The Efficacy of Risperidone in Reducing the Incidence of Postoperative Delirium in Vascular Surgery Patients: Preliminary Report of a Randomized Controlled Trial

Abstract

Objective: Postoperative delirium (POD) increases
postoperative morbidity, mortality, and health care costs.
POD has many risk factors, such as old age, preoperative
cognitive impairment, alcohol abuse, malnutrition, multiple
comorbidities, and vascular disease. Risperidone has
been reported as effective in POD prevention and
treatment. This study investigated the effectiveness of
risperidone in reducing the incidence of POD in vascular
patients.
Materials and Methods: Patients undergoing vascular
surgery were assigned randomly to two groups. Those in
the risperidone group received sublingual disintegrating
risperidone (1 mg) within one hour after surgery, while the
placebo-group patients received a sublingual Listerine
strip. All patients were evaluated for POD using the
CAM-ICU twice daily for seven days, with the DSM-5
delirium criteria being used to confirm POD by a
psychiatrist blinded to the group allocations. The possible
risk factors for POD were recorded. Results: The study unfortunately needed to be terminated
early as supplies of orally disintegrating risperidone
became unavailable in Thailand. Of the 35 participating
vascular surgery patients, 17 were in the risperidone
group, and 18 in the control. One patient (5.6%) in the
former group and one individual (5.9%) in the latter were
diagnosed with POD. The overall POD incidence was
5.7%. The groups demonstrated no statistically significant
differences in baseline characteristics, possible risk
factors, or lengths of hospital stay.
Conclusion: The study could not demonstrate the impact
of orally disintegrating risperidone (1 mg) on the incidence
of POD among vascular-surgery patients due to the very
low incidence and inadequate sample size.