The outcome and predictors of mortality in patients transitioned to invasive mechanical ventilation after non-invasive ventilation failure

Background: Despite its considerable efficiency, the application of Non-Invasive Ventilation (NIV) in patients with Acute Respiratory Failure (ARF) is associated with a significant risk of failure. The literature investigating outcomes of subjects transitioned to Invasive Mechanical Ventilation (IMV) after NIV failure suggests that patients may experience a high in-hospital mortality and prolonged hospitalization. Aims and objectives: To evaluate outcome of a population of patients transitioned from NIV to IMV and investigate what single or combination of factors may signal an increased risk of ICU mortality. Methods: Design : A retrospective analysis of outcomes in 145 pts being administered IMV for ARF after NIV failure. Setting : A 4 bed Respiratory Intensive Care Unit (RICU) in a university hospital. Outcome measures : Mortality rate during RICU stay. Survival rate following transition to IMV was also evaluated. Variables potentially useful in predicting RICU mortality were analyzed. Results: 76 out of 145 pts died during RICU stay (52.4%). The median survival after transition to IMV was 45d (95%CI:27-56) and was similar to that of 20 patients who refused transition to IMV [33d (95%CI: 8-47); p=0.19]. 25% of pts died within 14 days (95%CI:7-20) and 75% within 395 days (95%CI:162-876). Low levels of PaO 2 / FiO 2 and MAP at intubation and the diagnosis of Interstitial Lung Disease (ILD) were independent predictors of increased risk of RICU mortality. Conclusions: The outcome of patients transitioned to IMV is quite poor. Low oxygenation and hemodynamic instability at intubation and the diagnosis of ILD are simple markers for increased risk of death.