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Step 6: Understand utility of scoring system

•Scoring systems may be used to evaluate the performance of an ICU using the SMR.

–The SMR of 1 implies that mortality in the ICU is equal to what is predicted by the system. The SMR of less than 1 indicates that ICU performance is better than predicted, while the SMR of more than 1 implies poor performance.

–The SMR may be used to compare different ICUs, or the performance of the same ICU over a period. Differences in the SMR may represent differences in case mix, or differences in ICU practices between observed ICUs and the ICUs that contributed patients to the derivation dataset, or differences in quality of care.

–The trend of SMRs can be used to evaluate ICU performance over time, or to compare ICUs.

•Scoring systems have been used in clinical trials to ensure similarity of study groups in terms of severity of illness at baseline.

•APACHE IV gives predictions for ICU mortality as well as hospital length of stay.

•TISS can be used to quantify and optimize nursing workload, staffing patterns, and costs.

•The daily SOFA score is useful to monitor progress of organ dysfunction. If an ICU treats a large number of patients belonging to a specific group (e.g., trauma, cancer, and coronary), specific scoring systems may be used.

Suggested Reading

1.Vincent JL, Bruzzi de Carvalho F. Severity of illness. Semin Respir Crit Care Med. 2010; 31:31–8.

This article reviews the most commonly used severity-of-illness scoring systems and discusses some of their uses and limitations.

2.Vincent JL, Moreno R. Clinical review: scoring systems in the critically ill. Crit Care. 2010;14(2):207.

The different types of scores should be seen as complementary, rather than competitive and mutually exclusive. It is possible that their combined use could provide a more accurate indication of disease severity and prognosis. All these scoring systems will need to be updated with time as ICU populations change and new diagnostic, therapeutic, and prognostic techniques become available.

3.Khwannimit B. Serial evaluation of the MODS, SOFA and LOD scores to predict ICU mortality in mixed critically ill patients. J Med Assoc Thai. 2008;91(9):1336–42.

Serial assessment of organ dysfunction during the ICU stay is reliable with ICU mortality. The maximum score is the best discrimination comparable with APACHE II score in predicting ICU mortality.

4.Zimmerman JE, Kramer AA, McNair DS, et al. Acute physiology and chronic health evaluation (APACHE) IV: hospital mortality assessment for today’s critically ill patients. Crit Care Med. 2006;34:1297–310.

APACHE IV predictions of hospital mortality have good discrimination and calibration and are useful for benchmarking performance in US ICUs. The accuracy of predictive models is dynamic and should be periodically retested. When accuracy deteriorates they should be revised and updated.

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5.Moreno RP, Metnitz PG, Almeida E, et al. SAPS 3 investigators. 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;31:1345–55.

The SAPS III admission score is able to predict vital status at hospital discharge with use of data recorded at ICU admission. Furthermore, SAPS III conceptually dissociates evaluation of the individual patient from evaluation of the ICU and thus allows them to be assessed at their respective reference levels.

Websites

1.http://www.sfar.org/article/316/scoring-systems-for-icu-and-surgical-patients For calculation of various scores

2.http://www.medcalc.be/manual/roc.php Understand the ROC curve

Part XIV

Pediatrics

Praveen Khilnani and Krishan Chugh