Cough Reflex Testing in Dysphagia Following Stroke: A Randomized Controlled Trial

Abstract

BackgroundSignificant health issues and service delivery costs are associated with post-stroke pneumonia related to dysphagia. Silent aspiration is known to increase pneumonia and mortality in this population. The utility of cough reflex testing (CRT) for reducing pneumonia in acute stroke patients was the subject of this randomised, controlled trial.MethodsPatients referred for swallowing evaluation (N = 311) were assigned to either 1) a control group receiving standard evaluation or 2) an experimental group receiving standard evaluation with CRT. Participants in the experimental group were administered nebulised citric acid with test results contributing to clinical decisions. Outcomes for both groups were measured by pneumonia rates at 3 months post evaluation and other clinical indices of swallowing management.ResultsAnalysis of the data identified no significant differences between groups in pneumonia rate (P = 0.38) or mortality (P = 0.15). Results of CRT were shown to influence diet recommendations (P < 0.0001) and referrals for instrumental assessment (P < 0.0001).ConclusionsDespite differences in clinical management between groups, the end goal of reducing pneumonia in post stroke dysphagia was not achieved.

Effect of Dysphagia Screening Strategies on Clinical Outcomes After Stroke: A Systematic Review for the 2018 Guidelines for the Early Management of Patients With Acute Ischemic Stroke

“…11 That group also pointed out that the absence of consensus for a single best screening method does not mean that no screening should be performed. 11 Our review complements this work by showing that no recently published RCTs have compared different dysphagia screening methods for their ability to reduce death, dependency, or pneumonia, except for 1 single-center RCT 14 that failed to find evidence that screening with the cough reflex test reduced rates of pneumonia or death.…”

“…14 In the cough reflex test, nebulized citric acid was delivered by face mask, which normally induces a reflexive cough. If the test was failed, subsequent management was left to the treating physician.…”

“…[13][14][15] Interpretation of 2 of the trials, including the largest highest-quality trial, 13 was confounded by other concurrent quality improvement interventions. 13,15 One trial showed no difference in the rates of pneumonia in patients randomized to receive the cough reflex test.…”

Measuring voluntary and reflexive cough strength in healthy individuals

“…In a recent study conducted by Miles, Zeng, McLauchlan, & Huckabee (2013) Addington, Stephens, Widdicombe, & Rekab (2005) highlighted that strength of coughing is an important factor in identifying risk of aspiration pneumonia, as they found that 10% of stroke patients that were rated as having a weak cough went on to develop aspiration pneumonia compared with 15% of patients that were rated as having an 'absent' cough reflex. However, they did not provide clear definition as to what they meant by weak or how this rating was given.…”

An Investigation into the Stability and Sterility of Citric Acid Solutions Used for Cough Reflex Testing

“…Nebulised citric acid solution is used as a chemical irritant in cough reflex testing to identify patients at risk of developing aspiration pneumonia as a consequence of swallowing difficulties [1][2][3][4][5][6]. Inhaled citric acid is used in both respiratory medical practice and research to evaluate cough reflex sensitivity [7][8][9][10][11].…”