ARDS

Question 1

***T or F: ARDS is a cause of acute respiratory failure.

Answer 1

True

Question 2

***Among all of the causes of ARDS, what is the common denominator?

Answer 2

Intense Inflammation => mediators like IL-1, IL-6, TNF-alpha and other causes lung inflammation

• Inflammation results in destruction of alveoli and the leaking of HIGH protein (exudate) fluid into interstitial space

Question 3

***Name 4 common precipitating causes of Acute Respiratory Distress Syndrome.

Answer 3

PAST 
• Pneumonia 
• Aspiration
• Sepsis
• Trauma

Question 4

***T or F: edema in ARDS is associated with Left Ventricular Heart Failure.

Answer 4

FALSE, ARDS is severe NON-CARDIOGENIC pulmonary edema

Question 5

***Why do people with ARDS suffer from hypoxemia?

Answer 5

ARDS = PULMONARY SHUNT

• they can’t ventilate the lung (V/Q ~ 0)

Question 6

***What effect does ARDS have on lung compliance?

Answer 6

ARDS causes an acute decrease in lung compliance

Question 7

***How do we correct the ventilation defect in ARDS? Why does this work?

Answer 7

PEEP - positive end expiratory pressure

1. RECRUITS ATELECTATIC ALVEOLI
2. INCREASES FUNCTIONAL RESIDUAL CAPACITY (FRC)

Question 8

**What is the death rate of ARDS? **What causes death?

Answer 8

30-40% of people with ARDS die from it

people die from MULTI-ORGAN FAILURE

Question 9

• **Why is there a risk of dying form pneumothorax in ARDS patients?
• **WHEN is this most likely to happen?

Answer 9

WHY?
• PEEP distends alveoli and may cause lungs to develop holes that cause pneumothorax

WHEN?
• Most likely to happen after the 2nd week of illness

Question 10

***Do you want to use a high or low tidal volume when using Mechanical Ventilation on people with ARDS?

Answer 10

• LOW tidal volume is best because it reduces risk of rupture
• REDUCES MORTALITY
**Additionally, research by Dr. Waters has shown that increased lung distention can induce fibrosis thus increasing the long term complications of ARDS

Question 11

• **How do you want to manage the DIET of someone with ARDS?
• **WHY would you do this?

Answer 11

• Reduce fluids
• No salt

***Reducing fluids reduces the number of days patients have to spend on Mechanical Ventilation (MV)

Question 12

***T or F: Prone Ventilation reduces mortality in patients with ARDS.

Answer 12

TRUE

Question 13

***If you survive an ARDS, what are the long term consequences?
• how will these problems progress with time after ARDS?

Answer 13

Long Term Consequences:
• mild to moderate RESTRICTIVE ventilatory defect
• mild reduction in DLCO (DIFFUSION defect too)

***Lungs will gradually improve over the year after treatment

Question 14

***T or F: NO improves mortality in ARDS patients

Answer 14

FALSE, it improves oxygenation but DOES NOT reduce mortality

Question 15

Why is edema in ARDS exudative instead of transudative?

Answer 15

ARDS edema is due to destruction of tissue that leads to leakage of protein rich content

Cardiogenic etiologies causes transudative leakage because the filter is still in tact but pulmonary vascular pressure increases

Question 16

Will ARDS patients respond well to supplemental O2?

Answer 16

No because this is a shunting issue

Question 17

What 4 key things are you looking for in a patient that you suspect has ARDS?

Answer 17

1. ACUTE onset of RESPIRATORY FAILURE
2. BILATERAL infiltrates on CXR
3. NO evidence of VOLUME OVERLOAD
4. PaO2/FiO2

Question 18

Besides making it difficult to breath was does the protein rich exudate in ARDS do?

Answer 18

Exudate cause dysfunction of Surfactant in ARDS patients

Question 19

Causes of ARDS via direct injury:
• Pneumonia
• Pulmonary Contusion, Penetrating Injury
• Fat Emboli
• Near Drowning
• Inhalation Injury

Answer 19

Cause of ARDS via INdirect injury:
• SEPSIS
• Severe trauma with shock/hypoperfusion
• Drug over dose
• Cardiopulmonary Bypass
• Acute Pancreatitis 
• Transfusion of Blood products 
• TRALI - Transfusion Related, Acute Lung Injury

Question 20

How do you differentiate between Cardiogenic Pulmonary Edema and ARDS on CXR?

Answer 20

Cardiogenic - NOT dependent - aka it will be evenly distributed on CXR even when the patient is supine

Pulmonary Edema - DEPENDENT - it will be shifted to the front or back depending if the patient is prone or supine

Question 21

What are the 4 phases of ARDS?

Answer 21

Exudative (acute) phase
Proliferative Phase
Fibrotic Phase
Recovery

Question 22

***What are the 4 predictors of outcome in a patient with ARDS?

Answer 22

1. Chronic Liver DIsease
2. Non-pulmonary Organ Dysfunction
3. Sepsis
4. Advanced age

Question 23

Is PEEP normal in healthy people?

Answer 23

YES, our vocal cords shut when we expire to maintain PEEP

We must apply some PEEP to anyone with a tube down their throat to keep a near physiologic value of PEEP at least

Question 24

Why is laying people with ARDS in the prone position ideal?

Answer 24

Takes the pressure of the heart off of the lungs

Question 25

How is ARDS cured?

Answer 25

TREAT THE UNDERLYING CAUSE