Mechanical ventilation provides positive pressure to move gas into the lungs. There are two main types: volume-controlled ventilation which preselects tidal volume and pressure-controlled ventilation which preselects pressure. Modes include controlled mandatory ventilation (CMV), assisted control ventilation (AC), and synchronized intermittent mandatory ventilation (SIMV). Positive end-expiratory pressure (PEEP) is used to prevent alveolar collapse. Weaning involves gradually reducing ventilator support by shifting modes and rates until the patient can breathe independently. Complications include barotrauma, infection, and weakness.

1. NUR AINA BINTI AB KADIR
MECHANCAL VENTILATION

2. CONTENTS
Introduction Types Components
Indications Modes
Dual mode
ventilation
Complications Weaning

3. INTRODUCTION
 The fundamental operation of positive pressure
ventilation is to create a pressure that moves a
volume of gas into the lungs.
 1. Volume-controlled ventilation , where the inflation
volume (tidal volume) is preselected, and the
ventilator automatically adjusts the inflation pressure
to deliver the desired volume. The rate of lung
inflation can be constant or decelerating.
 2. Pressure-controlled ventilation, where the inflation
pressure is preselected, and the duration of inflation
is adjusted (by the operator) to deliver the desired
tidal volume. The rate of lung inflation is high at the
onset of lung inflation (to achieve the desired inflation
pressure), then rapidly decelerates (to maintain a

4. TYPES
INVASIVE
NON
INVASIVE

5. NON INVASIVE
 Have respiratory failure but no urgent need of
intubation
 Conscious and cooperative
 No risk of aspiration
 Tightly fitted mask

6. CONTRAINDICATION
 Contraindication :
 Cardiac and respiratory arrest
 Severe hypoxemia
 High risk of aspiration
 Facial trauma
 Inability to protect airways
 Upper GI bleed

7. COMPLICATIONS
 Leakage Hypoventilation
 Inconvenience and claustrophobia
 Increase chance of aspiration
 Skin breakdown, facial edema on prolonged use

8. INITIAL SETTING OF
VENTILATOR
 Tidal volume : 6-8 ml
 I:E ratio : 1:2
 Frequency : 10-12 breaths/min
 Inspiratory flow rate : 60-80 liters/min
 PEEP : 3-5 cmH2O
 Trigger sensitivity : -1 to -2 cmH2O
 FIO2 : 0.5 (50%)

9. INDICATIONS

10. OTHERS
 Excessive fatigue of respiratory muscle
 Loss of protective airway reflexes
 Inability to cough adequately

11. MODES
 Controlled mode ventilation (CMV)
 Assisted controlled ventilation (AC)
 Synchronized intermittent mandatory ventilation (SIMV)
 Positive end expiratory pressure (PEEP)
 Continuous positive airway pressure (CPAP)
 Inverse ratio ventilation (IRV)
 Pressure support ventilation (PSV)
 Pressure controlled ventilation (PCV)
 Bi-level positive airway pressure (BIPAP)
 Airway pressure release ventilation (APRV)
 High frequency ventilation

12. CONTROLLED MODE
VENTILATION(CMV)
 No spontaneous effort from patient.
 All breath are fully provided by ventilator.
 Control both pressure and volume

13. ASSISTED CONTROL
VENTILATION (VC)
 Patient’s spontaneous breath is assisted.
 If spontaneous breath exceed preset rate, no
control breath will be delivered and vise versa.

14. SYNCHRONIZED INTERMITTENT
MANDATORY VENTILSTION (SIMV)
 Similar to control
mode.
 Whatever the preset
mode, it is consider
mandatory.
 ventilator synchronize
its breath with
patient’s breath.

15. SYNCHRONIZED INTERMITTENT
MANDATORY VENTILSTION (SIMV)
 Advantages over
CMV :
 Less hemodynamic
depression (less
cardiac output)
 Less need of heavy
sedation or muscle
relaxants
 Less V/Q mismatch
 More rapid weaning
 Disadvantages :
 Use lots work of
breathing (leads to
muscle fatiggue)
 Increase chance of
hypocapnia (due
hyperventilation)

16. POSITIVE END EXPIRATORY
PRESSURE (PEEP)
 Positive pressure is
given at end of
expiratory :
 Prevent alveolar
collapse
 Lead to gas exchange
during expiration
 Used in :
 Pulmonary edema
 ARDS
 In thoracic surgery to
minimise bleeding
 Physiological PEEP

17. SIDE EFFECTS OF PEEP
 hypotension and
decrease cardiac
output
 Increase pulmonary
artery pressure and
right ventricular strain
 Increase dead space
 Increase pleural
pressure
 Increase mediastinal
pressure
 Increase intracranial
pressure

18. CONTINUOUS POSTIVE AIRWAY
PRESSURE (CPAP)
 Continuously the positive pressure is given.
 Help prevent alveolar collapse.
 Used for spontaneously breathing patient

19. INVERSE RATIO VENTILATION
 Inverse the inspiration and expiration ratio from
1:2 to 2:1.
 It prolonged the gas exchange time as inspiration
time is more

20. PRESSURE SUPPORT
VENTILATION
 Preset pressure is given to achieve desired tidal
volume.
 The PEEP preset are 8 cmH2O and then titrated
to achieve desired tidal volume.
 Can be used alone or combine with SIMV.
 Help in decrease work of breathing and overcome
resistance offered by endotracheal tube and
ventilator tubing.

21. PRESSSURE CONTROLLED
VENTILATION(PCV)
 Similar to pressure support ventilation.
 Difference is :
 Ventilator will cycle to expiration once a
predetermined time is elapse in the inspiration (time
cycle).
 Advantages :
 Less chance of barotrauma
 Have choice to extending the inspiratory time
 Disadvantages :
 Tidal volume can vary with airway pressure

22. BI-LEVEL POSITIVE AIRWAY
PRESSURE (BIPAP)
 Similar to continuous positive airway pressure.
 But it have typical setting :
 8-20 cmH2O on inspiration(IPAP)
 5 cmH2O on expiration(EPAP)
 Combination of PEEP and CPAP.

23. AIRWAY PRESSURE RELEASE
VENTILATION (APRV)
 Combine with PEEP and CPAP.
 Make a periodic release of pressure to decrease
incidence of barotrauma and hypotension.

24. HIGH FREQUENCY
VENTILATION
 Used in condition
where exact tidal
volume cannot be
delivered.
 Thus minute volume
is compensated by
high frequency.
 Indication :
 Bronchopleural fistula
 Bronchoscopies
 Microlaryngeal
surgery
 Emergency ventilation
through cricothyroid
membrane

25. HIGH FREQUENCY
VENTILATION
 High frequency ventilation may be :
 High frequency of positive pressure : 60-120
cycles/min
 High frequency jet ventilation : 100-300 cycles/min
with gases at high pressure
 High frequency oscillations : 600-3000 cycles/min

26. DUAL MODE VENTILATION
 Combine both pressure and volume ventilation.
 Modes used :
 Pressure controlled ventilation – volume guaranteed
 Bi-level volume guaranteed

27. COMPLICATIONS
 Pulmonary barotrauma
 Infection
 Due to prolonged intubation
 Due inadequate ventilation
 GIT
 Cardiovascular
 CNS
 Liver and kidney dysfunction
 Neuromuscular weakness
 Oxygen toxicity
 Physiological
 Due to prolonged bed rest

28. WEANING
 Discontinuing of ventilator support.
 Method :
 Shift from control/assist mode to SIMV.
 Decrease the rate of breathing till 1 to 2 breath/min.
 If tidal volume not sufficient give pressure support.
 Once tidal volume and frequency achieved,
disconnected it.
 If normal cardiac and pulmonary functions
maintained, extubation can be done.

29. WHEN??
 Initial setting in normal range
 Rapid shallow breathing index (RSBI)
 Normal arterial pH
 Normal hemoglobin
 Normal cardiac status
 Normal electrolyte
 Adequate nutritional status

30. REFERENCES
 Short textbook of Anaesthesia,Ajay Yaday,5th
edition
 The ICU Book, Paul L. Marino, 3rd Edition.