Review of current knowledge regarding usage of pre-hospital heart rate variability and complexity in triage and added value for predicting the need for life-saving interventions.

Background & aim: Analysis of heart rate variability metrics has shown added accuracy in pre-hospital trauma triage. These metrics include heart rate variability (HRV), meaning oscillations in the time interval between heartbeats, and heart rate complexity (HRC), which assesses intricate patterns of heart rate over time. This review article evaluates current knowledge regarding HRV and HRC and prediction of a subsequent life-saving intervention (LSI), an intervention executed by trained medical personnel to prolong the life of the patient. Our primary focus was on pre-hospital patients and the utility of HRV and HRC when added to existing trauma triage scores or vital signs such as heart rate (HR).

Methode: A literature search was carried out by searching the MEDLINE database via the PubMed website for original research published in English from 2008 to 2023. The combinations of search terms applied yielded 18 original studies of which only six met our criteria. We included another study as it contributed original research beneficial to our article.

Results: The studies showed a statistically significant increase in the ∆Area Under Curve (AUC) between 0.14 and 0.40 for predicting risk of LSI when adding the two heart rate variability metrics to existing trauma triage scores or vital signs such as HR. Calculation of HRV and/or HRC could be conducted using ECG recording hardware already accessible in most emergency pre-hospital settings with less ECG noise and therefore higher quality ECG data over time.

Conclusion: Both HRV and HRC showed potential for increasing ∆AUC in predicting risk of LSI when added to existing risk triage scores. Calculation of HRV and HRC could potentially be conducted using a preexisting hardware in most emergency pre-hospital settings.