Objective: To evaluate new indexes predicting weaning outcome from mechanical ventilation.
Experimental design: Prospective study with two main end-points: a comparison of weaning indexes between successful and unsuccessful groups and an evaluation of their predicting value.
Environment: Surgical-Medical Intensive Care Unit.
Patients: Patients ventilated for more than 72 hours and subjected to a weaning trial until spontaneous ventilation.
Measurements: Traditional weaning parameters [respiratory rate (fsb), expiratory minute volume (Vesb), Maximal Inspiratory Pressure (MIP)] along with the new indexes [fsb/Vtsb) (rate to tidal volume ratio), CROP index (Compliance Rate Oxygenation Pressure), P0.1/MIP, IEQ (Inspiratory Effort Quotient), WI (Weaning Index)] were measured before discontinuation of ventilation support.
Results: A statistically significant difference was observed between successful and unsuccessful groups for the following parameters: fsb, MIP, fsb/.Vtsb, CROP, Po.1/MIP and WI while no differences were observed for Vesb and IEQ. The sensitivity and specificity for the new indexes were respectively: fsb/Vtsb: 0.65 and 0.58; CROP: 0.70 and 0.63; P0.1/MIP: 0.85 and 0.36; WI: 0.69 and 0.47.
Conclusion: A statistically significant difference between successful and unsuccessful groups was observed for some but not all new indexes; the diagnostic accuracy of the new indexes were no better than additional parameters.