Shock Index, Pediatric Age-Adjusted (SIPA)

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.

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.