Post on 22-Mar-2016
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Ventilator
CONTENT…•What is a ventilator?•Types of ventilators•Modes of ventilators•Types of support•Methods of ventilatory support•Indications of ventilators
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
Types of ventilators…
•Negative pressure•Positive pressure
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
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
Modes of ventilators…•Time cycled ventilators•Volume cycled ventilators•Pressure cycled ventilators•High Frequency Ventilators
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
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
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
High Frequency Ventilators5 types•High frequency positive pressure ventilation •Jet ventilation•Flow interruption•Oscillation•Percussive ventilation
Types of support…
•Control mode•Support mode
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
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
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
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
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
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
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.
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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