Basics

Question 1

Exhalation on a ventilator is?

Answer 1

Passive. Affected by lung and tubing resistance

Question 2

CMV is?

Answer 2

Controlled mandatory ventilation - fixed volume at a fixed rate

Question 3

The IE ratio is normally?

Answer 3

1:2

Question 4

A higher IE ratio is useful in?

Answer 4

COPD, asthma

Question 5

A lower IE ratio is useful in?

Answer 5

Collapse

Question 6

The two variables of inspiratory time are?

Answer 6

Inspiratory flow and inspiratory pause

Question 7

CMV advantages?

Answer 7

Precise control of CO2. Simple

Question 8

CMV disadvantages?

Answer 8

Very uncomfortable, increasing resistance = increasing pressure until limit reached and cycles to expiration

Question 9

High tidal volumes cause?

Answer 9

Volu-trauma, or stretch related injury

Question 10

Limiting volumes to what mL/kg improves outcomes

Answer 10

7mL/kg or less

Question 11

CO2 in head injury should be?

Answer 11

Kept at the upper limit of normal

Question 12

Higher FiO2 can cause?

Answer 12

Nitrogen washout causing alveolar collapse, vasospasm, apoptosis, worsened patient outcomes

Question 13

PEEP minimises… ?

Answer 13

Derecruitment, Work of breathing

Question 14

PEEP side effects?

Answer 14

Reduced venous drainage from brain, pulmonary hyperventilation and increased shunting

Question 15

PCV is?

Answer 15

Pressure controlled ventilation

Question 16

Volume of breath in PCV is determined by?

Answer 16

Pressure, time pressure is applied over, and the circuit

Question 17

The inflow pattern in PCV can be adjusted by changing the?

Answer 17

Ramp time

Question 18

Advantages of PCV are?

Answer 18

Limits pressure applied to lungs, better distribution of flow to slow filling lung units

Question 19

Disadvantages of PCV are?

Answer 19

Less strict control of CO2, can lead to underventilation

Question 20

2 methods ventilators use to detect patient effort?

Answer 20

flow or pressure trigger

Question 21

Pressure trigger works by?

Answer 21

Detecting a drop in circuit pressure as the patient attempts to inhale, and opening the demand valve

Question 22

Flow trigger works because modern ventilators have?

Answer 22

Bias flow

Question 23

Flow trigger is detected by a reduction in flow to the?

Answer 23

Expiratory flow sensor

Question 24

Benefits of flow over pressure triggering?

Answer 24

Less effort to reach threshold, also a delay exists between effort and breath in pressure trigger

Question 25

Sensitivity of triggering needs to be goldilocks because?

Answer 25

Either does not recognise attempts to breathe or other stimuli can cause a breath ‘autocycling’

Question 26

What can cause autocyclings?

Answer 26

Condensate in the ventilator tubing, cardiac oscillations, patient movements

Question 27

ACV is?

Answer 27

Assist control ventilation - patient effort will result in a breath identical to the mandatory breath

Question 28

Limitations of ACV?

Answer 28

Increased respiratory rate from patient effort, tidal volume cannot be regulated by the patient, high proportion of time spent in inspiration - breath stacking and raised intrathoracic pressures

Question 29

In ACV, respiratory muscles are active…?

Answer 29

Through most/all of the duration of the breath, not just the start

Question 30

SIMV is?

Answer 30

Synchronised intermittent mandatory ventilation

Question 31

The point of SIMV is?

Answer 31

To set a mandatory backup breathing strategy, allowing the patient to otherwise regulate breathing

Question 32

In SIMV the mandatory breaths are?

Answer 32

Timed to coincide with patient effort

Question 33

SIMV works by?

Answer 33

A set assist window/synchronised period which waits to see if the patient will attempt a breath, then delivers a set breath

Question 34

Patient triggered breaths can be identified by?

Answer 34

A dip immediately prior to a delivered breath on a flow curve

Question 35

Additional breaths in SIMV are?

Answer 35

Pressure supported breaths, not mandatory breaths

Question 36

Advantages of SIMV?

Answer 36

Background strategy for safety
Synchronised
Additional breaths are supported
Patient can partly control volumes

Question 37

As a weaning tool, SIMV is?

Answer 37

Inferior to other methods

Question 38

Pressure support breaths are different from PCV because?

Answer 38

The length and tidal volume is influenced by patient effort

Question 39

Higher volumes occur with higher patient effort in pressure support because?

Answer 39

Negative intrapleural pressures

Question 40

Exhalation in pressure support is triggered by?

Answer 40

A fall in flow (

Question 41

Pressure setting in pressure support can be adjusted to?

Answer 41

Allow comfortable amount of effort to achieve a certain tidal volume

Question 42

If patient effort is too low in pressure support it will manifest as?

Answer 42

Tachypnoea and distress

Question 43

When is pressure support set to zero

Answer 43

Never, because of resistance of circuit

Question 44

Automated tube compensation is?

Answer 44

The exact pressure to match the resistance of a circuit

Question 45

Apnoea mode is?

Answer 45

In pressure support ventilation, as a safety feature

Question 46

Causes of a high pressure alarm are?

Answer 46

Biting, kinking, sputum, migration of tube, bronchoconstriction, ptx/htx, patient effort, intra-abdominal compartment syndrome

Question 47

High pressure caused by the patient can be detected by?

Answer 47

Bag valve masking the patient

Question 48

Causes of falling compliance?

Answer 48

Pneumonia, ptx, ARDS, APO, effusions, burns

Question 49

Low pressure alarms are used to?

Answer 49

Detect air leaks

Question 50

Low volume alarms are useful in?

Answer 50

Smaller volume leaks, such as around an underinflated cuff or an access port in the system

Question 51

High volume alarms usually occur when?

Answer 51

Compliance rises, RR increases or pressure support is too high. Can be from hypoxia, acidosis, anxiety, pain, fever or PE