Value of the PaO₂:FiO₂ Ratio and Rapid Shallow Breathing Index in Predicting Successful Extubation in Hypoxemic Respiratory Failure

Purpose: We sought to determine the predictive value of the PaO₂:FiO₂ ratio (PFR), both independently and in combination with the standard Rapid Shallow Breathing Index (RSBI), for successful extubations in patients with primary hypoxemic respiratory failure (HRF).

Materials And Methods: A retrospective chart review of 154 patients with HRF requiring mechanical ventilation for ≥24 hours was performed. The primary outcome was reintubation within 48 hours.

Results: 142 (92%) patients were successfully extubated. Pre-extubation PFR and RSBI values among reintubated and successfully extubated patients were similar. The areas under the curve of the receiver operating characteristic curves using RSBI and PFR were .5 and .62, respectively. A PFR < 200 or RSBI ≥ 70 when the PFR was ≥200 indicated a higher risk of reintubation, with .7 sensitivity and .56 specificity (area under the curve, .69), using a classification and regression tree model.

Conclusions: Neither the PFR independently nor the PFR in combination with the RSBI in a classification and regression tree model accurately predicted successful extubation in patients with HRF.