Recommendation 1
A formalised screening for dysphagia should be performed in all stroke patients (B).
A formalised screening for dysphagia should be carried out in all acute stroke patients as part of the initial examination or upon arrival of the patient on the hospital ward/stroke unit, i.e. normally within a few hours after hospital admission. The following three methods have been evaluated in acute stroke patients and may be considered.
Water-Swallowing-Test (WST). Several different protocols have been suggested and published with the main difference being the amount of water chosen for the swallowing screening [
11‐
17]. Based on the SIGN-guidelines, a 50 ml-WST may be recommended for the use in daily routine.
In case that clinical signs of aspiration occur during the testing, the WST is considered positive. Due to the overt risk of aspiration, the patient is kept nil by mouth and more sophisticated diagnostic procedures are initiated (see below). In case the patient passes the WST, oral feeding may be started, although concrete dietary recommendations are not deducible from this test. Therefore patients should continuously be observed during feeding for the occurrence of coughing and chest infection.
Multiple-Consistency-Test. Originally published as “Gugging Swallowing Screen (GUSS)”, this multiple-consistency-test has the important advantage over the WST that it results in detailed recommendations for dietary management [
18]. The GUSS is designed as a stepwise procedure enabling a graded rating of dysphagia with separate evaluations for nonfluid and fluid textures. As a result of this test dysphagia is graded in one of four categories (severe, moderate, mild or no dysphagia). For each severity code a special diet and further strategies are recommended.
Swallowing-Provocation-Test (SPT). The swallowing-provocation-test (SPT) examines exclusively the involuntary swallowing reflex by bolus injection of 0.4 ml of distilled water through a small nasal catheter into the oropharynx. The SPT is considered normal if the time from water injection to reflexive swallowing is equal or below three seconds. If the swallowing reflex is delayed for more than three seconds, the test is abnormal and the patient is deemed to be at risk of aspiration.
During the last years, the importance of dysphagia screening in patients with acute stroke has been supported by different, methodologically heterogeneous studies. Several prospective observational studies showed associations between a pathological dysphagia screening and an increased incidence of pneumonia [
19,
20] as well as a reduction of infectious complications after implementation of a systematic screening [
20,
21]. Hinchey and co-workers found in a large prospective, multicenter, observational study (N = 2532) that acute care institutions with a formal dysphagia screening show lower rates of pneumonia and mortality than institutions without such a formal arrangement [
22].
In spite of this evidence, the impact of bed-side dysphagia screening, in particular the accuracy of the WST (Water Swallow Test) has been repeatedly questioned during recent years. Two meta-analyses of Ramsey et al. and Bours et al. suggested that when compared to VFSS (videofluorosopic swallowing study) or FEES (fiberoptic endoscopic evaluation of swallowing) the sensitivity of the WST for detecting aspiration is markedly below 80% in nearly all reviewed studies [
23,
24]. This observation also applies to specificity and negative and positive predictive values [
23,
24].
The multiple-consistency test according to the GUSS protocol has been evaluated in one prospective study [
18] and performed with a sensitivity of 100% and a specificity of 50% when compared to FEES. Therefore this test seems to be more accurate in detecting dysphagic stroke patients than all versions of the simple WST. The main disadvantage of the GUSS protocol consists in its low specificity due to which dietary recommendations may be more restrained and nasogastric tubes may be inserted more often than actually necessary.
Subsequent to two smaller and retrospective studies [
25,
26] the SPT was prospectively evaluated in a collective of acute stroke patients [
27]. When compared to FEES, the SPT had a sensitivity of 74.1% and a specificity of 100% for detecting aspiration. Due to its moderate sensitivity the SPT should not be used as stand-alone screening tool. However, given its high specificity, the SPT may be used as complement to other screening tools.
Several authors have suggested that pulse oxymetry may provide a useful non-invasive method of bedside swallowing testing [
28‐
32]. In recent times however, this assumption has been rebutted by several studies [
33‐
36]. Therefore, pulse oxymetry, whether alone or in combination with a WST, is
not recommended for bedside dysphagia screening in stroke patients.
Finally, it has been suggested that an impaired pharyngeal sensation may be a suitable predictor of aspiration risk in stroke patients [
37]. However, there is only one older study, which featured some methodological limitations, in support of this approach [
15]. Therefore, and in agreement with the conclusion of Bours and co-workers [
24], assessment of pharyngeal sensation is not recommended as screening tool for stroke-related dysphagia.