Diagnosing delirium in very elderly intensive care patients.

OBJECTIVE: To determine the incidence of delirium in elderly intensive care patients and to compare incidence using two retrospective chart-based diagnostic methods and a hospital reporting measure (ICD-10).

DESIGN: Retrospective study.

SETTING: An ICU in a large metropolitan private hospital in Melbourne, Australia.

PATIENTS: English-speaking participants (n=348) 80+ years, admitted to ICU for >24 hours.

MEASUREMENTS AND MAIN RESULTS: Medical files of ICU patients admitted October 2009-October 2012 were retrospectively assessed for delirium using the Inouye chart review method, DSM-IV diagnostic criteria and ICD-10 coding data. General patient characteristics, first onset of delirium symptoms, source of delirium information, administration of delirium medication, hospital and ICU length of stay, 90 day mortality were documented. Delirium was found in 11-29% of patients, the highest incidence identified by chart review. Patients diagnosed with delirium had higher 90 day mortality, and those meeting criteria for all three methods had longer hospital and ICU length of stay.

CONCLUSIONS: ICU delirium in the elderly is often under-reported and strategies are needed to improve staff education and diagnosis.