-Positive pressure mechanical ventilation is achieved by placing Endotracheal Tube (ETT)

Mouth or nose

-ETT is smaller than our own airway

-Results with more resistance and increase work of breathing

-Tidal volume (TV):

-Volume of gas inhaled or exhaled

-Minute ventilation (MV):

-Total volume of gas entering or leaving the lung per minute

-Product of tidal volume and respiratory rate

-Tidal volume X respiratory rate

-Fraction of inspired oxygen (FiO2)

-Percentage of oxygen

-Positive end expiratory pressure (PEEP)

-The remaining pressure during the exhalation phase



– Assist-control ventilation (AC/VC):

-Preset tidal volume and pressure varies

-Pressure controlled (PCV):

-Preset pressure and the volume varies

-Both modes have:




– Assist-control ventilation (AC/VC):

-Provides specific tidal volume and respiratory rate but the patient can generate additional tidal volume breaths

-If the ventilator is stopping any patient’s own breath, then it is called control-mode ventilation (CMV)

-Simplicity and control the TV

-For spontaneously breathing patients with weakened respiratory muscles

-Hyperventilation and respiratory alkalosis (more of problem with stacking)

-Pressure controlled (PCV):

-Provides a constant pressure throughout the inspiratory phase over constant time

-Volume varies

-Initial severe ARDS management might require PCV

-Patients who failed AC/VC or have increased peak airway pressures during AC/VC or apneic patients

-MORE, MORE and MORE sedation, paralysis, and pneumothorax

-Pressure Support (PSV):

-All breaths are patient initiated

-Patient controls the rate, tidal volume, and minute ventilation

-Preset pressure that is delivered with each spontaneous patient breath

-Most comfortable

-Weaning mode, to decrease the airway resistance and dead space