Mechanical ventilation is a method used to assist or replace spontaneous breathing by using physical devices. It can be used to treat acute respiratory failure, provide prophylactic support, or induce hyperventilation. There are two main types: negative pressure ventilation which applies lower pressure outside the chest and positive pressure ventilation which applies higher pressure inside the lungs. Common ventilator modes include assist control, SIMV, pressure control, and pressure support. Proper monitoring, settings, and care are needed to prevent complications while the patient is ventilated.

1. MECHANICAL VENTILATION
Capt Femi

2. What is….
 Mechanical ventilation is a therapeutic method that is to
assist or replace spontaneous breathing.
 It is any means in which physical devices or machines are
used to assist or replace spontaneous breathing.

3. Indications….
Acute respiratory failure
Prophylactic ventilatory support
Hyperventilation

4. Acute Respiratory Failure
 Perfusion mismatch
 Right to left shunt
 Alveolar hypoventilation
 Decreased inspired oxygen
 Tissue hypoxia
 Example : CNS disorders, Neuro-muscular disorders
pleural occupying lesions,

5. Prophylactic support
 Suspected risk of future respiratory failure
 Its instituted to
 decrease the WOB
Minimize hypoxemia
Reduce cardiopulmonary stress
Control airway with sedation.

6. Hyperventilation therapy
 Ventilator support meant to control and manipulate
paCO2 to lower than normal levels.
- Head injury.

7. Types ….
Negative pressure ventilation: pressure
lower than atmospheric pressure is
applied to extra thoracic space during the
inspiration.
Positive pressure ventilation: pressure
higher than atmospheric pressure is
applied to the intra alveolar space during
inspiration.

8. Negative v/s Positive
Major Advantages
 Negative pressure : Non –invasive
No need for sedation
Patient able to eat & drink
 Positive pressure : Higher levels of FiO2
individualized treatment
full ventilator support.

9. VENTILATOR MODES
Volume modes Pressure modes
CMV or CV PCV
AMV or AV PSV
IMV CPAP
SIMV PEEP
BIPAP

10. Ventilator Modes
 Assist control: all breaths once triggered, are treated
the same, and have a consistent TV.
 SIMV: mandatory breaths are synchronised with
spontaneous breaths.
 Pressure control ventilation: patient unable to trigger
the ventilator.
 Pressure support ventilation: no mandatory breaths.

11. Assist or Control Mode
 Delivers a preset volume at a preset rate and a preset
flow rate
 The patient cannot generate spontaneous volume, or
floe rate
 Volume or Pressure control mode
parameters: V/P ,Rate, FiO2.

12. Synchronized Intermittent
Mandatory Ventilation.
 Delivers a preset no of breaths at a set volume and rate.
 Allows the patient to generate spontaneous breaths,
volumes, and flow rate between the set breaths.
 Detects patient’s spontaneous breaths .
 Works well as weaning mode.

13. Positive end expiratory pressure
 This is not a specific mode
 It is the amount of pressure remaining in the lung at
the end of expiratory phase.
 Improving oxygenation and prevents lung collapse.
 Usually 5-10 cmH2O

14. NIV-PPV
 Delivering O2 enriched gas under pressure without
endo tracheal intubation.
 Usually providing with tight fitting face mask
1. CPAP
2.BPAP
In both a preset positive pressure is applied during
inspiration and lower pressure is applied during
expiration at the mask.

15. Indications for NPPV
 Obstructive sleep apnea
 Neuromuscular disease
 Weaning from ventilator
 In immuno-compromised state.

16. CPAP
 A preset pressure is present in the circuit and lungs
throughout both the inspiratory and expiratory phases
of the breath.
 CPAP serves to keep alveoli from collapsing , better
oxygenation and less WOB
 Commonly used to evaluate the patients readiness for
extubation.

17. Intubation procedure
 Confirmation by
Auscultation
Bilateral chest rise
Length of the tube
 spO2 monitoring

18. Initiation of mechanical ventilation
 Initial setting
- Tidal volume 4-7ml/kg
- Respiratory rate 8-12 breaths/min
- Minute ventilation Tv*f
- PEEP 3-8 cmH2O
- FiO2 40%-100%
- Inspiratory flow
- set PEEP
-Inspiratory time

19. Monitoring
ABG : keep acid/base balance within normal range
pH 7.35-7.45 , pCO2: 35-45, pO2: 80-100mmHg
 spO2
 Hemodynamic status
 Need of sedation

20. Alarm settings…
 Low tidal volume: system leak, circuit disconnection
 High minute ventilation : 10-15% above set data
 High respiratory rate : above 16 breaths per minute
 High inspiratory pressure: kinking,water,secretions
 High/low FiO2 alarm
 Apnea alarm: less than 8 breaths per minute

21. Protective lung ventilation
 Tidal volume close to 6ml/kg body weight
 Lowest spO2 90%
 PEEP to maintain alveolar patency
 Sedation and analgesia
 DVT prophylaxis
 Bed sore prevention
 Nutrition

22. Complications …
 Airway complications: aspiration, clearance of
secretions, VAP
 Mechanical : hypo/hyperventilation, barotrauma,
failed alarms, overheated air
 Physiological : fluid overload, paralytic ileus, gastric
istension, starvation,ulcers

23. General measures
1.Infection control
2.multi-disciplinary
team
Aspiration
Head elevation
ET cuff pressure
Subglottic secretion
drainage
Decontamination
Oral decontamination
Selective GI decontamination
Early extubation
Early weaning
Sedation brakes
VAP

24. Nursing care
 Assess the patient
 Assess the artificial airway
 Assess the ventilator
 Assist in weaning