The objective medical emergency team activation criteria: A case–control study

Cretikos, Michelle; Chen, Jack; Hillman, Ken; Bellomo, Rinaldo; Finfer, Simon; Flabouris, Arthas; the MERIT study investigators,

doi:10.1016/j.resuscitation.2006.08.020

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Volume 73, Issue 1 , Pages 62-72, April 2007

The objective medical emergency team activation criteria: A case–control study☆

Michelle Cretikos
- The Simpson Centre for Health Services Research and the University of New South Wales, Sydney, Australia
- Correspondence to: Centre for Epidemiology and Research, NSW Health, 73 Miller St., North Sydney, NSW 2060, Australia. Tel.: +61 2 9424 5883; fax: +61 2 9391 9848.
Jack Chen
- The Simpson Centre for Health Services Research and the University of New South Wales, Sydney, Australia
Ken Hillman
- The Simpson Centre for Health Services Research and the University of New South Wales, Sydney, Australia
Rinaldo Bellomo
- Department of Intensive Care, Austin Hospital, Melbourne, Australia
Simon Finfer
- Intensive Therapy Unit, Royal North Shore Hospital, University of Sydney, Sydney, Australia
Arthas Flabouris
- Intensive Care Unit, Royal Adelaide Hospital, University of Adelaide, Adelaide, Australia
the MERIT study investigators
- See Appendix A.

Received 25 March 2006; received in revised form 10 August 2006; accepted 17 August 2006.

Summary

Objective

To evaluate the ability of pre-defined clinical criteria to identify patients who subsequently suffer cardiac arrest, unplanned intensive care unit admission or unexpected death; to determine the ability of modified criteria to identify these patients.

Design

Nested, matched case–control study.

Setting

Seven Australian public hospitals.

Patients and participants

Four hundred and fifty cases and 520 controls matched for age, sex, hospital, and hospital ward.

Interventions

None.

Measurements and results

Highest and lowest respiratory and heart rates, lowest systolic blood pressure, presence of threatened airway, seizures or decrease in Glasgow Coma Scale score of greater than two points and incidence of the three adverse events were measured. Combining a heart rate greater than 140, respiratory rate greater than 36, a systolic blood pressure less than 90mmHg and a greater than two point reduction in the Glasgow Coma Scale identified adverse events with a sensitivity of 49.1% (44.4–53.8%), specificity of 93.7% (91.2–95.6%), and positive predictive value of 9.8% (8.7–11.1%). Adding threatened airway, seizures, low respiratory rate and low heart rate did not substantially improve sensitivity (50.4%; 45.7–55.2%). After modifying the cut-off values for respiratory rate, heart rate and systolic blood pressure, the best achievable positive predictive value remained below 16%.

Conclusions

In combination, the respiratory rate, heart rate, systolic blood pressure, and level of consciousness identify patients at risk of cardiac arrest, unplanned intensive care admission or unexpected death with high specificity; however the sensitivity and positive predictive value are relatively low, even after modification of the activation criteria cut-off values.

Keywords: Adverse event, Heart arrest, Adult, Sensitivity and specificity, Predictive value