Formula reviewed
Modified Shock Index (MSI) Calculator
Modified Shock Index (MSI): Explanation and Clinical Context The Modified Shock Index (MSI) is a refinement of the traditional Shock Index (SI), which is defined as the ratio of heart rate (HR) to systolic blood pressure (SBP). MSI replaces SBP with mean arterial pressure (MAP) in the denominator, thereby improving sensitivity and specificity in detecting hemodynamic instability. It is calculated as: MSI = Heart Rate