Chest
Volume 135, Issue 3, March 2009, Pages 769-777
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Original Research
Cough
Predicting Aspiration in Patients With Ischemic Stroke: Comparison of Clinical Signs and Aerodynamic Measures of Voluntary Cough

https://doi.org/10.1378/chest.08-1122Get rights and content

Background

Clinical signs often fail to identify stroke patients who are at increased risk of aspiration. We hypothesized that objective measure of voluntary cough would improve the accuracy of the clinical evaluation of swallow to predict those patients who are at risk.

Methods

A comprehensive diagnostic evaluation was completed for 96 consecutive stroke patients that included cognitive testing, a bedside clinical swallow examination, aerodynamic and sound pressure level measures of voluntary cough, and “gold standard” instrumental swallowing studies (ie, videofluoroscopic evaluation of swallow [VSE] or fiberoptic endoscopic evaluation of swallow [FEES]). Stroke severity was assessed retrospectively using the Canadian neurologic scale.

Results

Based on the findings of VSE/FEES, 33 patients (34%) were at high risk of aspiration and (66%) were nonaspirators. Clinical signs (eg, absent swallow, difficulty handling secretions, or reflexive cough after water bolus) had an overall accuracy of 74% with a sensitivity of 58% and a specificity of 83% for the detection of aspiration. Three objective measures of voluntary cough (expulsive phase rise time, volume acceleration, and expulsive phase peak flow) were each associated with an aspiration risk category (areas under the curves were 0.93, 0.92, and 0.86, respectively). Expulsive phase rise time > 55 m/s, volume acceleration < 50 L/s/s, and expulsive phase peak flow < 2.9 L/s had sensitivities of 91%, 91%, and 82%, respectively; and specificities of 81%, 92%, and 83%, respectively for the identification of aspirators.

Conclusion

Objective measures of voluntary cough can identify stroke patients who are at risk for aspiration and may be useful as an adjunct to the standard bedside clinical assessment.

Section snippets

Materials and Methods

Subjects were consecutive consenting patients who had recently experienced an ischemic stroke who were admitted to the Durham (NC) Veterans Affairs Medical Center (DVAMC) between November 2000 and November 2002 in whom the necessary tests could be scheduled (n = 96). Patients with a history of radiation therapy to the head and neck, brain tumor, or brain surgery were excluded. The Institutional Review Board of the DVAMC approved the study protocol.

Subject characteristics including comorbidities

Results

The results of the VSE or FEES are listed in Table 1. Thirty-three subjects (34%) were classified as being at high risk for aspiration (penetration aspiration scale score, ≥ 5), and 63 subjects were nonaspirators (penetration aspiration scale score, ≤ 4). The interrater reliability for the instrumental swallow evaluations was 0.88 (95% confidence interval [CI], 0.82 to 0.92), reflecting excellent agreement.

Table 2 summarizes the subjects' demographic and clinical characteristics categorized by

Discussion

The primary finding of this analysis is that two of the objective measures of voluntary cough, expulsive phase rise time and volume acceleration, are independently associated with aspiration risk as measured by the VSE or FEES, which are tests generally considered to be “gold standards.” The prevalence of aspiration in this cohort was consistent with that reported in other studies4, 5, 6 of similarly aged acute stroke patients that also used the VSE, suggesting that our results are likely

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    This study was supported by the Department of Rehabilitation, Research and Development Service, Veterans Affairs National Headquarters.

    The authors have reported to the ACCP that no significant conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

    Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).

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