Test 5 Ch. 17 Concepts of MV

Question 1

What is the goal of MV ?

Answer 1

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

Question 2

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

Answer 2

pressure;
barotrauma

Question 3

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

Answer 3

preset peak inspiratory pressure (PIP) has been reached

Question 4

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

Answer 4

limit

Question 5

Pts with poor lung complaince require

Answer 5

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

Question 6

PEEP levels are usually kept between

Answer 6

3 to 5 cm H20

Question 7

Higher PEEP leads to…

Answer 7

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

Question 8

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

Answer 8

**

Question 9

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

Answer 9

20 to 40

Question 10

Preterm neonates may require rates as high as

Answer 10

60 bpm

Question 11

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

Answer 11

cycle the breath into exhalation once the preset IT is achieved

Question 12

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

Answer 12

**

Question 13

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

Answer 13

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

Question 14

MAP levels above ___ have been associated with barotrauma

Answer 14

12 cm H20

Question 15

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

Answer 15

tidal volume

Question 16

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

Answer 16

PIP and PEEP

Question 17

Minute ventilation (VE) is tidal volume x RR

Answer 17

**

Question 18

What vent changes can alter VE? (3)

Answer 18

• PIP
• PEEP (alters Vt)
• RR

Question 19

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

Answer 19

**

Question 20

Deadspace is any gas that does not particpate in

Answer 20

gas exchange

Question 21

Deadspace is divided into two categories:

Answer 21

anatomic and alveolar deadspace

Question 22

Anatomic deadspace is the

Answer 22

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

Question 23

Anatomic deadspace in a neonate is roughly (range)

Answer 23

2 to 2.2 mL/kg

Question 24

Alveolar deadspace is that portion of tidal gas that

Answer 24

fills unperfused alveoli and is impossible to determine

Question 25

The total of anatomic and alveolar deadspace is called

Answer 25

physiological deadspace (Vd)

Question 26

What is driving pressure?

Answer 26

The difference between the PEEP and the PIP

Question 27

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

Answer 27

**

Question 28

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.

Answer 28

**

Question 29

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

Answer 29

end of a passive exhalation

Question 30

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

Answer 30

**

Question 31

The ______ rate determines the wave pattern of the ventilator breath

Answer 31

flow

Question 32

PEEP may impact the FRC, which can alter ____________.

Answer 32

compliance

Question 33

A change in compliance might require altering

Answer 33

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

Question 34

Changes in Fio2 does not change other parameters

Answer 34

**

Question 35

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

Answer 35

tidal volume

Question 36

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

Answer 36

PaCO2

Question 37

A change in PEEP level also changes

Answer 37

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

Question 38

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.

Answer 38

**

Question 39

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

Answer 39

compliance

Question 40

Define static compliance

Answer 40

The change in volume for any given applied pressure

Question 41

How is static compliance measured? (Pplat)

Answer 41

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

Question 42

Compliance measured during an active breath is called (PIP)

Answer 42

dynamic compliance

Question 43

Dynamic compliance better reflects the

Answer 43

elastic recoil in the lungs

Question 44

What is normal compliance in a neonate

Answer 44

2.5 to 5 mL/cm H2O

Question 45

What are the 2 determinants of lung compliance?

Answer 45

- alveolar surface forces - elastic elements in the lung tissues

Question 46

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.

Answer 46

**

Question 47

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.

Answer 47

**

Question 48

Define airway resistance (Raw)

Answer 48

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

Question 49

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

Answer 49

Poiseuille’s

Question 50

What is normal airway resistance in a spontaneous neonatal?

Answer 50

20-30 cm H2O