Types of Mechanical Ventilators Flashcards
How are ventilators classified?
according to their mechanism of force, which is either negative or positive pressure
How in negative pressure ventilation performed?
the patient’s entire body or thoracic region is encased in an airtight unit
What is the amount of negative pressure needed determined by?
the desired tidal volume. The higher the desired tidal volume, the higher the negative pressure required
What do positive pressure ventilators commonly require?
an artificial airway to deliver ventilatory support
What are the 4 types of cycling done by positive pressure ventilators?
pressure cycled, volume cycled, time cycled, and flow cycled
How does pressure-cycle ventilation work?
delivers a preset pressure of gas to the lungs
How does volume-cycled ventilation work?
delivers a preset volume of gas to the lungs, making volume the constant and pressure the variable
What is the advantage of using volume-cycled ventilation?
it can overcome changes in lung compliance and airway resistance
What is a risk associated with volume-cycled ventilation?
barotrauma may occur
What is barotrauma?
injury to pulmonary tissue, particularly the alveoli, as a result of excessive pressure
How does time-cycled ventilation work?
the length of time allowed for inspiration is controlled and the volume and pressure of the ventilation may vary
What is limited for a time-cycled ventilator?
the amount of pressure that can be delivered
How does flow-cycled ventilation work?
A preset pressure augments the patient’s inspiratory effort and continues as long as the patient continues to inhales at a certain flow rate
Negative pressure ventilators adjust the tidal volume by doing what?
Altering the amount of negative pressure applied
The term cycle as it applies to mechanical ventilation refers to the mechanism by which what occurs?
Inspiration ceases and expiration starts.
