Correlation between maximum inspiratory pressure and inspiratory load compensation (ILC) ventilatory variables in the 16 difficult-to-wean subjects, prior to inspiratory muscle strength training (IMST), with a 10 cm H2O load. Correlation between maximum inspiratory pressure and inspiratory load compensation (ILC) ventilatory variables in the 16 difficult-to-wean subjects, prior to inspiratory muscle strength training (IMST), with a 10 cm H2O load. Before IMST the maximum inspiratory pressure in the subjects who ultimately weaned from mechanical ventilation after IMST (shaded data points) significantly correlated with peak inspiratory flow (r = 0.64, P = .008), and there was trend in inspired VT (r = 0.45, P = .08). The white data points represent the subjects who failed to wean. In contrast, no linear relationship was found between maximum inspiratory pressure and inspiratory or expiratory timing during ILC. Barbara Kellerman Smith et al. Respir Care 2014;59:22-31 (c) 2012 by Daedalus Enterprises, Inc.