Anesthesia Ventilators (Exam III)

Question 1

What were the deficiencies of older ventilators?

Answer 1

• Couldn’t provide high enough inspiratory pressure
• No PEEP
• Offered only volume control ventilation.

Question 2

What allows driving gas to exit the bellows housing?

Answer 2

Exhaust valve

Question 3

What is fresh gas compensation?

Answer 3

Machine compensation meant to prevent FGF from affecting set V_T.

Question 4

What is the inspiratory pause time?
What is another name for this?

Answer 4

Inspiratory Plateau = time in which lungs are held in the inflated position.

Question 5

What is the ratio for inspiration to expiration?

Answer 5

1:2 typically

Question 6

What is inverse ratio ventilation?

Answer 6

When I:E is inversed so that inspiratory time is double that of expiratory time.

Question 7

What is minute volume?

Answer 7

V_T for one minute = V̇_T

Question 8

When is peak pressure measured?

Answer 8

Inspiratory phase

Question 9

What ventilator valve that allows excess gas to scavenged during exhalation?

Answer 9

Spill valve

Question 10

What is work of breathing?

Answer 10

Energy expended by patient/ventilator to inhale and exhale.

Question 11

What are the factors that affect delivered V_T?

Answer 11

• FGF
• Compliance
• Leaks

Question 12

Decreases in compliance cause a decrease in _____.

Answer 12

V_T

Question 13

What is the driving gas?

Answer 13

O₂ and/or medical air

Question 14

What alarms are required on a ventilator?

Answer 14

Low Pressure
High Pressure

Question 15

What is a good set point for our pressure limiting mechanism?

Answer 15

10 cmH₂O above the patients average inspiratory pressure.

10 cmH₂O above peak pressure.

Question 16

What allows for observation of the bellows?

Answer 16

Bellows Housing (clear plastic cylinder)

Question 17

What are the advantages/disadvantages of an ascending bellows?

Answer 17

• Safer
• Descends on inspiration
• Fails to rise if disconnected

Question 18

Ascending bellows will _______ on inspiration.

Answer 18

descend

Question 19

What are the advantages/disadvantages of a descending bellows?

Answer 19

• Rises on inspiration
• Continues to descend (d/t gravity) even if disconnected

Question 20

What would occur with a bellows if an NGT were placed in the lung?

Answer 20

Bellow would collapse & “clap” due to lack of air in the lung.

Question 21

What factors affect deliver V_T?

Answer 21

• FGF
• Compliance
• Leaks

Question 22

What is the most commonly used ventilator mode?

Answer 22

Volume Control

Question 23

What parameters are set during VC ventilation?

Answer 23

• V_T
• Respiratory rate
• I:E ratio

Question 24

What should a patients V_T be set to?

Answer 24

4-6 cc/kg

Question 25

Would V̇_T increase or decrease with tachypnea in a patient on volume control?

Answer 25

Increase. ↑ RR = ↑ V̇_T on VC.

Question 26

What parameters are set with Pressure Control (PC) ventilation?

Answer 26

- PIP - RR - I:E ratio

Question 27

What factor changes with Pressure Control ventilation?

Answer 27

V_T

Question 28

What causes changes in tidal volume with pressure control ventilation?

Answer 28

Resistance & compliance

Question 29

________ lungs are necessary with pressure control ventilation.

Answer 29

Compliant

Question 30

What lung ventilation mode will protect the lung from excess pressures (and thus barotrauma) ?

Answer 30

PC (Pressure Control)

Question 31

How would one better fill the lung in pressure control mode?

Answer 31

- ↑ inspiratory time - ↑ RR

Question 32

This mode of ventilation prevents sudden V_T changes due to compliance.

Answer 32

Volume guarantee Pressure Control

Question 33

What's an example of something that would cause a rapid change in compliance?

Answer 33

Loss of insufflation

Question 34

How does Volume Guarantee Pressure Control ventilation work?

Answer 34

Maintains V_T by adjusting PIP over several breaths

Question 35

This mode of ventilation gives a set tidal volume in response to negative pressure (aka attempted breath).

Answer 35

Assist Control (AC) Ventilation

Question 36

Which type of ventilation allows for patient initiated inspiration at variable tidal volumes?

Answer 36

Intermittent Mandatory Ventilation (IMV)

Question 37

How do Intermittent mandatory ventilation and Assist Control ventilation differ?

Answer 37

Each requires a patient inspiratory effort & negative pressure. - AC = set tidal volume - IMV = variable tidal volumes

Question 38

Which type of ventilation allows for breath "stacking"?

Answer 38

IMV

Question 39

What is SIMV?

Answer 39

Spontaneous Intermittent Mandatory Ventilation This allows for synchronization of ventilator breaths w/ patient attempted breaths.

Question 40

Which parameters are set with Pressure Support?

Answer 40

- PIP - Inspiratory time

Question 41

Which ventilator mode necessitates an apnea alarm?

Answer 41

Pressure Support

Question 42

Which ventilator mode would be best for weaning off a ventilator?

Answer 42

1. Pressure Support (PS) 2. SIMV

Question 43

What are common causes of ventilator failure?

Answer 43

- Disconnection from power supply - ↑ ↑ ↑ FGF - Fluid in electronic circuitry - Leak in bellows housing

Question 44

What two factors could cause a loss of breathing system gas?

Answer 44

- Failure to occlude spill valve - System leak

Question 45

100% of a gas is ________ ppm.

Answer 45

1,000,000

Question 46

1% of a gas is ______ ppm.

Answer 46

10,000

Question 47

Where are higher levels of trace gas noted?

Answer 47

- Pediatric anesthesia - Dental surgeries - Poorly ventilated PACU's

Question 48

What issues are potentially associated with trace amounts of VAA's?

Answer 48

- **Spontaneous abortions** - **Infertility** - Birth defects - Impaired performance - Cancer - Liver disease - Cardiac disease

Question 49

What is a passive scavenging system?

Answer 49

Exhaled gasses are vented to OR atmosphere and then room ventilation system removes.

Question 50

What is an active ventilation system?

Answer 50

- High volume 30L/min - Lots of suction - Attached to central vacuum system that directly removes exhaled gasses.

Question 51

What are possible causes of hypercapnia associated with the anesthesia machine and ventilator?

Answer 51

- Hypoventilation - Absorbent failure - ↑ V_D - Defective Coaxial system