Vents

Question 1

Barotrauma Definition

Answer 1

Injury resulting from high airway pressures

Question 2

Compliance definition

Answer 2

ratio of a change in volume to a change in pressure
- decreases in compliance in breathing system causes a decreased in Vt as volume is used to expand the system (volume controlled)

Question 3

Definition of work of breathing

Answer 3

energy expended by the pt or vent to move gas in and out of the lungs

Question 4

peak pressure definition

Answer 4

maximum pressure during the inspiratory phase time

Question 5

inspiratory pause time definition

Answer 5

time during which lungs are held infleated at a fixed volume/pressure
inspiratory plateau

Question 6

What is the spill valve?

Answer 6

valve on the vent that allows excess gases to be sent to the scavending system during exhalation

Question 7

What is the exhaust valve?

Answer 7

valve that opens to allow driving gas to exit the bellows housing

Question 8

What is the most commonly used vent mode?

Answer 8

Volume control - preset tidal volume is delivered (this is a fixed parameter)
- can cause excessive inspiratory pressure
- certain pt positions can restrict compliance

Question 9

Describe pressure control

Answer 9

Preset pressure the machine delivers, so the Vt can be variable depending on the pressures in the lungs (changes with resistance and compliance)
- can cause atelectasis and hypoventilation

Question 10

Describe volume guaranteee pressure-control

Answer 10

• maintains Vt by adjsting PIP over several breaths
• prevents suddend changes to Vt based on compliance changes (i.e. insufflation)
• basically it adjusts itself by knowing the pattern

Question 11

Describe assist control ventilation

Answer 11

• pt tries to take a breath (the negative pressure activates the vent and the machine delivers another preset breath (but pt can stack breaths so be careful with hyperinflation)
  Pt initiated + machine preset parameters

Question 12

Describe intermittent mandatory ventilation

Answer 12

• mandatory breaths are set with vent
• but with negative pressure from the pt, the volume will only be delivered what the pt pulls
• can stack breaths (so be careful with hyperinflation)

Question 13

Describe SIMV

Answer 13

Synchronized intermittent mandatroy ventilation will synchronize the ventilator driven breaths with the pts spontaneous breaths (i.e. no breath stacking -fix to IMV - because SIMV has a mandatory inspiratory pause)

Question 14

describe pressure support

Answer 14

Pressure support has the PIP and inspiratory time set which helps keep alveoli open on exhalation (a little different than PEEP)
need apnea alarm because this is used for weaning and it completely pt triggered