Prevention and Management of Delirium in the Intensive Care Unit

Abstract

Delirium is a debilitating form of brain dysfunction frequently encountered in the intensive care unit (ICU). It is associated with increased morbidity and mortality, longer lengths of stay, higher hospital costs, and cognitive impairment that persists long after hospital discharge. Predisposing factors include smoking, hypertension, cardiac disease, sepsis, and premorbid dementia. Precipitating factors include respiratory failure and shock, metabolic disturbances, prolonged mechanical ventilation, pain, immobility, and sedatives and adverse environmental conditions impairing vision, hearing, and sleep. Historically, antipsychotic medications were the mainstay of delirium treatment in the critically ill. Based on more recent literature, the current Society of Critical Care Medicine (SCCM) guidelines suggest against routine use of antipsychotics for delirium in critically ill adults. Other pharmacologic interventions (e.g., dexmedetomidine) are under investigation and their impact is not yet clear. Nonpharmacologic interventions thus remain the cornerstone of delirium management. This approach is summarized in the ABCDEF bundle (Assess, prevent, and manage pain; Both SAT and SBT; Choice of analgesia and sedation; Delirium: assess, prevent, and manage; Early mobility and exercise; Family engagement and empowerment). The implementation of this bundle reduces the odds of developing delirium and the chances of needing mechanical ventilation, yet there are challenges to its implementation. There is an urgent need for ongoing studies to more effectively mitigate risk factors and to better understand the pathobiology underlying ICU delirium so as to identify additional potential treatments. Further refinements of therapeutic options, from drugs to rehabilitation, are current areas ripe for study to improve the short- and long-term outcomes of critically ill patients with delirium.

Fig. 1

Risk factors for and outcomes after ICU delirium. Pre-existing conditions, such as frailty or comorbid diseases, contribute to critical illness, and in combination with modifiable risks, such as immobility and drug use, lead to the development of delirium and its long-term complications. ICU, intensive care unit.

Fig. 2

Predisposing and precipitating factors for developing ICU delirium. Delirium is a result of both baseline, or predisposing, risk factors (top) and acquired, or precipitating, risk factors (bottom). These may be modifiable (left) or nonmodifiable (right). ICU, intensive care unit.

Fig. 3

Effects of haloperidol, ziprasidone, and placebo on ICU delirium or coma. In a randomized clinical trial of 566 ICU patients receiving haloperidol, ziprasidone, or placebo for treatment of hypoactive or hyperactive delirium, there were no significant differences among groups in days with delirium, days with coma, or days alive without delirium or coma. These analyses were adjusted for age, pre-existing cognitive impairment, Clinical Frailty Score and Charlson Comorbidity Index score at baseline, and modified Sequential Organ Failure Assessment score and Richmond Agitation–Sedation Scale score at randomization. ICU, intensive care unit. Reproduced with permission from Girard et al.

Fig. 4

Association between proportional performance of the ABCDEF bundle and patient outcomes. Adjusted hazard ratio and 95% confidence interval for ICU discharge, hospital discharge, and death, comparing patients with a given proportion of eligible ABCDEF bundle elements performed on a given day with patients with none of the bundle elements performed that day. Hazard ratios are adjusted for baseline, ICU admission characteristics, and daily covariates, measured the same day as bundle performance. ICU, intensive care unit. Reproduced with permission from Pun et al.