Objective Postoperative delirium (POD), especially after cardiac surgery with cardiopulmonary bypass (CPB), is a relatively common and severe complication increasing side effects, length of hospital stay, mortality and healthcare resource costs. This study aimed to determine the impact of using mannitol serum in the prime of CPB for preventing the occurrence of delirium in patients undergoing coronary artery bypass surgery.

Methods This study is a single-centre, double-blinded, randomised, controlled trial that was conducted from December 2022 to May 2023. Patients in the age range of 18–70 who underwent elective coronary artery bypass surgery were included in the study. In the control group (n=45), the prime solution included Ringer’s lactate serum. In the intervention group (n=45), the prime solution consisted of 200 mL mannitol serum and Ringer’s lactate serum. The primary outcome of the study was the incidence of POD. Secondary outcomes included the duration of mechanical ventilation, length of stay in the intensive care unit (ICU) and 30-day in-hospital mortality.

Results There were no statistically significant differences in demographic characteristics and risk factors between the control and intervention groups (p<0.05). However, the incidence of POD was significantly lower in the intervention group compared with the control group (22.25% vs 42.2%, p=0.035). There were no significant differences between the two groups regarding CPB time, aortic cross-clamp time, duration of mechanical ventilation and length of stay in ICU (p<0.05). Additionally, mortality rates and rates of return to the operating room did not differ significantly between the two groups (p<0.05).

Conclusions This study concluded that adding mannitol to the prime of CPB pump can help reduce the incidence of delirium after cardiac surgery.