Organ dysfunction: general approach, epidemiology, and organ failure scores

Abstract

Multiorgan dysfunction syndrome represents a continuum of cumulative organ dysfunction from very mildly altered function to total and, rarely, irreversible organ failure and is the major cause of death in the intensive care unit (ICU). The terms multiple organ failure syndrome (MOFS), multiple organ system failure (MOSF), and multiple organ failure (MOF) have since been used to describe this syndrome. Infections were initially thought to be the main cause of multiorgan dysfunction; however, other insults, such as severe trauma, burn injuries, and noninfectious inflammatory diseases may precipitate a similar condition. In 2001, several North American and European intensive care societies revisited the definitions for sepsis and related conditions. Additional criteria indicative of physiological derangements were added to the traditional systemic inflammatory response syndrome (SIRS) criteria, including clinical abnormalities (altered mental status, ileus) and biochemical evidence of a sepsis response [procalcitonin (PCT), C-reactive protein (CRP), creatinine, or cytokine levels]. The use of organ failure scores to describe organ dysfunction in ICU patients was encouraged. The pulmonary, cardiovascular, renal, hepatic, hematologic, and central nervous systems are the organs most commonly considered when describing organ dysfunction/failure in the ICU. Scoring systems for organ dysfunction/failure were designed primarily as descriptive tools, aimed at establishing standardized definitions to stratify and compare patients in the ICU in terms of morbidity rather than mortality. Sequential evaluation of organ dysfunction during the ICU stay may track disease progression and may be useful prognostically. We discuss the various scoring systems developed over the past 2 decades and present a rational approach to their role in assessing and following critically ill patients.