Introduction: Postoperative delirium (POD), a highly prevalent syndrome after cardiac surgery, is characterized by a rapid decline in brain function with inattention, disorganized thinking, and an altered level of consciousness. It is clinically important because it is associated with severe negative consequences. This study aimed to develop a protocol to help the prevent postoperative delirium in cardiac surgery.
Methods: This multiphase design study consisted of two phases. The first phase was a scoping review to identify risk factors associated with POD in cardiac surgery. The second phase included three consecutive rounds of expert panels based on a Delphi method to obtain consensus from experts to determine and use these risk factors to develop a protocol. A scoping review was performed using the Arksey and O'Malley framework. Literature searches using PubMed/MEDLINE, Scopus, Web of Science, and ProQuest databases were conducted. Two independent investigators performed the selection of studies and data extraction via checklists. In the second phase, based on two Delphi rounds, risk factors with a significant effect on postoperative delirium in cardiac surgery were identified according to the consensus of experts (≥75% agreement). In the third round of the expert panel, only modifiable factors that could improve based on existing conditions and context were used to develop a protocol.
Results: The final protocol was developed based on 20 pharmacological and non-pharmacological interventions to prevent POD in three stages pre-, intra-, and post-cardiac surgery.  
Conclusion: Interventions such as prescribing melatonin instead of benzodiazepines, dexmedetomidine treatment, preoperative education patients that were candidated for cardiac surgery, training nurses, use of arterial filters and pre-bypass filters in the perfusion circuit, prevention of intraoperative hyperglycemia, cerebral oximetry and temperature management during CPB and some interventions in ICU-OH can reduce POD in cardiac surgery.