Thickened liquids are a common intervention recommended by SLP’s. Garcia and Chambers (2008) found that 85% of SLP’s who responded to their survey reported that they believed thickened liquids to be an effective clinical intervention. Of those, 72% reported recommending nectar thick liquids most frequently and 19% reported they recommended honey thick liquids most frequently. This survey did not differentiate the use of thickened liquids as the first choice, second choice, or last choice. I would be very interested in learning more about the choices made by SLP’s in regards to thickened liquids. (Hint hint grad students)
My first question would be, are we recommending thickened liquids just to eliminate aspiration or are we taking the whole picture into account?
Let’s talk about what the positives of thickened liquids are. Thickened liquids have been shown to reduce prandial aspiration. We know that there is not a simple link from aspiration to pneumonia. Aspiration is just one factor needed for the development of pneumonia. Elimination of aspiration can offer relief to patients who cough excessively with thin liquids. Elimination of aspiration in the short term may also be important for those with very compromised pulmonary status. They may also have utility in the short term for individuals in the acute phase of CVA.
What about the possible negative consequences? What problems might they create?
Thickened liquids are not very palatable to patients in general. Cichero (2013) found that thickened liquids do not offer satiety of thirst. They do not offer that satisfying mouth feel when you are thirsty and get a drink of cold water. So even if someone drinks enough thickened liquids to achieve adequate hydration, they may not feel satisfied. Thickened liquids also create a feeling of fullness. So combined, people feel thirsty and full at the same time all of the time.
Thickened liquids can change the way that some medications are absorbed (Cichero, 2013). Medications are designed to be delivered in a specific part of the body at a specific rate and at a specific time. The thickener can also impact the availability of the active ingredients in the drugs. This is all very complicated but just know that there may be an impact.
Patients that are prescribed thickened liquids may have reduced access to the liquids (Cichero, 2013). Research has shown these patients to have limited access due to reliance on staff to get the liquids, difficulty opening containers of the liquids, or difficulty obtaining the containers of liquids. Patients already don’t like the thickened liquids in general, and limiting access reduces intake even further.
Dehydration is more common with patients consuming thickened liquids as compared to those consuming thin. Dehydration can cause a wide variety of problems including urinary tract infections, electrolyte imbalance, increased falls, poor muscle strength, and kidney failure among others. When we think about the whole patient, we need to think about the risks associated with dehydration. 75% of patients on thickened liquids were found to be dehydrated in a 2001 study by Finestone et al.
Aspiration of gastric contents is very dangerous and can quickly lead to respiratory infection and or failure. Thickened liquids increase reflux and subsequently increase risk of aspiration of that refluxed material.
All together, it’s clear that recommending thickened liquids is not a black and white decision. We need to think beyond just aspiration. My recommendation would be to avoid recommending thickened liquids whenever possible and to use thickened liquids as a tool to bridge a patient over into safe consumption of thin liquids by providing aggressive, evidence based dysphagia treatment.
One final thought: I would challenge all SLP’s to consume only thickened liquids for an entire day. Maybe even consume just honey-thick liquids. I think this would be an interesting experiment and may offer more insight into the experience of our patients.
Cichero J. A. (2013). Thickening agents used for dysphagia management: effect on bioavailability of water, medication and feelings of satiety. Nutrition journal, 12, 54. https://doi.org/10.1186/1475-2891-12-54
Finestone HM, Foley NC, Woodbury GM, Greene-Finestone L. Quantifying fluid intake in dysphagic stroke patients: a preliminary comparison of oral and nonoral strategies. Arch Phys Med Rehabil. 2001;82:1744–1746. doi: 10.1053/apmr.2001.27379.