Assessment of rapid shallow breathing index as a predictor for weaning in respiratory care unit

At present, air way support plays pivotal role in management of patients in the ICU (Intensive Care Unit) and also RCU (Respiratory Care Unit). Ventilator weaning is an important step in the care of ICU and RCU patients. It is the gradual removal of mechanical ventilatory support. Different predictors are used for initiation of weaning. This study was designed to investigate the rapid shallow breathing index (RSBI) as a predictor for successful weaning.

This cross-sectional study was conducted on 70 patients who had mechanical ventilation for more than 48 hours in a respiratory care unit in Tehran Labbafi Nejad Hospital. They were clinically stable and had the criteria for weaning from the ventilator. We measured RSBI, and then evaluated the value of RSBI for successful extubation. RSBI was calculated when patients were on spontaneous breathing mode with PSV=0 and PEEP=0 for one minute.

A total of 70 patients were included in this study; 63(90%) patients had RSBI ≤105 (breath/min/L), among them 49 (77%) patients had successful weaning and did not need re-intubation while the remaining had unsuccessful weaning (P=0.001). The mean weaning index for patients with successful extubation was 66 ± 57.2 and 76.9 ± 28.1 for patients with unsuccessful extubaion. We could not find a significant difference between the means (P=0.433).

Although RSBI <105 is a helpful index for weaning, application of RSBI alone may mislead the physicians. General status of the patient, concomitant diseases and duration of hospital stay should all be considered for successful weaning.