Mechanical Ventilation: The Basics In the most basic sense, ventilator modes are defined by their control variable and settings. Breaths are triggered (started) and cycled (ended) by specific parameters, which are determined by the mode. While there are many modes to choose from, we will review the most basic below. Assist Control / Volume Control (AC/VC): • Delivers mandatory breaths at a fixed rate with a set volume (control) and allows spontaneous breaths to be triggered, but will assist those breaths with the full set volume as well (assist). • Volume Cycled, Delivers volume until set volume goal is reached • Volume: 6-8 cc/kg IBW, RR: depends on pt/scenario, PEEP: ARDSnet PEEP ladder, FiO2: goal spO2 > 88% Assist Control / Pressure Control (AC/PC): • Delivers mandatory breaths at a fixed rate with a set pressure for a set inspiratory time (control) and allows spontaneous breaths to be triggered, but will assist those breaths with the full set pressure and i-time as well (assist). • Time Cycled, Delivers set pressure for set inspiratory time (i-time) • PC: adjust to achieve Vte, RR: depends on pt/scenario, PEEP: ARDSnet PEEP ladder, FiO2: goal spO2 > 88% Pressure Support Ventilation (PSV): • Often, a "weaning" mode. Unlike in AC modes, in PSV all breaths are spontaneous with pressure to support the breath, but not "control" it (no mandated volume or i-time). • Flow Cycled, Delivers pressure support until flow has reached 25% of its peak • PS: 0-8, if in an SBT, RR: spontaneous, PEEP: 5-8, FiO2: goal spO2 > 88% Dr. Meredith Greer @EmmGeezee #MechanicalVentilation #Basics #Modes #Comparison #management #criticalcare
