Introduction Background/Aims Clinical evidence supports a role for carbonated liquids in reducing aspiration in dysphagic patients compared to simple water (Bulow et al Acta Radiologica, 2003). However, there are limited data on how carbonation modulates swallowing performance. Here, we investigate the effects of equi-pH carbonated and sour (citric acid) water solutions on swallowing performance using a reaction time task (Mistry et al J Physiol.2007), in healthy volunteers.

Methods Twelve healthy participants (6 male, 33±4 years, mean± SEM) visited the laboratory on three separate occasions. Subjects were asked to perform 5 consecutive measurements of swallowing behaviour with 10 normal,10 fast and 10 challenged swallows per measurement (within a pre-determined time-window). For each task, subjects swallowed each of three solutions: carbonated, sour/citric acid and still water solutions with each attendance in a randomised order. The 5 blocks of 30 swallows were repeated over a 1 hour period at 0 15, 30, 45 and 60 minutes to control for fatigue and practise confounding variables. Measurements were performed through an intra-pharyngeal catheter with built-in pressure transducers to record change in pharyngeal pressure. A pair of electrodes on the back of subject’s hand was used to deliver an electrical pulse to cue the subject when to swallow. Subjects were invited for an additional visit to complete a ‘taste intensity’ questionnaire. Data were analysed with non-parametric Wilcoxon’s test in SPSS16.

Results Mean swallowing latencies of both normal and fast swallows were not significantly different across the three different sessions. However, for the challenged swallowing task, compared to still water, carbonated water significantly improved the number of correct swallows (Z = –2.044, p = 0.041). By contrast, sour (citric acid) solutions had no effects on challenged swallowing compared water [citric acid*water (Z = –0.045, P = 0.9640)], despite being similar to carbonated water [citric acid*carbonated (Z = –1.293, p = 0.196)]. Carbonated solutions also had the highest intensity score being greater than both sour and still water [carbonated*water (Z = –3.517, P = 0.000), carbonated *citric acid (Z = –3.520, p = 0.000)].

Conclusion Carbonation appears to alter swallowing performance compared to other liquids by improvement in complex tasks and showed greatest perceived taste intensity. These data support the using of carbonation as treatment option for dysphagic patients in preventing aspiration and lay the basis for further clinical research with carbonation on swallowing function.

Disclosure of Interest None Declared

References

1. Bulow et al. Acta Radiologica., 2003

2. Mistry et al. J Physiol., 2007