Quick take: Prehospital hemodynamic monitoring for shock
Current technology and vital signs limit the information EMS providers can communicate to hospital trauma teams
ORLANDO, Fla. — Hemodynamic monitoring to identify and detect shock by prehospital providers is challenging because of the capabilities and limitations of various current and proposed vital signs and shock index scales.
Sam Galvagno, DO, PhD, University of Maryland Shock Trauma, explored the history, as well as the potential future, of prehospital monitoring of patient hemodynamic status at the American Heart Association’s Scientific Sessions 2015. Currently assessment and monitoring of shock is most often with a single set of vital signs, manually reported and mostly tracked on hand-written patient status boards at the emergency department.
Memorable quotes on vital sign monitoring
These are three memorable quotes from Galvagno's presentation.
"In 2015 we have a hand-written scratch pad for reporting vital signs that we use to try to get a sense of what is going on with a patient. We need to evolve from here."
"What's the seventh, eighth or ninth vital sign for prehospital monitoring for shock? We have not been able to make one mobile or robust enough at Shock Trauma to use in the field."
"We need to move towards trending data, collected prehospital, to continuously monitor patients and make the technology more friendly."
Key takeaways on prehospital hemodynamic monitoring
Here are three key takeaways from Galvagno's presentation on prehospital monitoring capabilities and limitations.
1. Vital signs are general
Vital signs, as entry criteria into the trauma system, using the CDC Field Triage are very general. The interrelationship between heart rate, systolic blood pressure, and respiratory rate might not be as strong as has been taught in the advanced trauma life support course.
2. Hemodynamic monitoring is challenging
Other vital signs have been proposed and investigated for their ability to predict or identify shock. SpO2 measurement has a strong correlation with SaO2, but there are some limitations to pulse oximetry monitoring. Point of care lab testing might improve sensitivity and specificity. Low levels of end-tidal capnography (ETCO2) strongly predict mortality from shock. Continuous ETCO2 monitoring also helps prevent hypo/hyper-ventilation.
Prehospital utilization of patient scoring systems or scales was discussed. Shock index calculation in the field is difficult, unless automated into a monitoring device. The ABC score for shock, reliant on an ultrasound exam, is limited because of the equipment requirement.
3. Lactate monitoring
Prehospital monitoring of lactate is promising as an indicator of shock. The speaker discussed research underway at Shock Trauma using the Maryland State Patrol flight program to conduct prehospital lactate monitoring. A lactate greater than 2 is associated with increased mortality.
What are your thoughts on prehospital monitoring of a patient's hemodynamic status? Do you trend — take multiple sets — vital signs over time during patient assessment and transport?