Ch. 3 How a Breath is Delivered Test 2

Question 1

The phases of a breath and the variable that controls each portion of the breath is called a

Answer 1

phase variable

Question 2

The _________ variable begins with inspiration

Answer 2

trigger

Question 3

This limits the value of pressure, volume, flow, or time during inspiration

Answer 3

limit variable

Question 4

The limit variable does not

Answer 4

end inspiration

Question 5

This ends inspiration

Answer 5

cycle variable

Question 6

The baseline pressure establishes the….

Answer 6

baseline during exhalation before inspiration is triggered

Question 7

What is usually identified as the baseline variable

Answer 7

Pressure

Question 8

The mechanism the vent uses to begin inspiration is the

Answer 8

triggering mechanism (trigger variable)

Question 9

When the vent can initiate a breath after a set time, that is referred to as

Answer 9

time triggering

Question 10

When the pt can initiate a breath based on pressure, flow, or volume, is referred to as

Answer 10

pt triggering

Question 11

What are the most common triggering variables (2)

Answer 11

pressure and flow

Question 12

___________ triggering and _______ triggering from the diaphragm output can also be used

Answer 12

volume and neural

Question 13

The vent delivers a mandatory breath by beginning inspiration after a set time has elapsed

Answer 13

time triggering

Question 14

The number of mandatory breaths delivered by the vent is based on the

Answer 14

length of TCT
(Ex: If the vent is set a 10bpm, every 6 seconds the vent will trigger a breath)

Question 15

When the vent detects changes in pressure, flow,or volume what breath occurs?

Answer 15

a pt-triggered breath

Question 16

___________ and ______ are common pt-triggered mechanism

Answer 16

Pressure and flow

Question 17

How can the RT pt enable pt triggering?

Answer 17

The RT must specify the sensitivity setting called pt effort (pt-triggering) control

Question 18

Sensitivity can either be _________ or ______

Answer 18

pressure or flow

Question 19

The less pressure or flow change require to trigger a breath

Answer 19

the more sensitive the machine is to the pt’s effort

(Ex: The vent is more sensitive to the pt effort at a setting of 0.5 cm H20 than a setting of -1 cm H20)

Question 20

The sensitivity level for pressure triggering is usually set at about

Answer 20

-1 cm H20

Question 21

If the sensitivity level is set incorrectly the vent may not be

Answer 21

sensitive enough to the pt’s effort and the pt will need to work too hard to trigger the breath

Question 22

If the vent is too sensitive, it can cause

Answer 22

auto-trigger
(the machine triggers a breath w/o the pt making an effort)

Question 23

This occurs when the vent detects a drop in flow in the pt circuit during exhalation

Answer 23

Flow triggering

Question 24

Flow triggering has been shown to require less WOB than

Answer 24

pressure triggering

Question 25

Occurs when the vent detects a small drop in volume in the pt circuit during exhalation

Answer 25

Volume triggering (the machine interprets the decrease in volume as a pt effort and begins inspiration)

Question 26

______________ is timed from the beginning of inspiratory flow to the beginning of ____________.

Answer 26

Inspiration; expiratory

Question 27

A limit variable is the..

Answer 27

maximum valve that a variable (pressure, volume, flow, or time) can attain

Question 28

Reaching the set limit variable,

Answer 28

DOES NOT END INSPIRATION

Question 29

Example of limit variable: A ventilator is set to deliver a maximum pressure of 25 cm H20 and the inspiratory time is set to 2 seconds. The maximum pressure that can be attained during inspiration is 25 cm H20, BUT inspiration will end only after 2 seconds have passed. - Such breath is described as a pressure-limited, time-cycled breath

Answer 29

Something to know

Question 30

What are some types of variables (3)

Answer 30

- pressure - volume - flow

Question 31

This allows pressure to rise to a certain value but not exceed it

Answer 31

Pressure limited

Question 32

To prevent excessive pressure from entering the pt's lungs, what is set?

Answer 32

A high-pressure limit control

Question 33

When the vent reaches the high-pressure limit control...

Answer 33

excess pressure is vented through a spring-loaded pressure release pop-off valve

Question 34

This is controlled by an electronically operated valve that measures the flow passing through the vent circuit during a specific interval

Answer 34

volume limited

Question 35

If gas flow from the vent to the pt reaches but does not exceed a maximum value before the end of inspiration, the vent is

Answer 35

flow limited (only a certain amount of flow can be provided)

Question 36

The variable that the vent uses to end inspiration is called the

Answer 36

cycling mechanism

Question 37

Only one of four variables can be used at any given time by the vent to end inspiration. What are they?

Answer 37

- volume - time - flow - pressure

Question 38

When a breath is terminated when the Vt has been delivered

Answer 38

Volume cycled

Question 39

Example of volume cycled: If I have a pt set to get 500mL of Vt, once that 500mL has been given, the breath will end and the pt will cycle into expiration

Answer 39

Something to know

Question 40

In most cases this remains constant even if the pt's lung characteristics change

Answer 40

volume

Question 41

The __________ required to deliver the set volume and gas flow will vary as the pt's respiratory system compliance and Raw changes

Answer 41

pressure

Question 42

The volume of gas that leaves the vent outlet is not the volume that enters the pt's lungs

Answer 42

Tubing compressibility

Question 43

During inspiration, positive pressure builds up in the pt circuit resulting in..

Answer 43

expansion of the pt circuit and compression of some gas in the circuit. The compressed gas never reaches the pt's lungs (Boyle's)

Question 44

For every 1 cm, how much gas is lost to tubing compressibility? (range)

Answer 44

1 to 3mL

Question 45

Example of time cycled If I set the vent at 10bpm, every 6 seconds the time will cycle the breath into expiration.

Answer 45

This is based on TCT

Question 46

The interval is controlled by a timing mechanism in the vent, which is not affected by the pt's

Answer 46

respiratory system compliance or airway resistance

Question 47

With this, an increase in airway resistance or a decrease in compliance does not affect the flow pattern or volume delivery as long as the working pressures of the vent are adequate

Answer 47

time-cycled, volume control ventilation

Question 47

A breath is considered ______ ___________ if the inspiratory phase ends when a predetermined time has elapsed

Answer 47

time cycled

Question 48

With this both volume and flow vary

Answer 48

time-cycled, pressure control

Question 49

Time-cycled, pressure controlled is commonly called

Answer 49

pressure-controlled ventilation

Question 50

Why is pressure-controlled ventilation used?

Answer 50

The inspiratory pressure can be limited, which protects from lung injuries caused by high pressures, however the variability of the Vt delivery can be a concern

Question 51

With flow-cycled ventilation, the vent

Answer 51

cycles into the expiratory phase once the flow has decreased to a predetermined value during inspiration

Question 52

With flow-cycled what 3 things can vary based on changes in lung CharacterIstics

Answer 52

- volume - pressure - time

Question 53

Flow cycling is the most common cycling mechanism used in

Answer 53

pressure support mode

Question 54

In pressure cycled ventilation, inspiration ends when a

Answer 54

set pressure threshold is reached at the mouth or **upper airway**

Question 55

During pressure-cycled ventilation, the volume delivered to the pt depends on the... (4)

Answer 55

- flow delivered - the duration of inspiration - the pt's lungs characeteristics - the set pressure

Question 56

What is an advantage of pressure cycle vents?

Answer 56

They limit peak airway pressures (avoids barotrauma)

Question 57

What is a disadvantage of pressure-cycled vents?

Answer 57

Anytime lung characteristics change, the pt may not receive the Vt that is intended

Question 58

Pressure cycling occurs in...

Answer 58

volume-controlled breaths when the pressure exceeds the maximum safety high-pressure limit

Question 59

This is designed to maintain air in the lungs at th end of inspiration before the exhalation valve opens

Answer 59

Inflation hold (Inspiratory pause)

Question 60

During an inflation hold, the

Answer 60

inspired volume remains in the pt's lung and the expiratory valve remains closed for a brief period or pause time

Question 61

Inflation hold is done to?

Answer 61

To get the plateau pressure (Pplat)

Question 62

What calculation is the Pplat used in?

Answer 62

static compliance

Question 63

What is the purpose of doing an inflation hold?

Answer 63

It used to increase peripheral distribution of gas and improve oxygenation

Question 64

The expiratory phase encompasses the period from the

Answer 64

end of inspiration to the beginning of the next breath

Question 65

The main concern during expiration is

Answer 65

Does the pt have enough time to exhale to baseline

Question 66

During MV, expiration begins when inspiration

Answer 66

ends, the expiratory valve opens, and the expiratory flow begins

Question 67

What can occur if the expiratory time is to short

Answer 67

Air-trapping

Question 68

If an adequate amount of time is not provided for exhalation, air-trapping and hyperinflation can occur leading to a phenomenon called

Answer 68

auto-PEEP or intrinsic PEEP

Question 69

The baseline variable is the parameter that generally is

Answer 69

controlled during exhalation

Question 70

Baseline pressure can be..... Or it can be

Answer 70

zero (atmospheric) zero end-expiratory pressure (ZEEP); positive if the baseline pressure is above zero, positive end-expiratory pressure (PEEP)

Question 71

REMEMBER Baseline pressure is PEEP in the Dynamic and static equation

Answer 71

something to know

Question 72

____________ is the most common baseline

Answer 72

Pressure

Question 73

______________ _______ or end-expiratory pause is a maneuver transiently performed at the end of expiration

Answer 73

Expiratory hold

Question 74

What is the purpose of the expiratory hold?

Answer 74

To measure pressure associated w/ air trapped in the lungs at the end of expiration (auto-PEEP)

Question 75

Can you do this measurement on a spontaneous breathing pt?

Answer 75

No

Question 76

How can pts accomplish a prolonged expiration?

Answer 76

Pursed-lip breathing

Question 77

What is the purpose of pursed-lip breathing

Answer 77

To create back pressure so that the alveoli do not collapse on expiration

Question 78

How do vents mimic pursed-lip breathing?

Answer 78

Expiratory retard, which added a degree of resistance to exhalation

Question 79

Expiratory retard should prevent

Answer 79

early airway closure and improve ventilation

Question 80

What are 2 methods of applying continuous pressure to the airways which have developed to improve oxygenation in pt's w/ refractory hypoxemia?

Answer 80

- CPAP - PEEP

Question 81

CPAP involves the application of

Answer 81

pressure above ambient pressure throughout inspiration and expiration to improve oxygenation in a spontaneous breathing pt

Question 82

PEEP involves applying

Answer 82

positive pressure to the airway throughout the respiratory cycle

Question 83

_______ becomes the baseline pressure during MV

Answer 83

PEEP

Question 84

CPAP and PEEP help prevent early airway closure and alveolar collapse at the end of expiration by

Answer 84

increasing (and normalizing) the pt's FRC, which in turn allows for better oxygenation

Question 85

PEEP is defined as

Answer 85

positive pressure at the end of exhalation during spontaneous breathing or MV