ARDS

Question 1

How does the Berlin Definition describe ARDS?

Answer 1

-Acute, diffuse inflammatory lung injury
-Causes alveolar damage
-Leads to hypoxia
-Increased vascular permeability
-Decreased lung compliance

Question 2

What is the mortality rate of ARDS?

Answer 2

40-50%

Question 3

What are the criteria for mild, moderate, severe ARDS?

Answer 3

For all the PEEP or CPAP needs to be at least 5
-Mild = PaO2/FiO2 200-300
-Moderate = PaO2/FiO2 100-200
-Severe = PaO2/FiO2 <100

Question 4

What are the components of the Berline Definition for ARDS?

Answer 4

-Must develop within 1 week of known clinical insult or new or worsening respiratory symptoms
-Associated with bilateral opacities on chest imaging not fully explained by other pulmonary or cardiac processes

Question 5

What are the most common inciting events for ARDS?

Answer 5

aspiration and sepsis

Question 6

What are some risk factors for developing ARDS?

Answer 6

age
smoking
alcohol use
lactic acidosis
hypoalbuminemia

Question 7

What is the pathophysiology behind the b/l patchy opacities seen on imaging?

Answer 7

proteinaceous intersitial ededma

Question 8

What are the tidal volume and plateau pressure goals in ARDS?

Answer 8

Tv 4-6mL/kg
Pplat </= 30cmH2O
First try to fix Pplat >30 w/ lower Tv if able

Question 9

What ventilatory changes are seen as a result of low tidal volume ventilation?

Answer 9

-reduced minute ventilation
-this leads to elevated pCO2 (permissive hypercapnia) and a resulting acidosis (can be as low as pH 7.2)

Question 10

What changes can be made if a patient develops asynchrony and breath stacking due to lower Tv?

Answer 10

-increasing sedation (especially problem is tachypnea with patient overbreathing vent)
-alter I:O ratio so longer expiratory times
-if really needed can increase Tv to 7-8

Question 11

What are the oxygenation goals in ventilation for ARDS?

Answer 11

-FiO2 < 0.7
-pO2 > 55mmHg
-sats >88%

Question 12

What is an unintended consequence of high PEEP?

Answer 12

increased plateau pressures

Question 13

What is an uninteded consequnces of low tidal volume?

Answer 13

breath stacking and severe acidosis/hypercapnia

Question 14

What is the mechanical ventilation variable that is most associated with survival in ARDS patients?

Answer 14

driving pressure (delta P)
-Tv and PEEP aren’t independently associated with survival unless they subsequently cause a decrease in driving pressure

Question 15

What is the goal range for driving pressure in ARDS?

Answer 15

less than or equal to 13cmH2O

Question 16

What are contraindications to ECMO?

Answer 16

-inability to anticoagulate
-metastatic cancer w/ decreased life span
-severe TBI or intracranial bleed
-high pressure or high FiO2 requirements for >7 days
-irreversible lung conditions

Question 17

What is one finding that helps differentiate ARDS from cardiogenic pulmonary edema?

Answer 17

PCWP
-cardiogenic pulmonary edema will have PCWP > 18mmHg

Question 18

What are the pathophysiologic changes seen in ARDS?

Answer 18

-decreased lung volume
-decreased compliance
-increased physiologic dead space
-higher inflection point on vol-pressure curve