Acute Respiratory Distress Syndrome

Taylor Wofford, MD

UNC Internal Medicine

July 14, 2009

Over the years…

• Shock lung

• Wet lung

• DaNang lung

• Stiff lung

• Pump lung

• …

• Actut Respiratory Distress Syndrome

ARDS

• PaO2/FiO2 <200

• Acute onset

• Bilateral infiltrates c/w pulmonary edema

• No clinical evidence for elevated LA pressure

(1994 American-European Consensus Conference Committee)

Pathophysiology

ARDS Normal lung

Causes of ARDS

• Sepsis• Aspiration• Pneumonia• Severe trauma/burns• Massive blood

transfusion• TRALI• Relief of airway

obstruction

• Lung and BMT• Drug overdose• Pancreatitis• Near drowning• Smoke inhalation• Cardiopulmonary bypass• Venous air embolism• Neurogenic pulmonary

edema

Evaluation of ARDS

• ABG

• CXR

• Consider bronchoscopy

• Infectious workup

Management of ARDS

• Mechanical ventilation– Vt <6 mL/kg– PIP goal <40 cmH20– Permissive hypercapnea– High PEEP– Pressure mode > volume mode– FiO2 as low as possible

• ARDS Network Study

Notable options

• Airway Pressure Release Ventilation (APRV) = BiVent

• NO

• Prone positioning

• High Frequency Oscillation

• Recruitment maneuvers

Outcomes of ARDS

• 10-15% of ICU admissions

• 190,600 cases in US per year

• Approximately 41% mortality

Bibliography

• Evans TW. Respiratory Management in Critical Care. BMJ, 2004.

• Fishman, AP. Shock lung: A distinict nonentity. Circulation 1973;47;921-923.

• Green GB et al. The Washington Manual of Medical Therpeutics, 31st ed. Philadelphia: Lippincott Williams & Wilkins, 2004.

• Husain AN. Pulmonary Pathology. www.meddean.luc.edu.

• Siegel, MD. Acute respiratory distress syndrome: Pathophysiology; clinical manifestations; prognosis; and outcome. UpToDate.com, 2009.