Calc Function

    • Calcs that help predict probability of a diseaseDiagnosis
    • Subcategory of 'Diagnosis' designed to be very sensitiveRule Out
    • Disease is diagnosed: prognosticate to guide treatmentPrognosis
    • Numerical inputs and outputsFormula
    • Med treatment and moreTreatment
    • Suggested protocolsAlgorithm





    Chief Complaint


    Organ System


    Patent Pending

    Log in to create a list of your favorite calculators!

    Shock Index, Pediatric Age-Adjusted (SIPA)

    Predicts mortality in children with blunt trauma.


    Use in blunt trauma patients 4-16 years of age.

    When to Use
    Why Use
    • Patients 4-16 years old who have sustained blunt trauma.

    • Do not use in young infants, toddlers, or patients with penetrating trauma.

    • SIPA should be calculated on presentation to the emergency department.

    • Uptrending SIPA between the field and ED may predict poor outcomes but was not examined by the original authors.

    • The use of SIPA to predict morbidity and mortality following admission has not yet been validated. However, a prognostic study in the Journal of Pediatric Surgery (Vandewalle 2018) found that patients who developed an elevated SIPA within the first 24 hours of admission were at increased risk of complications compared to those whose SIPA remained normal throughout the first 48 hours of admission. In addition, time to normalize SIPA directly correlated with length of hospital and ICU stay.

    • Per the authors, the age-specific cutoffs originally chosen will require further validation in a second cohort.

    • Better differentiates severely injured children from those with mild injury than the Shock Index (SI). In the original study, an elevated SIPA was shown to identify approximately 25% of the most severely injured children, regardless of age, while SI >0.9 has been shown to identify anywhere from 32-71% of injured children, depending on age.

    • Being able to accurately identify severely injured children is critical in reducing the over-triage of children that have sustained injuries.

    • Elevated SIPA is associated with the following outcomes (Acker 2015; Nordin 2017):

      • Higher injury severity.

      • Need for blood transfusion in the first 24 hours.

      • Longer ICU and hospital length of stay.

      • Higher number of ventilator days.

      • Discharge to a rehabilitation facility.

      • Increased risk of mortality.

    mm Hg


    Please fill out required fields.

    Next Steps
    Creator Insights


    Patients that present with an elevated SIPA are at higher risk of morbidity and mortality following blunt trauma. Early recognition and treatment in these cases, including a possible decision to transfer to a higher level of care, will improve outcomes in these children.


    • General management of pediatric blunt abdominal trauma includes primary and secondary survey and determination of extent, type, and severity of injury.

    • A thorough abdominal exam is extremely important as abdominal injuries are often not apparent on exam. The use of imaging may be warranted depending on exam findings.

    Critical Actions

    Remember that there is no value or finding that necessarily defines shock, and children can compensate more readily than adults. Hypotension is often a late finding in children with hypovolemic shock.


    SIPA = maximum heart rate/minimum systolic blood pressure, where normal values are as follows:


    Heart rate

    Systolic blood pressure

    Maximum normal SIPA

    4–6 years




    7–12 years




    13-16 years




    Facts & Figures




    Risk of blunt injury if SIPA is elevated

    4–6 years



    7–12 years



    13-16 years



    Overall in-hospital mortality for elevated SIPA (at each cutoff) was 11%, versus 7% for non-age-adjusted shock index.

    Evidence Appraisal


    • The SIPA was originally developed by researchers at the Children’s Hospital of Colorado to help identify severely injured children following blunt trauma.

    • Mechanism alone has been found to be a poor predictor of injury severity in children (Qazi 1998), whereas clinical and physiologic parameters are better indicators (Wang 2001), and previous studies (Rousseaux 2013; Yasaka 2013) have shown that the Shock Index (SI) helps identify a higher risk of mortality versus using HR and BP alone. The SIPA furthers builds on that by taking into account specific vital sign cutoffs by age group.

    • Realizing that pediatric vital signs vary with age and that the standard SI may not be as useful in children, the researchers sought and defined maximum normal heart rate and minimum normal systolic blood pressure using reference ranges from two pediatric textbooks and the U.S. Department of Health and Human Services’ Pediatric Basic and Advanced Life Support guidelines.

    • Using these numbers, they determined the maximum normal SI for each age group.

    • The researchers then retrospectively looked at 543 children who presented to Children’s Hospital Colorado and Denver Health Medical Center between 1/2007 and 6/2013 following blunt trauma with Injury Severity Score >15.

    • Elevated SI was present in 49% of children, while elevated SIPA was present in only 27.6% of children (all of whom had the same adverse outcomes identified by using the SI).

    • SIPA demonstrated improved discrimination of severe injury relative to SI in the following categories:

      • Injury Severity Score >30: 37% vs 26%.

      • Blood transfusion within first 24 hours: 27% vs 20%.

      • Grade III liver/spleen laceration requiring blood transfusion: 41% vs 26%.

      • In-hospital mortality: 11% vs 7%.

    • The researchers concluded that SIPA misses fewer children with severe injury while also minimizing over triage.

    Validation studies:

    • A multicenter prospective observational study of 386 patients aged 4-16 years (Linnaus 2017) validated the original study with level II quality evidence.

    Follow-up studies:

    • A study in the Journal of Pediatric Surgery (Nordin 2017), in which the authors developed cutoff values for SIPA for patients 1-3 years of age, found SIPA to be a significantly better predictor than SI of transfusion needs, injury severity, ICU admission, ventilator use, and mortality following blunt and penetrating trauma.

    • The authors of the original SIPA study conducted a follow-up study (Acker 2017) and found the SIPA to be superior to age-adjusted hypotension in identifying injured children that required trauma team activation. Criteria used as indicators included early blood transfusion, endotracheal intubation, and requiring emergency operation.

    • A comparison of the SIPA, SI, and Revised Trauma Score (RTS) (Nordin 2017) presented at the 2017 Annual Pediatric Trauma Society meeting found that SIPA compares favorably to RTS in predicting pediatric trauma outcomes (and outperformed the SI).


    Other References

    Research PaperVandewalle RJ, Peceny JK, Dolejs SC, Raymond JL, Rouse TM. Trends in pediatric adjusted shock index predict morbidity and mortality in children with severe blunt injuries. J Pediatr Surg. 2018;53(2):362-366.Research PaperYasaka Y, Khemani RG, Markovitz BP. Is shock index associated with outcome in children with sepsis/septic shock?*. Pediatr Crit Care Med. 2013;14(8):e372-9.Research PaperRousseaux J, Grandbastien B, Dorkenoo A, Lampin ME, Leteurtre S, Leclerc F. Prognostic value of shock index in children with septic shock. Pediatr Emerg Care. 2013;29(10):1055-9.Research PaperQazi K, Wright MS, Kippes C. Stable pediatric blunt trauma patients: is trauma team activation always necessary?. J Trauma. 1998;45(3):562-4.Research PaperWang MY, Kim KA, Griffith PM, et al. Injuries from falls in the pediatric population: an analysis of 729 cases. J Pediatr Surg. 2001;36(10):1528-34.
    Dr. Shannon N. Acker

    From the Creator

    Why did you develop the SIPA? Was there a particular clinical experience or patient encounter that inspired you to create this tool for clinicians?

    Children have a remarkable ability to compensate for hypovolemic shock and are able to maintain a normal blood pressure until they reach cardiovascular collapse. Because shock index incorporates not only blood pressure but also heart rate, we hypothesized that an age adjusted shock index would help us to identify these children before the point of cardiovascular collapse. Our motivation to create SIPA came from an ongoing desire to improve pediatric trauma care and our desire to more accurately identify severely injured children prior to the point of cardiovascular collapse.

    What pearls, pitfalls and/or tips do you have for users of the SIPA? Do you know of cases when it has been applied, interpreted, or used inappropriately?

    As with all pieces of information we use in medicine, SIPA is a single piece of information that must be considered in combination with all other pieces of data to help physicians make clinical decisions. It should be used, not as an isolated data point, but within the context of the bigger clinical context. I am not aware of any specific instances where it has been applied inappropriately. However, I could imagine that if it were used as an isolated data point on which to make clinical decisions, a normal SIPA at a single point in time could be associated with missed injuries/undertriage as the sensitivity of an elevated SIPA in identifying all severely injured patients is not 100%. While SIPA is a great tool to help us identify severely injured children, it is not perfect and should not be used in isolation.

    What recommendations do you have for doctors once they have applied the SIPA? Are there any adjustments or updates you would make to the score based on new data or practice changes?

    Our hypothesis is that the SIPA can be followed over time and a rising SIPA will help alert the clinician to a child with ongoing/worsening shock. Since our initial publication defining SIPA, many other groups have contributed to the literature both validating our findings as well as demonstrating that a rising SIPA after admission can be used to identify children with ongoing or worsening shock. This is something we initially hypothesized when we defined SIPA and are excited about following the trend over time to help guide care. Future work will aim to clarify how changes in SIPA can be used during the ongoing resuscitation of pediatric trauma patients.

    How do you use the SIPA in your own clinical practice? Can you give an example of a scenario in which you use it?

    At our institution, we recently added elevated SIPA to our trauma activation criteria. For every incoming trauma patient, the SIPA is calculated and if elevated, the full trauma team, including surgeons, is called to perform the initial patient evaluation.

    Following arrival, we use the patient's SIPA to assist in clinical decision making regarding need for ongoing resuscitation, need for operative intervention, and need for ICU level care. Our primary application of SIPA is in the initial evaluation of our trauma patients but it is used in the ICU as well to determine need for ongoing resuscitation in these children.

    Any other research in the pipeline that you’re particularly excited about?

    SIPA was initially defined in the pediatric trauma population. However, I suspect that it has application among other populations such as those with sepsis or other forms of hypovolemic shock. Future work will aim to evaluate the application of SIPA among these other groups of critically ill children. Additionally, as mentioned above, we think that SIPA is likely a marker that can be followed over time, the same way that other vital signs are followed throughout a patient's hospital course, to help guide ongoing care. Future work will aim to clarify the application of ongoing SIPA monitoring during the course of a child's hospitalization.

    About the Creator

    Shannon N. Acker, MD, is a pediatric surgeon at the University of Colorado. Dr. Acker’s primary research is focused on trauma and surgical complications in adolescents.

    To view Dr. Shannon N. Acker's publications, visit PubMed

    Content Contributors
    • Christian Hietanen, DO
    About the Creator
    Dr. Shannon N. Acker
    Content Contributors
    • Christian Hietanen, DO