Background: In assisted mechanical ventilation, the work of breathing (WOB) should be shared by patient and ventilator. In PAV+, there is an association between respiratory muscle pressure and the pressure generated by the ventilator. There are still knowledge deficits about the influence of different types of inspiratory efforts on mechanical ventilator outputs during PAV+ assistance.Methods: A mechanical simulator (ASL-5000 Ingmar Medical®) set with Compliance of 100 mL/cmH20 and resistance of 10 cmH20-L-s) was coupled to the Medtronic 980 (Purittan-Benett ®) mechanical ventilator in the Laboratory of Mechanical Ventilation of INCOR-Faculdade de Medicina Universidade de São Paulo, Brazil. A sequential script of three different inspiratory efforts (-3, -7 and -11 cmH2O) and three different respective inspiratory delays (5%, 15% and 20%), pre-programmed in the ASL5000 simulator software started to run and triggered the ventilator 15 times for each of the 9 sequences, in 19 levels of PAV+ assistance (from 5% to 95%) in a total of 2.565 combinations. The measured outputs from the ventilator were: Expired Tidal Volume (ETV: mL); Inspiratory time (IT: s); Peak inspiratory flow (PIF: cmH20); Peak inspiratory pressure (PP: cmH20); and Work of breathing (WOB) that were recorded in the ASL-5000_ software and analyzed by R software for Windows, version 4.0.5.Results: A exponential significant increase in ETV (from 88.46 mL to 1095.34 mL), IT (from 0.83 to1.64 s), PIF (from 10.88 to 125.53 L/min) and PP (from 7.53 to 33.23 cmH20) were observed with the increase of both inspiratory efforts and PAV+ assistance. This increment was amplified by the addition of 5%, 10% and 15% of inspiratory delays. WOBpt was compensated by PAV+ % of assistance increment as the inspiratory effort increase. Conclusion: PAV+ responded promptly to increments of inspiratory effort and progressive increase of inspiratory assistance. Delaying the inspiratory muscle effort significantly booster PAV+ ` outputs proportionally to inspiratory efforts levels and PAV+ % of assistance.