Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a severe lung condition that causes respiratory failure. Individuals with ALI/ARDS often require the use of a respirator or artificial breathing machine, known as a mechanical ventilator, while in an intensive care unit (ICU). Past research has shown that improved short-term clinical outcomes result from the use of a protective mechanical ventilation technique for the lungs. This study will evaluate the effects of lower tidal volume ventilation, and other aspects of critical illness and ICU care, on the long-term clinical outcomes of individuals with ALI/ARDS.

ALI/ARDS is a life-threatening condition that involves inflammation of the lungs and fluid accumulation in the air sacs, which leads to low blood oxygen levels and respiratory failure. Common causes include pneumonia, septic shock, and lung trauma. Symptoms usually develop within 24 to 48 hours of the original injury or illness, and most patients require immediate care in an intensive care unit (ICU). The main form of treatment for ALI/ARDS is the delivery of oxygen and a continuous level of pressure to the damaged lungs through mechanical ventilation. Past research has shown that lower tidal volume ventilation (LTVV), a protective ventilator management technique in which lower volumes of oxygen are administered, improves short-term clinical outcomes in individuals with ALI/ARDS. However, the long-term impact of LTVV remains unknown. The purpose of this study is to evaluate the effects of LTVV on long-term outcomes in individuals with ALI/ARDS.

This study will enroll individuals admitted to an ICU who have been recently diagnosed with ALI/ARDS. Once enrolled, participants' medical records will be reviewed for demographic and medical information. Participants will be examined to determine level of cognition and delirium. Questionnaires will be used to assess the participant's status prior to ICU admittance, including level of hearing, physical functioning, quality of life, employment, and living status. Questionnaires will be given to participants as well as a close contact to increase the reliability of feedback. While in the ICU, participants will receive normal clinical care. Data on laboratory tests, mechanical ventilator settings, arterial blood gas values, and medical status will be collected throughout the ICU stay. Information regarding the medical staff-to-patient ratio and the use of different medical treatments and therapies will also be collected by reviewing medical records and interviewing nurses. Follow-up evaluations, lasting approximately four hours each, will occur 3, 6, 12, 24, 36, 48 and 60 months following the ALI/ARDS diagnosis. At each follow-up visit, participants will undergo a physical examination, and standardized surveys and tests will be used to assess medical outcomes, organ impairment, pulmonary function, mental function, and quality of life. If participants are unable to return to the research clinic for the follow-up evaluations, visits may occur at their home or over the phone.

The original 2-year follow-up duration, for which participants were consented, was subsequently extended to allow 5-year follow-up. In recruiting these previously consented participants into the 5-year follow-up extension, they will be randomized to selected recruitment strategies (e.g., different mailing and telephone strategies) in order to gain insight regarding the most effective methods of recruiting participants.

Inclusion Criteria:

• Residing in the ICU
• Receiving mechanical ventilation
• Meets criteria for the diagnosis of ALI/ARDS, as defined by the American-European Consensus Conference

Exclusion Criteria:

• Received diagnosis of ALI/ARDS more than 96 hours prior to study entry
• Received more than five days of mechanical ventilation during the present hospitalization prior to study entry
• Pre-existing ALI/ARDS for more than 24 hours when transferred to the study ICU
• Pre-existing illness with a life expectancy of less than six months
• Any limitations in ICU care at study entry (e.g., no vasopressor)
• Previous lung resection
• Inability to speak or understand English
• No fixed address

13 critical care units at 4 academic hospitals in Baltimore, MD