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
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
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.