The Shock Index

The Shock Index (SI) is a tool to help identify patients at risk for hypotension in the peri-intubation phase. The patient should receive a focused physical exam and history, if possible, to identify other potential predictors of hypotension.

This SI is not applicable to Pediatric Patients.

Shock Index = Heart Rate / Systolic BP (SI=HR/BP)

Normal Physiology

HR < SBP

Shock Index < 1

Shock Physiology

HR > SBP

Shock Index > 1

Shock States

Cardiac

• Too big / Too slow / Too fast / Too little / Too inflamed and flow limited
• Obstructive disease (e.g. aortic stenosis, cardiomyopathies, tamponade)
• Acute ischemia
• Extremes of brady/tachycardia

Vessels / Volume

• Volume depletion (e.g. hemorrhage, polyuria, diuretics, limited liquid intake)
• Vasoplegia (e.g. burns, sepsis, cardiogenic, neurogenic shock, severe acidosis)

Pulmonary

• Auto-peep (e.g. positive pressure ventilation without adequate exhalation time; severe asthma)
• Pulmonary hypertension/obstruction (e.g. pulmonary hypertension/emboli, tension pneumothorax)