Pre-hospital point-of-care testing: increasing the value of EMS care

Emergency Medical Technicians are trained to assess patient signs and symptoms and deliver specific, protocol-based treatments in the pre-hospital setting. While EMTs are not trained as diagnosticians, one common presentation we are trained to recognize and treat is hypoglycemia, or a low blood glucose level. Testing for hypoglycemia by EMTs in the field involves sampling blood – commonly through a finger prick – and testing the blood glucose level with a glucometer device. This approach to bedside sampling of blood where the result is available immediately is called point-of-care testing (POCT). POCT for blood glucose is very accurate with a specificity of 99.3%.  When patients have hypoglycemia, we as EMTs can often address the problem by administering sugar solutions or intravenous dextrose. However, beyond POCT for blood glucose, there are other ways that EMTs can use POCT to help patients. Below I describe several studies where EMS personnel have used additional POCT in useful ways.

A study by Guerra et al. examined the feasibility of EMS personnel recognizing an acute sepsis patient using venous lactate measures. Their study found that although there was a lack of EMS education on sepsis identification, mortality from severe sepsis decreased from 26.7% to 13.6% after the implementation of the protocol. While the reported treatment effect seems unfeasibly large, the authors concluded that by having a Sepsis Alert Protocol in place, both EMS and the ED personnel were able to initiate treatment in the early phases of illness.  Sepsis is a time-sensitive disease where earlier resuscitation and care can improve outcomes.

Another study by Venturini et al. examined the reliability of pre-hospital POCT for troponin levels, which can be useful to detect acute heart damage during heart attacks. They found no significant difference in whole-blood troponin results between those performed in the ED and in the moving ambulance (p <0.005). Immediate access to troponin results can aid in the diagnosis of acute myocardial infarction (specifically without ST-elevation). Stengaard et al. also predicts that pre-hospital POCT will be central in pre-hospital heart attack care in the near future.

Beynon et al. used pre-hospital POCT to examine whether the pre-hospital physician assessment of hemostatic parameters is feasible. Point-of-care INR testing was performed on a total of 103 patients, revealing a pre-hospital sensitivity of 100% and specificity of 98.7% for detecting coagulopathy. Furthermore, the median time saved through POCT compared to results being sent to a central lab upon transfer of care was 69 minutes (ranging from 33 to 336min) – substantially beneficial for patients with intracranial hemorrhage.

From the results of these studies, we see that POCT in the pre-hospital setting seems to be reliable, valid, and in many cases helpful to clinical care. Along with pre-hospital initiation of care, information relayed to a receiving facility can allow for the mobilization of resources to improve timely access to definitive care. As medicine moves from volume to value, there are many ways that EMS can contribute to a higher-value healthcare system. POCT is one, important way that is feasible and effective, but will require further EMS education and protocol development prior to widespread implementation.

Ameer Khalek is a MPH Candidate of the GWU Milken Institute School of Public Health