Comparison of Ketamine- Versus Nonketamine-Based Sedation on Delirium and Coma in the Intensive Care Unit

Background: At this time, there are no studies evaluating the risk of delirium or coma with the use of ketamine in mechanically ventilated adult patients, compared to conventional therapies such as propofol or dexmedetomidine. Objective: The objective of this study was to evaluate the number of days alive without delirium or coma in mechanically ventilated patients in the intensive care unit receiving analgosedation infusions with ketamine versus without ketamine. Methods: This was a retrospective cohort study conducted at an academic medical center in the United States. Consecutive mechanically ventilated adult patients between November 2015 and April 2017 were evaluated. Patients were divided into 2 groups based on the sedative regimen used: ketamine based or nonketamine based. The primary outcome was the number of days alive without delirium or coma. The secondary outcomes were incidence of delirium, incidence of coma, and ventilator-free days at day 28. Results: The study cohort consisted of 79 patients, of which 39 received ketamine- and 40 received nonketamine-based sedation. The number of days alive without delirium or coma was 6 days (interquartile range [IQR]: 2-9 days) with ketamine and 4 days (IQR: 3-7 days) with nonketamine (P = .351). Delirium occurred in 29 (74%) of 39 patients with ketamine and 34 (85%) of 40 patients with nonketamine (P = .274). Coma occurred in 16 (41%) of 39 patients with ketamine and 6 (15%) of 40 patients with nonketamine (P = .013). The median ventilator-free days were 13 days (IQR: 0-23 days) with ketamine and 21 days (0-25 days) with nonketamine (P = .229). Conclusions: Sustained ketamine-based sedation in mechanically ventilated patients may be associated with a higher rate of observed coma but similar delirium- and coma-free days compared nonketamine-based regimens.