Tracheostomy in children promotes persistent neutrophilic airway inflammation

Background Tracheostomies in children are associated with significant morbidity, poor quality of life, excess healthcare costs, and excess mortality. The underlying mechanisms facilitating adverse outcomes in tracheostomised children are poorly understood. We aimed to characterise airway host defence in tracheostomised children using serial molecular analyses. Methods Tracheal aspirates, tracheal cytology brushings, nasal swabs and stool samples were prospectively collected from children with a tracheostomy and controls. Transcriptomic, proteomic, and metabolomic methods were applied to characterise the impact of tracheostomy on host immune response and the airway microbiome. Results Children followed up serially from the time of tracheostomy up to three months post-procedure (n=9) were studied. A validation cohort of children with a long-term tracheostomy was also enrolled (n=24). Controls (n=13) comprised children without a tracheostomy undergoing bronchoscopy. Tracheostomy was associated with new, rapidly emergent and sustained airway neutrophilic inflammation, superoxide production and evidence of proteolysis when compared with controls. In contrast, reduced airway microbial diversity was established pre-tracheostomy and sustained thereafter. Conclusions Childhood tracheostomy is associated with rapidly emergent and persistent airway neutrophil recruitment and activation, with sustained proteolysis and superoxide generation. These findings suggest neutrophil recruitment and activation as potential exploratory targets in seeking to prevent recurrent airway complications in this vulnerable group of patients. Key message The effect tracheostomy has on children is not described. Tracheostomy in children results in persistent local airway neutrophilic inflammation, proteolysis, superoxide production and dysbiosis. ### Competing Interest Statement MB: Not related to this work: investigator-led research grants from Pfizer and Roche Diagnostics; speaker fees paid to Newcastle University from Novartis, Roche Diagnostics and TEVA. Travel expenses to educational meetings Boehringer Ingelheim and Vertex Pharmaceuticals. Other authors: None. ### Funding Statement This study was funded by; Academy of Medical Sciences Grant SGL020\1003; Newcastle University Wellcome Trust Institutional Strategic Support Fund; Newcastle Hospitals Charity; SHIELD consortium; Barbour Foundation. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics committee of Yorkshire & The Humber (Reference 19/YH/0061) gave ethical approval for this work I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors