Nursing Swallow Screen Validated for Detection of Dysphagia in

Acute Stroke Patients

Janet Carlson, RN, MSN

Melissa Hofmann, PhD

Financial Disclosures

We have no disclosures

Background

• The importance of screening for dysphagia in stroke patients is well established, yet an optimal tool has not been identified.

• The CCW (cough on command, control of saliva and water swallow) Swallow Screen builds on existing data for item selection.

Purpose

The purpose of the study was to compare the CCW Swallow Screen against the Gold Standard speech language pathology (SLP) swallow evaluation for detection of dysphagia in acute stroke patients.

Definitions• Dysphagia refers to swallowing disorders.

• Swallowing screening is a pass/fail procedure to identify individuals who require a swallow evaluation for comprehensive assessment of swallowing function. Swallow screening is usually performed by registered nurses.

• A clinical swallow evaluation is a behavioral assessment of swallowing function that consists of an extensive cranial nerve evaluation and direct examination of swallowing using food and liquids of various textures and consistencies. Swallow evaluations are performed by speech language pathologists (SLP).

CCW Swallow Screen

Item Response and Direction Rationale

Item Selection and RationaleBased on Review of the Literature

Pre-screen

Patient alert,

able to follow

commands,

and sit up?

Yes No Comment:

_________________________________

If No, STOP screening and re-evaluate

patient when appropriate and before

anything PO is given.

Determine if patient can

participate.

Earlier studies included

some measure of alertness

either as a pre-screen or

initial item.

Patients failing this item

were not included in the

study

Can the patient cough

when asked?

Yes No Comment:

_______________________________

If No, STOP screening. Keep patient

NPO. Obtain order for Speech

Therapy Swallow Evaluation

Non-swallow items:

volitional cough and

control of saliva

These items had

stronger agreement

with finding of

dysphagia in two

earlier studies.

Supports safety by

identifying patients at

higher risk for

aspiration.

Patient able to maintain

control of their saliva?

Yes No Comment:

_______________________________

If No, STOP screening. Keep patient

NPO. Obtain order for Speech

Therapy Swallow Evaluation

Item Response and Direction Rationale

Patient able to

swallow a teaspoon

of water?

Yes No Comment: Water swallow:

One teaspoon of water

Water swallow protocols in earlier

studies varied in amount of water

and number of trials. Beginning with

a teaspoon of water one time

supported feasibility.

Three-ounce water swallow

Earlier studies, that required drinking

3 ounces in uninterrupted fashion,

reported high sensitivity and

moderate specificity for predicting

aspiration.

This study did not specify drinking

water in an uninterrupted fashion,

with the hypothesis that higher levels

of specificity would be achieved

without sacrificing sensitivity.

Present patient with a teaspoon of water

If no attempt to swallow, water leaks out of mouth, coughs,

exhibits choking, breathlessness, clears throat, voice becomes

wet/hoarse or makes gurgling sounds: STOP screening. Keep

patient NPO. Obtain order for Speech Therapy Swallow

Evaluation

Patient able to

drink 3 ounces of

water ?

Yes No Comment:

Present the patient with a glass of water (3 ounces)

If no attempt to swallow, water leaks out of mouth, coughs,

exhibits choking, breathlessness, clears throat, voice becomes

wet/hoarse or makes gurgling sounds: STOP screening. Keep

patient NPO. Obtain order for Speech Therapy Swallow

Evaluation

If no problem swallowing water, test patient’s ability to chew

and swallow solid food.

Item Response and Direction Rationale

Patient able to

chew and swallow

solid food?

Yes No Comment: Solid food trial

Earlier studies varied in

inclusion of solid food,

some with direction to

observe first meal after

passing swallow screen.

Included to support

earlier SLP swallow

evaluation for patients

with difficulty in

swallowing solid food.

May test with crackers.

If coughing, pocketing food, or any

symptoms of choking on the solid

food: Keep the patient NPO. Obtain

order for Speech Therapy Swallow

Evaluation

If no problems, patient may have

oral intake. Check for a diet order.

Item Response and Direction Rationale

Methods

• Using the CCW Swallow Screen and SLP swallow evaluation outcome measures, a prospective correlation study was performed on a sample of 88 acute stroke patients. (SEM = 1.63).

• Inclusion required passing the CCW pre-screen component: be alert, follow commands and sit up.

• SLP swallow evaluation was completed within 3 hours after the nurse administered CCW screen, to support concurrent criterion-related validity.

• Data analysis included sensitivity and specificity, and positive (+LR) and negative (-LR) likelihood ratios.

• Specific statistics generated included chi-square (χ2), correlation (Phi ≥ .80).

• Inter-rater reliability (IRR) was supported by prior training, testing and competency validation of nurses, plus performance monitoring during data collection. IRR was computed with Cohen’s kappa.

Demographic Characteristics of the SampleDemographic Variables Subgroups N M/SD Frequency (%)

Age - 88 71.92/15.25 -

NIHSS Score - 88 5.55/6.60 -

Time Interval (Minutes) Between

Swallow Screen and SLP Evaluation

- 88 58.45/43.67 -

GenderMale

Female

88 - 48 (55)

40 (45)

CVA TypeIschemic

Hemorrhagic

88 - 78 (89)

10 (11)

CVA Location

Right Hemisphere

Left Hemisphere

Cerebellar

Brainstem

Other

88 - 34 (39)

36 (41)

6 (7)

2 (2)

10 (11)

Hospital-Acquired Pneumonia No

Yes

88 - 85 (97)

3 (3)

Results• CCW Swallow Screen correctly detected the presence and absence of dysphagia

• Sensitivity = 84%; Specificity = 95%)

• Likelihood ratios indicated strong certainty that dysphagia was present or not present

• +LR = 16.8; -LR = 0.17

• A statistically significant association between the CCW Swallow Screen and the SLP evaluation indicated that the CCW Swallow Screen and the SLP evaluation equally measured dysphagia in this stroke sample.

• χ2 (1) = 56.66, p < .001

• The association between the two tests was found to be strong

• Phi = .80

• IRR results revealed zero variance as both raters observed and passed all nurses in perfect agreement for competency validation and data collection observation.

• IRR = 1

Results – Summary Statistics Table

Statistical Test ResultsChi-Square (𝜒2)

Estimate

df

p

56.66

1

<.001

Phi Correlation .80

Sensitivity 84%

Specificity 95%

Positive Likelihood Ratio 16.80

Negative Likelihood Ratio 0.17

Discussion

•Specificity improved to 95% with the 3-ounce water swallow not taken in an uninterrupted fashion.

•Sensitivity remained high at 84%.Sensitivity in detecting dysphagia is especially important in avoiding the risk of aspiration.

Discussion - continued•Safety of the tool supported•Hospital acquired pneumonia – 3% of sample• False negatives (4) – None had clinical findings of

aspiration pneumonia •Pre-screening and the two non-swallow items

appeared to support safety

•Testing with solid food – Important component• Four (4) subjects failed at this point, indicating need

for SLP evaluation

Limitations•24/88 subjects failed the swallow screen

•Relatively small number of subjects who failed, could be attributed to study design• Subjects who failed pre-screen were excluded• Consent requirement excluded potential subjects with

more severe strokes who were unable to consent, and did not have a legally authorized representative available within the time constraints of the study.

• These exclusions may have had an unfavorable effect on sensitivity results.

Conclusions

•The CCW Swallow Screen is a reliable, valid tool for detection of dysphagia in acute stroke patients.

•The simplicity of the tool supports feasibility in a variety of clinical settings.

•Cross validation with a similar sample is warranted.