Lower Sedation, Frequent Wakening of ICU Patients Minimizes Long-Term Cognitive Impairment

Martha Kerr
Medscape Medical News 2009. © 2009 Medscape

Late-breaking results of the Awakening and Breathing Controlled (ABC) trial, presented here at the Society of Critical Care Medicine 38th Critical Care Congress, show that cognitive function is better if the patient is wakened early and frequently during a stay in the intensive care unit (ICU).

“The thinking has been that if the patient is heavily sedated, then he [or she] won’t remember the experience and that will be less traumatized. In fact, it appears that the opposite is true,” James C. Jackson, PsyD, of the ICU Delirium and Cognitive Impairment Study Group of the Vanderbilt Center for Health Services Research, in Nashville, Tennessee, told meeting attendees as he presented the findings of the ABC trial.

The ABC trial involved 93 ICU patients randomized to daily attempts to halt sedation (spontaneous awakening trials, or SAT) combined with daily assessments of patients while they are breathing on their own (spontaneous breathing trials, or SBT, also called the wake-up-and-breathe protocol) and 94 patients randomized to a control group undergoing daily spontaneous wakening and usual care.

Baseline characteristics and severity of illness were similar in the 2 groups. Cognitive function, posttraumatic stress disorder (PTSD), and depression were assessed at discharge, and at 3 months and 12 months after discharge.

“We conducted a full neuropsychological battery, including a range of memory types,” Dr. Jackson explained. Cognitive performance was scored on a 4-point scale, with 0 for no impairment, 1 for mild-to-moderate impairment, 2 for severe cognitive dysfunction, and 3 for death.

Median number of ventilation-free days in the hospital was 15 in the study group and 12 in the control group. Median number of days to ICU discharge was 9 in the study group and 13 in the control group. Days to hospital discharge was 15 in the study group and 19 in the control group.

There was no difference between the 2 groups in incidence of PTSD, but there were few cases, overall. There was no difference in the incidence of depression, but the incidence was high in both groups, ranging from 50% to 60% at 12 months, Dr. Jackson reported.

“ABC was associated with improved cognitive function at all time points compared with controls, and the difference was statistically significant at all time points,” he announced.

The odds ratio was 2.13 for good long-term cognitive function with SAT-SBT, compared with SAT and usual care (P = .01).

“This is the first direct evidence that intervention [and early arousal] significantly improves neurological outcome at 1 year and that prolonged sedation is independently associated with impaired brain function . . ., with impairment seen in the avoidance domain, primarily . . . . These patients really don’t want to go back to the hospital,” Dr. Jackson told Medscape Critical Care.

There is a strong association between heavy sedation and an increased risk of delirium,” Richard R. Riker, MD, director of critical care research at Maine Medical Center, in Portland, said in an interview after Dr. Jackson’s presentation.

“Delirium appears to be an independent factor for an adverse outcome,” Dr. Riker said. “We don’t know the reason behind that at this point. We do know that infection rates are 2-fold higher if delirium is present . . . . There may be a neutropenic effect somehow involved.”

“The culture of the ICU should change,” Dr. Jackson added. “The concept of keeping the patient down should be considered an antiquated concept.”

Dr. Riker receives support from Aspect Medical Systems Inc., AstraZeneca, Eli Lilly, Hospira, and Takeda. Dr. Jackson has disclosed no relevant financial relationships.

Society of Critical Care Medicine (SCCM) 38th Critical Care Congress. Latebreaker. Presented February 2, 2009.

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