Clinical Conundrum: What is shock index? How can we apply shock index in the ED?
Background:
Shock index (SI) was first introduced in 1967 as a simple tool assessing the intensity of hypoperfusion states
Shock index = HR/SBP, normal range 0.5-0.7
Elevated SI is correlated with disease severity and adverse outcomes
There is a remarkable consensus among ED studies for predicting the risk of:
Post-intubation hypotension with SI ≥ 0.8
Post-intubation cardiac arrest with SI ≥ 0.9
Answer:
Approach to SI: Useful noninvasive bedside assessment of circulatory status which elevated SI may help identify possible post-intubation hypotension and post-intubation cardiac arrest early on.
If SI ≥ 0.8, consider:
Proper fluid challenge: Adequately fluid resuscitate prior to, and during, intubation (FLUID RESUSCITATE BEFORE INTUBATE)
Treat the underlying cause of hypotension:
Trauma patients with active internal bleeding: blood products and interventional surgical procedure
Profound fluid loss: vomiting/diarrhea, burn, profound sepsis
Tension pneumothorax, tamponade, pulmonary embolism, cardiogenic or distributive shock
Choose an induction agent and a dose that is least likely to exacerbate hypotension (i.e, ketamine, etomidate)
Prepare push dose pressors and/or vasopressor infusion to be started if MAP ≤ 65
Written by:
Joanne C. Routsolias, PharmD, RN, BCPS
Clinical PharmD Specialist - Emergency Medicine/Toxicology
Cook County Health
Hannah Kim
EM Pharmacy Resident, PGY-2
University of Illinois Chicago
References:
Althunayyan SM, et al. Shock index as a predictor of post-intubation hypotension and cardiac arrest; A review of the current evidence. Bull Emerg Trauma.2019;7(1):21-27
Heffner AC, et al. Predictors of the complication of postintubation hypotension during emergency airway management. Journal of Critical Care. 2012; 27(1):587-593.
Koch E, et al. Shock index in the emergency department: utility and limitations. Open Access Emerg Med. 2019;11:179-199