Critical Illness Stress-induced Immune Suppression

Despite the use of Centers for Disease Control and Prevention (CDC) recommended practices to minimize infection risk, nosocomial sepsis and multiple organ failure (MOF) remain a leading cause of morbidity and mortality in critically ill patients. It is well documented that the use of immunosuppressant therapies dramatically increases this risk in patients with cancer, transplantation, and immunologic disease. Although immune monitoring has yet to be universally embraced, withdrawal of immunosuppressant therapies and use of immune restoration therapies is the standard of care when these patients develop sepsis. Critical illness stress can also induce a level of immunosuppression which is as life-threatening as is seen in the purposefully immunosuppressed patient. This chapter reviews the role of critical illness stress-induced immunosuppression in the development of nosocomial sepsis and MOF, and outlines clinical strategies which can be employed to maintain and restore immune function, and reduce morbidity and mortality in critically ill patients.