Prevention trials utilizing behavioral and environmental approaches have demonstrated a reduction in delirium incidence (absolute risk reduction 5–18 %) [8, 9]. Geriatrics consultation has also been shown to be helpful [9]. Pharmacologic prevention trials in high-risk patients have not consistently shown a reduction in delirium incidence, but may affect duration and severity. In the absence of better data, prophylactic antipsychotics are not warranted for most patients [10]. Anticholinesterase inhibitors have not been shown to effectively prevent delirium. During postoperative ICU care, the use of dexmedetomidine instead of benzodiazepines for sedation has been associated with lower rates of delirium, but is more costly and associated with bradycardia [11]. Effective prevention strategies are shown in Table 46.3.

First, confirm the diagnosis of delirium by excluding other neurologic and psychiatric conditions. Then, focus on identifying precipitants with history, medication review, physical exam (particularly neurologic and cognitive exam), and basic lab tests (CBC, Chem 7, UA). When appropriate, ECG, CXR, drug levels, or a toxin screen may confirm a suspected etiology. Remember that the etiology may be multifactorial. Head CT scan is often not helpful unless there is a risk factor for intracranial bleeding (e.g., history of fall or anticoagulant use) or evidence of new focal neurologic impairment.