4. Tidal Volume
• Amount of air delivered with each breath
• 8 ml/kg (IBW)
• ARDS – 6 ml/kg
• PC variable
• VC fixed
• Avoid very high tidal volumes to prevent
volume trauma
5. Respiratory Rate
• Neuro, post operative patients – 14-18
• ARDS – 28-34
• OAD – 12-14 prevention of air trapping
• Septic, Acidotic patients – 28-34
• Monitor
– pH
– PCO2
– Air trapping
8. Pressures
• PC – Set driving pressure Pi
– To achieve desired tidal volume
• VC – monitor Ppeak, Pplatue
– Ppeak – peak inspiratory pressure
• Function of resistance and compliance
– Pplatue – inspiratory pressure during inspiratory hold
• Function of lung comliance
• Target <30 cm H2O
• Important in prevention of Barotrauma
9.
10. Peak flow
• Maximum flow delivered by the ventilator during
inspiration
• Normal Peak flow rate - 60 L per minute
• Higher rates are frequently necessary
– Acidotic patient
– OAD
• Insufficient peak flow rate is
– Dyspnea
– Spuriously low peak inspiratory pressures, and
scalloping
11.
12. Flow pattern
• Can be chosen in VCV
• In PCV always ramp wave
• square wave (constant flow)
• ramp wave (decelerating flow)
• The ramp wave is preferred
– distribute ventilation more evenly particularly in
OAD
– decreases peak airway pressure, physiologic dead
space, and PaCO2
13.
14. Inspiratory time / I:E ratio
• Normal – 1:2
• ARDS – 1:1/ 1:1.5
• OAD – 1:3-1:5 or even prolonged
• Look for adequate expiratory time on flow
time scaler
• Inadequate expiratory time causes air trapping
15.
16. Trigger
• Pressure trigger
– Drop of pressure in airway due to patient effort
• Flow trigger
– Returned flow is less then delivered flow
– More sensitive decreases WOB
• Keep 1-3
– More sensitive – auto trigger
– Less sensitive – increased WOB
17. FiO2
• The lowest possible FiO2 to meet oxygenation goals
should be used
• To decrease the likelihood that adverse consequences
of supplemental oxygen
– absorption atelectasis
– accentuation of hypercapnia
– airway injury parenchymal injury
• Most patients - >88%
• >95%
– ACS
– CVA
– Post cardiac arrest
– pregnant