This ppt is about how to set basic ventilatory parameters. Tidal volume, RR, Peak flow, IE ratio etc... Must learn for a working in ICU

1. Basic Ventilatory Parameters
Dr. Ankit Gajjar

2. Primary goal
• Achieve a desired minute ventilation that
matches the patient's metabolic needs
• Adequate gas exchange
• Minimal lung injury

3. Basic parameters
• Tidal volume
• Respiratory rate
• Minute ventilation
• Lung Pressures
– Peak Pressure
– Platue pressure
• Flow / Inspiratory time / I:E ratio
• Flow pattern
• Trigger
• FiO2
• PEEP

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

7. Minute ventilation
• Monitor
• Normal – 6-8 LPM
• Achieve desired
– pH
– PO2

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

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

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

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

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

18. PEEP
• Avoid end expiratory alveolar collapse
• Usual – 5
• Lesser
– OAD???
– BPF
• Higher
– ARDS

19. VCV for 60 kg male
Condition Airway
protection
ARDS OAD Septic Acidotic
VTE 420-480 240-360 400-450 450-500
RR 16-18 28-34 12-14 28-34
I:E 1:2 1:1-1:2 1:3-1:6 1:2
Flow pattern decelerating Decelerating Decelerating decelerating
Trigger Flow 3 Flow 3 Flow 3 Flow 3
FiO2 30 30-100 30 30
PEEP 5 5-20 0-5 5

20. Monitor
• Pplat
• MV
• SPO2
• PCO2
• pH

21. THANK YOU