ICU · Ethics
ICU severity scoring systems
Also known as APACHE II · SOFA score · SAPS II · qSOFA · Mortality prediction
ICU scoring systems predict mortality, compare quality between units, and stratify patients for research. APACHE II (Acute Physiology And Chronic Health Evaluation): 12 physiological variables + age + chronic health — most widely used. Score 0-71 (higher = worse); in the 1985 derivation cohort, rising scores tracked a rising risk of hospital death. SOFA (Sequential Organ Failure Assessment): 6 organ systems (respiratory, coagulation, liver, cardiovascular, CNS, renal) — daily tracking. SOFA =2 defines organ dysfunction (Sepsis-3). qSOFA: 3 items (RR 22, altered mentation, SBP <100) — for screening outside ICU. SAPS II/3: alternative to APACHE. Scores are for POPULATIONS not individuals — do NOT use alone for treatment limitation decisions.
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- Scoring systems predict POPULATION mortality, not INDIVIDUAL outcomes — never use alone for end-of-life decisions
- SOFA >=2 = organ dysfunction (Sepsis-3 definition of sepsis)
- qSOFA is for SCREENING (outside ICU) — NOT for diagnosis in ICU
- APACHE II is calculated from worst values in first 24h — not real-time
Meet the patient
A 64-year-old man arrives in septic shock from a urinary source — noradrenaline 0.25 mcg/kg/min for a mean arterial pressure of 65, mechanically ventilated, lactate 4.8 mmol/L. His admission SOFA is 10. Three days into Surviving Sepsis care his SOFA is 12 and the noradrenaline has climbed, not fallen. The registrar asks the question that ends careers: his APACHE II is 34, deep in the high-risk end of a 0-71 scale whose rising scores tracked rising hospital mortality in the 1985 cohort — so should we be de-escalating?[3][5]
Hold that question. It bundles every error this topic exists to prevent — quoting a population percentage at an individual, reading a rising trajectory as a verdict, and reaching for a number to do the work of a multidisciplinary conversation. By the end of this page you will know exactly why the answer is no, and what the scores are actually for.[3]
References12ShowHide
- [1]Raith EP, Udy AA, Bailey M, MacIsaac C, Bellomo R, Pilcher DV. Prognostic Accuracy of the SOFA Score, SIRS Criteria, and qSOFA Score for In-Hospital Mortality Among Adults With Suspected Infection Admitted to the Intensive Care Unit JAMA, 2017.PMID 28114553
- [2]Moreno RP, Metnitz PGH, Almeida E, et al. SAPS 3: From evaluation of the patient to evaluation of the intensive care unit. Part 2: Development of a prognostic model for hospital mortality at ICU admission Intensive Care Med, 2005.PMID 16132892
- [3]Knaus WA, Draper EA, Wagner DP, Zimmerman JE. APACHE II: a severity of disease classification system Crit Care Med, 1985.PMID 3928249
- [4]Vincent JL, Moreno R, Takala J, Willatts S, et al. The SOFA (Sepsis-related Organ Failure Assessment) score to describe organ dysfunction/failure. On behalf of the Working Group on Sepsis-Related Problems of the European Society of Intensive Care Medicine Intensive Care Med, 1996.PMID 8844239
- [5]Singer M, Deutschman CS, Seymour CW, Shankar-Hari M, et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) JAMA, 2016.PMID 26903338
- [6]Seymour CW, Liu VX, Iwashyna TJ, et al. Assessment of Clinical Criteria for Sepsis: For the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) JAMA, 2016.PMID 26903335
- [7]Le Gall JR, Lemeshow S, Saulnier F. A new Simplified Acute Physiology Score (SAPS II) based on a European/North American multicenter study JAMA, 1993.PMID 8254858
- [8]Paul E, Bailey M, Kasza J, Pilcher DV. Assessing contemporary intensive care unit outcome: development and validation of the Australian and New Zealand Risk of Death admission model Anaesth Intensive Care, 2017.PMID 28486891
- [9]Finfer S, Chittock DR, Su SY, et al. Intensive versus conventional glucose control in critically ill patients N Engl J Med, 2009.PMID 19318384
- [10]van den Berghe G, Wouters P, Weekers F, et al. Intensive insulin therapy in critically ill patients N Engl J Med, 2001.PMID 11794168
- [11]Brunkhorst FM, Engel C, Bloos F, et al. Intensive insulin therapy and pentastarch resuscitation in severe sepsis N Engl J Med, 2008.PMID 18184958
- [12]Harrison DA, Parry GJ, Carpenter JR, Short A, Rowan K. A new risk prediction model for critical care: the Intensive Care National Audit & Research Centre (ICNARC) model Crit Care Med, 2007.PMID 17334248