Objective— To determine the incidence of dysphagia and associated pulmonary compromise in stroke patients through a systematic review of the published literature. Methods— Databases were searched (1966 through May 2005) using terms “cerebrovascular disorders,” “deglutition disorders,” and limited to “humans” for original articles addressing the frequency of dysphagia or pneumonia. Data sources included Medline, Embase, Pascal, relevant Internet addresses, and extensive hand searching of bibliographies of identified articles. Selected articles were reviewed for quality, diagnostic methods, and patient characteristics. Comparisons were made of reported dysphagia and pneumonia frequencies. The relative risks (RRs) of developing pneumonia were calculated in patients with dysphagia and confirmed aspiration. Results— Of the 277 sources identified, 104 were original, peer-reviewed articles that focused on adult stroke patients with dysphagia. Of these, 24 articles met inclusion criteria and were evaluated. The r...

Dysphagia After Stroke Incidence, Diagnosis, and Pulmonary Complications

Aspiration is defined as the inhalation of oropharyngeal or gastric contents into the larynx and lower respiratory tract.1,2 Several pulmonary syndromes may occur after aspiration, depending on the amount and nature of the aspirated material, the frequency of aspiration, and the host's response to the aspirated material.2 Aspiration pneumonitis (Mendelson's syndrome) is a chemical injury caused by the inhalation of sterile gastric contents, whereas aspiration pneumonia is an infectious process caused by the inhalation of oropharyngeal secretions that are colonized by pathogenic bacteria. Although there is some overlap between these syndromes, they are distinct clinical entities (Table 1). Other . . .

https://www.nejm.org/doi/pdf/10.1056/NEJM200103013440908

Aspiration Pneumonitis and Aspiration Pneumonia

https://www.archives-pmr.org/article/S0003-9993(05)00196-6/pdf

Initial Psychometric Assessment of a Functional Oral Intake Scale for Dysphagia in Stroke Patients

https://journal.chestnet.org/article/S0012-3692(15)36028-1/pdf

Aspiration pneumonia and dysphagia in the elderly.

Within the context of screening tests, it is important to avoid misconceptions about sensitivity, specificity, and predictive values. In this article, therefore, foundations are first established concerning these metrics along with the first of several aspects of pliability that should be recognized in relation to those metrics. Clarification is then provided about the definitions of sensitivity, specificity, and predictive values and why researchers and clinicians can misunderstand and misrepresent them. Arguments are made that sensitivity and specificity should usually be applied only in the context of describing a screening test’s attributes relative to a reference standard; that predictive values are more appropriate and informative in actual screening contexts, but that sensitivity and specificity can be used for screening decisions about individual people if they are extremely high; that predictive values need not always be high and might be used to advantage by adjusting the sensitivity and specificity of screening tests; that, in screening contexts, researchers should provide information about all four metrics and how they were derived; and that, where necessary, consumers of health research should have the skills to interpret those metrics effectively for maximum benefit to clients and the healthcare system.

/pdf/sensitivity-specificity-and-predictive-values-foundations-1w5bsgmxh3.pdf

Sensitivity, Specificity, and Predictive Values: Foundations, Pliabilities, and Pitfalls in Research and Practice.

To assess the frequency and natural history of swallowing problems following an acute stroke, 121 consecutive patients admitted within 24 hours of the onset of their stroke were studied prospectively. The ability to swallow was assessed repeatedly by a physician, a speech and language therapist, and by videofluoroscopy. Clinically 51% (61/121) of patients were assessed as being at risk of aspiration on admission. Many swallowing problems resolved over the first 7 days, through 28/110 (27%) were still considered at risk by the physician. Over a 6-month period, most problems had resolved, but some patients had persistent difficulties (6, 8%), and a few (2, 3% at 6 months) had developed swallowing problems. Ninety-five patients underwent videofluoroscopic examination within a median time of 2 days; 21 (22%) were aspirating. At 1 month a repeat examination showed that 12 (15%) were aspirating. Only 4 of these were persistent; the remaining 8 had not been previously identified. This study has confirmed that swallowing problems following acute stroke are common, and it has been documented that the dysphagia may persist, recur in some patients, or develop in others later in the history of their stroke.

The natural history of dysphagia following a stroke.

Objective: to investigate the ability of a bedside swallowing assessment to reliably exclude aspiration following acute stroke. Subjects: consecutive patients admitted within 24 h of stroke onset to two hospitals. Methods: a prospective study. Where possible, all patients had their ability to swallow assessed on the day of admission by both a doctor and a speech and language therapist using a standardized proforma. A videofluoroscopy examination was conducted within 3 days of admission. Results: 94 patients underwent videofluoroscopy; 20 (21%) were seen to be aspirating, although this was not detected at the bedside in 10. In 18 (22%) of the patients the speech and language therapist considered the swallow to be unsafe. In the medical assessment, 39 patients (41%) had an unsafe swallow. Bedside assessment by a speech and language therapist gave a sensitivity of 47%, a specificity of 86%, positive predictive value (PPV) of 50% and a negative predictive value (NPV) of 85% for the presence of aspiration. Multiple logistic regression was used to identify the optimum elements of the bedside assessments for predicting the presence of aspiration. A weak voluntary cough and any alteration in conscious level gave a sensitivity of 75%, specificity of 72%, PPV of 41% and NPV of 91% for aspiration. Conclusion: bedside assessment of swallowing lacks the necessary sensitivity to be used as a screening instrument in acute stroke, but there are concerns about the use of videofluorosc opy as a gold standard. The relative importance of aspiration and bedside assessment in predicting complications and outcome needs to be studied.

Can bedside assessment reliably exclude aspiration following acute stroke

We have assessed the measurement of oxygen saturation (SaO2) as a means of detecting aspiration in patients with stroke. For 10 weeks all acute stroke [AS] admissions were seen within 48 hours. Basal SaO2 was measured by pulse oximetry. Patients swallowed 10ml water while sitting up and SaO2 was noted for 2 minutes. Two control groups [young, fit (YF) and inpatient age- and sex-matched, non-neurological disease (IP)] underwent the same assessment. AS subjects underwent independent assessment of swallowing by a speech and language therapist (SLT). Exclusion criteria comprised impaired consciousness, other neurological disease and chest infection. Forty-nine AS subjects [20 men; aged 46-93 (mean 71) years], 55 YF [26 men; aged 18-55 (mean 32) years] and 65 IP [28 men; aged 53-96 (mean 71) years] were studied. Mean (SD) SaO2 fall in AS subjects [2.6 (2.9)%)] was significantly more than in YF [1.1 (0.8)%] or IP [1.1 (0.9)%]. The lower 95% confidence limit for variation in SaO2 did not differ between YF and IP (3.0% 'fall'); 19 (39%) AS subjects desaturated below this 95% lower confidence limit. Mean (SD) SaO2 fall was significantly more in SLT-graded 'aspirators' [4.6 (2.7)%] than 'nonaspirators' [1.4 (1.0)%]. We conclude that (1) a fall in SaO2 on swallowing fluid is common in patients with acute stroke; (2) the presence or absence of desaturation agrees statistically with SLT assessment of aspiration; (3) SaO2 measures may aid bedside assessment of swallowing.

Oxygen Desaturation on Swallowing as a Potential Marker of Aspiration in Acute Stroke

This pilot study investigated the effect of oral electrical stimulation on swallow function in stroke patients with chronic dysphagia. The purpose was to determine whether an innovative technique could make an improvement in swallow function that might be developed as a potential treatment for patients with persistent dysphagia. Four stroke patients with chronic dysphagia were recruited on the basis of videofluoroscopic findings of a delayed swallow reflex. A single case design was used. Oral electrical stimulation of swallowing was carried out using a palatal prosthesis starting at an output pulse of 0.5 mA, with a fixed duration of 200 μsec, repeated at 1-sec intervals. Barium paste (1 × 5 ml) was introduced at the level of the patient's maximum tolerance of stimulation and any effect on swallow function was recorded by videofluoroscopy. The findings from the pilot study indicated that oral electrical stimulation resulted in an improvement in swallow function in 2 of the 4 patients. The stimulation was well tolerated in all cases with no serious adverse effects. These early results are promising, but further research is needed.

C Park

Papers

The natural history of dysphagia following a stroke.

Can bedside assessment reliably exclude aspiration following acute stroke

Oxygen Desaturation on Swallowing as a Potential Marker of Aspiration in Acute Stroke

A Pilot Exploratory Study of Oral Electrical Stimulation on Swallow Function following Stroke: An Innovative Technique