Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Boards: Respiratory > Ventilator Waveform Interpretation. Corona > Flashcards

Ventilator Waveform Interpretation. Corona Flashcards

1
Q

What are the different types of ventilator patient dyssynchrony?

A
  • trigger dyssynchrony
  • flow dyssynchrony
  • cycle dyssynchrony
  • expiratory dyssynchrony
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What determines the inspiratory time in MV?

A
  • flow rate and tidal volume

TI (inspiratory time) = VT / flow rate

can use set inspiratory time and flow rate to determine VT –> VT = flow rate x inspiratory time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What determines the cycle time in MV?

A

cycle time (Tc) = inspiratory time (Ti) + expiratory time (TE)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how can you approximate pleural pressure?

A

by measuring esophageal pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Explain the pressure changes in the pleural space (Ppl) and alveoli (PA) during spontaneous breathing

A

at the end of inspiration or expiration PA is equal atmospheric (0 cm H2O), i.e., no air flow

Ppl is about - 5 cm H2O at end of expiration and - 10 cm H2O at end of inspiration

during inspiration PA is about -3 to -5 cm H2O –> air flow in

during expriation PA is about + 5 cm H2O –> air flow out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What can you assess with the plateau pressure?

A
  • approximation of the PA (alveolar pressure)
  • assess airway resistance
  • assess static respiratory system compliance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are risk factors for Auto-PEEP?

A
  • short expiratory times
  • high minute ventilation
  • inreased airway resistance leading to collapse of small airways before expiration is complete (bronchospasms, increased secretions, mucosal edema)
  • small endothracheal tube
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the respiratory compliance

A

ease at which the lungs distend, i.e., elastic forses that oppose lung inflation

change in volume for a given change in pressure –> C = volume change/ pressure change

sum of the lung compliance and compliances of surrounding thoracic structures (influences by lungs, pleural space, chest wall, intra-abdominal structures)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe respiratory elastance

A

elastic properties arising from the lungs and thorax

elastic forces together with frictional forces oppose lung inflation

elastance describes the tendency of the lungs and chest wall to return to their origninal form after being distended (recoil)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does the resistance to airflow through conductive airways depend on?

A

viscosity and density of the gas
flow rate of the gas
length and diameter of the conductive airways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe the equation of motion during mechanical or spontaneous ventilation

A

The pressure applied to the respiratory system that must work against the compliance and resistance of the respiratory system

ventilator pressure + muscle pressure = elastic recoil pressure + flow resistance

elastic recoil pressue = elastance x volume
flow resistance = resistance x flow

so … ventilator pressure + muscle pressure = (elastance x volume0 + (resistance x flow)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the two ways a patient can trigger a breath in assist-control mode?

A
  • change in pressure (e.g., - 2 cm H2O)
  • change in flow (e.g., 2 L/min)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the rise time?

A

determines how quickly the ventilator achieves the set target pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are your differentials for a patient where the volume does not reach 0 by the end of expiration of the volume/time scalar?

A
  • air leak
  • bronchopulmonary fistula
  • gas trapping (auto-PEEP)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are your differentials for a patient where the volume goes below 0 at the end of expiration of the volume/time scalar?

A

active exhalation by the patient
flow transducer malfunction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What determines the expiratory flow limb on the flow/time scalar?

A
  • airway resistance
  • resistance of the artificial airways
  • elastic recoil
17
Q

what directions do volume/pressure loops move in spontaneous versus PPV?

A

clockwise in spontaneous breath as whith volume increase negative pressure is needed (inspiratory limb on the left of the y axis, and expiratory on the right/positive side)

counter-clockwise in PPV, pressure increases with volume increase during inspiration. both inspiration and expiration are on the right side of the y axis

18
Q

What does this volume pressure loop indicate?

A

Volume doesn’t return to 0 –> doesn’t expire all air that is given, e.g., bronchopulmonary fistula, air leak

19
Q

What does a left/up or down/right shift of the pressure/volume loop indicate?

A

up/left - increased compliance
down/right decreaed compliance

20
Q

What does a widening of the pressure/volume loop indicate?

A

increased resistance

21
Q

Explain what the upper and lower inflection points indicate and how you can use these values to improve ventilation strategies.

A

Lower inflection point (LIP) indicates pressure at which large number of alveoli are recruited

upper inflection point (UIP) indicates pressure at which alveoli become overdistended (“beaking”)

ideally ventilate patient between LIP and UIP - i.e., set PEEP above LIP and set VT below UIP

22
Q

what is this flow-volume loop change indicative of?

A
  • airway obstruction, i.e., increased resistance
  • “scooping”
23
Q

What is this change in the flow-volume loop indicative of?

A
  • “saw tooth” sign
  • commonly from increased airway secretions
24
Q

What is this change in the flow-volume loop indicative of?

A
  • gap between the expiration and the beginning of inspiration
  • indicative of an air leak (volume does not return to baseline
25
Q

What are the most common causes of trigger dyssynchrony?

A
  • insensitive or too sensitive trigger settings
  • Auto-PEEP –> makes triggering more difficult –> patient needs more inspiratory effort to generate large enough change in baseline pressure or baseline flow
26
Q

What is another term for flow dyssynchrony?

A

Flow starvation

27
Q

Which mode of ventilation is more likely to cause flow dyssynchrony? how can this ventilation mode be adjusted to reduce flow starvation?

A

volume-controlled ventilation - constant flow rate may not be sufficient

can change this to descending flow pattern - starting with stronger flow

pressure-controlled ventilation is more synchronous in patients with high flow demands

28
Q

What is this mode of ventilation and what dyssynchrony is seen in B?

A
  • Volume-controlled mandatory machine-triggered breaths
  • flow-starvation/flow dysynchrony

scooped out appearance of the inspiratory limb indicating patient is actively trying to pull in more air than the machine is giving - patient effort inspiration lowers pressure –> so inspiratory pressure is lower

29
Q

How can flow dyssynchrony lead to auto-PEEP?

A

as the flow is insufficient –> may lead to prolonged inspiratory time –> decreases time for expiraiton –> auto-PEEP

30
Q

What are the two types of cycle dyssynchrony?

A
  • patient exhales before ventilator completed inspiration - delayed breath termination
  • ventilator stops inspiratory flow before the patient has completed inspiraiton - premature breath termination
31
Q

What does this PV loop indicate?

A

flow starvation

32
Q

Explain what is seen on these flow and pressure scalars

A

cycle dyssynchrony

premature/early breath termination - patient is trying to still breathe in after the machine terminated the breath

33
Q

Explain what is seen on thse flow and pressure scalars

A

cycle dyssynchrony

delayed breath termination - patient is trying to exhale while the machine is continuing the breath

34
Q

Explain the dyssynchrony in A and what was changed to achieve patient-machine synchrony as seen in B

A

A: delayed breath termination - patient is trying to exhale while the machine is still giving a breaht

B: shortening the inspiratory time

35
Q

What are the two types of expiratory dyssynchrony?

A
  • Prolonged expiratory time –> leads to hypoventilation
  • Shortened expiratory time –> leads to auto-PEEP
36
Q

What does this Flow-time scalar indicate?

A

Auto-PEEP

37
Q

What does this Flow-Volume loop indicate?

A

Auto-PEEP

Boards: Respiratory (27 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions