1. MECHANICAL
VENTILATION
BY
P. ARUL VALAN

2. DEFINITION
A mechanical ventilator is a
positive or a negative
pressure breathing device
that can maintain
ventilation and oxygen
delivery for a prolonged
period.

3. INDICATIONS
• Acute lung injur y.
• Apnea with respirator y
ar rest.
• COPD.
• Acute respir ator y acidosis.
• Hypoxemia.

4. TERMINOLOGIES
• Tidal volume ( vt )
• Inspiratory reserve volume ( IRV )
• Expiratory reserve volume (ERV )
• Residual volume ( RV )
• Vital capacity ( Vc )
• Inspiratory capacity ( IC )
• Functional residual capacity ( FRC )
• Total lung capacity ( TLC )
• Minute volume

5. CLASSIFICATIO
N OF
VENTILATORS
 NEGATIVE PRESSURE
VENTILATOR.
 POSITIVE PRESSURE
VENTILATOR.

6. NEGATIVE PRESSURE
VENTILATOR

7. THE IRON LUNG

8. POSITIVE
PRESSURE
VENTILATOR
 INFLATES THE LUNG BY
EXERTING POSITIVE
PRESSURE ON THE
AIRWAY FORCING
ALVEOLI TO EXPAND
DURING INSPIRATION
AND EXPIRATION
OCCURS PASSIVELY.

9. TYPES
• PRESSURE CYCLED
• VOLUME CYCLED
• TIME CYCLED

10. PRESSURE CYCLED
 ENDS INSPIRATION WHEN A PRESET PRESSURE
HAS BEEN REACHED.
 THE PRESSURE APPLIED TO THE AIRWAY IS
CONSTANT.
 VOLUME OF AIR VARY AS PATIENTS AIRWAY
RESISTANCE CHANGES.
 THEY ARE ALSO TIME CYCLED ( BREATHS ARE
GIVEN AT FIXED INTERVALS )

11. VOLUME CYCLED
 THE VOLUME OF AIR DELIVERED
TO THE PATIENT AT EACH
INSPIRATION IS PRESET .
 ONCE THE PRESET VOLUME IS
DELIVERED THE VENTILATOR
CYCLES OFF AND EXHALATION
OCCURS PASSIVELY.
 VOLUME OF AIR DELIVERED IS
CONSTANT DESPITE VARYING
PRESSURE.

12. TIME CYCLED
 ENDS INSPIRATION AFTER THE
PRESET TIME.
 VOLUME OF AIR THE PATIENT
RECIEVES IS REGULATED BY THE
LENGTH OF INSPIRATION AND THE
FLOW RATE.

13. OTHERS
 INVASIVE VENTILATION .
 NON INVASIVE
VENTILATION.
 FULL VENTILATION.
 PARTIAL VENTIATION.

14. VENTILATOR SETTINGS
TIDAL VOLUME.
6 TO 8 ml/Kg
Predicted body weight :
MALE : 50+2.3 X { Ht – 60 }
FEMALE : 45.5+2.3 X { Ht – 60 }
6ml/Kg : ARDS
6 to 8ml/Kg : OBSTRUCTED LUNG
DISEASE
8 to 10ml/Kg :NEUROMUSCUL AR
DIEASE

15. RESPIATORY RATE
15 TO 25 /min TO ACHIEVE A
MINUTE VOLUME OF 7 TO 10
L/min.
LOWER RR PREVENTS AIR
TRAPPING.

16. I:E RATIO,Fio2
I:E RATIO IS 1:2
START Fio2 WITH 1 . O AND
REUCE IT TO 0.6
TITRATE USING PULSE
OXYMETRY.

17. What is the extent of the What is the patient' chest
patient's lung injury? wall (Cw) compliance?
NORMAL
Target PaO2>60-80 LOW
-obesity
What FiO2 is required to
-edema
achieve this? -abdominal hypertension
Normal Cw Compliance Low Cw Compliance
FiO2
PEEP in cmH2O PEEP in cmH2O
0.3 5 10
0.4 8 12
0.5 10 14
0.6* 12 16
0.7* 14 18
0.75* 16 20
0.8* 18 22
0.9* 20 22
1* 22 24

18. MODES OF VENTILATOR
CONTROLED
VENTILATION
 PRESET VOLUME OF AIR IS
DELIVERED UNDER POSITIVE
PRESSURE.
 SPONTANEOUS PATIENT
RESPIRATION IS LOCKED OUT.

19. ASSIST CONTROL
VENTILATION
 ALLOWS PATIENT TO INTIATE
MECHANICAL BREATH BUT CAN
ALSO DELIVER A PRESET
LEVEL OF MINUTE
VENTILATION IF THE PATIENT
CANNOT TRIGGER.
 PATIENT IS FULLY RESTED ON
THE VENTILATOR AND CAN
BREATH SPONTANEOULY
WITHOUT WORKING.

20. ASSIST CONTROL
VETILATION

21. SIMV MODE
• GAS FLOWS IN THE SIMV
MODE .A PRESET MINIUM
NUMBER OF BREATHS
ARE DELIVERED TO THE
PATIENT BUT THE PATIENT
ALSO TAKES
SPONTANEOUS BREATHS
OF VARIOUS VOLUMES.

22. SYNCHRONIZED
INTERMITENT MANDATORY
VENTILATION

24. PRESSURE SUPPORT
VENTILATION

25. IMV CONTROLLED BREATH

26. IMV SPONTANEOUS
BREATH

27. SYNCHRONIZED INTERMITENT
MANDATORY VENTILATION

28. SENSOR MEDICS 3100 A

29. SEIMON SERVO 900C

30. DRAGER BABYLOG 8000