Modeling blood urea nitrogen (BUN) dynamics to estimate dialysis adequacy

Cardiogenic shock is the most frequent kind of shock in cardiac intensive care, and cardiac dysfunction and hypoxia are often seen in critically ill patients. Inadequate organ and tissue perfusion and hypoxia result in anaerobic metabolism with hyperlactatemia and oxygen debt accumulation. However, the role of accumulated oxygen debt in the course of cardiogenic shock and hypoxia has not been clearly described. Here, we first described the existence of several patterns of oxygen debt repayment in cardiogenic shock patients maintained by an extracorporeal life support system. Oxygen debt was computed from the lactate concentration at five time points, covering the first 26 h of ECLS. Patterns representing basic pathophysiological processes were independent of the cause of the primary insult. Groups of patients classified into specific patterns differed in terms of survival rate from 51.5% to only 4.6%. It is very important that the initial group not predetermine the fate of the patient and may change in the course of treatment due to ‘between-cluster migration’. We believe that our finding of different patterns of oxygen debt repayment in cardiogenic shock patients may offer new insights for a more rational, goal-directed treatment of highly morbid conditions such as hypoxia and cardiogenic shock.