Serial rapid shallow breathing index as predictor of weaning in tracheostomized patients

Rationale: The variation of 20% in the rapid-shallow-breathing index (RSBI) is described as a predictor weaning failure of mechanical ventilation (MV) in intubated patients. However, it has not been studied in tracheostomized patients. We aim to evaluate this aplicability in tracheostomized patients. Methods: Tracheostomized patients in MV for more than 14 days elegible to weaning were included. They were divided into two groups (≤20 days and ≥21 days MV) and submitted to STB, 2h and 6h in T-tube, so that the serial was collected. This group was disconnected from ventilator and allowed to breathe unassisted if tolerated the first two hours as recommended in simple weaning. In the group ≥21 days MV, there was a second period of 6 hours in T-tube in the same day and its progression. Differences in RSBI were assessed as percent change from baseline. Results: In the group ≤20 days, there was a reduction in tidal volume (Vt) (p=0,003), increase in respiratory rate (p=0,009) and RSBI (p=0,0004). In the group ≥21 days, a reduction in Vt (and an increase in the RSBI were observed (p=0,0001). RSBI variation in the group ≤20 days was greater than 20% in the patients who failed. The RSBI variation is demonstrated in figure 1. Conclusion: The serial evaluation of the ventilatory pattern and the analysis of the RSBI variation seem to predict the failure of weaning of MV in tracheostomized patients.