Different levels of delirium are linked to different risk factors, according to Canadian nurse researchers.
They studied 71 older patients admitted to hospital from a care home, half of whom suffered mild delirium and the remainder moderate-to-severe delirium.
The authorsfound severe cognitive impairment was the most significant factor linked with moderate-severe delirium, whilepatients with mild delirium tended to use more medication, especially opioid drugs.
They said: 'There should be an increased awareness on the part of nurses concerning delirium severity when they are admitting an older patient with a low mini-mental state examination score.'
'Future study should also assess whether nursing interventions can prevent older patients with mild delirium from evolving to a severe delirium,' they added.
In a separate Swedish study, researchers interviewed 15 patients who had experienced delirium. Subjects described it as 'like dreaming but still being awake' and that it produced strong emotional feelings such as fear, panic and anger.
Journal of Clinical Nursing (2007) 16: 810-31