Adult Respiratory Distress Syndrome

Question 1

What is ARDS?

Answer 1

Adult Respiratory Distress Syndrome (also known as Acute
Respiratory Distress Syndrome) which is defined as acute
hypoxemic respiratory failure due to inflammatory pulmonary injury.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases. 6th
ed. Philadelphia, PA: Elsevier-Saunders; 2012: 205.

Question 2

What are the first signs of ARDS?

Answer 2

The first sign of ARDS is arterial hypoxemia that is resistant to
treatment. The chest xray will be indistinguishable from
cardiogenic pulmonary edema. Increased airway resistance,
reduced functional residual capacity, and increased
intrapulmonary shunt also result from ARDS.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases. 6th
ed. Philadelphia, PA: Elsevier-Saunders; 2012: 205.

Question 3

What is the pathogenesis of ARDS?

Answer 3

The acute phase of ARDS is due to an accumulation of proteinfilled
fluid into the alveoli due to increased pulmonary capillary
permeability. The inflammatory response that results in increased
capillary permeability is mediated by neutrophils and cytokines
within the lungs.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases. 6th
ed. Philadelphia, PA: Elsevier-Saunders; 2012: 205.

Question 4

What disorder has the highest risk of progression from

acute lung injury to ARDS?

Answer 4

Sepsis
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases. 6th
ed. Philadelphia, PA: Elsevier-Saunders; 2012: 205.

Question 5

How is ARDS diagnosed?

Answer 5

For a patient to meet the diagnosis of Adult Respiratory Distress
Syndrome (also known as Acute Respiratory Distress Syndrome),
four criteria must be met: acute onset, PAO2 to FiO2 ratio

Question 6

How is the pulmonary capillary wedge pressure

affected by ARDS?

Answer 6

The PCWP is typically normal in these patients.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases. 6th
ed. Philadelphia, PA: Elsevier-Saunders; 2012: 205.

Question 7

How does right-sided heart failure result from ARDS?

Answer 7

Pulmonary vasoconstriction due to hypoxemia results in
pulmonary hypertension that can cause right-sided heart failure if
severe enough.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases. 6th
ed. Philadelphia, PA: Elsevier-Saunders; 2012: 205.

Question 8

What are the current recommendations for the use of
high tidal volumes and PEEP in the treatment of
patients with ARDS?

Answer 8

Currently, high tidal volumes (12-15 ml/kg) are known to be
associated with decreased pulmonary compliance and the risk for
barotrauma. It is recommended to adjust ventilator settings so
that peak inspiratory pressures do not exceed 35-40 cm H2O.
PEEP is extremely useful in these patients as it helps prevent
alveolar collapse, increases functional residual capacity,
decreases right-to-left shunting, and improves V:Q matching.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases. 6th
ed. Philadelphia, PA: Elsevier-Saunders; 2012: 206-207.