time.
If you’re less familiar with the terms “prolonged time-to-laryngeal vestibule closure (LVC)”, aka “laryngeal vestibule closure reaction time,” checkout a super helpful and comprehensive overview of this in the review: R-E-S-P-E-C-T for LVC: Laryngeal Vestibule Closure in the Spotlight. Otherwise just know that we’re really talking about the same thing in both articles, and we can can all thank the authors for trying to get everyone on the same page in the article even when our field still can’t agree on the most simple but important terms!😩🥴
But what we can agree on is that incomplete LVC does increase the risk of penetration and aspiration! If your SLP brains are buzzing about the impact the respiration+swallowing relationship may have on how long LVC can be in the COPD population, you’re not alone, and the authors beat you to it!
“It is tempting to speculate that the shorter durations of LVC seen in the COPD cohort might reflect some aspect of disordered respiratory–swallow coordination and an urgency to resume breathing in the context of pulmonary hyperinflation and reduced expiratory volumes.”
“However, given that the respiratory pause in swallowing is under neural control and not necessarily time-linked to mechanical closure of the laryngeal vestibule, simultaneous measures of airflow or chest wall movement with videofluoroscopy would be needed to properly explore this hypothesis in future studies.” p.11
🔍🧐Guess we’ll all have to be on the lookout until then!🧐🔎
The authors kept their curiosity caps on to really investigate why those in the COPD group had a longer swallow reaction time, specifically on thin and mildly thick liquids. Luckily they put our minds at ease explaining there’s no real motor deficit reason why these individuals would have difficulty swallowing on time. So they turn to the all-too-forgotten sensory story behind everything:
“However, impairments in laryngeal sensation have been reported in the COPD population (Clayton et al., 2014), with one possible contributing factor being the high use of inhaled corticosteroid medications in this population. Whether sensory deficits also exist in the oropharynx and manifest in the form of long swallow reaction times remains less clear.” p.12
To squeeze or not to squeeze
__ That is the question __
Unfortunately, despite all the methodical planning and protocols, some of the imaging quality was still less-than-superb to measure exact hyoid movements. Which first of all, bummer!😕 But, don’t forget that research/researchers are not perfect unicorns in labcoats🦄👩🔬, and they can’t solve all problems (no matter how much we ask and they might want to😂).
On the bright side, they were able to still capture some elements that, we as clinicians, can definitely find important on the day-to-day:
“Higher odds of pharyngeal residue were also found in the COPD cohort for all consistencies in all locations, although significant group differences in the frequencies of at-risk residue were only seen with the mildly thick and extremely thick stimuli.” p.12
So more residue is more likely, especially for the thicker stuff. But if you’ve read any recent evidence, listened to any podcast or lecture, or taken any CEU from the experts who drill into our ever-expanding SLP brains that residue is NOT an impairment, you’ll likely be wondering why the residue is there!🤓
“Figure 8 illustrates one of the most dramatic findings in this study…COPD cohort showed significantly higher frequencies of poor pharyngeal constriction for all consistencies” p.8
But the researchers still weren’t happy with this answer, and wanted to know why the COPD group might be more at-risk for pharyngeal residue. After further scrutiny and investigation, they concluded it really was two-fold:
“in the COPD cohort, the coexistence of short UES opening and poor pharyngeal constriction was both common and strongly predictive of residue that was worse than that seen with poor pharyngeal constriction alone.” p.13
If you lie awake at night wondering if your COPD patient can just have thickened liquids to be “on the safe side” until an instrumental, you’re gonna have to keep reading to finally get some shut-eye:
“The odds ratios for residue-of-concern were particularly high on thicker consistencies in our study cohort, suggesting that texture modification should not be implemented in people with COPD without proper evaluation.” p.14
Whatever mantra resonates with you most,
- “we can’t diagnose/treat what we can’t see”
- “we don’t have x-ray vision at bedside”
- “thicker does not always mean better”
Just keeping these little messages in mind the next time could mean the world (and life) for your next COPD patient’s recovery.❤️
While this study really was designed pretty awesomely (scientific term?🤔), again, nothing is ever perfect no matter how hard some of the most talented scientists try.
Some quick limitations to keep in mind before comparing it to other research:
- since there was a pretty obvious age difference between the 2 groups, after some after-the–fact statistics, the authors found that some of their results may have been due to presbyphagia versus COPD (more future research please!🙏)
- different barium products for this study compared to the originally referenced study data
- difference in bolus administration methods
- other differences compared to other previous studies
- COPD severity
- all patients were relatively stable versus having more severe or exacerbated COPD complications
Every person with COPD, just like every patient, is incredibly different. But now we are more aware of what this population might be more at-risk for!
“The study results revealed impairments of the integrity, timing, and duration of LVC as risk factors in this regard.” p.14
We also know more about which impairments to keep our eyes on when watching our instrumentals!
“The observation of poor pharyngeal constriction in our COPD cohort for all consistencies highlights impaired swallowing efficiency, which has received little attention in previous studies.”
“The combination of poor pharyngeal constriction and short durations of UES opening represents a particular risk for postswallow residue, which may represent a further risk for subsequent aspiration.” p.14
We can also relate all of this to any setting. What are your patients with COPD usually like at your facility? Maybe they’re more on the stable side like those in this study, or maybe they are there for an acute exacerbation or other medically compromising diagnosis. Now you can hypothesize that if someone is more medically acute, they could be even more at-risk for these issues. At the end of the day, that’s what we always need to do as clinicians. Start with a hypothesis, understand the evidence, and use our current clinical skills to navigate how to work with our patients’ wishes to get them better.👍
How can you use this article?!?
Have you found a lot of these impairments on your instrumentals already?!
What was your biggest “aha” moment from this article?
What other research or treatments have you found to be beneficial for this population??
- “Differences in the integrity, timing, and duration of LVC represent a heightened risk for penetration–aspiration, while poor pharyngeal constriction and shorter UES opening represent risks for pharyngeal residue”
- “In the COPD cohort, significantly higher frequencies of at-risk values involving long swallow reaction times, short UES opening durations, and long pharyngeal transit times were seen with thin liquid”
- “If significantly higher frequencies of at-risk values for particular parameters are seen in patients with a given disease compared to healthy controls, this would point to patterns of pathophysiology that can be considered hallmark characteristics of swallowing impairment in that disease”
- “it is important to explore whether treatment strategies focusing on respiratory–swallow coordination, which have recently been shown to be effective for adjusting the timing of swallowing within the respiratory cycle (Martin-Harris et al., 2016), also have beneficial impact on the duration of UES opening”
Article referenced: [FREE ASHA ACCESS]
Mancopes, R., Peladeau-Pigeon, M., Barrett, E., Guran, A., Smaoui, S., Pasqualoto, A. S., & Steele, C. M. (2020). Quantitative Videofluoroscopic Analysis of Swallowing Physiology and Function in Individuals With Chronic Obstructive Pulmonary Disease. Journal of Speech, Language, and Hearing Research, 63(11), 3643-3658. doi:10.1044/2020_jslhr-20-00154