AR participated in the study design and helped draft the manuscript. All authors read and approved the final manuscript.Supplementary MaterialAdditional file 1: A Word file containing a list of selected definitions used in this study. This is a list of definitions of selected complications and pre-existing conditions selleck screening library based on the Pennsylvania Trauma Systems Foundation 2008 Operations Manual for the Pennsylvania Data Base Collection System.Click here for file(27K, DOC)
To date, no weaning predictive index has proven to be ideal .
According to the Sixth International Consensus Conference on Intensive Care Medicine , patients who meet the following satisfactory criteria should be considered ready for weaning: frequency to tidal volume ratio (f/Vt) less than 105 breaths/min/L, respiratory rate (f) of 35 breaths/min or less, maximal inspiratory pressure (MIP) of -20 or less to -25 cmH2O, tidal volume (Vt) more than 5 mL/kg, vital capacity more than 10 mL/kg, and arterial oxygen saturation (SaO2) above 90% with a fraction of inspired oxygen (FiO2) of 0.4 or less (or partial pressure of arterial oxygen (PaO2)/FiO2 ratio of 150 mmHg or above). After the assessment of these indexes regarding readiness for weaning, a spontaneous breathing trial (SBT) should follow as a diagnostic test to determine the likelihood of successful extubation .Weaning decisions based only on expert clinical judgment are not always correct [4,5]. Premature discontinuation places severe stress on the respiratory and cardiovascular systems , while unnecessary delays can lead to diaphragmatic atrophy  that can worsen its force generation and, as a consequence, the MIP.
Several predictors of weaning are therefore used to aid decision-making .On reviewing the evidence base for ventilator weaning , none of the predictors of weaning demonstrate more than modest accuracy in predicting the weaning outcome. In the McMaster review and guidelines [8,9], 66 predictors of weaning were reviewed and analyzed. Only eight, including the rapid shallow breathing index (RSBI) or the f/Vt ratio, presented significant likelihood ratios to predict the weaning outcome [8,9]. The f/Vt ratio was evaluated by at least 22 studies [10,11], and can be considered the most used predictor of weaning.
The daily screening of the respiratory function followed by SBTs in selected patients can reduce the time of mechanical ventilation and the cost of intensive care, besides being associated with fewer complications . As many factors can be responsible for weaning failure, we hypothesized that a weaning index that integrates significant physiological weaning parameters could be a better index predictor than the traditional ones .The objective of this study is to test the predictive performance of a new integrative weaning index (IWI). We evaluated two groups of patients. Anacetrapib In the first one (training set), the threshold values for each weaning parameter were selected.