PURPOSE: To evaluate the assisted RSBI value on pressure support of 7cmH2o and CPAP of 5cmH20 as a predictor for successful extubation.
METHODS: 88 patients who were clinically stable and considered ready to undergo weaning trial by the intensivist were recruited for our study. All patients had assisted breathing trial with CPAP of 5cmH2O and pressure support of 7cmH2O with a flow-by of 6 and RSBI was calculated after twenty minutes on ventilator (VelaTM Viasysis Healthcare).RSBI <105 was considered as a gold standard and patients were extubated if they met all other criteria as per American college of chest physician.Patients were followed until their discharge out of ICU.
RESULTS: 88 patient were enrolled from October 2007-march 2008 .10 patient were reintubated within forty-eight hours (11% reintubation).Out of 75 patients in the category of RSBI < 80, only 5 were reintubated (i.e. 6.6%) 3 of them had a new event different from the primary indication for Mechanical Ventilation.Out of 13 patients in the category of RSBI >80, five were reintubated (i.e. 38.5%) and only 1 patient had a new event. The overall results of RSBI <80,Sensitivity 90.3%Specificity 50%Positive predictive value 93.7 Negative predictive value 38.4.
CONCLUSION: In our study Rapid shallow breathing index of less than 80 calculated on assisted breathing trial reliably predicts positive outcome.
CLINICAL IMPLICATIONS: Rapid shallow breathing index (RSBI) has been utilized as a marker since its original report. The original described method of calculating RSBI was with a hand held spirometer which has been largely replaced by calculating it on the ventilator, unfortunately there is no consensus on the method and different intensive care unit (ICU) use there own methods which may or may not include any continuous positive airway pressure (CPAP) or pressure support (PS).Here we have proposed that RSBI< 80 generated on assisted support reliably predicts successful weaning and this number is less than the originally reported number of <105 with hand held spirometer.
DISCLOSURE: Safdar Khan, No Financial Disclosure Information; No Product/Research Disclosure Information