Failure of First Transition to Pressure Support Ventilation After Spontaneous Awakening Trials in Hypoxemic Respiratory Failure: Influence of COVID-19.

OBJECTIVES: To describe the rate of failure of the first transition to pressure support ventilation (PSV) after systematic spontaneous awakening trials (SATs) in patients with acute hypoxemic respiratory failure (AHRF) and to assess whether the failure is higher in COVID-19 compared with AHRF of other etiologies. To determine predictors and potential association of failure with outcomes.

DESIGN: Retrospective cohort study.

SETTING: Twenty-eight-bedded medical-surgical ICU in a private hospital (Argentina).

PATIENTS: Subjects with arterial pressure of oxygen (AHRF to Fio2 [Pao2 /Fio2 ] < 300 mm Hg) of different etiologies under controlled mechanical ventilation (MV).

INTERVENTIONS: None.

MEASUREMENTS AND MAIN RESULTS: We collected data during controlled ventilation within 24 hours before SAT followed by the first PSV transition. Failure was defined as the need to return to fully controlled MV within 3 calendar days of PSV start. A total of 274 patients with AHRF (189 COVID-19 and 85 non-COVID-19) were included. The failure occurred in 120 of 274 subjects (43.7%) and was higher in COVID-19 versus non-COVID-19 (49.7% and 30.5%; p = 0.003). COVID-19 diagnosis (odds ratio [OR]: 2.22; 95% CI [1.15-4.43]; p = 0.020), previous neuromuscular blockers (OR: 2.16; 95% CI [1.15-4.11]; p = 0.017) and higher fentanyl dose (OR: 1.29; 95% CI [1.05-1.60]; p = 0.018) increased the failure chances. Higher BMI (OR: 0.95; 95% CI [0.91-0.99]; p = 0.029), Pao2 /Fio2 (OR: 0.87; 95% CI [0.78-0.97]; p = 0.017), and pH (OR: 0.61; 95% CI [0.38-0.96]; p = 0.035) were protective. Failure groups had higher 60-day ventilator dependence ( p < 0.001), MV duration ( p < 0.0001), and ICU stay ( p = 0.001). Patients who failed had higher mortality in COVID-19 group ( p < 0.001) but not in the non-COVID-19 ( p = 0.083).

CONCLUSIONS: In patients with AHRF of different etiologies, the failure of the first PSV attempt was 43.7%, and at a higher rate in COVID-19. Independent risk factors included COVID-19 diagnosis, fentanyl dose, previous neuromuscular blockers, acidosis and hypoxemia preceding SAT, whereas higher BMI was protective. Failure was associated with worse outcomes.