ABSTRACT
Background: The indications for Long Term Ventilation (LTV) are expanding. Pneumonia is common in these patients and transmission of bacterial infections, and more recently COVID-19 infection, between users of ventilators is a concern. UK national standards recommend bacterial/viral filters for use with acute Non-Invasive Ventilation (NIV) to protect the ventilator from contamination. However, there are no recommendations made for LTV. UK National guidance also explicitly states that there is no airflow from the patient to the ventilator.1 Aims and objectives: To investigate whether exhaled gas reaches the ventilator outlet. Method(s): We conducted experiments on three ventilators with different circuits during NIV delivered to a member of the study team using standard clinical settings. We used a side-stream end tidal CO2 (EtCO2) analyser attached to the tubing adjacent to the ventilator outlet as shown in the figure. Result(s): Regardless of ventilator and circuit used we demonstrated that exhaled gas reaches the ventilator outlet during NIV. EtCO2 values were 1.6-3.7kPa. Conclusion(s): Exhaled gas reaches the ventilator outlet during NIV. This raises an urgent requirement within the LTV community to test ventilators for bacterial and viral colonisation, consider the use of bacterial/viral filters, and discuss routine decontamination of these devices between individual patient uses. (Figure Presented).
ABSTRACT
Introduction: Pneumothorax and pneumomediastinum have both been noted to complicate cases of coronavirus disease 2019 (COVID-19) requiring hospital admission. We report the largest case series yet described of patients with both these pathologies (including nonventilated patients). Methods: Cases were collected retrospectively from UK hospitals with inclusion criteria limited to a diagnosis of COVID-19 and the presence of either pneumothorax or pneumomediastinum. Patients included in the study presented between March and June 2020. Details obtained from the medical record included demographics, radiology, laboratory investigations, clinical management and survival. Results: 71 patients from 16 centres were included in the study, of whom 60 had pneumothoraces (six with pneumomediastinum in addition) and 11 had pneumomediastinum alone. Two of these patients had two distinct episodes of pneumothorax, occurring bilaterally in sequential fashion, bringing the total number of pneumothoraces included to 62. Clinical scenarios included patients who had presented to hospital with pneumothorax, patients who had developed pneumothorax or pneumomediastinum during their inpatient admission with COVID-19 and patients who developed their complication while intubated and ventilated, either with or without concurrent extracorporeal membrane oxygenation. Survival at 28 days was not significantly different following pneumothorax (63.1 +/- 6.5%) or isolated pneumomediastinum (53.0 +/- 18.7%;p=0.854). The incidence of pneumothorax was higher in males. 28-day survival was not different between the sexes (males 62.5 +/- 7.7% versus females 68.4 +/- 10.7%;p=0.619). Patients aged >= 70 years had a significantly lower 28-day survival than younger individuals (>= 70 years 41.7 +/- 13.5% survival versus <70 years 70.9 +/- 6.8% survival;p=0.018 log-rank). Conclusion: These cases suggest that pneumothorax is a complication of COVID-19. Pneumothorax does not seem to be an independent marker of poor prognosis and we encourage continuation of active treatment where clinically possible.