Indications, modes and detailed description of the mechanical ventilation.

1. MECHANICAL
VENILATION
DR. FARRUKH
FINAL YEAR RESIDENT

2. DEFINITION:
 Mechanical Ventilation is a method to
mechanically assist or replace spontaneous
breathing.

3. INDICATIONS
 Airway Compromise/ Respiratory Failure
 Type 1 respiratory failure or
 Type 2 respiratory failure
 Acute lung injury (including ARDS, trauma)
 Apnea or Respiratory Arrest including cases from Intoxication,
Chronic obstructive pulmonary disease (COPD), Myasthenia
gravis or Spinal cord injury.

4. INDICATIONS continued..
 Increased work of breathing as evidenced by significant
tachypnea, retractions, and other physical signs of respiratory
distress
 Hypotension including sepsis, shock, congestive heart failure
 Neurological diseases such as Muscular Dystrophy
Amyotrophic Lateral Sclerosis
 Airway Protection/Prophylactic Ventilatory Support

5. Types or Forms Of Mechanical
Ventilation
Negative Pressure Ventilator Positive Pressure Ventilator

6. Settings of Mechanical Ventilation
 Mechanical Ventilator Settings regulates the rate,
depth and other characteristics of ventilation. Settings
are based on the patient’s status (ABGs, Body
weight, level of consciousness and muscle strength)

7. Ventilator Circuit

8. Air Filters

9. Vent Mount/Catheter

10. Flow Sensor

11. Ventilator

12. Basic Ventilator Parameters
 Tidal volume
 Frequency
 Peak Inspiratory Pressure PIP
 Positive End Expiratory Pressure PEEP
 Inspiratory Time
 Expiratory time
 I:E Ratio

13. PARAMETERS OF MECHANICAL
VENTILATION
 Respiratory Rate (f) :-Normally 10-20b/m
 Tidal Volume (VT) :-5-15ml/kg
 Oxygen Concentration(FIO2):-b/w 21-90%
 I:E Ratio:-1:2
 Flow Rate:-40-100L/min
 Sensitivity/Trigger:- 0.5-1.5 cm H2O
 Pressure Limit:-10-25cm H2O
 PEEP :- Usually, 5-10 cmH2O

14. Modes of Mechanical Ventilation
• Controlled Mandatory Ventilation (CMV)
• Asst-Control Mandatory Ventilation (ACV)
• Synchronized Intermittent Mandatory
Ventilation(SIMV)
• Positive Expiratory End Pressure(PEEP)
• Continuous Positive Airway Pressure (CPAP)
• Pressure Support Ventilation (PSV)

15. Ventilatory Phases
• Inspiration: Inspiratory valve opens and
expiratory valve is closed
• Inspiratory pause: inspiratory valve and
expiratory valve closed
• Expiration: Inspiratory valve closed and
expiratory valve open
• Expiratory pause: Inspiratory valve and
expiratory (or PEEP) valve closed at end
of expiration
Ti Te
0

16. Phase variables
 Trigger : ventilator (time)- triggered or patient (pressure or flow)
triggered
 Limit: flow-limited orpressure-limited

17. Starting a ventilator: Mode
 Mode denotes interplay b/w patient and the
ventilator
 Describes the style of breath support based on
relationship between the various possible types of
breath and inspiratory – phase variables

18. Where to Start?
 CPAP, IPAP, EPAP, NIV
 Pressure control, Volume control
 CMV, Assist Control, IMV, SIMV,
 PSV, ASV, MMV,
 APRV
 PCV, PRVC, PSV, VCIRV, Volume
Support,
 Auto Mode,
 BiLevel, BiPAP,
 HFJV, HFOV

19. Mode?

20. Mechanical
Time (sec)
SpontaneousPaw
(cm H2O)
Inspiration
Expiration
Expiration
Inspiration
Breath type:
Spontaneous vs Mechanical vs Assisted
Assisted

22. Controlled Mandatory
Ventilation(CMV)
The ventilator delivers
 Preset tidal volume (or pressure) at a time triggered (preset) respiratory
rate.
 As the ventilator controls both tidal volume (pressure) and respiratory rate,
the ventilator “controls” the patients minute volume.
Pressure

23. Volume Control Ventilation
Pressure
Volume
FlowPreset Peak Flow
Preset Vt
Dependent on
Cl &Raw
Time (sec)

24. Pressure Control Ventilation
Flow
Pressure
Volume
Cl Cl
Set PC level
Time (sec)

25. Controlled mandatory
ventilation(CMV)
Patient can not breath spontaneously
Patient can not change the ventilator respiratory
rate
Suitable only when patient has no breathing
efforts
 Disease or
 Under heavy sedation and muscle relaxants

26. Controlled Mandatory
Ventilation (CMV)
Asynchrony and increased work of breathing.
Not suitable for patient who is awake or has own
respiratory efforts
Can not be used during weaning

27. Controlled mandatory Ventilation
(CMV) – Volume Controlled

28. Pressure Control Ventilation (PCV)

29. Intermittent Mandatory Ventilation(IMV)Pressure
 Machine breaths are delivered at a set rate (volume or pressure
limit)
 Patient is allowed to breath spontaneously from either a
demand valve or a continuous flow of gases but not offering
any inspiratory assistance.
Time (sec)

30. Intermittent Mandatory Ventilation(IMV)Pressure
 Patient’s capability determines Tidal volume of spontaneously
breaths
 Some freedom to breath naturally even on mechanical ventilator
Time (sec)

31. Intermittent Mandatory Ventilation(IMV)
 Freedom for natural
spontaneous breaths even
on machine
 Lesser chances of
hyperventilation
 Asynchrony
 Random chance of breath
stacking.
 Increase work of breathing
 Random high airway pressure
(barotrauma) and lung volume
(volutrauma)
Setting appropriate pressure limit is important to reduce the risk of barotrauma
Pros: Cons:

32. Can we synchronize
it?

33. Synchronized Intermittent Mandatory
Ventilation (SIMV)
Ventilator delivers either patient triggered assisted
breaths or time triggered mandatory breath in a
synchronized fashion so as to avoid breath stacking
 If the patient breathes between mandatory breaths, the
ventilator will allow the patient to breathe a normal breath
by opening the demand (inspiratory) valve but not
offering any inspiratory assistance.

34. SIMVPressure
If patient does not make an inspiratory effort then ventilator will deliver a
time triggered mandatory breath.
Patient trigerred
synchronized breath
Time trigerred
mandatory breath

35. Synchronized Intermittent Mandatory
Ventilation
Pressure
3 types of breathing:
1. Patient initiated assisted ventilation,
2. Ventilator generated controlled ventilation,
3. Unassisted spontaneous breath.

36. Synchronized Intermittent Mandatory
Ventilation (SIMV)
 It allows patients to assume a portion of their ventilatory drive:
Weaning is possible
 Greater work of breathing and therefore some may not consider
it as the initial ventilator mode
 Friendly cardiopulmonary interaction: Negative inspiratory
pressure generated by spontaneous breathing leads to increased
venous return, which theoretically may help cardiac output and
function

37. Synchronized Intermittent Mandatory
Ventilation (SIMV)

38. Pressure Support Ventilation
 Pressure (or Pressure above PEEP) is the setting
variable
 No mandatory breaths
 Applicable on Spontaneous breaths
 Patient effort determines size of breath and flow
rate.

39. Pressure Support Ventilation
 It augments spontaneous VT, decreases spontaneous rates
and WOB.
 Used in conjunction with spontaneous breaths in any mode
of ventilation.
 No back up ventilation in the event of apnea.

40. Pressure Support Ventilation
 Provides pressure support to overcome the increased work of
breathing imposed by the disease process, the endotracheal
tube, the inspiratory valves and other mechanical aspects of
ventilatory support.
 Allows for titration of patient effort during weaning.

41. Spontaneous Mode

42. Pressure-controlled Synchronized Intermittent
Mandatory Ventilation (PSIMV)

43. Adaptive Support Ventilation (ASV)

44. Thank you!! You have done
it!!!

45. Example 1

46. Example 2

47. Read more…
 https://www.aic.cuhk.edu.hk/web8/mechanical_ventilation.htm