Mean inspiratory work of breathing during assisted breaths and spontaneous breaths across the spectrum of ventilatory support continuous mandatory ventilation (100%) to CPAP (0). Mean inspiratory work of breathing during assisted breaths and spontaneous breaths across the spectrum of ventilatory support continuous mandatory ventilation (100%) to CPAP (0). At each level of synchronized intermittent mandatory ventilation (SIMV), the work of breathing increased; however, the work during the assisted breaths was higher than during the spontaneous breaths. Bars indicate SE. * P < .01; † P < .05. Adapted from Reference 28. Robert M Kacmarek, and Richard D Branson Respir Care 2016;61:854-866 (c) 2012 by Daedalus Enterprises, Inc.