Sepsis, previously called blood poisoning, is an out of control immune response to an infection that attacks and destroys the organs of the person infected. It's a "mistake" that kills. Sepsis is responsible for 20% of all deaths worldwide in any given year. A process similar to sepsis is called the cytokine storm. Both sepsis and the cytokine storm (cytokine release syndrome) show up in severe cases of COVID-19 and are responsible for many of the deaths reported.
I encourage you to read the study and be uplifted. It appears that sepsis can in most cases be controlled and eliminated. Using thiamine, Vitamin C and hydrocortisone, Dr. Marik's protocol reduced mortality from 19 out of 47 infected to only 4 of 47 infected. (CHEST journal, 2017).