Pendelluft in prolonged tracheostomized patients with speaking valve is associated with the time to decannulation：a pre-post study

Abstract Objective: The aim of this study was to assess the impact of speaking valve (SV) on ventilation changes, spontaneous effort and their potential effectiveness in difficult-to-decannulate patients with diverse medical conditions. Methods:Patients with prolonged tracheostomy were included, who had been weaned from a ventilator for more than 48 hours, clinically stable and tolerance to the SV. Wearing time of the SV was extended continuously for 4 hours. Electrical impedance tomography (EIT) measurements were conducted at three time points: Tbaseline: prior to the SVs wearing; TSV ~ 3.5 hours after wearing the SVs; Tpost: 10 minutes after removal of SVs after a 4-hour SVs usage. Results: A total of 102 patients were included for the final analysis. No adverse event was recorded in ECG. Oxygenation and respiratory rate were stable. Ventilation distribution was homogeneous in some patients but not in the other after 3.5 hours SV training. Ventilation distributed towards dorsal regions during SV (p<0.001). As spontaneous effort increased during SV, EIT-derived pendelluft increased in most of the patients as well (p<0.001). The correlations between the days to decannulation and the change of EIT-based parameters were significantly correlated (p<0.001). The highest correlations were between Days and temporal ventilation heterogeneity indices (r=0.61 and 0.57, intra-tidal gas distribution and pendelluft, respectively, p<0.001). Conclusion: SV activated patients’ respiratory muscles by increasing the ventilation distribution portions in the dorsal regions, as well as introducing the temporal heterogeneity between ventral and dorsal regions. Such heterogeneity was associated with the day to decannulation.