Intensive Care Unit Delirium: A Review of Diagnosis, Prevention, and Treatment

Abstract

A 77 year-old male is admitted to the hospital after sustaining a hip fracture. He has a past medical history of chronic obstructive pulmonary disease, hypertension, hyperlipidemia, chronic back pain, and hearing loss. Prior to surgery he receives midazolam for agitation and morphine for pain control. He undergoes a general anesthetic for his fracture repair, requiring high doses of fentanyl for pain control. Postoperatively, he has poor pulmonary mechanics and is taken to the ICU intubated and mechanically ventilated. On postoperative day one, his sedation is weaned and he is put on a spontaneous breathing trial. While he appears intermittently awake, he will not follow commands and only intermittently makes eye contact. The patient is left intubated due to his altered mental status.

Conflict of interest statement

in past 36 months: Christina J Hayhurst: None Pratik P Pandharipande: Research grant from Hospira Inc. in collaboration with National Institutes of Health Christopher G Hughes: None

Figures

Figure 1. Potential Mechanisms and Therapies for ICU Delirium

Hypothesized mechanisms for intensive care unit (ICU) delirium include systemic inflammation, endothelial dysfunction, increased blood brain barrier permeability, and reduced cholinergic control of the inflammatory response that, along with baseline patient vulnerability factors, predispose patients to neuroinflammation and subsequent neuronal injury. Primed and over activated microglia from these processes may also exacerbate the pathophysiologic changes. Therapeutic agents studied for the prevention or treatment of ICU delirium have targeted these pathways. Abbreviations: BBB, blood brain barrier

Figure 2. The ABCDEF Building Blocks of ICU Delirium Management

Multidisciplinary intensive care unit (ICU) care bundles focusing on pain management, liberation from mechanical ventilation, light sedation or no sedation, avoidance of benzodiazepines, routine delirium monitoring, and early mobility have been shown to reduce delirium and improve patient outcomes. More information on the ABCDEF bundle can be found online., Abbreviations: ADLs, activities of daily living; BPS, Behavioral Pain Scale; CAM-ICU, Confusion Assessment Method for the Intensive Care Unit; CPOT, Critical-Care Pain Observation Tool; ICDSC, Intensive Care Delirium Screening Checklist; MV, mechanical ventilation; SAT, spontaneous awakening trial; SBT, spontaneous breathing trial