“…Based on the formation mechanism of PI, many scholars have proposed that the development of PI begins with muscle tissue damage, penetrating from the deep to surface within 48 h (Bennett et al, 2017; Judy et al, 2011; Mayrovitz et al, 2018; Moore et al, 2017). When the pressure goes beyond tissue resistance threshold, tissue damage starts immediately, which often precedes visual recognition (Bennett et al, 2017; Judy et al, 2011; Mayrovitz et al, 2018; Moore et al, 2017). Therefore, how to identify potential damage within 48 h before visual recognition provides a possibility to reduce the incidence of PI to some extent.…”