Comparison between CROP and Rapid Shallow Breathing index as predictors of weaning in predicting the outcome of discontinuation from mechanical ventilation in ICU patients

Usage of indicators to predict the outcome of weaning from the ventilator is a controversial issue. An index with high diagnostic accuracy can properly identify the Patients ready for weaning from mechanical ventilation and prevents premature weaning and its complications. Two of the introduced weaning indicators are RSBI and CROP but their predictive value in predicting the outcome of weaning from mechanical ventilation is different or contradictory.
This study was to Compare RSBI and CROP in predicting the outcome of weaning from mechanical ventilation in patients admitted to ICU.
This prospective, single-blind study was performed on 80 adult patients who were on mechanical ventilation for more than 24 hours in 3 ICUs (Internal-General-stroke) of Mashhad Ghaem hospital from October 2015 to May 2016. All the patients ready for weaning were identified and studied in one group. All of them were ventilated with PSV mode with minimum support for 30 mins. If the patient’s vital signs were stable during those 30 mins, we measured the required respiratory variables and arterial blood gas values to calculate CROP and RSBI. Then the SBT was performed, with a T-piece for 120 mins. finally the diagnostic accuracy of each index was evaluated according to the weaning outcome and prediction of indexes.
There were 57 successful and 23 unsuccessful weaning cases. The specificities were CROP 0.85 and RSBI 98.2. The sensitivities were CROP 0.75 and RSBI 0.26. The diagnostic accuracy were CROP 85.2 and RSBI 77.5. The new threshold value obtained in this study was very different for RSBI.
According to the analysis performed by the cut-off points obtained in previous studies, CROP index has the highest diagnostic accuracy, sensitivity and specificity were both high. The cut-off point of RSBI previously reported for non-homogeneous patients population is not extensible to all with different etiologies.