Early Treatment with Risperidone for Subsyndromal Delirium after On-pump Cardiac Surgery in the Elderly A Randomized Trial

Background: The aim of this randomized, parallel-arm trial was to study the effect of treating subsyndromal delirium with risperidone on the incidence of clinical delirium in elderly patients who underwent on-pump cardiac surgery. Methods: One hundred one patients aged 65 yr or older who experienced subsyndromal delirium after on-pump cardiac surgery were randomized using a computer-generated list to receive 0.5 mg risperidone (n = 51) or placebo (n = 50) every 12 h by mouth. Patients were assessed at 8 h by a blinded observer using the Intensive Care Delirium Screening Checklist, and those scoring more than 3 were evaluated by a blinded psychiatrist to confirm delirium. Patients in either group who experienced delirium were treated according to the same algorithm. Initially, risperidone was administered and if symptoms were not controlled, haloperidol was administered. The primary outcome was the proportion of patients who experienced delirium in either group. Results: Seven (13.7%) patients in the risperidone group experienced delirium versus 17 (34%) in the placebo group (P = 0.031) Competing-risks regression analysis showed that failure to treat subsyndromal delirium with risperidone was an independent risk factor for delirium (subhazard ratio, 3.83; 95% CI, 1.63-8.98; P = 0.002). Two (3.9%) patients in the risperidone group experienced extrapyramidal manifestations versus one (2%) in the placebo group (P = 1.0). Conclusion: Administration of risperidone to elderly patients who experienced subsyndromal delirium after on-pump cardiac surgery was associated with significantly lower incidence of delirium. Larger studies are required to determine whether early administration of risperidone during the subsyndromal phase of delirium would influence the clinical course of such patients.