Shock index: blunt clinical predictions

Abstract

We appreciate the work of Mutschler and colleagues regarding shock index (SI) in trauma patients [1]; however, we would like to discuss a few points of interest. The SI obtained at the scene differed from the SI obtained in the emergency department (ED). Patients with SI category III had a SI at the scene of 0.7 to 1.5. This indicates that SI can vary with time and vary with changes in medical condition. Patients classified as ‘no shock’ still had a 10.9% mortality rate, a 12.5% risk of multi-organ failure, and a 6.3% risk of sepsis. We do not know when the onset of sepsis occurred in these trauma patients. Thus, a single SI taken within ‘the first hours’ of ED admission might not accurately reflect a patient’s condition, especially if the initial SI is category I or II. Other studies have shown that SI may also lead to an undertriage of those patients most likely to develop early and progressive hemorrhagic shock [2]. In addition, prehospital SI alone was found to have diminished accuracy for patients aged over 60 years [3]. SI may be of limited value in the assessment of systemic oxygen transport [4], which is a more direct measurement of end-organ perfusion and tissue viability than the SI. Finally, the results of this study can best be applied to male patients with blunt trauma injuries who develop hypovolemic shock, but not to every trauma patient on presentation to ED with high risk of other types of shock.