Cardiogenic shock was the most common type of shock encountered in cardiac intensive care, and cardiac dysfunction and hypoxia were frequently observed in critically ill patients—anaerobic metabolism with hyperlactatemia and oxygen debt accumulation results from insufficient organ and tissue perfusion and hypoxia. However, the role of accumulated oxygen debt in cardiogenic shock and hypoxia progression was not well understood. Researchers first described several patterns of oxygen debt repayment in cardiogenic shock patients receiving extracorporeal life support. The oxygen debt was calculated using the lactate concentration at 5 different time points during the first 26 hours of ECLS. Patterns representing basic pathophysiological processes were unaffected by the primary insult’s cause. Survival rates for groups of patients classified into specific patterns ranged from 51.5% to only 4.6%. It was critical that the initial group not predetermine the patient’s fate, which might change during treatment due to ‘between-cluster migration.’ Investigators believed that discovering various patterns of oxygen debt repayment in cardiogenic shock patients might provide new insights for a more rational, goal-directed treatment of highly morbid conditions like hypoxia and cardiogenic shock.