Shock index:
Shock index is defined as the heart rate divided by systolic blood pressure. It has been studied in patients either at risk of or experiencing shock from a variety of causes such as trauma, myocardial infarction, hemorrhage, pulmonary embolism, sepsis, and obstetric haemorrhage. Schroll R. Et al reported Shock Index ≥1 had a sensitivity of 67.7% (95% CI 49.5%-82.6%) and specificity of 81.3% (95% CI 78.0%-84.3%) for predicting massive transfusion in trauma patients. In obstetrics, Nathan et al reported that SI ≥ 1.7 had 25.0% sensitivity (95% CI 5.5-57.2) and 97.7% specificity (CI 94.8-99.3), for predicting ICU admission in postpartum haemorrhage.(13). Welsh et al reported SI de 0.9 as a good predictor of necessity for transfusion in postpartum haemorrhage (14). This study determined that the value of the shock index, dynamically evaluated, at the time of diagnosis, and 30 minutes after diagnosis, allows early identification of those patients who present massive bleeding with the sensitivity of 0.43 and specificity of 0.98 and 0.64 sensitivity and specificity 0.7 respectively. Our study’s cut point did not differ much from other studies. As a general rule SI > 1 is the predictor of adverse effects in most of the clinical scenarios independent of the moment of its determination. At initial phases of shock, the compensatory mechanism of the cardiovascular system responds by increasing the heart rate, increasing myocardial contractility and constricting peripheral blood vessels as a result of the direct stimulation via the sympathetic system although this compensatory mechanism makes the shock index an early indicator of severe haemorrhage.