Relationship Between Delirium and Ventilatory Outcomes in the Medical Intensive Care Unit

Delirium is a common neuropsychiatric diagnosis in intensive care units and often leads to extended hospital stays and an increased rate of complications. Delirium can be classified as hypoactive, hyperactive, or mixed. Hyperactive delirium is often accompanied by agitation, which is a predictive factor for unplanned extubation. Hypoactive delirium does not include outward agitation; its incidence and relationship to ventilatory outcomes, specifically unplanned extubation and duration of mechanical ventilation, are relatively unexplored.

To determine the occurrence rate of each delirium type in the first 7 days after intensive care unit admission and explore the relationship between delirium type and ventilatory outcomes.

This was a retrospective cohort study that enrolled adult patients consecutively admitted to a medical intensive care unit over 12 months. Data were abstracted on patient demographic variables, daily clinical variables (morning and evening delirium, coma, and sedation scores), and outcome variables (unplanned extubation, length of stay, and duration of mechanical ventilation).

We enrolled 171 patients in the study. Hypoactive delirium occurred in up to 44% of patients. Of 25 instances of unplanned extubation, up to 74% of patients had hypoactive delirium. Delirium was not a predictor of unplanned extubation; smoking history, chronic obstructive pulmonary disease, and failed breathing trials best predicted unplanned extubation (odds ratios = 3.2, 5.2, and 12.6, respectively; P < .05).

Hypoactive delirium is common among intensive care unit patients and may precede unplanned extubation. Patient history and comorbidities remain the strongest predictors of unplanned extubation.