Widely used in New Zealand and Japan, cough reflex testing is an objective measure of the sensation on cranial nerve ten (Vagus) that is only being used in a handful of UK hospitals to date.
Following strict protocols and adherence to the Medicines Administration Code, Citric acid is nebulised and administered to the patient and, because it is a laryngeal irritant, albeit very short lasting, this should cause a strong cough response.
Failure to cough indicates that there is reduced sensation in the larynx and this has been linked through research to increased chances of silent aspiration and pneumonia. An intact cough reflex helps the Speech and Language Therapist to trust the bedside assessment without fear of silent aspiration; confidence in the recommendations for these patients is much increased.
The patients who fail CRT are kept nil-by-mouth, as any bedside assessment will not identify silent aspiration, and instead they go to videofluoroscopy for their initial swallow assessment. All new patients admitted to the Acute Stroke Unit who need a swallow assessment receive cough reflex testing as part of the cranial nerve examination.
As a result, patients who passed, have been able to eat and drink suitable textures and sufficient amounts more quickly because the SLTs knew that aspiration would be indicated by coughing. For those that failed CRT, they have been kept safe from the consequences of silently aspirating oral intake they may otherwise have been recommended.