Abstract
Stress index is a useful indicator in mechanical ventilation to assess improper ventilation settings. It can indicate tidal overdistension or tidal recruitment, which are two major mechanisms of ventilator-induced lung injury. However, it's implementation require dedicated hardware and software and is not a widespread parameter used in commercial ventilators. In this work, an alternative, simple way to visually inspect the concavity of the pressure-time curve during mechanical ventilation is presented, by calculating the pressure difference of the pressure-time curve. This proves useful when implemented in low-cost emergency devices, such as those designed to cope with the COVID-19 pandemic, because of the reduced computational load required to perform its calculation. The method was implemented in a low-cost emergency mechanical ventilator and tested with an artificial lung for a proof-of-concept. Results show that this alternative method can be effectively used to qualitatively assess the concavity of the pressure-time curve.