Baden Prevention and Reduction of Incidence of Postoperative Delirium Trial (PRIDe): a phase IV multicenter, randomized, placebo-controlled, double-blind clinical trial of ketamine versus haloperidol for prevention of postoperative delirium

Background: Delirium is a neurobehavioural syndrome that frequently develops in the postoperative setting. The incidence of elderly patients who develop delirium during hospital stay ranges from 10 to 80% (Schonauer et al., J Pept Sci. 2017). Delirium was first described more than half a century ago in the cardiac surgery population (Blachy and Starr, Am J Psychiatry 121: 371-5, 1964), where it was already discovered as a state that might be accompanied by serious complications such as prolonged ICU and hospital stay, reduced quality of life and increased mortality. Furthermore, the duration of delirium is associated with worse long-term cognitive function in the general ICU population (Sessler et al., Am J Respir Crit Care Med 166: 1338-44, 2002). This long-term experience with delirium suggests a high socioeconomic burden and has been a focus of many studies (Nishio et al., Crit Care Med 5: 953-7, 1997; Ehlenbach et al., JAMA 303: 76370, 2010; Jahangir et al., World J Cardiol 3: 383-7, 2011; Abegunde et al., Lancet 370: 1929-1938, 2007; Darmon et al., Intensive Care Med 43: 829-840, 2017; Marino et al., J Nephrol 28: 717-24, 2015; Ng LL et al., J Am Coll Cardiol 69: 56-69, 2017; Sezen et al., J Pharmacol Exp Ther 287: 238-45, 1998; Kim et al., Ann Lab Med 37: 388-97, 2017). Due to the multifactorial origin of delirium, we have several but no incontestable options for prevention and symptomatic treatment. Overall, delirium represents a high burden not only for patient and family members, but also for the medical care team that aims to prevent postoperative delirium to avoid serious consequences associated with it. The purpose of this study is to determine whether postoperative delirium can be prevented by the combination of established preventive agents. In addition, measured levels of pre-and postoperative cortisol, neuron specific enolase (NSE) and S-100 beta will be used to investigate dynamics of these parameters in delirious and non-delirious patients after surgery. Methods/design: The Baden PRIDe Trial is an investigator-initiated, phase IV, two-centre, randomised, placebo-controlled, double-blind clinical trial for the prevention of delirium with haloperidol, ketamine, and the combination of both vs. placebo in 200 patients scheduled for surgery. We would like to investigate superiority of one of the three treatment arms (i.e., haloperidol, ketamine, combined treatment) to placebo. Discussion: There is limited but promising evidence that haloperidol and ketamine can be used to prevent delirium. Clinical care for patients might improve as the results of this study may lead to better algorithms for the prevention of delirium.