Association of extubation failure rate with patient outcomes

Background: While the propensity of evidence indicates the potential harm of failed extubation attempts, avoidance of any such risk may unnecessarily expose patients to prolonged invasive ventilation. We aimed to study the effects of extubation failure rate (EFR) on patient mortality and ventilation-free days (VFD). Methods: Adult patients admitted to the medical intensive care unit who underwent planned extubation were included. Extubation failure was defined as death or return to invasive positive pressure ventilation within 7 days from extubation. The primary outcome was 30-day mortality and the secondary outcome was VFD. For each calendar month, the average 30-day mortality or VFD was plotted against the EFR, with polynomial regression models of increasing complexity fitted until no further increase in the adjusted R2 could be achieved. Results: Of the 774 patients included in final analysis, 262 (33.8%) failed extubation. Matched by the propensity for extubation failure, the 30-day mortality analysis for both groups showed no significant difference (18.4% vs. 16.2%, P=0.34). The relationship between monthly EFR and 30-day survival or VFD was best described by a quadratic regression model (adjusted R2=0.816 and 0.624, respectively). Based on this model, the optimal EFR was calculated at 33.1% (for 30-day survival) and 28.8% (for VFD). Conclusions: Our data support the notion of an optimal EFR. This optimum may be higher than the minimal failure rate achievable.