Two-year outcomes, health care use, and costs of survivors of acute respiratory distress syndrome

Patients with respiratory failure increase ambulation after transfer to an intensive care unit where early activity is a priority

OBJECTIVE

Ambulation of patients with acute respiratory failure may be unnecessarily limited in the acute intensive care setting. We hypothesized that ambulation of patients with acute respiratory failure would increase with transfer to an intensive care unit where activity is a key component of patient care.

DESIGN

Pre-post cohort study of respiratory failure patients.

SETTING

Adult intensive care units at LDS Hospital.

PATIENTS

Respiratory failure patients requiring >4 days of mechanical ventilation who were transferred from other LDS Hospital intensive care units to the respiratory intensive care unit.

INTERVENTIONS

We prospectively applied an early activity protocol to all consecutive respiratory failure patients transferred to the respiratory intensive care unit.

MEASUREMENTS AND MAIN RESULTS

We studied 104 respiratory failure patients who required mechanical ventilation for >4 days. Transferring a patient to the respiratory intensive care unit substantially increased the probability of ambulation (p < .0001). After 2 days in the respiratory intensive care unit, the number of patients ambulating had increased three-fold compared with pretransfer rates. Female gender (p = .019), the absence of sedatives (p = .009), and lower Acute Physiology and Chronic Health Evaluation II scores (p = .017) also predicted an increased probability of ambulation. Improvements in ambulation with transfer to the respiratory intensive care unit remained significant after adjustment for Acute Physiology and Chronic Health Evaluation II scores and other covariates.

CONCLUSIONS

Transfer of acute respiratory failure patients to the respiratory intensive care unit substantially improved ambulation, independent of the underlying pathophysiology. The intensive care environment may contribute unnecessary immobilization throughout the course of acute respiratory failure. Sedatives, even given intermittently, substantially reduce the likelihood of ambulation. Controlled studies are needed to determine whether intensive care unit immobilization contributes to long-term neuromuscular dysfunction or whether early intensive care unit activity improves outcomes.

Year in review 2006: Critical Care--Respirology

The present article summarises and places in context original research articles from the respirology section published in Critical Care in 2006. Twenty papers were identified and were grouped by topic into those addressing acute lung injury and ventilator-induced lung injury, those examining high-frequency oscillation, those studying pulmonary physiology and mechanics, those assessing tracheostomy, and those exploring other topics.

Health policy and future planning for survivors of critical illness

PURPOSE OF REVIEW

Few health policy decisions directly address the needs of intensive care unit survivors. This review will assess some of the health system-level barriers to effective post-intensive care unit care and provide a framework for policy decisions directed at improving outcomes for survivors of critical illness.

RECENT FINDINGS

Intensive care unit survivors incur significant morbidity, and account for enormous financial and opportunity costs. Despite our understanding of these burdens, relatively little is known about how to structure the healthcare system to improve outcomes after intensive care unit discharge. Several ongoing clinical trials will aid in system design and inform policy decisions. While we await more evidence, lessons learned in other disease states such as coronary care, acute stroke and traumatic brain injury can help us understand the attributes of a comprehensive longitudinal care model for critical illness. Future planning for the care of intensive care unit survivors should include defining the post-intensive care unit syndrome, expanding the use of information technology, educating providers, and developing a robust public health infrastructure that integrates acute and chronic care.

SUMMARY

Advances in our understanding of the long-term outcomes of critical illness must be accompanied by healthcare system changes designed to meet the specific needs of intensive care unit survivors.

Physical consequences of critical illness

Patients who survive critical illness are at risk of permanent physical and functional deficits which decrease the health-related quality of life. The reasons for physical morbidity include the nature of and treatment for the inciting critical illness, new decrements in organ function and worsening of pre-existing organ dysfunction, and prolonged physical immobility and long intensive care unit stay.

Mechanical ventilation and acute respiratory distress syndrome in older patients

As the population of the United States ages, an increasing number of elderly adults will be cared for in intensive care units. An understanding of how aging affects the respiratory system is important for patient care and ongoing research. The incidence rates of acute respiratory failure and of acute respiratory distress syndrome increase dramatically with age, and therefore understanding the relationship between age and ARDS is important. This article focuses on the age-specific changes in respiratory function. We present a discussion of the management of acute lung injury and acute respiratory distress syndrome with a focus on the role of mechanical ventilation. We conclude with what is known about age and its impact on mortality and functional outcomes after mechanical ventilation.

Transcription factors in muscle atrophy caused by blocked neuromuscular transmission and muscle unloading in rats

The muscle wasting associated with long-term intensive care unit (ICU) treatment has a negative effect on muscle function resulting in prolonged periods of rehabilitation and a decreased quality of life. To identify mechanisms behind this form of muscle wasting, we have used a rat model designed to mimic the conditions in an ICU. Rats were pharmacologically paralyzed with a postsynaptic blocker of neuromuscular transmission, and mechanically ventilated for one to two weeks, thereby unloading the limb muscles. Transcription factors were analyzed for cellular localization and nuclear concentration in the fast-twitch muscle extensor digitorum longus (EDL) and in the slow-twitch soleus. Significant muscle wasting and upregulation of mRNA for the ubiquitin ligases MAFbx and MuRF1 followed the treatment. The IkappaB family-member Bcl-3 displayed a concomitant decrease in concentration, suggesting altered kappaB controlled gene expression, although NFkappaB p65 was not significantly affected. The nuclear levels of the glucocorticoid receptor (GR) and the thyroid receptor alpha1 (TRalpha1) were altered and also suggested as potential mediators of the MAFbx- and MuRF1-induction in the absence of induced Foxo1. We believe that this model, and the strategy of quantifying nuclear proteins, will provide a valuable tool for further, more detailed, analyses of the muscle wasting occurring in patients kept on a mechanical ventilator.

Experimental animal models of muscle wasting in intensive care unit patients

The muscle wasting and loss of muscle function associated with critical illness and intensive care have significant negative consequences for weaning from the respirator, duration of hospital stay, and quality of life for long periods after hospital discharge. There is, accordingly, a significant demand for focused research aiming at improving our understanding of the mechanisms underlying the impaired neuromuscular function in intensive care unit (ICU) patients. However, the study of generalized muscle weakness in critically ill ICU patients is further complicated by the coexistence of multiple independent factors, such as different primary diseases, large variability in pharmacologic treatment, collection of muscle samples several weeks after admission to the ICU, and exposure to causative agents. This has led to the design of specific animal models mimicking ICU conditions. These models have often been used to study the mechanisms underlying the paralysis and muscle wasting associated with acute quadriplegic myopathy in ICU patients. This short review aims at presenting existing and recently introduced experimental animal models mimicking the conditions in the ICU (i.e., models designed to determine the mechanisms underlying the muscle wasting associated with ICU treatment).

Review of retention strategies in longitudinal studies and application to follow-up of ICU survivors

OBJECTIVE

To review the literature on retention strategies in follow-up studies and their relevance to critical care and to comment on the Toronto experience with the acute respiratory distress syndrome (ARDS) and severe acute respiratory syndrome (SARS) follow-up studies.

DESIGN AND SETTING

Literature review and two cohort studies in a tertiary care hospital in Toronto, Canada.

PATIENTS AND PARTICIPANTS

ARDS and SARS patients.

MEASUREMENTS AND RESULTS

Review articles from the social sciences and medicine are summarized and our own experience with two longitudinal studies is drawn upon to elucidate strategies that can be successfully used to attenuate participant drop-out from longitudinal studies. Three key areas for retention of subjects are identified from the literature: (a) respect for patients: respect for their ideas and their time commitment to the research project; (b) tracking: collect information on many patient contacts at the initiation of the study and outline tracking procedures for subjects lost to follow-up; and (c) study personnel: interpersonal skills must be reinforced, flexible working hours mandated, and support offered. Our 5-year ARDS and 1-year SARS study retention rates were 86% and 91%, respectively, using these methods.

CONCLUSIONS

Strategies to reduce patient attrition are time consuming but necessary to preserve internal and external validity. When the follow-up system is working effectively, researchers can acquire the necessary data to advance knowledge in their field and patients are satisfied that they have an important role to play in the research project.

Intensive care unit exposures for long-term outcomes research: development and description of exposures for 150 patients with acute lung injury

PURPOSE

Long-term follow-up studies in critical care have described survivors' outcomes, but provided less insight into the patient/disease characteristics and intensive care therapies ("exposures") associated with these outcomes. Such insights are essential for improving patients' long-term outcomes. This report describes the development of a strategy for comprehensively measuring relevant exposures for long-term outcomes research, and presents empiric results from its implementation.

MATERIALS AND METHODS

A multistep, iterative process was used to develop the exposures strategy. First, a comprehensive list of potential exposures was generated and subsequently reduced based on feasibility, redundancy, and relevance criteria. Next, data abstraction methods were designed and tested. Finally, the strategy was implemented in 150 patients with acute lung injury with iterative refinement.

RESULTS

The strategy resulted in the development of more than 60 unique exposures requiring less than 45 minutes per patient-day for data collection. Most exposures had minimal missing data and adequate reliability. These data revealed that evidence-based practices including lower tidal volume ventilation, spontaneous breathing trials, sedation interruption, adequate nutrition, and blood glucose of less than 6.1 mmol/L (110 mg/dL) occurred in only 23% to 50% of assessments.

CONCLUSIONS

Using a multistep, iterative process, a comprehensive and feasible exposure measurement strategy for long-term outcomes research was successfully developed and implemented.

Inhaled nitric oxide for acute respiratory distress syndrome

Theoretical promise of benefit does not translate to improvements in morbidity and mortality

Heterotopic ossification--a long-term consequence of prolonged immobility

Heterotopic ossification is a condition affecting an appreciable minority of critical care patients; it can have long-lasting effects on recovery and return to functional status. Ectopic bone forms in soft tissues near the large joints, causing pain, swelling, limitation of movement and ultimate disability. X-ray changes may be delayed for several weeks after the diagnosis is clinically suspected. Magnetic resonance imaging may be more sensitive for detecting early changes, yielding positive results several weeks before X-rays. However it is not clear that diagnosing the process early will influence long-term patient outcome, because no effective treatments are available.

Epidemiology and Outcomes of Acute Lung Injury

Acute lung injury (ALI) and its presentation with more severe hypoxemia, the ARDS, is a challenging entity for clinical investigation because, like many critical illness syndromes, it lacks an accepted diagnostic test and relies on a constellation of clinical findings for diagnosis. Despite these barriers, there have been important advances in the clinical and population epidemiology of ALI. This article will review recent studies of the incidence, diagnosis, etiologic and prognostic factors, relevant disease subsets, mortality, and long-term outcomes of ALI. A detailed understanding of the epidemiology and outcomes of ALI is essential for future research on mechanisms of both the acute presentation and long-term sequelae, for designing studies to identify genetic risk factors for developing ALI, and to develop strategies to treat or prevent the morbidity encountered by survivors.

Quality of life, emotional abnormalities, and cognitive dysfunction in survivors of acute lung injury/acute respiratory distress syndrome

This article provides a brief discussion of the recent literature linking quality-of-life impairment to physical dysfunction after acute lung injury/acute respiratory distress syndrome. Its main focus is a review of the current knowledge concerning cognitive and emotional outcomes after lung injury and their impact on long-term quality of life.