-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
Monitoring
Modes
– Assist-control ventilation (AC/VC):
-Preset tidal volume and pressure varies
-Pressure controlled (PCV):
-Preset pressure and the volume varies
-Both modes have:
-Trigger
-Cycle
-Limit
– 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