Analysis of the effectiveness of equations for calculating pulmonary mechanical power: Integrative review

Pulmonary mechanical power (MP) was interpreted as the force applied by the ventilator to displace a volume of air within the lungs, deforming the epithelium and cellular endothelium, per unit of time, expressed dimensionally in Joules per second (J/s) or Joules per minute (J/min). This applied force generates energy, and the degree of energy transfer can lead to direct damage to the alveolar capillary membrane and mechanotransduction, which is the conversion of a mechanical stimulus into biochemical and molecular signals; in addition to being dependent on the ventilatory parameters adjusted at the bedside. MP is important because it is a ventilator parameter that has been associated with mortality. Therefore, the objective of this review is to analyze the effectiveness of the equations for calculating pulmonary mechanical power. This is a comprehensive integrative review, with searches in the following databases: BVS (BIREME), BVS (LILACS), CINAHL (EBSCO), Cochrane Library, Embase, IEEEXplore, PEDro, PubMed/MEDLINE, SciELO, ScienceDirect, Scopus, and Web of Science (Clarivate Analytics). Eight eligible articles were found that proposed MP calculations. It was observed that studies on this topic began in 2016 with an equation proposed by Gattinoni, with the number of studies being relatively small, although MP is a variable associated with mortality. Six distinct equations were identified, three used in controlled volume and three in controlled pressure. It can be concluded that the calculation of MP is important for lung protection, can be used at the bedside without interruption of ventilation, and should be part of clinical practice. Finally, the simplified equations are more practical to apply and are highly accurate when compared to the gold standard of measurement.