Sometimes, the need for a massive transfusion in trauma patients is immediately apparent when they arrive in the emergency department trauma room. However, occasionally, a seemingly stable trauma patient may suddenly experience a drop in blood pressure, surprising the trauma team.
In the trauma data world, trauma registry professionals must come to know predictive tools that they must be able to document accurately. Such predictive tools would include Revised Trauma Score (RTS), Injury Severity Score (ISS), Glasgow Coma Scale (GCS). We are going to look at another predictive tool, Shock Index (SI) and break it down in what it is predicting.
Shock Index defined
Blood pressure and heart rate, when used individually, fail to accurately predict the severity of hypovolemia and shock in major trauma. The Shock Index (SI) is a straightforward calculation, derived by dividing the heart rate (HR) by the systolic blood pressure (SBP). This index can be quickly determined by Emergency Medical Services (EMS) and is valuable in assessing whether a patient needs transport to a trauma center. Additionally, in the Emergency Department triage area, SI helps identify patients at risk of hemorrhagic shock (HS) and the potential need for massive transfusions. It has been researched in patients who are either at risk of or experiencing shock due to various causes, including trauma, hemorrhage, myocardial infarction, pulmonary embolism, sepsis, and ruptured ectopic pregnancy.
Shock Index Levels
When it is broken down, the SI is looking at different levels of shock:
- No Shock: <0.6
- Mild Shock: ≥0.6 to <1.0
- Moderate Shock: ≥1.0 to <1.4
- Severe Shock: ≥1.4
Trauma Registry professionals should be able to understand all the predictive tools and help them know the SI and to not simply add it to the trauma registry should the trauma center be collecting the data but be able to know that the higher the SI, be looking for use of the massive transfusion policy (MTP) and find the type and number of units of different blood products being used. Being able to link their critical thinking to potential performance improvement issues will make the trauma registry professional stand out and aid in better care for the trauma patient.
To read more about the SI, in 2010 the paper was presented at the 23rd Annual Scientific Assembly of the Eastern Association for the Surgery of Trauma:
“Identifying Risk for Massive Transfusion in the Relatively Normotensive Patient: Utility of the Prehospital Shock Index”
*Vandromme, M. J., Griffin, R. L., Kerby, J. D., McGwin, G., Jr, Rue, L. W., 3rd, & Weinberg, J. A. (2011). Identifying risk for massive transfusion in the relatively normotensive patient: utility of the prehospital shock index.
The Journal of trauma,
70(2), 384–390. https://doi.org/10.1097/TA.0b013e3182095a0a
Identifying risk for massive transfusion in the relatively normotensive patient: utility of the prehospital shock index – PubMed (nih.gov) 
