Patients with ICU related delirium typically suffer from disturbances in consciousness, disorganized thinking or may become delusional. Delirium in the ICU may be caused by underlying medical conditions, and can be triggered by stress, lack of sleep, unfamiliar surroundings, lights and sounds in the unit, or develop as a side effect of medications.

The meta-analysis, which appears in General Hospital Psychiatry, found that ICU patients with delirium were three times more likely to die than patients without delirium and six times more likely to have one or more complications. They were also kept in the ICU for more than seven days longer and were hospitalized more than six days longer than non-delirious patients.

"This is important since it further confirms that delirium is a disease entity that has significant impact on clinical outcome," said lead author Zhongheng Zhang, MM, an intensive care specialist at Jinhua Municipal Central Hospital in Jinhua, Zhejiang, China. Further research can help determine whether control or management of delirium can alter the disease course of critical illness, he said.

Methods of dealing with ICU delirium include adjusting medications and taking steps to keep the patient oriented in reality, which can include having a family member present. "The presence of family members with the patient has never been formally investigated," Zhang said. "But in our experience, for some hyperactive delirium patients, we allow their family members to be with them, and this seems effective in reducing the use of sedatives and [improving] control of delirious symptoms," Zhang said.

ICU delirium is an acute brain failure rather than a mental illness and is reversible in most cases, said Alexandru Serghi, M.D., assistant professor in the department of psychiatry at the University of Hawaii in Honolulu. "Many times, all we need to do is keep the patient and family informed and to treat the underlying medical causes."

ICU delirium is being more widely recognized as a risk factor for death and dementia, he added. "The more severe the delirium, the worse the outcome." Even when reversible, delirium in the ICU can be scary for both the patient and the patient's family, Serghi said. "Being disoriented and having profound impairment in consciousness is a frightening experience."