Chapter 29-ARDS

Question 1

What causes pulmonary edema

Answer 1

When the rate of leakage into the lungs exceeds the lungs capacity to remove fluid

Question 2

How do the lungs clear fluid

Answer 2

Lymphatic drainage

Question 3

Net exchange of fluid between intravascular space and lung interstitum is controlled by

Answer 3

Hydrostatic and osmotic pressure within the blood and interstitum

Question 4

Capillary hydrostatic and interstitial osmotic forces are normally (more/less) than the capillary osmotic and interstitial hydrostatic forces opposing

Answer 4

More

This encourages a small fraction of cardiac output from the capillaries into the interstitial space

Question 5

What is seen on a chest X-ray with pulmonary edema

Answer 5

Kerley b lines

Question 6

Large increases in interstitial hydrostatic pressure are caused by

Answer 6

Small increases in lung fluid content

Question 7

Hydrostatic pulmonary edema occurs when?

Answer 7

The pressure or volume of water exceeds the lungs ability to remove fluid and the alveoli flood

Question 8

Non hydrostatic pulmonary edema occurs when?

Answer 8

There is a hole in the interstitum which fluid leaks through

Question 9

What are common cardiac causes of hydrostatic pulmonary edema

Answer 9

Left ventricular failure

Valve disease

Question 10

What are volume related causes of hydrostatic pulmonary edema

Answer 10

Excessive fluids
Renal or liver failure
Hypoalbuminemia

Question 11

Hydrostatic pulmonary edema causes what type of pleural fluid

Answer 11

Transudate fluid

Question 12

Non hydrostatic pulmonary edema causes what type of pleural fluid

Answer 12

Exudate

Question 13

Ards is caused by

Answer 13

Non hydrostatic pulmonary edema

Question 14

Congestive heart failure is caused by

Answer 14

Hydrostatic pulmonary edema

Question 15

Symptoms that present in both ards and chf

Answer 15

Anxiety
Dyspnea
Tachypnea
Hypoxemia

Question 16

Features favouring chf

Answer 16

Diffuse, bilateral infiltrates
Elevated pcwp
Response to diuretics
Transudate fluid

Question 17

Features favouring ards

Answer 17

Asymmetric infiltrates on cxr
Little to no improvement with diuretics in first 24 hrs
Exudate fluid

Question 18

Risk factors of ards

Answer 18

Pneumonia
Aspiration
Near drowning
Sepsis
Trauma
Burns 
Pancreatis

Question 19

Chf typically presents with

Answer 19

Caridomegaly
Perihilar infiltrates
Pleural effusions

Question 20

Ards typically presents with

Answer 20

Air bronchgrams
Alveolar infiltrates
Normal cardiac size

Question 21

When is the educative phase

Answer 21

Day 1-7

Question 22

When is the fibroproliferative phase

Answer 22

3 days- weeks

Question 23

What happens in the exudaitive phase

Answer 23

Damage to alveoli and blood vessels
Influx of fluid and cells into interstitial space and alveoli
Fully reversible if the cause is found and treated early

Question 24

What causes barotrauma

Answer 24

High pressures rupturing alveoli

Question 25

What is the result of barotrauma

Answer 25

Air leaks outside of alveoli causing pneumothorax or pneumomediastinum

Question 26

What is volutrauma

Answer 26

Stretch injury caused by high tidal volumes

Question 27

What happens to alveoli in volutrauma

Answer 27

Overstretching results in leaky alveolar capillary walls which triggers an inflammatory cascade

Question 28

What is the risk with high respiratory rates? ( 35+)

Answer 28

Can cause auto peep and impaired perfusion

Question 29

Where is consolidation the worst in ards

Answer 29

Dependant lung regions (posterior regions when patient is supine)

Question 30

How does proning work?

Answer 30

We are putting the good parts of the lungs down to improve V/q mismatch

Question 31

How do vasodilator work in ards

Answer 31

Well ventilated areas of the lungs receive mist of the vasodilator. This means well ventilated areas receive a greater portion of blood flow, reducing v/q mismatch

Question 32

Two examples of pul Kmart vasodilators

Answer 32

Epoprostenol

Nitric oxide

Question 33

When should inhaled vasodilators be considered in ards

Answer 33

Pf less than 80

Question 34

When should proning be done in ards

Answer 34

Pf less than 150

Question 35

Treatments for ards?

Answer 35

Ventilation with low tidal volumes
Proning
Inhaled vasodilators
Ecmo