Respiratory Mechanics

Question 1

Formula for pressure

Answer 1

P = vol/compliance + resistance x flow

Question 2

Name the four mechanical barriers to effectively ventilate

Answer 2

Increase surface tension

Decreased elastance/recoil forces

Decreased compliance

Increased Aw resistance

Question 3

Define elastance

Answer 3

Resistance to stretch

Question 4

What do elastin fibers do to the alveoli

Answer 4

Stretch them out and snap them back

Question 5

Which way do the elastic fibers go

Answer 5

Outwards

Question 6

What does the opposing direction of the elastic fiber of the thorax do

Answer 6

Creates sub-atmopheric pressure in the pleura space

Question 7

What is a major contributor of the elastic recoil force of the lungs

Answer 7

Surface-tension forces

Question 8

What’s the formula for compliance

Answer 8

Change in volume/change in pressure

Question 9

What are the major factor that determine CL

Answer 9

Distensibility of lung tissues and chest wall

Surface tension of alveoli

Question 10

What is the avg. compliance in the lungs and chest wall of a health adult

Answer 10

.2L/cmH2O or 200mL

Question 11

What is the compliance of the entire system

Answer 11

0.1L/cmH2O

Question 12

What is the normal respiratory compliance of a MV patient

Answer 12

0.05-0.1L/cmH2O

Question 13

Formula for Cdyn

Answer 13

VT/PIP-PEEP

Question 14

What is the formula for Cstat

Answer 14

VT/Pplat-PEEP

Question 15

What are the two types of resistance

Answer 15

Tissue: 20%

Aw: 80%

Question 16

What happens to the pleura pressure when inhale forcefully

Answer 16

Becomes more negative

Question 17

What is the transpulmonary/transmural pressure (PL)

Answer 17

Difference inside and outside the lungs

Aw opening and Pleura pressure

Make alveoli expand and prevents collapse

Question 18

What equals the intra-alveolar pressure

Answer 18

The sum of chest wall and lung recoil pressure

Question 19

Intrapulmonary pressure is the sum of

Answer 19

Palv and PA

Question 20

The transpulmonary pressure is the sum of

Answer 20

Palv and Ppl

Pao and Ppl

Question 21

Units of measurement for aw resistance

Answer 21

CmH20/L/sec

Question 22

How much aw resistance does the average person have

Answer 22

0.5-2.5cmH2O/L/sec

Base flow 30L/min

Question 23

Formula for Raw

Answer 23

See photos

Question 24

PIP of a 20 year old

Answer 24

10-15cmH2O

Question 25

PIP of a 50-60 year old

Answer 25

20-30cmH2O

Question 26

PIP of a very sick person

Answer 26

>35cmH2O

Question 27

Pplat of a health 20 year old

Answer 27

10-15cmH2O

Question 28

Pplat of a 50-60 year old

Answer 28

15-30cmH2O

Question 29

Pplat of a very sick person

Answer 29

>30cmH2O

Question 30

PEEP for a health 20 year old

Answer 30

5-8cmH2O

Question 31

PEEP for a 50-60 year old

Answer 31

8-10cmH2O

Question 32

PEEP of a very sick person

Answer 32

>10cmH2O

Question 33

MAP of a 20 year old

Answer 33

7-8cmH2O

Question 34

MAP of a 50-60 year old

Answer 34

15-18cmH2O

Question 35

MAP of a very sick person

Answer 35

>20cmH2O

Question 36

Other name for intra-alveolar pressure

Answer 36

Alveolar/intrapulmonary pressure

Question 37

Other name for pleural pressure

Answer 37

Intrapleural pressure

Question 38

Other names for Pao

Answer 38

PATM PB

Question 39

What is the value of pleural pressure

Answer 39

755

Question 40

What is the transpulmonary pressure the sum of

Answer 40

The difference between the intraalveolar on intrapleural Or Airway opening and pleural (+4)

Question 41

Other name for transpulmonary (PTP)

Answer 41

Transmural pressure (PL)

Question 42

What pressure gradient is responsible for keeping the lungs inflated

Answer 42

Transpulmonary pressure

Question 43

What what is the other name for the three zones of the lungs

Answer 43

West zones

Question 44

Describe lower zone

Answer 44

More perfusion Less ventilation Optimal gas exchange Small numerous alveoli Pv> PA

Question 45

Describe middle zone

Answer 45

Balanced perfusion to ventilation PRESSURE Pa> PA Both > Pv

Question 46

Describe upper zone

Answer 46

More ventilation to perfusion Larger alveoli ⬆️ pressure than artery Both> pulmonary vein

Question 47

What influences blood flow

Answer 47

Gravity-Dependent

Question 48

How is the blood flow for the middle zone

Answer 48

Moderate, and or inconsistent and intermittent

Question 49

Why standing is the lower zone better

Answer 49

Higher perfusion and ventilation Even though it’s a lower ratio comparatively

Question 50

When a person is standing where is the V/Q higher

Answer 50

Apices Perfusion is nearly absent

Question 51

What happens when there is unventilated alveoli

Answer 51

Localized vasoconstriction

Question 52

How does the lung compensate when alveoli receives a low level of CO2

Answer 52

Constriction of alveolar duct

Question 53

Order of bottom section of hysteresis

Answer 53

PEEP Alveolar recruitment and AW resistance Optimal compliance Alveolar overdistention

Question 54

Mechanical causes of VILI

Answer 54

Overdistension Alveolar recruitment/ derecruitment Stress concentration

Question 55

Chemical cause of VILI

Answer 55

Biotrauma Oxygen toxicity

Question 56

Types of overdistension

Answer 56

Barotrauma Voltrauma

Question 57

Type of alveolar recruitment

Answer 57

Atlectrauma

Question 58

Types of biotrauma

Answer 58

Release of inflammatory mediators Activation/proliferation of neutrophils

Question 59

What triggers prostaglandins

Answer 59

Proliferation of neutrophils

Question 60

Types of inflammatory mediators

Answer 60

Endotoxins Cytokines Microparticles Prostaglandin

Question 61

What do endotoxins do

Answer 61

Synthesizes NO1 causing vasodilation (Hypotension and septic shock)

Question 62

What does endotoxins injure

Answer 62

Endothelium of vessels

Question 63

What do prostaglandins do

Answer 63

Increase clotting by causing platelets aggregation

Question 64

What triggers cytokines

Answer 64

T-cells responding to inflammation

Question 65

What do cytokines do

Answer 65

Trigger activation and response of neutrophils

Question 66

What do neutrophils do to capillaries

Answer 66

Adhere to endothelium and occlude and damage cells increasing permeability.

Question 67

Define the upper inflection point

Answer 67

Point where there is regional overdistension

Question 68

Define lower inflection point

Answer 68

Minimum pressure required for for alveolar recruitment