Viva Crash Course

Question 1

Phases of breath delivery/variables:

Answer 1

1. Trigger (how it begins)
2. Control or target (preset)
3. Cycling (how it ends)

Question 2

Common triggers:

Answer 2

1. Time trigger
2. Flow trigger
3. Pressure trigger

Question 3

Control variable

Answer 3

Defines which aspect of inspiration is the primary variable controlled by the ventilator during inspiration
(pressure and flow)

Question 4

What is a trigger variable?

Answer 4

Variable which determines when a ventilator initiates a machine-driven breath

Question 5

2 control variables:

Answer 5

1. Flow

2. Pressure

Question 6

Calculate compliance

Answer 6

Compliance= ^Volume/ ^Pressure

Question 7

3 Cycling variables:

Answer 7

1. Flow
2. Volume
3. Time

Question 8

3 breath types:

Answer 8

1. Mandatory
2. Assisted
3. Spontaneous

Question 9

Describe mandatory breaths (trigger/support)

Answer 9

Triggered by the ventilator with full level of support

Question 10

Describe assisted breaths (trigger/support)

Answer 10

Triggered by the patient, either full support or partial support

Question 11

Describe spontaneous breaths (trigger/support)

Answer 11

Non-triggered and no support

Question 12

Tidal volume

Answer 12

Volume of each breath

Question 13

Respiratory rate:

Question 14

I:E Ratio

Answer 14

The ratio of inspiratory time to expiratory time

Question 15

Fi02

Answer 15

The fraction of inspired oxygen delivered on inspiration to the patient

Question 16

PEEP is?

Answer 16

Residual airway pressure at the end of inspiration

Question 17

Why is humidification important

Answer 17

1. Warm and moisten gas to facilitate cilia action and mucous removal
2. Prevent drying and irritation or mucosa
3. prevent solidification of secretions

Question 18

Describe CMV

Answer 18

Controlled mandatory ventilation

Breaths = mandatory; nil pt trigger

Requires deep sedation and paralysis so is not usually used outside of OT

Question 19

Describe assist-control ventilation

breath type, trigger, cycle

Answer 19

Mix of machine (mandatory) or patient (assisted) triggered breaths, but ALL ARE CYCLED by the VENTILATOR.

Ventilator senses inspiratory effort by the patient and responds by delivering breath.

Patient can vary RR, but a backup rate is set to prevent hypo ventilation.

Question 20

Disadvantages of assist-control ventilation:

Answer 20

Can lead to:

1. Resp alkalosis
2. Auto-peep
3. Hypotension in ^ventilating pts

Question 21

Advantages of Assist control ventilation

Answer 21

activation of the diaphragm with patient triggering

Question 22

SIMV (stands for?) uses what breaths?

Answer 22

Synchronized intermittent mandatory ventilation

Preset minimum number of mandatory breaths (Pi or VC) AND also allows spont breaths inbetween

Question 23

Describe the 3 breaths in SIMV

Answer 23

Mandatory breaths: non-synchronized, time triggered, time cycled)

Synchronized breaths: non-sychronized, pressure or flow triggered, time cycled)

Non- Synchronized breaths: Pressure or flow triggered, flow cycled)

Question 24

Difference between AC & SIMV spontaneous breaths?

Answer 24

AC- Full support

SIMV - Partial support

Question 25

Cycling variable:

Answer 25

What signals the ventilator to terminate ventilation

Question 26

Volume controlled ventilation

Answer 26

Flow (preset tidal volume) delivered to the airway is constant. Changes in airway resistance or compliance results in variable pressures

Question 27

Pressure control

Answer 27

Pressure delivered to the airway is constant regardless of airway resistance or compliance (variable tidal volumes)

Question 28

Pressure control ventilation indications:

Answer 28

Patients with particularly high chance of barotrauma

Question 29

Pressure control ventilation

Answer 29

Mandatory breaths only, patient unable to trigger Time: pressure:time

Question 30

Pressure support ventilation

Answer 30

No mandatory breaths, all patient triggered Pressure applied by the vent augments patient effort during the breath

Question 31

Time variable

Question 32

COPD patients may do better with what trigger?

Answer 32

Flow

Question 33

With volume controlled ventilation, when will the ventilator cease inspiration?

Answer 33

After the preset volume has been delivered

Question 34

With flow cycled ventilation, when will the ventilator cease inspiration?

Answer 34

After airflow drops below a preset threshold, typically approx 25% peak flow

Question 35

With time cycled ventilation, when will the ventilator cease inspiration?