Neurostimulation therapies improve swallowing function in acutely ill patients with a standardized mean difference of -0.74

This systematic review and network meta-analysis assessed the efficacy of various neurostimulation therapies for dysphagia in acutely and critically ill patients. The analysis included 2198 patients across acute and critical care settings. Interventions examined included transcutaneous auricular vagus nerve stimulation, neuromuscular electrical stimulation, repetitive transcranial magnetic stimulation, transcranial direct current stimulation, and pharyngeal electrical stimulation. These were compared against traditional dysphagia therapy, usual care, or sham stimulation. The review utilized both pairwise and network meta-analysis methods to synthesize data on swallowing function and related clinical outcomes.

The primary outcome measured was swallowing function post-treatment. The analysis demonstrated a significant improvement in this metric with a standardized mean difference of -0.74. The 95% confidence interval for this effect size ranged from -0.90 to -0.58. This improvement was observed across the pooled data from the included studies. Secondary outcomes included the rate of patients regaining the ability to take food orally, pneumonia incidence, aspiration events, decannulation rates, and hospital stay duration.

Regarding the rate of patients regaining the ability to take food orally, the data showed an increase in this outcome. The risk ratio was 1.39 with a 95% confidence interval of 1.12 to 1.74. This suggests a statistically significant benefit for the intervention group compared to controls. Swallowing function was also evaluated at specific follow-up intervals of 1 month, 2 months, and 3 months. At 1 month, swallowing function was enhanced with a standardized mean difference of -1.28 and a 95% confidence interval of -1.76 to -0.81. At 2 months, the enhancement was more pronounced with a standardized mean difference of -2.24 and a 95% confidence interval of -3.25 to -1.23.

At the 3-month follow-up, swallowing function showed no significant improvement. The standardized mean difference was -0.43 with a 95% confidence interval of -1.08 to 0.22. Pneumonia incidence was reduced in the intervention group with a risk ratio of 0.62 and a 95% confidence interval of 0.39 to 0.98. However, the analysis found no significant improvement in decannulation rates with a risk ratio of 3.47 and a wide 95% confidence interval of 0.60 to 20.23. Aspiration post-intervention showed no significant reduction with a risk ratio of 0.67 and a 95% confidence interval of 0.36 to 1.26. Hospital stays showed no significant shortening with a mean difference of -1.74 and a 95% confidence interval of -4.78 to 1.30.

Safety and tolerability data were not reported for the included studies. Serious adverse events, discontinuations, and general tolerability metrics were not provided in the source data. The authors noted that the efficacy of transcutaneous auricular vagus nerve stimulation combined with traditional dysphagia therapy requires further investigation as supported by only one study. This limitation highlights the need for more robust safety data in future research. The heterogeneity of the neurostimulation modalities reviewed also complicates direct comparisons between specific techniques.

Clinical implications suggest that neurostimulation therapies may offer a potential adjunct to traditional dysphagia therapy for acutely ill patients. The most potentially effective therapy may be neuromuscular electrical stimulation combined with traditional dysphagia therapy, though this conclusion is tentative. Practitioners should consider these findings when evaluating options for patients with dysphagia in critical care. However, the lack of safety reporting and the limited number of studies for specific interventions like ta-VNS necessitate caution. Questions remain regarding the long-term sustainability of benefits beyond 3 months and the optimal protocols for different patient subgroups.