Adult Respiratory Distress Syndrome John

Adult Respiratory Distress Syndrome

John Smith, a 30-year-old male, was brought into the Emergency Department following a near drowning. He was diving with friends when the found him floating face down in the river. He was not breathing when he was pulled from the river and his friends administered CPR. John was awake when the EMS unit arrived.

Upon arrival to the Emergency Department, John was extremely fatigued but was oriented X3. His blood pressure was 122/80, heart rate 120/minute, and respiration 28/minutes. His breath sounds were diminished bilaterally with crackles and expiratory wheeze audible throughout all lung fields. He was receiving 50% 02 via venturi mask and his ABGs were as follows:

pH

PaCO2

PaO2

SaO2 91%

HCO3

All other laboratory data were normal. John was admitted to the ICU with a diagnosis of near drowning. He was stable for 24 hours, at which time he manifested dyspnea, tachypnea, tachycardia, and progressive hypoxemia. Despite increasing the FIO2 via venturi mask, Brian's ABGs continued to deteriorate. Twenty- six hours after admission, his ABGs on a nonrebreathing mask were:

pH 7.50

PaCO2 26

PaO2 48

SaO2 76%

HCO3 23

He was intubated and placed on a volume-controlled ventilator at the following settings:

Mode Assist Control

Rate 12

FIO2 0.60

Tidal Volume 800

PEEP +5

His initial static compliance was 30ml/cm H2O, and his post-intubation chest x-ray revealed appropriate endotracheal tube placement and bilateral, diffuse, patchy infiltrates. A pulmonary artery catheter was placed with the following data obtained:

PAP 24/10

PCWP 9

CVP 6

CO 7.5

What is the definition of ARDS? What are the associated clinical indicators?

ARDS is a clinical syndrome that includes pulmonary insufficiency caused by sepsis, trauma, severe metabolic conditions or exposure to toxic gases; clinical manifestations include arterial hypoxemia (low oxygen) and the presence of bilateral infiltrates in the lung.

ARDS," all definitions of this syndrome include patients who meet the following criteria: www.ispub.com/ostia/index.php?xmlFilePath=journals/ijeicm/vol1n1/ards.xml" 5

Clinical evidence of respiratory distress.

Chest radiograph revealing diffuse bilateral airspace disease ("pulmonary edema").

Hypoxemia that is difficult to correct with oxygen supplementation.

Hemodynamic evidence of a pulmonary artery occlusion (wedge) pressure < 18 mm Hg.

Thoracic static compliance less than 40 mL/cm of water

What clinical conditions did this patient experience that are common risk factors associated with ARDS?

Patients who have nearly drowned can develop ARDS. It is slightly more common to see ARDS with a salt water aspiration. The onset of symptoms may be slow. Lung infiltrates and the hypoxia are not usually seen until 12-24 hours of the accident.

The aspiration of the water is considered to be damaging to the lung tissue, and then results in situation where the osmotic gradient prefers the movement of water into the lung.

Describe the major pathophysiological alterations in ARDS. What is the common

V/Q mismatch associated with ARDS? What is the cause of hypoxemia in ARDS?