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Title: The role of HFNC and NIV prior Mechanical Ventilation in Critical COVID-19 pneumonia
INTRODUCTION/HYPOTHESIS,
We aimed to determine the mortality risk associated with delaying intubation with High Flow Nasal Cannula (HFNC) and Non-invasive ventilation (NIV) in the setting of critical COVID-19 pneumonia patients that required mechanical ventilation.
METHODS,
A single-center retrospective study. Data were collected for Covid-19 patients that required mechanical ventilation between March 5th, 2020 to March 31st, 2021. Intubated for a different reason other than respiratory failure, mechanical ventilation that lasts less than 24 hours or palliative extubated were excluded from the analysis. All patients were discharged alive or deceased. HFNC or NIV was used to delay endotracheal intubation (ET); the decision for ET was taken for the primary team supported by clinical experience and guidelines from our institution during the pandemic. Kaplan Meier analysis was conducted to determine survival rate and Cox Proportional Hazard regression to determine mortality risk associated with delaying intubation.
RESULTS,
Of 520 patients that required mechanical ventilation due to Covid-19 infection, 477 (91.7%) were included in the analysis. 139 (29.1%) underwent delaying intubation with HFNC/NIV with a median time to intubation of 2.9 (IQR,0.78-6.16) days, longer compared with the non-intervention group, 0.42 (IQR, 0.11-2.0) days. Patients with delaying intubation had a median time to survive of 15.5 (13.1-18.0) days, while the non-intervention group had a median time of 10.8 (9.1-12.4) days. The prior use of HFNC/NIV reduced mortality risk by 21% (HR 0.79, 95%CI, 0.63-0.98, p=0.036) for mechanically ventilated patients in the regression analysis; when the model is adjusted to baseline characteristics (age, sex, and BMI) or risk factor/confounders (comorbidities, Apache score, ARDS, vasopressors, Mechanical ventilation days) the protective effect remain significant; 0.73 (0.58-0.92,p=0.007) and 0.58 (0.46-0.73, p=0.001) respectively.
CONCLUSION,
The use of HFNC or NIV prior to Mechanical Ventilation decreases the risk of self-inflicted lung injury during spontaneous breathing preventing excessive changes in volume/pressure, lowering inspiratory effort, unloading the respiratory muscle, and improving oxygenation parameters which confer mortality risk reduction and a longer survival rate in this cohort.