1. Ventilator

2. CONTENT… What is a ventilator? Types of ventilators
Modes of ventilators
Types of support
Methods of ventilatory support
Indications of ventilators

3. What is a ventilator???
A ventilator is a machine that supports breathing
These machines mainly are used in hospitals
Ventilators
Get oxygen into the lungs
Remove carbon dioxide from the body
Help people breathe easier
Breathe for people who have lost all ability to breathe on their own

5. Types of ventilators…
Negative pressure
Positive pressure

6. Negative Pressure Ventilators
Applies negative pressure around the chest wall. This causes intra airway pressure to become negative. Thus drawing air into the lungs through the patients nose and mouth
No artificial airway is necessary – patient must be able to control and protect own airway
Indication
Selected patient with neuromuscular problems
Adjunct to weaning from PEEP(Positive end expiratory pressure)
Negative pressure ventilators are simply to use and do not require intubation of the airway

7. Positive Pressure Ventilators
Positive pressure ventilators inflate the lungs by exerting positive pressure on the airway, forcing the alveoli to expand during inspiration
Expiration occurs passively, endotracheal intubation or trachestomy is necessary in most cases
These ventilators are widely used in the hospital setting
There are Three types of positive pressure ventilators
Pressure cycled
Time cycled
Volume cycled

9. Modes of ventilators… Time cycled ventilators
Volume cycled ventilators
Pressure cycled ventilators
High Frequency Ventilators

10. Time delivery of gas flow; tidal volume = flow rate x inspiration time
Time cycled ventilator
Time delivery of gas flow; tidal volume = flow rate x inspiration time
Delivers relatively constant Tidal Volume
Allows precise control of gas delivery
Types: IMV-Bird, Foregger 210, Emerson 

11. Volume Cycled Ventilator
Inspiratory gas flow terminated after preselected volume delivery
Pressure in circuit determined by tidal volume and Compliance
Delivered Tidal volume changes with changes in Compliance
Types: Bennett, Ohio 560, Bourns Bear 1, Monaghan, Siemons Servo 

12. Pressure cycled ventilators 
Gas flow continues until preset pressure develops
Tidal volume = flow rate x time until pressure is reached
Variable volume if circuit pressure varies (change in compliance)
Types: bird mark, bennett PR 

13. High Frequency Ventilators
5 types
High frequency positive pressure ventilation 
Jet ventilation
Flow interruption
Oscillation
Percussive ventilation 

14. Types of support…
Control mode
Support mode

15. Control mode
In control mode, the ventilator delivers the preset tidal volume once it is triggered regardless of patient effort
If the patient is apneic or possesses limited respiratory drive, control mode can ensure delivery of appropriate minute ventilation

16. Support mode
In support mode, the ventilator provides inspiratory assistance through the use of an assist pressure
The ventilator detects inspiration by the patient and supplies an assist pressure during inspiration
It terminates the assist pressure upon detecting onset of the expiratory phase
Support mode requires an adequate respiratory drive
The amount of assist pressure can be dialed in

17. Methods of Ventilatory Support…
Continuous mandatory ventilation
Assist-control ventilation
Intermittent mandatory ventilation
Synchronous intermittent mandatory ventilation
Pressure support ventilation
Noninvasive ventilation
Continuous positive airway pressure - CPAP

18. Continuous mandatory ventilation
Breaths are delivered at preset intervals, regardless of patient effort
This mode is used most often in the paralyzed or apneic patient
Assist-control ventilation
The ventilator delivers preset breaths in coordination with the respiratory effort of the patient

19. Intermittent mandatory ventilation
With intermittent mandatory ventilation (IMV), breaths are delivered at a preset interval, and spontaneous breathing is allowed between ventilator-administered breaths
Synchronous intermittent mandatory ventilation
The ventilator delivers preset breaths in coordination with the respiratory effort of the patient

20. Pressure support ventilation
For the spontaneously breathing patient, pressure support ventilation (PSV) has been advocated to limit barotrauma and to decrease the work of breathing
Noninvasive ventilation
The application of mechanical ventilatory support through a mask in place of endotracheal intubation is becoming increasingly accepted and used in the emergency department

21. Continuous positive airway pressure - CPAP
Improves pao2 by stabilizing the airway and allowing alveolar recruitment. CO2 retention may result from excessive CPAP
Most commonly, nasal CPAP prongs (also mask, nasopharyngeal, endotracheal) used to respiratory assistance in mild rds(respiratory distress syndrome), or weaning from mechanical ventilation
Maintains upper airway patency, so useful in apnea of infancy
Gastric distension may occur; place OG tube for decompression
2-6 cm H20 commonly used.

22. Indications of ventilators …
Hypercapnic respiratory failure
Hypoxemic respiratory failure
Correction of life-threatening acidemia in the setting of salicylate intoxication
Intentional hyperventilation in the setting of major head injury with elevated intracranial pressure
Suspicion of clinical brain herniation from any cause
Patient in critical condition with cyclic antidepressant toxicity

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