Does Thickening Liquids Work to Prevent Aspiration in Patients with Dementia?

Posted by | January 17, 2011 | Dysphagia, Dysphagia Articles

There is still debate over the use of thickening agents to prevent aspiration and aspiration pneumonia.  Some clinicians frequently use thickened liquids on all patients showing signs of aspiration, while other clinicians rarely use thickening agents.  Thickened liquids DO prevent aspiration in SOME patients, but are certainly not for everyone with a swallowing disorder.  Results from the largest clinical trial for dyphagia treatment showed that thickened liquids do not always prevent aspiration pneumonia in patients with dementia.

Liquids are the most common consistency aspirated in the elderly population.  Thickening liquids is a very common practice, even in the absense of evidence such as a modified barium swallow study.  Thickened liquids costs approximately $200 a month.  It also reduces the patient’s quality of life, as they may not enjoy drinking liquids anymore.  Patients may then refuse to drink liquids althogether, leading to dehydration.  Other problems may be that the liquids are not mixed to the appropriate consistency, either too thick or too thin to their target level.  This may increase risk for further medical complications (Garcia, J.M, et al).

One study, “Comparison of 2 Interventions for Liquid Aspiration on Pneumonia Incidence: A randomized Trial” (2008) looked at patients with dementia who had thin liquid aspiration and compared the effect of chin down posture with the effect of nectar and honey thickened liquids.  The study is the largest clinical trial for dysphagia treatment. The most frequently successful intervention to eliminate thin liquid aspiration was honey thick liquid, followed by nectar thick liquids and then the chin-tuck posture.  This was shown during video flurouscopy.  To determine pneumonia rates, if the patient’s aspiration was eliminated by all of the interventions (chin down, nectar thick liquids and honey thick liquids), the patient was randomly assigned to one of those conditions.  If the patient aspirated on all the interventions, but still wished to participate in oral intake, the patient was also randomly assigned.  Patients who aspirated on one or two interventions were not included. About half the patients did not benefit from any intervention (aspirated on all interventions).  The study then determined the incidence of aspiration pneumonia.

It was determined if the patient got aspiration pneumonia within 3 months of the study. Pneumonia was defined as evidence of pneumonia on a chest xray or three or more of the following: sustained fever greater than 100 degrees F, rales or rhonchi on chest auscultation, sputum gram stain showing significant leukocytes, sputum culture showing respiratory pathogen.

Pneumonia occured in 11% of the individuals in the study, which is lower than the incidence of pneumonia in patients with dementia-20-40%.  The incidence of pneumonia in the chin down group was  0.098,  nectar thick was 0.084, and 0.150 in the honey thick liquids group.  Therefore participants in the nectar thick liquid group had lower incidence of pneumonia than those drinking honey thick liquids.  Nectar thick liquids may be easier to clear from the airway because they are less viscous than honey thick liquids.

More patients in the thickend liquid group than in the chin tuck group experienced dehydration (6% vs. 2%), urinary tract infection (6% versus 3%), and fever (4% versus 2%).  Length of stay was longer in the honey thick liquid (18 days) compared to 6 days for chin tuck and 4 days for nectar thick.

The study shows that the thicker the liquid is not always best.  Patients in the study randomly assigned to the thickened liquid group had more complications such as dehydration, UTI, and fever.  The incidence of pneumonia was lowest in chin-down, followed by nectar and then honey thick liquids.  An important factor is that the study only included patients who either aspirated on all interventions, or aspirated on none of the interventions were included.  It is still not determined if patients whom honey thick liquids reduces aspiration on videofluroscopy, and treated with honey thick liquids will have better outcomes.  It appears that chin tuck is a good option if the patient is able to follow the commands and the patient can then still enjoy the taste.  Nectar thickened liquids is advantageous, with less need for training and supervision during the swallow process.  Honey thickened liquids should be used with caution, without first evaluating other interventions.

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References:

Garcia, J.M, Chambers, E., Clark, M., Helverson, J., & Matta, Z (2010). Quality of Care Issues for Dysphagia: Modifications. Journal of Clinical Nursing. Jun;19(11-12):1618-24. Epub 2010 Apr 7.

Robbins, J., Gensler, G., Hind, J.A., Logemann, J.A., Linblad, A.S., & Brandt, D.K., et al. (2008). Comparison of two interventions for liquid aspiration on pneumonia incidence: A randomized controlled trial. Annals of Internal Medicine, 148, 509-518.

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