Non-invasive ventilation in community acquired pneumonia

We have greatly enjoyed reading the recently published article by Al-Rajhi et al. [ ]. This retrospective cohort study was conducted among consecutive patients who received a diagnosis of community-acquired pneumonia (CAP) and needed ventilator support upon presentation to two tertiary care, university-affiliated EDs. The use of non-invasive ventilation (NIV) in severe acute respiratory failure due to CAP is controversial, and the risk factors for NIV failure in these patients are not well known. Previous reports have shown that, severity scores at admission and worse respiratory and cardiovascular function were associated with NIV failure [ , ]. Variables related with initial severity and worse clinical evolution in pneumonia, such as the need for vasoactive drugs, organ system dysfunction, and extension and worsening of radiological infiltrates, were also associated with failure [ , ]. Similar to previous studies, Al-Rajhi and colleagues found that NIV failure was associated with the absence of chronic obstructive airway disease, APACHE II score, the need for hemodynamic support and the number of CXR quadrants involved. However, we think that the present study has several limitations. First, the effectiveness of any treatment must be determined by a randomized controlled trial. In the absence of a control group, definitive conclusions cannot be drawn. Second, the study was conducted in two centres with major experience in the use of NIV, and therefore these results cannot be extrapolated to less trained and equipped hospitals. Third, no data were provided on the severity of acute respiratory failure in the patients included in the study (for instance: PaO2/FiO2). It is different to use NIV at an early stage of respiratory failure (for instance when the PaO2/ FiO2 ratio is <250) or a late stage of acute respiratory failure in patients presenting with intubation criteria. The lack of these data does not allow comparison of this study with previous studies dealing with hypoxaemic respiratory failure. Moreover, intensive care admission and intubation criteria were not standardized and delay time of intubation after NIV failure was not recorded.