Learn how to use the BOLUS framework to assess the risk of dysphagia-related adverse events. This framework is the work of Phyllis M. Palmer, Ph.D., CCC-SLP at the University of New Mexico and Aaron H. Padilla, M.S., CCC-SLP at Presbyterian Healthcare Services. While I watched this excellent presentation as part of the 2021 ASHA Convention, you can watch it on YouTube: Aspiration and the Pulmonary Biome: A Clinical Framework for Dysphagia Management. You can also read the tutorial they published in the American Journal of Speech-Language Pathology.
Free download: Aspiration and the Pulmonary Biome by Phyllis Palmer and Aaron Padilla. (Email subscribers get free access to all the resources in the Free Subscription Library.)
Outline:
- Why should we assess dysphagia risk?
- Read the published tutorial.
- The lung microbiome.
- Pulmonary homeostasis depends on the balance of immigration and elimination.
- BOLUS: the clinical framework for clinical decisions in dysphagia.
- B: Bolus variables.
- O: Oral health and oral care.
- L: Lifestyle and level of activity.
- U: Unintended (iatrogenic) influences.
- S: System status (general health).
- Applying BOLUS to determine level of risk.
- Related Eat, Speak, & Think posts.
Why should we assess dysphagia risk?
Watch Part 1 of “Aspiration and the Pulmonary Biome”, or read on to learn the highlights of this ASHA Convention 2021 presentation.
When we treat swallowing impairments, we make recommendations intended to improve our patient’s safety and efficiency in eating and drinking. But how do we decide what to recommend?
In the “old days”, aspiration was the big enemy. Many SLPs were taught that our job is to eliminate aspiration at any cost.
However, we now know that the risk of aspiration does not equal the risk of an adverse event from aspirating. Prandial aspiration does not lead to an adverse event in every person.
And we know that modifying a person’s diet can lead to increased risk of dehydration, aspiration pneumonia, and longer hospital stays. Plus, making a person NPO (nothing by mouth) increases their risk of disuse atrophy, thereby worsening swallow function.
“So how do we differentiate from those patients who aspirate who will be okay and those who aspirate who will not be okay?”
Phyllis Palmer, PhD, CCC-SLP
Read the published tutorial
Dr. Palmer and Aaron Padilla published their work in a tutorial, which provides “a guiding framework… to encourage clinicians to assess more than the presence of aspiration and consider the individual’s ability to cope with the aspirated material.”
ASHA members have free access. Here’s the reference:
- Palmer, P. M., & Padilla, A. H. (2022). Risk of an Adverse Event in Individuals Who Aspirate: A Review of Current Literature on Host Defenses and Individual Differences. American journal of speech-language pathology, 31(1), 148-162. https://pubs.asha.org/doi/10.1044/2021_AJSLP-20-00375
The lung microbiome
Aaron Padilla talks about the lung microbiome and how it relates to chronic aspiration.
A key point to understand is that the lungs are not sterile. A healthy lung contains colonies of bacteria, particularly in the upper airway.
As we move down into the lower airway, toward the level of the alveoli, we don’t find much bacteria due to the lack of a food source, particularly protein or iron.
However, in someone with chronic aspiration, the lung biome can look like the gut biome, and we may find colonies of bacteria thriving in the lower airway.
Some people are able to tolerate chronic aspiration for long periods of time, whereas other people develop an “adult-onset pulmonary condition such as adult-onset asthma, bronciectasis, or even a pulmonary fibrosis.”
“So we’ll be talking about a little later in the presentation who can we take that risk with and when can we not.”
Aaron Padilla
Pulmonary homeostasis: Immigration and elimination
Dr. Phyllis Palmer talks about how the lung maintains a healthy environment that does not support large bacterial colonies, particularly in the lower airways.
You can see the model in the handout they provided and learn more from the video, but here are some key ideas:
- Immigration is material moving into the lungs, via micro- and macro-aspiration.
- Micro-aspiration is aspiration of saliva, which occurs in all healthy people, especially while asleep.
- Macro-aspiration can occur with food, liquid, or refluxed material.
- Elimination is how we move material out of the lungs.
- Material that penetrates into the airway is ejected via a throat clear or cough.
- Aspirated material may be removed via cough, the mucociliary escalator, phagocytosis, or aquaporin absorption.
Dr. Palmer and Aaron Padilla go on to talk about these processes in detail, as well as what to look for in our patients in terms of proactive and reactive defenses.
What is the BOLUS framework?
Dr. Palmer and Aaron Padilla have presented the BOLUS framework as a tool to assist clinical decision-making in the management of patients with dysphagia.
The BOLUS framework guides us to consider the whole patient, including:
- Bolus variables.
- Oral health and oral care.
- Lifestyle and activity level.
- Unintended (iatrogenic) risks.
- System status (general health).
B: Bolus variables
Watch Part 2 of “Aspiration and the Pulmonary Biome” to learn about each variable in the BOLUS framework.
Aaron Padilla talks about bolus variables that we should take into account in our clinical decision making. For instance, we should consider:
- The acidity of what is being aspirated.
- Aspirating highly acidic foods such as tomato juice, orange juice, or stomach contents increase the risk of a pneumonitis.
- Water has a nearly neutral pH, so it is much less harmful if aspirated. In addition, the aquaporin channels have some ability to remove water from the lungs.
- The density of what is being aspirated.
- Aspirating solids is more likely to lead to an adverse event compared to aspirating liquids.
- Aspirating thicker liquids is more likely to cause harm than aspirating thinner liquids.
- The quantity and frequency of aspiration.
- Aspirating larger volumes of food or liquid can be more harmful than aspirating smaller volumes.
- Frequent aspiration is likely to be more harmful than intermittent aspiration.
O: Oral health and oral care
Dr. Palmer talks about oral health and oral care routines. Interestingly, she stated that “we have distinct bacterial habitats in our teeth, tongue, cheek, palate, and gingival sulcus”.
When someone aspirates, these bacteria can be transferred to the lungs.
Patients who have xerostomia (chronic dry mouth) are at higher risk for slow clearance of food residue from the oral cavity. They also tend to have lower cohesion of the bolus, which is more likely to break apart during the swallow and adhere to the oropharyngeal tissues.
“Good oral care routines can overcome poor oral health.”
Dr. Phyllis Palmer
Good oral care, including brushing and rinsing of the oral surfaces, lowers the bacterial load which lowers the risk of adverse event when aspiration occurs.
L: Lifestyle and activity level
Aaron Padilla talks about research from our field and physical therapy that indicates that being mobile is related to lower risk of dysphagia-related adverse events.
People who are dependent on others for feeding and oral care are at higher risk for adverse events, as well.
U: Unintended (Iatrogenic) influences
Dr. Palmer discusses iatrogenic influences that we should consider in our clinical decision making: tubes, mechanical ventilation, and risk from another physiologic system.
For instance, tubes that pass through the nose or mouth may introduce bacteria that can make its way into the lungs via micro-aspiration. A feeding tube increases the risk of aspiration of gastric contents, which increases the risk of pneumonitis.
Mechanical ventilation can lead to pulmonary edema, which reduces the mucociliary escalator process. Many patients receiving ventilation are kept in a supine or prone position, which increases the risk of aspiration and reduces the body’s natural elimination pathways.
“So here we’re asking that when we treat a patient for dysphagia, that we don’t shift the risk from the oropharyngeal cavity and the respiratory system to another physiologic system.”
Dr. Phyllis Palmer
Dr. Palmer goes on to provide a familiar example of recommending thickened liquids which a patient doesn’t like and therefore doesn’t drink. Now we’ve transferred the risk from the respiratory system to the renal system.
S: System status (general health)
Aaron Padilla discusses the impact of general health on the risk of an adverse event from dysphagia. The following factors impact immigration and elimination of material in the lungs:
- Deconditioned or frail?
- Cognitive impairment?
- Acute or chronic medical conditions involving respiratory or upper GI systems?
- Cough strong or weak?
- Immune system strong or compromised?
Dr. Palmer mentioned earlier in the video that based on limited data, a strong cough of approximately 270 L/minute may be required to expel material from the upper airway. Cough strength can be measured with a peak flow meter or a portable spirometer.
Applying BOLUS to determine level of risk
Watch Part 3 of “Aspiration and the Pulmonary Biome” to see Dr. Palmer and Aaron Padilla present two case studies for using the BOLUS framework to influence clinical decision making. (Apologies that the video can only be viewed on YouTube. We weren’t able to change the settings.)
They use the BOLUS framework to assess the level of risk of adverse event for two patients. For each BOLUS variable, they ask three or four questions and assign a stoplight color for each one: green for low risk, yellow for moderate risk, and red for high risk. You can see all of these questions in their handout or in their paper.
The BOLUS framework offers a clear way to estimate the risk of an adverse event in our patients who have oropharyngeal dysphagia.
Using this framework, we can:
- Look at the pattern of high risk and low risk factors.
- Consider if any of these risk factors are modifiable through skilled intervention.
- Take all of this into account, along with our patient’s preferences and goals, to make informed recommendations.
- Explain our recommendations to our patients and other stakeholders.
Related Eat, Speak, & Think posts
- 10 factors that increase risk of aspiration pneumonia.
- What you need to know about chronic dry mouth.
- How to help an adult with eating and drinking.
Free download: Aspiration and the Pulmonary Biome by Phyllis Palmer and Aaron Padilla. (Email subscribers get free access to all the resources in the Free Subscription Library.)
Featured image by jarmoluk from pixabay.
Lisa earned her M.A. in Speech-Language Pathology from the University of Maryland, College Park and her M.A. in Linguistics from the University of California, San Diego.
She participated in research studies with the National Institute on Deafness and other Communication Disorders (NIDCD) and the University of Maryland in the areas of aphasia, Parkinson’s Disease, epilepsy, and fluency disorders.
Lisa has been working as a medical speech-language pathologist since 2008. She has a strong passion for evidence-based assessment and therapy, having earned five ASHA Awards for Professional Participation in Continuing Education.
She launched EatSpeakThink.com in June 2018 to help other clinicians be more successful working in home health, as well as to provide strategies and resources to people living with problems eating, speaking, or thinking.
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