How it's calculated
Diastolic Shock Index = Heart rate ÷ Diastolic blood pressure. A low diastolic BP relative to heart rate reflects reduced vasomotor tone and has been studied as a marker of haemodynamic compromise, particularly in septic and haemorrhagic shock.
Interpretation
| DSI | Interpretation |
|---|---|
| < 1.5 | Not elevated |
| ≥ 1.5 | Elevated — associated with greater haemodynamic compromise in observational studies |
Clinical use
- Studied as an early marker of vasoplegia and haemodynamic compromise in septic shock, sometimes changing before more overt hypotension develops.
- Also studied in haemorrhagic shock and trauma populations as a simple bedside marker of physiological compromise.
- Cutoffs vary between studies and populations — this is a research-derived marker to complement, not replace, standard shock assessment (lactate, capillary refill, mental status, urine output).
- Should be trended over time alongside other vital signs rather than acted upon as a single isolated reading.
Frequently asked questions
What is the Diastolic Shock Index used for?
It's a simple bedside ratio of heart rate to diastolic blood pressure, studied as an early marker of haemodynamic compromise, particularly in septic and haemorrhagic shock.
Why diastolic BP rather than systolic or mean BP?
Diastolic BP falls with vasodilation and loss of vascular tone, which occurs early in vasoplegic states like sepsis — making the diastolic-based ratio a potentially earlier signal than systolic BP alone.
What DSI value is considered elevated?
A commonly cited research cutoff is around 1.5-2.0, though exact thresholds vary by study population; this should complement rather than replace standard shock assessment.
Can this replace other markers of shock like lactate?
No — it is a simple adjunct marker, not a replacement for lactate, capillary refill time, mental status, or urine output in assessing shock severity.
References
- Ospina-Tascón GA, et al. Diastolic shock index and clinical outcomes in patients with septic shock. Ann Intensive Care. 2020;10(1):41.
- Pandit V, et al. Shock index predicts mortality in geriatric trauma patients: an analysis of the National Trauma Data Bank. Am Surg. 2014;80(6):613-617.