Margaret S. Herridge

Study protocol: The Improving Care of Acute Lung Injury Patients (ICAP) study

IntroductionThe short-term mortality benefit of lower tidal volume ventilation (LTVV) for patients with acute lung injury/acute respiratory distress syndrome (ALI/ARDS) has been demonstrated in a large, multi-center randomized trial. However, the impact of LTVV and other critical care therapies on the longer-term outcomes of ALI/ARDS survivors remains uncertain. The Improving Care of ALI Patients (ICAP) study is a multi-site, prospective cohort study that aims to evaluate the longer-term outcomes of ALI/ARDS survivors with a particular focus on the effect of LTVV and other critical care therapies.MethodsConsecutive mechanically ventilated ALI/ARDS patients from 11 intensive care units (ICUs) at four hospitals in the city of Baltimore, MD, USA, will be enrolled in a prospective cohort study. Exposures (patient-based, clinical management, and ICU organizational) will be comprehensively collected both at baseline and throughout patients ICU stay. Outcomes, including mortality, organ impairment, functional status, and quality of life, will be assessed with the use of standardized surveys and testing at 3, 6, 12, and 24 months after ALI/ARDS diagnosis. A multi-faceted retention strategy will be used to minimize participant loss to follow-up.ResultsOn the basis of the historical incidence of ALI/ARDS at the study sites, we expect to enroll 520 patients over two years. This projected sample size is more than double that of any published study of long-term outcomes in ALI/ARDS survivors, providing 86% power to detect a relative mortality hazard of 0.70 in patients receiving higher versus lower exposure to LTVV. The projected sample size also provides sufficient power to evaluate the association between a variety of other exposure and outcome variables, including quality of life.ConclusionThe ICAP study is a novel, prospective cohort study that will build on previous critical care research to improve our understanding of the longer-term impact of ALI/ARDS, LTVV and other aspects of critical care management. Given the paucity of information about the impact of interventions on long-term outcomes for survivors of critical illness, this study can provide important information to inform clinical practice.

Recovery and Long-Term Outcome in Acute Respiratory Distress Syndrome

Interest in longer-term outcomes after acute respiratory distress syndrome (ARDS) and the understanding of patterns of recovery have increased enormously over the past 10 years. This article highlights important advances in outcomes after ARDS and describes pulmonary outcomes, the most recent data on functional and neuropsychological disability in patients, health care cost, family caregivers, and early models of rehabilitation and intervention.

Lung function and quality of life in survivors of the acute respiratory distress syndrome (ARDS)

Recent studies have begun to describe the long-term outcomes of acute respiratory distress syndrome (ARDS) survivors. These patients experience a number of physical, mental and psychological morbidities that significantly impair their health-related quality of life (HRQL). The trajectory of pulmonary recovery in survivors of ARDS, as it relates to lung function, structure and health-related quality of life (HRQL), is predictable and often persists years after hospital discharge. True pulmonary parenchymal morbidity is uncommon and when present, persistent restrictive disease is likely related to diaphragmatic weakness with a mild reduction in diffusion capacity (DLCO). Future research should focus on identifying patients at risk for long-term functional limitations and the design of rehabilitation interventions tailored to individual patient needs.

Muscle wasting and early mobilization in acute respiratory distress syndrome.

Survivors of acute respiratory distress syndrome often sustain muscle wasting and functional impairment related to intensive care unit (ICU)-acquired weakness (ICUAW) and this disability may persist for years after ICU discharge. Early diagnosis in cooperative patients by physical examination is recommended to identify patients at risk for weaning failure and to minimize prolongation of risk factors for ICUAW. When possible, early rehabilitation in critically ill patients improves functional outcomes, likely by reducing disuse atrophy. Interventions designed to correct the functional impairment are lacking and further research to delineate the molecular pathways that give rise to ICUAW are needed.