NIV Could Delay the Timing of Intubation

By providing high level of inspired oxygen and improving oxygenation, NIV may delay the timing of intubation by masking a progressive worsening. By contrast to hypercapnic acute respiratory failure, where delayed intubation in case of NIV failure does not seem to be associated with worst outcome [28-29, 31], in acute hypoxemic respiratory failure, delayed intubation could be associated with an increase in mortality [32]. Considering that acute hypoxemic acute respiratory failure represents a syndrome of variable etiology and severity, it is not so surprising that the benefit of NIV within this syndrome varies. A recent secondary analysis of a prospective observational cohort study published by Kangelaris et al. analyzed data on 457 patients with ARDS [33]. Among them, 106 (23%) were not intubated at the time of meeting all ARDS criteria. Non-intubated patients had lower morbidity and severity of illness than intubated patients. However, mortality at day 60 was the same (36%) in both groups (p = 0.91). Among the 106 non- intubated patients, 36 (34%) required intubation within the subsequent 3 days of follow-up, and this late-intubation subgroup had significantly higher 60-day mortality (56%) when compared with both early intubation group (36%, p = 0.03) and patients never requiring intubation (26%; p = 0.002). The increased mortality in the late-intubation group persisted at 2-year follow-up. In another prospective cohort, among 170 patients meeting the Berlin definition for ARDS [14], 96 (56%) were initially managed with NIV [34]. Among them, 42 patients (44%) were intubated. NIV failure and mortality were significantly higher in moderate and severe ARDS.