Paediatric Age-Adjusted Shock Index (SIPA) Calculator

Overview

Calculates paediatric shock index and compares it with commonly used age-adjusted upper thresholds. The calculator is intended to make the underlying equation transparent while preserving the requirement for clinical assessment and source-data verification.

Clinical Significance

An elevated age-adjusted shock index has been associated with adverse outcomes after paediatric blunt trauma. It must be combined with paediatric assessment, mechanism and local trauma activation criteria.

When to Use

• Support early risk assessment after paediatric blunt trauma.
• Use age-appropriate threshold bands.
• Reassess after deterioration or resuscitation.

How It Is Calculated

• SIPA = heart rate ÷ systolic blood pressure, interpreted against age bands: 4–6 years 1.22; 7–12 years 1.00; 13–16 years 0.90.
• MedicalC validates required values, applies the stated equation and rounds only the displayed result.
• Review intermediate measurements and assumptions whenever the result appears discordant with the clinical picture.

Interpretation

• An elevated age-adjusted shock index has been associated with adverse outcomes after paediatric blunt trauma. It must be combined with paediatric assessment, mechanism and local trauma activation criteria.
• Interpret trends only when the same technique, units and clinical conditions are reasonably comparable.

Worked Example

Enter the required measurements in the displayed units. MedicalC applies: SIPA = heart rate ÷ systolic blood pressure, interpreted against age bands: 4–6 years 1.22; 7–12 years 1.00; 13–16 years 0.90. Confirm the result against the original observations before using it in a clinical decision.

Patient Considerations

• Consider age, body size, pregnancy, organ support, medication, rhythm, ventilation, measurement conditions and acute physiological change where relevant.
• Use the earliest reliable values for prognostic trauma scores unless the score definition specifies otherwise.
• Repeat calculations only when a changed result could influence care and the source data remain valid.

Limitations

• The commonly cited thresholds were derived in selected trauma populations.
• Pain, fever, anxiety and medication affect heart rate.
• Do not use outside the validated age range without specialist judgement.

Clinical Pearls

• Treat the calculator as a transparent equation, not an autonomous recommendation.
• Record the exact time and method of important measurements.
• Resolve a clinically implausible result by checking inputs before assuming unusual physiology.

Common Mistakes

• Entering values in the wrong unit.
• Combining measurements obtained at different clinical time points.
• Applying a published threshold outside its validated population or setting.
• Allowing a score to delay urgent treatment.

Evidence Base

The calculator implements the stated published or established relationship. Principal source: Acker SN, et al. Pediatric specific shock index accurately identifies severely injured children. J Pediatr Surg. 2015.

References

1. Acker SN, et al. Pediatric specific shock index accurately identifies severely injured children. J Pediatr Surg. 2015. — Primary publication, authoritative guideline or recognised specialty source.