• Understanding how airway injury can lead to long-term breathing difficulties.

    Dr Emma Dorris is a senior postdoctoral researcher working on Dr Madeline Murphy (Principal Investigator in the the Conway Institute and School of Medicine, UCD) and Mr John Russell’s (Consultant Paediatric Otolaryngologist at CHI, Crumlin) NCRC funded paediatric research project “Investigation into prevention of fibrotic scar formation as treatment for subglottic stenosis”. Emma, John, and Madeline recently published a review article entitled “Post-Intubation Subglottic Stenosis: Aetiology at the Cellular and Molecular Level” in the journal “European Respiratory Review”.

    You can read Emma’s plain English summary of the review article below.

    Lay Summary

    When a person requires assistance breathing due to a critical illness or surgery, they may have a small tube placed into their airways to help them breathe. This process is called intubation which allows air to move into and out of the lungs. Intubation is typically relatively safe. Intubation is not, however, completely risk free. Complications from intubation range from minor airway injury to severe, long-term, and potentially life-threatening complications.

    In new-born infants, the airway is so small that there are often multiple intubations attempts before the breathing tube is successfully placed. This increases the risk of serious complications. Just below the vocal cords is the narrowest and least flexible part in the airway. The presence of a breathing tube in this area, along with other factors, may cause swelling and damage to the airway tissue. If this damage does not correctly heal, it can form a scar, leading to narrowing of the airways. When this narrowing occurs just below the vocal cords, it is called subglottic stenosis; one of the most serious complications of intubation.

    Subglottic stenosis can result in partial or complete narrowing of the airway, causing serious breathing difficulties. We are researching ways to prevent this narrowing from happening. It is likely that subglottic stenosis will increase in the adult population because of the COVID-19 pandemic. The risk of subglottic stenosis increases with the length of time a person is intubated. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the associated COVID-19 respiratory distress has led to an unprecedented increase in critically ill patients requiring prolonged intubation. As such, it is likely that the cases of post-intubation subglottic stenosis will increase in the wake of COVID-19.

    In this article we review the current knowledge and discuss how intubation can affect the airway and create conditions that promote scarring, leading to subglottic stenosis. We also discuss how better understanding of the biology of disease development can be used to inform how we prevent or treat subglottic stenosis in the future.