Title: Oropharyngeal swallowing in chronic renal failure
Authors: Pinto, Silva, Pinato
Journal: Communication Disorders, Audiology and Swallowing (CoDAS)
Year of Publication: 2016
Design Type: Observational cross-sectional study
Purpose: “The objective of this study was to describe the oropharyngeal swallowing profile of patients with CRF”
Population: 20 patients with medical diagnosis of chronic renal failure admitted in hospital stay for hemodialysis
Inclusion criteria: able to give informed consent
Exclusion criteria: use of psychoactive drugs; presenting with neurological changes; or invasive medical intervention such as intubation

I don’t know about you, but sometimes it feel like a revolving door while working in the medical field. You see one diagnosis, then another, then a completely new one you can’t even begin to pronounce. But eventually, wherever you are, you start to pick up the ever-changing flow while noticing the constants that remain. Among these, patients with “waste emptying” problems, otherwise known as chronic renal/kidney disease/failure (relating to CKD, CKF, ESRD etc. other names seen in medical charts), has been a constant ever since my very first clinical fellowship placement. Granted, there’s usually a LOT more going on beyond that one issue and which can sometime end up tagging on almost every other common diagnosis that either cause, impact, or worsen the original chronic renal failure problem.
“CRF may present, in addition to the inflammatory process, changes in regulation of the hypothalamic pituitary gland, the immune system, sleep patterns, mood, and swallowing, and the occurrence of symptoms depend on the disease, dietary habits, and the level of reduction in renal function” p.72
The main reason for picking this article out of the thousands of others I would have normally perused to review was essentially the déjà vu moment after seeing yet another CKD patient, in the hospital, for a dysphagia-related consult. Maybe you’ll get that same déjà vu reading it too!?!💫
- Only got a sec?
- Chronic Kidney-related illnesses may impact swallowing safety and warrant further evaluation or management for dysphagia
- Only got a minute?
- “VFS showed high incidence (80%) of abnormalities in oral and pharyngeal phases in subjects with CRF, a lower percentage (15%) of cases with abnormalities in the pharyngeal phase only, and one case (5%) of abnormalities in the oral phase of swallowing“
- “Other possible factors as causes of oropharyngeal dysphagia in CRF would be complications and/or co-morbidities that impact the neuromotor system, such as neuropathy and uremic encephalopathy, changes in levels of consciousness, attention and associated alert or sleeping disorders, neuronal damage induced by uremic toxins, ischemic brain injury, oxidative stress, chronic inflammation, endothelial dysfunction, and anemia, which also need to be investigated“
- “On the whole, these findings suggest that abnormalities in oropharyngeal swallowing can be a part of CRF clinical image and highlight the need to investigate the causes of this phenomenon“
- Got more time? Keep Reading!!
This article was interesting to me in 2 ways:
1) Like I mentioned above, I want to know more about this population, and the fact that the title basically had all my search terms was a 👏Win👏
2) It was NOT the “best” article (#imo😬). But, when I realized exactly what the article was supposed to say and do given its design and purpose, and what it was NOT, it made much more sense to graciously accept what it was trying to tell me.
So instead of focusing more on the article specifics I decided to lean more towards describing how this article may be different from others and what to expect (or not expect) from it. On the bright side, the article is not only a quick read but also not nearly as complicated as any experimental study where you may have countless groups, comparing as many variables as there are states, searching for that darn p-value like it’s Harry’s golden snitch🧐, and all the mathematical foreign language that might make your head spin. Nope. None of that!🙅♀️
Since this is an observational study, the authors literally just get to watch what happens with no interference. Also, because the type of statistics (aka “fancy schmancy math”) used are just descriptive, all they can tell you is that “this thing happened” using simple ideas like averages, super simple percentages, and even suuuper simpler charts.

Now, that is GREAT for you as a busy clinician reader! Not exactly as great for being able to prove anything😕…
But because we’re not looking to necessarily prove anything and just here to learn more, we can still read with ease since the authors are merely just trying to pick a moment in time (the time of the study) to try to figure out any common factors or risks with the population in order to let us know that ‘hey, we may want to think twice about this or that.🤔’ Also keeping in mind that since these types of studies are way less expensive and time consuming than others having only 20 subjects was likely an easier option for them (obviously more=better, but ya gotta start somewhere?😉).
The Good

➕They used INSTRUMENTATION!!! I can’t tell you how much my heart danced knowing there was some type of visualization done versus the x-ray vision skills that can be overly relied on (don’t get me wrong, I actually wish they would have included a bedside exam along with the video swallow study just to add a lil something extra😉, but I’ll take this over that anyway)
➕They used another evidence-based tool→ Functional Oral Intake Scale (FOIS) to assess the functional oral intake of the patients pre and post VFSS!! That means they were simply judging what the patient should be consuming, then rating it based on this super simple scale
➕The clinical process seemed pretty relatable and applicable, much like what we would do in any setting: medical chart review, relied on a metric like Glasgow Coma Scale as far as alertness goes, and had a patient/family interview revealing “the only complaint reported by 100% of CRF patients was the feeling of xerostomia, under the name of “dry mouth”
➕The Methods were mostly systematic… By felt like being positive and giving credit to completing the video swallow study the first day of hospitalization before the first hemodialysis session (anyone else pulled your hair out just trying to schedule it that week?!). When describing just how they did their video swallow studies I’ll admit it was a tad confusing as far as the order of different consistencies (only nectar and honey?), but at least they actually included the amounts provided (5, 10, 15 mL) with the specific cornstarch thickener and allowed for “freely swallowing (in a glass)“ by patients. Sometimes it’s the little things, ya know🫠?
➕It might just be me, but I appreciated the fact that they generally describe how they were visualizing each patient in a more-or-less standardized way, stating “To perform the examination, patients were sitting at 90°. The anatomical limits ranged from the oral cavity into the esophagus, anterior limit was set by the lips, posterior limit by the pharyngeal wall, upper limit by the nasopharynx, and the lower limit by cervical esophagus.”
The Not-So-Good

➖While this may not be a huge negative since I’m not very familiar with the barium products that were used given the study was published in Brazil nor am I an expert on measures and mixtures, someone else is gonna have to help me out if “barium sulfate at 50% to 50% food consistency, so it would not go through changes” is a viable option, or if “diet pear-flavored juice powder (previously diluted in 500 mL of water)” are legit options🤔? Some additional info or explanations would have been much appreciated😵💫
➖I can’t speak on behalf of all the clinicians who do video swallow studies, but I can say that FRAME RATES/FRAMES PER SECOND (fps) MATTER [checkout Steele’s lab for more]!! Just a quick Google search will shed light on this and you’ll see where I’m coming from when I say you can miss the difference between aspiration/penetration versus a completely normal swallow along with other important biomechanics. (To add a positive note, they did use recorded imaging which we know can also significantly impact critical decisions during testing (Vose et al., 2018)
➖While I actually really loved that they classified swallowing characteristics by “effectiveness and safety” based off the video swallow study (using both these measures are great!), it could have been a step up to use more standardized measures such as the Penetration-Aspiration Scale (PAS) or other methods for efficiency we’re now aware of (granted the date of the article and also origin, can’t be too harsh here)
The Results
“Swallowing profiles defined by analyzing VFS findings of individuals with CRF showed that among 20 patients studied, 16 presented abnormalities in oral and pharyngeal phase (mean age 53.75 ± 3.8 years), 3 presented changes only in the pharyngeal phase (mean age 65 ± 2.5 years), and 1 of them presented changes in the oral phase of swallowing (43 years). None of the subjects presented unchanged swallowing biomechanics” p.73 [emphasis added]
Now, take this with a grain of salt because they CANNOT say that this is a) representative of the whole chronic renal failure population, or b) that there are correlations/causes/specific relationships identified. So just like the time a kid pointed and laughed at me for using crutches with a broken ankle, all they can do is say:

Another quick interesting idea the article brought up is a new term I don’t think I’ve ever come across: “dialysis dementia”
“Dialysis could be responsible for a case also known as ‘dialysis dementia’ that may include speech and language disorders or even swallowing disorders (during or after dialysis); months later, these features become persistent, associated with myoclonus, seizures, balance, and cognitive disorders, affecting mainly the memory.” p.74
Wait, whaaaaaaaat?!?!😲🤯
I’ll definitely be looking more into this (or if anyone wants to help a girl out and send me as much info/research on this!!)
One more final Result:
“With respect to oral intake, FOIS put 4 individuals (20%) with CRF at level 5 and 16 individuals (80%) at level 7, before VFS. On completion of VFS, there was a change in FOIS levels of six subjects to level 1, seven to Level 4, four to level 5, and three to level 6 (Figure 2B).” p.73
When you do look at the simplified graph Figure 2B, it really did shock me that so many patients dropped SO low in the FOIS, going from “Independent/I can eat anything and everything I want at anytime” like I did to consuming nada by mouth!😧
Now, can you imagine going about your hospital stay, trying to deal with all these things medically wrong with you, then on top of that being told you’re no longer “safe” to eat the foods you enjoy? Or maybe you’re going about your day as usual all the while likely inhaling foods/liquids into the lungs, further contributing to your disease exacerbation/dehydration/malnutrition? Either way, the article does make a fairly neutral conclusion from this data that:
“On the whole, these findings suggest that abnormalities in oropharyngeal swallowing can be a part of CRF clinical image and highlight the need to investigate the causes of this phenomenon.” p.74
Now how we might go about that seems to be a different story…
The article suggests medical staff requesting “routine clinical examinations of swallowing in this population” which was set forth in the study’s institution.
After thinking more and more about this I started to feel like Auguste Rodin’s The Thinker statue…

Should we be clinically evaluating or at the very least, “screening” this entire population?
OR would we be over-stretched despite lack of concrete evidence stating we need to be doing this?
Should CRF/CKD be automatically included as a “Risk factor” for dysphagia along with all the other red flags (CVA, COPD, TBI, etc.)? Would all hospitals/therapy departments consider this factor?
Making sure to keep in mind the difference between an acute illness versus a possible more chronic condition that has gone unchanged, I think there are a bunch of different ways to go moving forward when working with this population.
At this point, when I see this diagnosis I’ve typically had a vague idea what I might expect and have my “hypotheses” ready to go once I see the patient in the room. But for others, maybe this article may make you think twice about looking closer, going deeper, and pushing harder for what that specific patient (and others) really need to improve their quality of life, but also their quality of care.
Referenced Article: 💥FREE ACCESS💥
Pinto, A., Silva, R., & Pinato, L. (2016). Deglutição orofaríngea na insuficiência renal crônica. Codas, 28(1), 71-76. doi: 10.1590/2317-1782/20162015041
(Spanish translations also available)
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