INTRODUCTION: Necessity of mechanical ventilation is one of de most frequent cause of admission to the intensive care and mortality rate is still elevated for this reason. OBJECTIVE: To identify some factors determine in a successful weaning. METHODS: A prospective descriptive and longitudinal trial in the Joaquin Albarran hospital´s intensive care unit was carried out from January 2015 to June 2016. From 253 patients who needed mechanical ventilation were selected 70 of them in which was started the weaning process. It was created a database using SPSS and it was used the X² test to analyse relation between variables. RESULTS: More than 80% of patients with a successful weaning had controlled the cause of beginning the mechanical ventilation (p=0,000), higher consciences level, they were not in sepsis (p=0,038), with adequate hemodynamic status, without acid-basic and electrolyte disturbance and adequate level of haemoglobin. Oxygen indexes more used were arterial oxygen pressure, PaO2 /FiO2 index, and alveolus-arterial oxygen gradient) which were between normal records, in relation with a successful. CONCLUSION: It was demonstrated that better general basic conditions and a Tobin’s index less than 105, were related with a successful weaning.
