The 24-hour mechanical power (MP) variation rate is an independent risk factor for ICU mortality among patients with acute respiratory failure (ARF) with elevated MP, according to a study published in BMC Pulmonary Medicine. To explore the relationship between dynamic changes in MP and prognosis in critically ill patients, investigators conducted a single-center, retrospective cohort study. Patients receiving mechanical ventilation with ARF and MP greater than 10 J/min on admission in the ICU were included. Patients were divided into two groups according to whether MP decreased 24 hours after admission (MP-improved group defined as 24-hour MP variation rate greater than 0% vs MP-worsened group defined as 24-hour MP variation rate of 0% or less). The MP-improved group had a lower ICU mortality rate than the MP-worsened group (24% vs 36%). The 24-hour MP variation rate was associated with ICU mortality after adjusting for confounders (OR, 0.906), while baseline MP and 24- hour MP were not. All MP components improved in the MP-improved group, while minute ventilation and positive end-expiratory pressure contributed to the increase in MP in the MP-worsened group.