HONOLULU – Although large numbers of patients are surviving acute lung injury/adult respiratory distress syndrome, long-term impairments are common and "striking for their relationship to neuropsychiatric dysfunction," Dr. Jesse Hall said at the annual meeting of the American College of Chest Physicians.
"The pace of recovery is protracted and likely incomplete in the current paradigm of care," said Dr. Hall, professor of medicine, anesthesia, and critical care at the University of Chicago. "Interventions including those begun at the onset of critical illness will hopefully improve these outcomes."
Dr. Jesse Hall
According to the best epidemiologic study on the topic, an estimated 191,000 cases of acute lung injury (ALI) and 141,500 cases of adult respiratory distress syndrome (ARDS) occur each year in the United States, causing a combined 133,500 deaths annually (N. Engl. J. Med 2005;353:1685-93). Implementation of low-tidal-volume ventilation over the past decade has led to an improvement in survival among this patient population, Dr. Hall said, but "we are just beginning to understand through descriptive studies what the path is for these patients down the road. We really lack many prospective trials in that arena."
One study of 109 ARDS patients who were followed for 1 year found that most developed a restrictive lung lesion that improved in the first 6-12 months (N. Engl. J. Med 2003;348:683-93). "The most consistent pulmonary function test abnormality tends to be low diffusion capacity that often resolves over time," Dr. Hall said. Some of their general functional limitation correlates to their pulmonary dysfunction, "but much of it does not," he said. "In fact, it’s not what the patients report. They start to have a very low functional status 6, 12, and more months out, and they don’t ascribe it primarily to their lung dysfunction."
Residual areas of fibrosis are not unusual on follow-up CT scans of ALI/ARDS patients, and many of these patients develop airway abnormalities such as bronchiectasis associated with their lung injury, said Dr. Hall, who is also section chief of pulmonary and critical care medicine at the University of Chicago.
The 2003 study of 109 ARDS patients found that all subjects reported poor function due to loss of muscle bulk, proximal weakness, and fatigue. Some (12%) reported persistent pain at the chest tube site, 7% reported entrapment neuropathies, 7% had tracheotomy site problems, 5% had large joint enlargement/immobility from heterotopic ossification, and 4% had immobility in the form of contracted fingers or frozen shoulders. "It can be up to a year before patients regain their body weight after this episode," Dr. Hall said.
Neuromuscular sequelae may include myopathy, peripheral neuropathy, or deconditioning. "Any given patient can have any combination of those," he said. "Some of these disorders are reasonably strongly associated with some of our therapies. Most of our patients have a combination of peripheral neuropathies and myopathies that may by themselves be modest but are attended by extreme deconditioning. The neuromuscular sequelae of critical illness are variable in terms of recovery over months and years, and some patients seem to never fully recover."
The impact of neuropsychiatric sequelae can be significant. One study of 55 ARDS patients found that 100% had cognitive and affective impairments at hospital discharge, and 30% had generalized cognitive decline 1 year later (Am. J. Respir. Crit. Care Med. 1999;160:50-6). In the 2003 study, only 49% of the ARDS patients who had been employed were back to work at 1 year. "This is an astounding economic and financial consequence for the patient and the family," Dr. Hall commented. "Scores on the Short Form-36 were below normal in all eight domains at 3-, 6-, and 12-month follow-up from ICU discharge. There were improvements in most SF-36 categories, but almost none were back to normal."
Dr. Hall said that changes in the current health care system are needed to improve outcomes for ALI/ARDS patients. Currently, "it’s difficult for those in our discipline to figure out how to become a change agent, or help our patients acquire what they need to optimize their recovery," he explained. "It’s not likely, in fact, to be done by critical care doctors down the road."
One study from the United Kingdom sought to determine if giving patients a self-help rehabilitation manual would affect their general functional status "and therefore their psychiatric axes as well, and maybe even make them more functional," Dr. Hall said. For the study, patients in the control group received ward visits, three telephone calls at home, and clinic appointments at 8 weeks and 6 months, whereas patients in the intervention group received the same plus a 6-week self-help rehabilitation manual. At the end of 6 weeks, patients in the intervention group had significantly better physical function scores, compared with controls (Crit. Care Med. 2003;31:2456-61). Unfortunately, such benefits were not seen in another recent prospective trial.