For many people bedridden in the intensive care unit (ICU) of a hospital, a serious physical illness or injury can often times only be the beginning of their woes.

As many as one-third of ICU patients will go on to develop delirium, a state of impaired cognition and confusion indicating brain dysfunction. Aside from the frightening reality of losing touch with your surroundings, these patients face an even greater danger, according to an extensive review in the British Medical Journal published today. It found that, overall, delirium patients are at greater risk of lengthier hospital stays and an early death. "Every patient who develops delirium will on average remain in the hospital at least one day longer," said Dr. Robert Stevens, study author and associate professor at the Johns Hopkins University School of Medicine, in a statement released by Johns Hopkins,"[I]f you're admitted to the intensive care unit and you develop brain dysfunction, your risk of not surviving your hospital stay is doubled."

The authors examined the literature surrounding the health outcomes of delirium patients, ultimately analyzing 42 studies that together involved 16,535 ICU patients (studies involving patients with prior neurological damage were excluded). Validating earlier, if smaller, findings, the authors concluded that the one-third of those who suffered mental impairment were twice as likely to die in the hospital than those who didn’t, even after controlling for factors like the severity of illness that landed them in the ICU. Even for those who survive their ordeal, the authors additionally found long-term effects, with delirium patients at a 20 to 30 percent increased risk of developing further cognitive decline. "We're seeing that even though you may have a very severe illness or injury and you're lucky enough to survive, you're still not quite out of the woods," Stevens said. “We need to think about the measures we can put into place to decrease these long-term burdens."

Currently there is little certain known about the exact causes of delirium, though age and the use of sedatives and ventilators are factors heavily associated with the onset of the condition. Up to 80 percent of ICU patients mechanically ventilated go on to develop delirium, according to the ICU Delirium and Cognitive Impairment Study Group founded by the Vanderbilt University Medical Center. Similarly, there are few reliable measures that have been proven to prevent or shorten the duration of delirium, though the Group reports there has been some success seen with physical and cognitive rehabilitation techniques as well as a careful management of sedative use in the ICU. For a small percentage of patients, the cessation of sedatives has been shown to end a bout of delirium without long-term damage, but the majority of cases are difficult to resolve. The Group advocates guidelines intended to provide physical and mental exercise while limiting the use of sedatives and ventilators for ICU patients whenever possible.

Source: Stevens R, et al. British Medical Journal. 2015