Respiratory Mechanics

Question 1

In the pons, the apneustic center has what kind of effect on the respiratory system?

Answer 1

Excitatory

Question 2

In the pons, the pneumotaxic center may do what in some situations?

Answer 2

Inhibit inspiration

Question 3

In the medulla oblongata, what complex is responsible for respiratory rhythm generation?

Answer 3

Dorsal/ventral respiratory groups
Pre-Botzinger complex

Question 4

Label the volumes for total lung capacity:

Answer 4

Question 5

What is kussmaul breathing?

Answer 5

Rapid, deep breathing at a constant pace that is often associated with a medical emergency with metabolic acidosis such as DKA

Question 6

In Kussmaul breathing, what components do the peripheral chemoreceptors (primarily carotid bodies - glomus type I cells), detect which increases ventilation via the glossopharyngeal nerve?

Answer 6

Hypoxemia
Hypercarbia
Acidemia
Decreased perfusion

Question 7

These types of receptors are mostly concerned with circulation, but in severe hypotension can lead to hyperventilation

Answer 7

Baroreceptors

Question 8

For the 4 non-central receptors that can affect ventilation in kussmaul breathing, where are they located and what are they?

Answer 8

Carotid baroreceptor
Carotid body (chemoreceptor)
Aortic chemoreceptor
Aortic baroreceptor

Question 9

Where is the central chemoreceptor located in the medulla, which as blood CO2 diffuses into the CSF, it increases hydrogen ions and decreases pH?

Answer 9

Retrotrapezoid nucleus

Question 10

In kussmaul breathing, what part of the total lung capacity chart is being used to increase TV?

Answer 10

IRV

Question 11

What determines the movement of O2 and CO2 across the blood gas interface in the alveolus?

Answer 11

Fick’s law
Wall thickness
Surface area
Diffusion gradient / pressures

Question 12

CO2 is _____x more diffusible than O2

Answer 12

20x

Question 13

Changes in surface area, diffusion constant, pressure and wall thickness preferentially decrease _____ over _____

Answer 13

Preferentially decrease O2 over CO2

Question 14

Write Fick’s Law of diffusion of a gas

Answer 14

SA x D x (P1-P2)/T
SA = surface area
D = diffusion constant
P = pressure
T = thickness

Question 15

What are the transpulmonary, intrapleural and intra-alveolar pressures?

Answer 15

Question 16

What is the equation for dynamic compliance?

Answer 16

Cdyn = changeV / ChangeP

Question 17

What is the relationship between change in pressure, resistance and flow?

Answer 17

changeP = R x V*
where V* = flow

Question 18

What two components of the endotracheal tube determine the pressure drop from Paw to P1?

Answer 18

Diameter and length

Question 19

Label the pressure waveform:

Answer 19

Question 20

Define pendelluft?

Answer 20

The movement of gas between two regions of the lung, usually between regions of differing compliance or airway resistance.

Question 21

Which alveoli (upper, middle, lower) are much lower on curve due to weight of lungs above, and can accept more volume/change in pressure?

Answer 21

Lower

Question 22

With the numbers of 20, 35, 45, what is the distribution of tidal volume?

Answer 22

Upper: 20
Middle: 35
Lower: 45

Question 23

What are the 2 components that affect the pressure-volume relationship?

Answer 23

Resistance and static compliance

Question 24

30kg 6y/o MC MBD
VT = 250mL
RR = 18
Tinsp = 1 sec
PIP = 12 cmH2O
Pplat = 11 cmH2O
PEEP = 5 cmH2O

Calculate Cdyn
Calculate Cstat
Calculate R

Answer 24

Cdyn = VT/(PIP-PEEP)
35.7mL/cmH2O

Cstat= VT (Pplat-PEEP)
41.7cmH2O

R= PIP - Pplat / flow
4cmH2O/L/s

Question 25

What is the equation for Cdyn using body weight?

Answer 25

Cdyn = BW(kg) + 9

Question 26

Label the following graph and describe what procedure is being performed:

Answer 26

Expiratory hold
Helps determine air-trapping