Ventilator

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 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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