Effect of Mannitol on Electrolytes and Its Relation With Kidney Injury in Cardiopulmonary Bypass

The optimal composition of the priming solution used in cardiopulmonary bypass (CPB) during human cardiac surgery is still uncertain. Mannitol is a common component of CPB priming solutions, but its efficacy is debated. To clarify the effect of mannitol on CPB prime solutions, a prospective, randomized, double-blind trial was conducted on 40 patients with sound cardiac and renal functions who were undergoing coronary artery bypass grafting. The trial included two groups: one received Ringer's acetate-based prime (n = 20), and the other received a combination of Ringer's acetate and 200 mL mannitol as prime (n = 20). The study examined changes in renal-related parameters, electrolytes, osmolality, and acid-base balance. Interestingly, no significant differences in osmolality were observed between the Mannitol and Ringer's acetate groups. However, the Mannitol group showed a significant decrease in sodium levels from 138.7±2.8 mmol/L at the start of anesthesia to 133.9±2.6 mmol/L after the initiation of CPB (p <0.001). Renal parameters remained consistent across groups, except for a temporary effect of mannitol on post-surgery urine output (p = 0.003). In conclusion, this study found no significant differences in osmolality between Ringer's acetate-based prime and Mannitol-based prime in individuals with healthy cardiac and renal function. However, the addition of mannitol to the prime resulted in a significant, albeit short-term, reduction in sodium levels. These findings contribute to the ongoing discourse on optimizing CPB prime solutions, especially in cardiac surgical procedures involving mannitol inclusion.