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HYD: Effect of Thickened Beverages on Fluid Intake (2007)

Garon BR, Engle M, Ormiston C. A Randomized Control Study to Determine the Effects of Unlimited Oral Intake of Water in Patients with Identified Aspiration. J Neurol Rehabil. 1997; 11: 139-148.
Study Design:
Randomized Controlled Trial
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Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To examine the effects of water ingestion on patients who aspirate thin liquids.


  1. Patients who aspirate thin liquids and are given controlled water intake will not develop pneumonia
  2. Patients who are allowed access to water will sharply reduce the amount of thickened liquids ingested
  3. Patients who are allowed access to water would have increased liquid intake and less risk of dehydration
  4. Patient satisfaction will improve.
Inclusion Criteria:

Selected only patients who aspirated drinking thin liquids, to ensure that the aspiration of food textures or thickened liquids would not be complicating variables.


Exclusion Criteria:

Patients were excluded if they had:

  • History of previous CVA
  • Degenerative neurological dysfunction
  • Pneumonia
  • Multiple medical diagnosis
  • Reflux or esophageal disorders
  • A severe cough reflex reaction to aspiration of thin liquids due to the strain of prolonged bronchial-tracheal coughing
  • Pre-existing concern regarding hydration status.

Other exclusion criteria:

  • If unable to comprehend the risks of the study or with poor cognition
  • If unable to rinse and expectorate
  • If unable to hold a cup or self-feed
  • If impulsive.
Description of Study Protocol:


  • Any newly admitted CVA patient who had aspiration drinking only thin liquids, as documented by a videofluoroscopic swallow evaluation, was approached for inclusion in the study
  • Thirty-four patients declined participation
  • Ninety-four patients did not meet inclusion criteria
  • Informed consent was obtained by the patient (or spouse), referring physician and family physician.


  • One-year randomized, controlled, prospective design study
  • Twenty patients on a stroke rehabilitation unit who were randomly assigned to one of two groups
  • All patients had suffered a recent CVA (within three weeks; range, four to 19 days; mean, 12.8 days) and had documented aspiration of thin liquids only, as verified by a barium videofluoroscopic swallow evaluation.

Blinding Used

None used.


  • Water was placed out of the patient’s immediate reach in his or her room
  • Patients were instructed to notify a nurse or family member when they wanted water
  • Amounts of intake were recorded daily on flowcharts, with 200-cc cups used for measurement
  • Amounts of water intake given to the patients during therapy and outings were also recorded
  • No water was allowed with meals or for an hour following meals and a pre-rinse was utilized prior to any water intake to reduce the possibility of ingesting oral bacteria or oral food stasis
  • Control group patients were allowed as much thickened liquids as they desired with meals and as requested
  • Intake amounts were recorded in the same manner as the study group.

Statistical Analysis

T-test for independent means were used to check for any significant differences.

Data Collection Summary:

Timing of Measurements

Follow-up evaluations were based on clinical observation of the subject’s neurologic improvement, rather than on a fixed timeframe (e.g., every two weeks).

Clinical observation criteria included:

  • Improvement in oral-motor and tongue control
  • Bedside assessment of cough reflex with a brief water screening
  • Speech intelligibility improvement
  • Overall neurologic improvement
  • Reduced drooling and pocketing
  • Increased laryngeal evaluation
  • Improved bolus control
  • Vocal quality noted during meals.

Dependent Variables

  • Occurrence of aspiration pneumonia
  • Occurrence of dehydration
  • The need for intravenous fluids
  • The amounts of thickened liquids and water consumed
  • The length of time from X-ray documentation of aspiration to the endpoint of no documented aspiration on videofluoroscopic evaluation
  • Patient satisfaction (measured by a multiple-response questionnaire).

Independent Variables

Administration of water, with all other liquids thickened to a level at which no aspiration was noted on the videofluoroscopic evaluation.

Control Variables

The control group (10 patients) received only thickened liquids.
Description of Actual Data Sample:
  • Initial N: Twenty patients
  • Attrition (final N): Not discussed.


Mean Age



CVA Type

Consistency of Aspiration (Percentage of Swallows)

Protective Cough Reflex at Vocal Folds?

Cough Reflex Functional?

When Did Aspiration Occur

Interval Post-Stroke (Mean Days)

Control Group (Thickened Liquids Only)


77.5 years

Male: 8

Female: 2

Euro-American, 10

Right hemisphere: 2

Brain stem: 4

Left hemisphere: 3

Bilateral: 1

Consistent (>50% of swallows): 5

Inconsistent (10-50% of swallows): 2

Infrequent (<10% of swallows): 3

No: 7

Yes: 3

No: 8

Yes: 2

During swallow: 6

Before swallow: 2

Before, during and after swallow: 1

Before and during swallow: 1


Study Group (Thickened Liquids Plus Free Water)


Male: 6

Female: 4

Euro-American: 10

Right Hemisphere: 3

Brain Stem: 1

Left hemisphere: 6

Consistent (>50% of swallows): 1

Inconsistent (10-50% of swallows): 3

Infrequent (<10% of swallows): 6

No: 5

Yes: 5

No: 7

Yes: 3

During swallow: 6

Before and During Swallow: 1

During and After Swallow: 2

(*Note-only 9 reported)


  • Location: Bethesda Lutheran Hospital and Rehabilitation Center.
Summary of Results:


Mean Interval Post-Stroke Days

Length of Time in Study Prior to Reaching End Point of No Aspiration (Mean Days)

Length of Time Post Stroke to End Point of No Aspiration (Days)

Average Number of Follow-Up Videofluroscopic Exams Prior to End Point

Mean Thickened Liquid Intake per Day (cc)**

Water Intake per Day (cc)

Total Liquid Intake per Day (cc)



Need for IV Fluids

Control Group (Thickened Liquids Only)


11.8 (range, 4-17 days)

27.2 (range, 8-64 days)

39.0 (range, 20-77 days)

1.6 (24.3 days)

1,210cc (range, 400-1,800 cc/day)


1,210cc (range, 400-1800 cc/day)




Study Group (Thickened Liquids Plus Free Water)

13.8 (range, 7-17 days)

19.1 (range, 7-35 days)

32.9 (range, 15-46 days)

1.3 (25.3 days)

855cc (range, 640-1,173cc/day)

463cc (range, 200-800cc/day)

1,318cc (range, 800-1,900 cc/day)




**A significant difference (P=0.03) was found between groups on average daily intake of thickened liquids.

Other Findings

  • Only one patient in the control group reported satisfaction with thickened liquids
  • None of the study group reported satisfaction with thickened liquids
  • All of the study group subjects reported high satisfaction with access to water.
Author Conclusion:
  • No one in either group developed aspiration pneumonia, dehydration or complications during the study or during a 30-day follow-up period
  • The amount of water intake was not higher than the amounts of thickened intake for any given subject
  • Even though there was a significant difference noted in the amount of thickened liquids consumed between groups, the amount of water taken by the study group was considerably less than expected by the research team
  • A follow-up satisfaction survey indicated that all subjects in the study group were highly pleased to have had access to water.
Funding Source:
University/Hospital: Bethesda Lutheran Hospital Rehabilitation Center, University of Alabama
Reviewer Comments:
Discussion noted the sample size was limited due to the numerous subjects who declined participation (34) or did not meet inclusion criteria (94). Because of such a small sample size, many of the results showed no significant difference.
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? No
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) Yes
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? N/A
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? N/A
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? N/A
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? No
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) Yes
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? Yes
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? No
  6.6. Were extra or unplanned treatments described? No
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? ???
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? Yes
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? No
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? No
  10.2. Was the study free from apparent conflict of interest? Yes