Correlation between modified shock index and severity index in predicting outcome in patients with hemorrhagic shock

Introduction
Trauma is the main cause of death in age group less than 45 years. A lot of clinical parameters including heart rate, pulse rate, blood pressure, shock index (SI), and modified shock index (MSI) are used to predict the severity of hemorrhage in trauma patients. In 2012 Choi and colleagues proposed for the first time a new index (NI) based on lactate concentration and peripheral perfusion index for assessment of shock in a rat model. In this trial, we propose for the first time a new severity predicting index (NI) based on lactate concentration/peripheral perfusion ratio as an indicator of hemorrhage-related mortality in humans.
Materials and methods
This prospective trial is a single-center study of 122 consecutive adult polytraumatized patients with hemorrhagic shock admitted to trauma center within 6 h of the trauma, and underwent resuscitation according to the advanced trauma life support protocol (2016). Protocol-related measurements were obtained immediately after admission and over 48 h postresuscitation for metabolic perfusion parameters, serum lactate, perfusion index, and other hemodynamic parameters. The period of the study corresponds to the outcome after 48 h of admission. Resuscitation measures were considered successful when lactate levels were less than or equal to 2 mmol/l in addition to stable macrohemodynamic parameters at the end of this period.
Results
Characteristically, the survivors had NI of 40 ± 2.7 on admission, compared with 87.1 ± 13 of nonsurvivors with highly significant difference. MSI showed a significant difference (nearly doubled) between survivors and nonsurvivors. SI showed nearly the same change, nearly doubled. NI showed lower prediction value for mortality than MSI and SI ( = 0.05) 0.884, 0.905, and 0.908, respectively.
Conclusion
This study confirms, for the first time in humans, the validity of severity index as independent parameter in prediction of mortality in comparison with MSI.