Paramedic diagnostic processes: An experimental study of dual process theory

Background: Paramedics care for the sick in a variety of settings and diagnose a range of medical conditions but little is known about their diagnostic process. We report two experiments on Australian paramedics (n=129) and paramedicine undergraduates (n=127). Experiment 1 considered the processes underlying the formation of an intuitive impression. Experiment 2 added a second step with additional clinical information as found by paramedics after meeting a patient. Method: In experiment 1, participants completed four brief written clinical vignettes under time pressure and with a concurrent navigation task to simulate common paramedic work practice. Diagnostic impression, confidence and subjective typicality of the vignette were self-reported while answer fluency was measured. The vignettes varied the normative likelihood of a diagnosis of Acute Coronary Syndrome (ACS). Results: Likelihood, answer fluency, self-reported typicality and confidence predicted the impression but there was no effect of experience. Students and experienced paramedics had comparable accuracy and performance. The impression was associated with the final diagnosis, increasing diagnostic errors. Errors were most pronounced in experienced paramedics. Conclusion: Overall, paramedics both under-diagnosed cases likely to be ACS and over-diagnosed unlikely cases. Self-reported confidence in the impression and diagnosis predicted final diagnosis, suggesting potential error-reduction strategies. Keywords: paramedic, emergency medical services, decision making, diagnosis, dual process theory, fuzzy trace theory Abbreviations: ACS: Acute Coronary Syndrome