Test 5 Ch. 17 Concepts of MV Flashcards

1
Q

What is the goal of MV ?

A

To reduce the WOB by providing adequate alveolar gas exchange with minimal damage to lung tissue (barotrauma) and/or interference with the circulatory system

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

Most common conventional neonatal ventilators use _____________- limited modes in order to protrct the newborn’s lungs from _______________.

A

pressure;
barotrauma

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

In pressure-limited modes, a mechanical positive pressure breath will be terminated once a

A

preset peak inspiratory pressure (PIP) has been reached

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

PIP is a ________ variable that will not allow the delivered breath to result in a pressure greater than the set PIP

A

limit

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

Pts with poor lung complaince require

A

higher PIP levels than those with good compliance to achieve the same tidal volume

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

PEEP levels are usually kept between

A

3 to 5 cm H20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Higher PEEP leads to…

A

increased Pmean which results in increased intrathoracic pressure and possible reduction of cardiac output

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Frequency or rate is considered a trigger variable determined by the cycle time of each breath

A

**

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

The initial breath rate varies but should be started at ___ to ___ bpm

A

20 to 40

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

Preterm neonates may require rates as high as

A

60 bpm

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

inspiratory time (itime) is set by the operator and is a cycle variable that will

A

cycle the breath into exhalation once the preset IT is achieved

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

Mean airway pressure (MAP) is the average pressure exerted on the airway and lungs from the beginning of inspiration until the beginning of the next inspiration

A

**

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

MAP is the most powerful influence on oxygenation and must be carefully monitored because high levels of MAP lead to (3)

A

decreased cardiac output, pulmonary hypoperfusion, and increased risk of barotrauma

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

MAP levels above ___ have been associated with barotrauma

A

12 cm H20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The amount of gas inhaled in a single breath is called the

A

tidal volume

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

What are the 2 ventilator parameters that most directly affect the tidal volume in pressure control ventilation are

A

PIP and PEEP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Minute ventilation (VE) is tidal volume x RR

A

**

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What vent changes can alter VE? (3)

A
  • PIP
  • PEEP (alters Vt)
  • RR
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

VE is broken down into alveolar ventilation, the portion participating in gas exchange and dead space ventilation, the portion not participating in gas exchange

A

**

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Deadspace is any gas that does not particpate in

A

gas exchange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Deadspace is divided into two categories:

A

anatomic and alveolar deadspace

22
Q

Anatomic deadspace is the

A

volume of tidal gas that fills the airways at the end of inspiration

23
Q

Anatomic deadspace in a neonate is roughly (range)

A

2 to 2.2 mL/kg

24
Q

Alveolar deadspace is that portion of tidal gas that

A

fills unperfused alveoli and is impossible to determine

25
Q

The total of anatomic and alveolar deadspace is called

A

physiological deadspace (Vd)

26
Q

What is driving pressure?

A

The difference between the PEEP and the PIP

27
Q

In theory, when mechanically ventilating a neonate, the driving pressure must be equal to the opening pressure to open and ventilate the alveoli.

A

**

28
Q

For example, if the opening pressure is determined to be 20 cm H2O and we desire a PEEP of 4 cm H2O, a PIP of 24 cm H2O would have to be used to achieve a driving pressure that is equal to opening pressure.

A

**

29
Q

FRC is the amount of gas remaining in the lungs at the

A

end of a passive exhalation

30
Q

Alveolar ventilation is also affected by the length of time that the gas is in contact with the alveoli, or the diffusion time.

A

**

31
Q

The ______ rate determines the wave pattern of the ventilator breath

A

flow

32
Q

PEEP may impact the FRC, which can alter ____________.

A

compliance

33
Q

A change in compliance might require altering

A

PIP, resulting in possible alterations of time constants, expiratory time, and the I:E ratio

34
Q

Changes in Fio2 does not change other parameters

A

**

35
Q

A change in PIP will change both compression pressure and ______ _________ leading to a change in VE and an alteration of alveolar ventilation

A

tidal volume

36
Q

The alteration of alveolar ventilation leads to changes in ________ which changes pH

A

PaCO2

37
Q

A change in PEEP level also changes

A

driving pressure and Vt leading to the same alterations mentioned with PIP changes

38
Q

According to Hooke’s law of elasticity, when an elastic substance is stretched, tension develops that is proportional to the degree of deformation that is produced. Thus, the more it is stretched, the more force it produces to recoil to its original size and shape.

A

**

39
Q

recoil is measured by applying a known pressure to the lung and the change in volume that occurs is measured. This relationship between a given change in volume and the pressure difference required to achieve that volume change is called

A

compliance

40
Q

Define static compliance

A

The change in volume for any given applied pressure

41
Q

How is static compliance measured? (Pplat)

A

When there is no airflow through the lungs at the end of inhalation through an inspiratory hold maneuver

42
Q

Compliance measured during an active breath is called (PIP)

A

dynamic compliance

43
Q

Dynamic compliance better reflects the

A

elastic recoil in the lungs

44
Q

What is normal compliance in a neonate

A

2.5 to 5 mL/cm H2O

45
Q

What are the 2 determinants of lung compliance?

A
  • alveolar surface forces
  • elastic elements in the lung tissues
46
Q

The thorax, like the lungs, is an elastic structure. It differs from the lung in that it recoils inward or outward, whereas the lung only recoils inward. The direction of thoracic recoil depends on the volume in the thorax.

A

**

47
Q

Diseases that increase surface forces in the alveoli (RDS) decrease compliance and increase the amount of pressure required to ventilate the lungs. As the alveoli shrink in size, the FRC is reduced. Higher pressure is now needed to inflate the alveoli.

A

**

48
Q

Define airway resistance (Raw)

A

The driving pressure needed to move gases through the airways at a constant flow rate

49
Q

For every decrease in the radius, resistance increases to the fourth power. Who’s law is that?

A

Poiseuille’s

50
Q

What is normal airway resistance in a spontaneous neonatal?

A

20-30 cm H2O