ObjectiveTo specify the degree of probative force of the statistical hypotheses in relation to mortality at 28 days and the threshold value of 17 J/min mechanical power (MP) in patients with respiratory failure secondary to SARS-CoV-2. DesignCohort study, longitudinal, analytical. SettingIntensive care unit of a third level hospital in Spain. PatientsPatients admitted for SARS-CoV-2 infection with admission to the ICU between March 2020 and March 2022. InterventionsBayesian analysis with the beta binomial model. Main variables of interestBayes factor, mechanical power. ResultsA total of 253 patients were analyzed. Baseline respiratory rate (BF10: 3.83 × 106), peak pressure value (BF10: 3.72 × 1013) and neumothorax (BF10: 17,663) were the values most likely to be different between the two groups of patients compared. In the group of patients with MP < 17 J/min, a BF10 of 12.71 and a BF01 of 0.07 were established with an 95%CI of 0.27–0.58. For the group of patients with MP ≥ 17 J/min the BF10 was 36,100 and the BF01 of 2.77e-05 with an 95%CI of 0.42–0.72. ConclusionsA MP ≥ 17 J/min value is associated with extreme evidence with 28-day mortality in patients requiring MV due to respiratory failure secondary to SARS-CoV-2 disease.