Occurrence of elevated shock index in acute patients and development of a proportional shock index metric

Although shock index, as the ratio between heart rate and systolic blood pressure, is a well-recognized predictor for adverse outcomes, it is seldom integrated into clinical evaluation procedures as it requires on-the-fly evaluation of multiple terms. In this paper, we investigate the prevalence of elevated shock index in emergency department patients through an analysis of automatic heart rate and blood pressure readings from 809 admissions to an acute bedside ward at a large Danish hospital. The analysis is conducted by evaluating differences in terms of 30 day mortality. Our results indicate that elevated shock indexes are frequent in acute patients. This finding should spur a discussion on the utility of interventions relying on calculations of shock index based on spot measurements. As an alternative, we propose a novel proportional representation of shock index based on automated calculations of temporal shock index aspects.