322 Acute Respiratory Distress Syndrome

Question 1

It is a clinical syndrome of severe dyspnea of rapid onset, hypoxemia, and diffuse pulmonary infiltrates leading to respiratory failure

Answer 1

Acute respiratory distress syndrome (ARDS)

Question 2

Causes of Direct Lung Injury

Answer 2

Pneumonia
Aspiration of gastric contents
Pulmonary contusion
Near-drowning
Toxic inhalation injury

Question 3

Causes of Indirect Lung Injury

Answer 3

Sepsis
Severe Trauma (Multiple bone fractures, flail chest, head trauma, burns)
Multiple transfusions
Drug overdose
Pancreatitis
Postcardiopulmonary bypass

Question 4

Clinical variables associated with the development of ARDS

Answer 4

Older age, chronic alcohol abuse, metabolic acidosis, and severity of critical illness

Question 5

Diagnostic Criteria for ARDS

Answer 5

Severity: Oxygenation
Mild: 200 mmHg
< Pao2/Fio2 ≤ 300 mmHg

Moderate: 100 mmHg
< Pao2/Fio2 ≤ 200 mmHg

Severe: Pao2/Fio2 ≤ 100 mmHg

Onset: Acute

Chest xray: Bilateral alveolar or interstitial infiltrates

PCWP: ≤18 mmHg or no clinical evidence of increased left atrial pressure

Question 6

Three phases of ARDS

Answer 6

Exudative
Proliferative
Fibrotic

Question 7

In this phase, significant concentrations of cytokines (e.g., interleukin 1, interleukin 8, and tumor necrosis factor α) and lipid mediators (e.g., leukotriene B4) are present in the lung in this acute phase

Answer 7

Exudative Phase

Question 8

In this phase, alveolar capillary endothelial cells and type I pneumocytes (alveolar epithelial cells) are injured, with consequent loss of the normally tight alveolar barrier to fluid and macromolecules

Answer 8

Exudative Phase

Question 9

This phase encompasses the first 7 days of illness after exposure to a precipitating ARDS risk factor, with the patient experiencing the onset of respiratory symptoms

Answer 9

Exudative Phase

Question 10

In this phase, condensed plasma proteins aggregate in the air spaces with cellular debris and dysfunctional pulmonary surfactant to form hyaline membrane whorls

Answer 10

Exudative Phase

Question 11

This phase of ARDS usually lasts from day 7 to day 21

Answer 11

Proliferative Phase

Question 12

In this phase, some patients develop progressive lung injury and early changes of pulmonary fibrosis

Answer 12

Proliferative Phase

Question 13

In this phase there is initiation of lung repair, the organization of alveolar exudates, and a shift from a neutrophil- to a lymphocyte-predominant pulmonary infiltrate

Answer 13

Proliferative Phase

Question 14

In this phase, the alveolar edema and inflammatory exudates of earlier phases are now converted to extensive alveolar-duct and interstitial fibrosis

Answer 14

Fibrotic Phase

Question 15

In this phase, type II pneumocytes proliferate along alveolar basement membranes as part of the reparative process

Answer 15

Proliferative Phase

Question 16

Grade A recommendation for treatment of ARDS

Answer 16

Low tidal volume

Early neuromuscular blockade

Question 17

Two processes of ventilator-induced lung injury

Answer 17

Repeated alveolar overdistention

Recurrent alveolar collapse

Question 18

In the initial management of ARDS, what is the goal tidal volume?

Answer 18

Tidal volume ≤ 6 ml/kg PBW

Question 19

In the initial management of ARDS, what is the goal plateau pressure?

Answer 19

Plateau pressure ≤ 30 cmH2O

Question 20

In the initial management of ARDS, what is the goal RR?

Answer 20

RR ≤ 35 bpm

Question 21

In the initial management of ARDS, what is the goal FiO2? PEEP? SpO2?

Answer 21

FIO2 ≤ 0.6

PEEP ≤ 10 cmH2O SpO2 88 – 95%

Question 22

In the initial management of ARDS, what is the goal pH? MAP?

Answer 22

pH ≥ 7.30

MAP ≥ 65 mmHg

Question 23

This mode of ventilation has the advantage of improving oxygenation with diminished time to exhale, dynamic hyperinflation leads to increased end-expiratory pressure, similar to ventilator-prescribed PEEP

Answer 23

inverse-ratio ventilation

I:E > 1:1

Question 24

True or False: Current evidence support the use of high-dose glucocorticoids in the care of ARDS patients

Answer 24

False

Question 25

This increase the rate of survival and ventilator-free days without increasing ICU-acquired paresis in patients with ARDS.

Answer 25

Early neuromuscular blockade

Question 26

Major risk factors for ARDS mortality

Answer 26

Advanced age

Preexisting organ dysfunction from chronic medical illness—in particular, chronic liver disease, cirrhosis, chronic alcohol abuse, chronic immunosuppression, sepsis, chronic renal disease, failure of any nonpulmonary organ

Increased APACHE III scores

Question 27

Mortality estimates for ARDS

Answer 27

26% to 44%