The Weaning Index combining EtCO2 and respiratory rate early identifies Spontaneous Breathing trial failure. A pilot study

International audience; BACKGROUND: We aimed to evaluate the predictive value of the end-tidal CO2 (EtCO2) alone or combined with ventilation related parameters on spontaneous breathing trial (SBT) outcome on mechanically ventilated patients.METHODS: Prospective observational study in a medical ICU. Mechanically ventilated adult patients who met predefined criteria for weaning were included. Patients underwent a T-piece SBT for 30 minutes and the usual hemodynamic and respiratory clinical parameters including EtCO2 were recorded every 5 minutes.RESULTS: 280 patients were studied (age: 64±17 years, SAPS II: 44 [34-56]) during a first SBT and 76 patients during a second SBT. The Weaning Index, defined as the product of the respiratory rate and EtCO2, was a strong early predictive factor of SBT outcome; at 10 minutes, the area under the curve (AUC) was 86% ([80-90], P1100 identified patients that will not successfully complete the SBT at 30 minutes with a specificity of 98%.CONCLUSIONS: In unselected mechanically ventilated patients, the Weaning Index is helpful to early identify patients who will fail the SBT during a first and a second trial.