Older survivors of mechanical ventilation can expect significant disability

Patients aged 65 and older who survive an episode of mechanical ventilation during a hospitalization are more likely to suffer from long-term disabilities after leaving the hospital than those who survive hospitalization without mechanical ventilation, according to researchers at the University of Pittsburgh. These results were borne out even though the levels of functional disability prior to hospitalization were similar in both groups.

The study was published online ahead of the print edition of the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.

12 dec 2010--"Our findings offer the first nationally-representative estimates of functional status outcomes for elderly patients who have survived mechanical ventilation, using a prospective population-based sample," said Amber Barnato, MD, associate professor of medicine, University of Pittsburgh. "Unfortunately, 70 percent of elders who receive mechanical ventilation will not survive the year. And the 30 percent who are strong enough to survive will be very disabled."

Previous studies of the effects of mechanical ventilation on elderly patients have offered conflicting results, and were limited by their local patient sampling and lack of first-person information about physical function before the illness.

"This study puts to rest the controversy: doctors can confidently tell their elderly patients that if they survive an episode of mechanical ventilation they will be much more disabled than before, and may require nursing home care," noted Dr. Barnato.

To complete their study, the researchers used data collected over a seven-year period in the Medicare Current Beneficiary Survey (MCBS), a continuous survey of a nationally representative sample of aged, disabled and institutionalized Medicare beneficiaries sponsored by the Centers for Medicare and Medicaid Services. MCBS conducts in-person interviews with each sampled beneficiary four times per year for four years, after which they rotate off the panel and new beneficiaries are invited to join. Questions related to health and functional status are asked every autumn.

For this study, the researchers linked beneficiaries' survey responses from the autumn survey with their responses one year later. Beneficiaries who were hospitalized during the 12-month period and who survived until their next autumn interview were included and divided into two groups: those who had received mechanical ventilation during hospitalization and those who had not. The researchers reviewed more than 130,000 person-years of data, from which about 12,000 person-years of data qualified for inclusion in the study.

"We restricted the study to include Medicare beneficiaries aged 65 and older who were living in the community at the time of the initial interview, and who were not enrolled in a group health plan, since these plans do not report claims data to Medicare," said Dr. Barnato. "Each beneficiary could contribute up to three years of observation during their four years of participation in the MCBS."

Researchers rated patients' pre- and post-hospitalization disability levels with regard to mobility and activities of daily living (ADL), rating patients in both areas using scores ranging from 0 (not disabled) to 100 (completely disabled).

Comparing the two groups, the researchers found those who survived mechanical ventilation experienced 30 percent greater ADL disability (14.9 vs. 11.5) and 14 percent greater mobility difficulty (25.4 vs. 22.3) than non-ventilated counterparts.

"This is especially important because the pre-hospitalization scores of the patients who were and weren't mechanically ventilated were similar," Dr. Barnato said. "Being sick enough to require mechanical ventilation, and perhaps even the experience of mechanical ventilation itself, really takes the vim and vigor out of people."

Although mechanical ventilation may be lifesaving, the possibility of prolonged disability could influence health-care decision-making, she noted.

"The greater risk of significant disability for those who survive mechanical ventilation has implications for patients' treatment goals, since Dr. Terri Fried, at Yale, has shown that many elders might not elect to receive a high-burden intervention if they knew it would result in survival with substantial disability," Dr. Barnato said.

"Clinicians should discuss outcomes that are important to patients, such as disability, as well as mortality, when working with patients and their families to make decisions about the use of mechanical ventilation," she added.

Provided by American Thoracic Society

AGS: Protocol Shortens Time on Ventilator

By Peggy Peck
WASHINGTON, 10 may 2008 -- ICU patients put on a coordinated, combination weaning protocol spent three fewer days on a ventilator than those for whom traditional methods were used, researchers here reported.The intervention, called the "wake up and breathe" protocol, combines tests of spontaneous breathing along with a reduction in sedative use to trigger awakening, Timothy Girard, M.D., of Vanderbilt University in Nashville, Tenn., told attendees at the American Geriatrics Society meeting. The protocol has demonstrated efficacy in younger adults, but had not previously been tested in older patients, Dr. Girard said. Presenting results of a prespecified subgroup analysis from the Awakening and Breathing Controlled (ABC) Trial, Dr. Girard said that longer ventilator use was associated with worse outcomes, so several strategies aimed at shortening ventilator time have been studied.
"In general the weaning period, the period following fulminate disease, is considered the most amenable to shortening," he said.
Previous studies have investigated weaning with trials of spontaneous breathing, in which the ventilator is turned off or very low and the patient is observed to see if he or she is able to breathe on his or her own. Typically, this test is conducted by a respiratory therapist.
Other studies have investigated spontaneous awakening in which sedation is turned off and the patient is observed for signs of agitation or other problems. Such sedation management is usually handled by nurses.
The two processes are not necessarily coordinated.
In this study, "we developed a very streamlined process that combined both sedation and mechanical support," Dr. Girard said.
The patient was first evaluated to determine if he or she was a candidate for a trial of awakening using a safety screen that evaluated use of paralytics, pain, agitation, whether the patient was suffering alcohol withdrawal, and other factors.
If the patient passed the safety screen, "we had the green light to turn off the sedation," he said. A patient passed this stage of the protocol if he could respond to a simple command to open his eyes.
Patients who failed the trial were again sedated and the protocol was attempted again the following day.
Patients who passed the wake-up stage proceeded to the "breathe" stage of the protocol. Again they were evaluated with a safety screen that assessed weaning risks.
If they passed that safety screen, the ventilator was turned off or to a very low level, and the patient was closely observed for two hours. Patients who completed the two-hour trial without incident were extubated, those who had difficulty were returned to increased or full ventilator support.
The study endpoint was number of days free of ventilator support.
The trial, which was conducted at four participating centers, enrolled 335 mechanically ventilated patients, including 147 who were 65 or older. Consent, Dr. Girard said, was usually obtained from a family member because most patients could not communicate.
Patients were randomized to the wake up and breathe intervention or to usual care in which both ventilator weaning and sedation were managed based on sporadic clinical observation.
Overall, the intervention was associated with a three-day reduction in ventilator time and, for the oldest patients, "those in their 70s, the reduction was four days, which was statistically significant (P=0.04)," Dr. Girard said.
Average coma time was two days shorter (P=0.03) for the intervention patients and ICU stay was seven days shorter (median stay six days versus 13 days P=0.02), he said.
One-year mortality was also lower in the intervention group (37 deaths versus 52 in the control group), but that difference was not statistically significant.
Most importantly, Dr. Girard said, was "the homogeneity tests for treatment interaction with age. The treatment effects in older patients did not differ significantly from those observed in younger patients."
The study was funded by the Saint Thomas Foundation, Hartford Geriatrics Health Outcomes Research Scholars Award Program, Vanderbilt University, and the National Institutes of Health.
Dr. Girard reported no conflicts of interest.

Primary source: American Geriatrics SocietySource reference:Girard TP, et al "Outcomes among older mechanically ventilated icu patients treated with a wake up and breathe protocol" P 34.