Pharmacological Treatments for Delirium in Critically Ill Adults

Abstract

What effects do pharmacological treatments for delirium have on the duration of delirium in critically ill adults?Delirium is one of the most common behavioral manifestations of acute brain dysfunction in patients in intensive care units (ICUs), affecting up to 80% of those who are critically ill.1 Delirium is characterized by inattention, altered consciousness, and disorganized thinking, and it is associated with various serious adverse outcomes including hospital and ICU mortality, longer duration of mechanical ventilator support, prolonged ICU and hospital stays, and long-term cognitive impairment.2 For this reason, nurses must appropriately manage delirium to minimize adverse outcomes.Treatment options include both pharmacological and nonpharmacological interventions, although serious illness often requires a pharmacological treatment. The effectiveness of such regimens vary and are not standardized internationally.2 The most common pharmacological interventions are antipsychotic medications, yet published evidence provides mixed support for their use. A Cochrane systematic review by Burry et al3 compared the 6 main types of medications and assessed their impact on delirium in critically ill patients.This summary describes the review by Burry et al,3 which included data from 14 randomized controlled trials with a combined total of 1844 participants. The review explored 1 primary outcome: Duration of delirium (ie, the time from when delirium was identified until it resolved) measured in days.The randomized controlled trials evaluated by Burry et al3 compared various medications with placebo:The review also evaluated various secondary outcomes:Burry et al3 independently assessed the risk of bias in each study, including selection, performance, detection, attrition, reporting, and publication biases. They resolved any disagreements by reviewing and discussing the data together.The authors used medians and means with 95% CIs as measures of treatment effects among various comparisons and outcomes. They used the internationally approved Grades of Recommendation, Assessment, Development and Evaluation approach to determine the quality of evidence for each outcome. This approach assigns a level of high, moderate, low, or very low regarding the confidence of an outcome or conclusion: (1) high, which indicates that further research is very unlikely to change the confidence in the conclusion; (2) moderate, which means that further research is likely to have an important impact on the confidence in the conclusion and may change it; (3) low, which indicates that further research is very likely to have an important impact on the confidence in the conclusion and is likely to change it; and (4) very low, which means the conclusion is uncertain.4When each drug class was directly compared with a placebo, only the α2-adrenergic agonist dexmedetomidine reduced the duration of delirium; the cholinesterase inhibitor rivastigmine prolonged the duration. Both of these results are based on findings from a single small study. The other drugs, when compared with placebo, did not change delirium duration. In addition, the results did not indicate that any drug reduced the duration of coma, the length of stay, or mortality, nor did the drugs improve long-term cognitive outcomes. Some results did show that dexmedetomidine shortened the duration of mechanical ventilation.The following points provide additional detail about the main results of this systematic review.Delirium continues to be a challenge in the critical care setting, and health care teams continue to use pharmacological interventions to treat it. The main outcomes explored in the systematic review by Burry et al3 suggest that the α2-adrenergic agonist dexmedetomidine may help shorten the duration of both delirium and mechanical ventilation, but those results are based on the findings of only a single small study. No other pharmacological intervention—including antipsychotics, the medication most commonly prescribed for treating delirium—had any effect on delirium duration or on any of the secondary outcomes.One key result was that the cholinesterase inhibitor rivastigmine was associated with harm and a longer stay in the ICU; as such, clinicians should advocate against and carefully consider its use for treating delirium in patients in the ICU. One study showed advantages to using dexmedetomidine to treat delirium in such patients, but additional evidence is needed to fully support this. Health care teams should evaluate the options and make the most appropriate clinical decision on the basis of the best available evidence. The results of ongoing studies such as the international work from the group Del-COrS (Development of core outcome sets for effectiveness trials of interventions to prevent and/or treat delirium) may provide further insight into and guidance regarding delirium management.5Advocating for the best evidence-based treatment is an important part of our role as nurses caring for critically ill patients. We must always consider the best available evidence and understand the feasibility, appropriateness, meaningfulness, and effectiveness of any intervention to determine whether it is appropriate for our particular patient.