Silent Aspiration: What Do We Know?

Ramsey, Deborah; Smithard, David; Kalra, Lalit

doi:10.1007/s00455-005-0018-9

Cited by 211 publications

(143 citation statements)

References 68 publications

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“…Keywords Deglutition Á Deglutition disorders Á Aspiration Á Aspiration risk Á Swallow screening Silent aspiration, i.e., aspiration that occurs with no coughing or other overt signs of disordered swallowing despite evidence of material below the level of the true vocal folds [1], is a crucial factor in dysphagia diagnostics and relevant to both the clinical (bedside) swallow screen and objective dysphagia evaluation, but for different reasons. While silent aspiration cannot be determined simply with a clinical swallow screen [2,3], objective identification of silent aspiration, by either videofluoroscopy swallowing study (VFSS) or fiberoptic endoscopic evaluation of swallowing (FEES), is important for diagnostic precision [4] and optimal dysphagia management [5].…”

mentioning

confidence: 99%

Silent Aspiration Risk is Volume-dependent

Leder

Suiter²,

Green

2010

Dysphagia

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Clinical swallow protocols cannot detect silent aspiration due to absence of overt behavioral signs, but screening with a much larger bolus volume, i.e., 90 cc vs. 1-10 cc, may elicit a reflexive cough in individuals who might otherwise exhibit silent aspiration. A swallow screen that maintains high sensitivity to identify aspiration risk while simultaneously reducing the false-negative rate for silent aspiration would be beneficial. The purpose of this study was to investigate whether silent aspiration risk was volume-dependent by using a 3-oz. (90-cc) water swallow challenge to elicit a reflexive cough when silent aspiration occurred on smaller bolus volumes. A prospective, consecutive, referral-based sample of 4102 inpatients from the acute-care setting of a large urban tertiary-care teaching hospital participated. Silent aspiration was determined first by fiberoptic endoscopy and then each participant was instructed to drink 3 oz. of water completely and without interruption. Criteria for challenge failure were inability to drink the entire amount, stopping and starting, or coughing and choking during or immediately after completion. Improved identification of aspiration risk status occurred for 58% of participants who exhibited silent aspiration on smaller volumes, i.e., an additional 48% of liquid silent aspirators and 65.6% of puree silent aspirators coughed when attempting the 3-oz. water swallow challenge. A low false-negative rate was observed for the entire population sample, i.e., ≤2.0%. A combined false-negative rate for participants who silently aspirated was 6.9%, i.e., 7.8% if silently aspirated liquid and 6.1% if silently aspirated puree consistency. Determination of silent aspiration risk was shown to be volume-dependent, with a larger volume eliciting a reflexive cough in individuals who previously silently aspirated on smaller volumes. A 3-oz. water swallow challenge's previously reported high sensitivity for identification of aspiration risk combined with the newly reported low false-negative rate mitigates the issue of silent aspiration risk during clinical swallow screening.

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mentioning

confidence: 99%

Silent Aspiration Risk is Volume-dependent

Leder

Suiter²,

Green

2010

Dysphagia

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“…SA can cause aspiration pneumonia in the elderly [8]. Patients with laryngeal penetration, tracheobronchial aspiration, or silent tracheobronchial aspiration were approximately 4 times, 10 times, and 13 times, respectively, more likely to develop pneumonia than those with normal swallowing [9].…”

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confidence: 99%

Screening Test for Silent Aspiration at the Bedside

et al. 2008

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Many screening tests for dysphagia can be given at bedside. However, they cannot accurately screen for silent aspiration (SA). We studied the usefulness of a cough test to screen for SA and combined it with the modified water swallowing test (MWST) to make an accurate screening system. Patients suspected of dysphagia (N = 204) were administered a cough test and underwent videofluorography (VF) or videoendoscopy (VE). Sensitivity of the cough test for detection of SA was 0.87 with specificity of 0.89. Of these 204 patients, 107 were also administered the MWST. Fifty-five were evaluated as normal by the screening system, 49 of whom were evaluated as normal by VF or VE. Sixteen were evaluated as "SA suspected" by the screening system; seven of them were normal, and seven were evaluated as having SA by VF or VE. Nineteen were evaluated as aspirating with cough, 14 of whom had aspiration with cough as shown by VF or VE. Seventeen were evaluated as having SA, 15 of whom had SA shown by VF or VE. The cough test was useful in screening for SA. Moreover, a screening system that included MWST and a cough test could accurately distinguish between the healthy who were safe in swallowing and SA patients who were unsafe.

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“…It is possible that dysphagia can occur in the absence of overt signs of swallowing diffi culty: so called "silent" aspiration [ 43 ]. Certain conditions, such as stroke or impaired cough refl ex may increase the frequency of such silent aspirations.…”

Section: Pathogenesismentioning

confidence: 99%