Endotracheal Tube Obstruction Among Patients Mechanically Ventilated for ARDS Due to COVID-19: A Case Series

Background: Patients with COVID-19 and ARDS on prolonged mechanical ventilation are at risk for developing endotracheal tube (ETT) obstruction that has not been previously described in patients with ARDS due to other causes. The purpose of this report is to describe a case series of patients with COVID-19 and ARDS in which ETT occlusion resulted in significant clinical consequences and to define the pathology of the obstructing material. Methods: Incidents of ETT occlusion during mechanical ventilation of COVID-19 patients were reported by clinicians and retrospective chart review was conducted. Statistical analysis was performed comparing event rates between COVID-19 and non-COVID 19 patients on mechanical ventilation over the predefined period. Specimens were collected and submitted for pathological examination. Findings: Eleven COVID-19 patients experienced endotracheal tube occlusion over a period of 2 months. Average age was 69 (14.3, range 33-85) years. Mean APACHE III score was 73.6 (17.3). All patients had AKI and cytokine storm. Nine exhibited biomarkers for hypercoagulability. Average days on mechanical ventilation before intervention for ETT occlusion was 14 (5.18) days (range of 9 to 23 days). Five patients were discharged from the ICU, and 4 expired. Average documented airway resistance on admission was 14.2 (3.0) cm H2O/L/sec. Airway resistance before tube exchange was 28.1 (8.0) cm H2O /L/sec. No similar events of endotracheal tube occlusion were identified in non-COVID patients on mechanical ventilation during the same time period. Microscopically, the material consisted of mucin admixed with necrotic cell debris, variable numbers of degenerated inflammatory cells, oral contaminants and red blood cells. Interpretation: Patients with COVID-19 and ARDS on prolonged mechanical ventilation are at risk for developing ETT obstruction due to deposition of a thick, tenacious material within the tube that consists primarily of mucin and cellular debris. Clinicians should be aware of this dangerous but treatable complication.