A validation study of a continuous automatic measurement of the mechanical power in ARDS patients

The mechanical power (MP) is the energy delivered into the respiratory system over time. It can be computed as a direct measurement of the inspiratory area of the airway pressure and volume loop during the respiratory cycle or calculated by “power equations”. The absence of a bedside computation limited its widespread use. Recently, it has been developed an automatic monitoring system inside of a mechanical ventilator. Purpose: Our aim was to investigate the repeatability and the accuracy of the measured MP at different PEEP values and tidal volume compared with the calculated MP. Material and methods: MP was measured and calculated in sedated and paralyzed ARDS patients at low and high tidal volume, at 5–10–15 cmH2O of PEEP both in volume and pressure-controlled ventilation. The same measurements were performed twice. Results: Fifty ARDS patients were enrolled. MP was measured and calculated for a total of 300 measurements. The bias and limits of agreement were 0.38 from −1.31 to 2.0 J/min. The measured and calculated MP were similar in each ventilatory condition. Conclusions: The mechanical power measured by a new automatic real time system implemented in a mechanical ventilator was repeatable and accurate compared with the computed one.