Intensive Care Unit delirium: A wide gap between actual prevalence and psychiatric referral

The study aimed to assess the rates of delirium in an Intensive Care Unit (ICU) prospectively assessed with a delirium screening instrument and confirmed through psychiatrist evaluation. In addition, the referral rate to psychiatric consultation liaison services from the same ICU was assessed through the rates of psychiatric referral over the previous 10 years.

In the prospective part of the study, consecutive patients aged 16 years or more admitted to the ICU of a tertiary care hospital were assessed daily for delirium using confusion assessment method for the ICU, a validated instrument that can be used for both mechanically ventilated and nonventilated patient by trained heath care personnel. Retrospectively, records of patients referred to psychiatric referral team for delirium from the ICU over the last 10 years were drawn out and the referral rate was calculated.

In the prospective study, 109 patients were recruited of which 43 patients remained comatose throughout their ICU stay and could not be assessed for delirium. Of the 66 assessable patients, 45 (68.2% prevalence rate) patients developed delirium. Incidence rate of delirium was 59.6%. In contrast, the retrospective study showed that only 53 cases out of 3094 admissions in ICU over 10 years (1.71%) were referred to psychiatry consultation liaison team for management of delirium. In the prospective study, hypoactive delirium was the most common subtype of delirium.

There is a mismatch between the incidence and prevalence of delirium in ICU patients prospectively diagnosed with structured, validated instruments and the diagnosis of delirium in cases referred to psychiatry consultation-liaison services.