Objective. Routine vital signs assessment is considered a fundamental component of patient assessment. This study was undertaken to determine whether advanced life support (ALS) emergency medical services (EMS) providers depend on vital signs information in managing their patients.Methods. Emergency medical technician-paramedics (EMT-Ps) and EMT-Intermediates (EMT-Is) were presented with 20 randomized patient scenarios that did not included vital signs information. The participants were asked to identify all of the interventions they would perform for each hypothetical patient. At least six weeks later the same scenarios were presented in a new order, with vital signs information, and the participants again identified the interventions they would perform. The participants' estimations of the patients' blood pressures, as well as the frequencies with which 18 specific interventions were performed, were compared for the no-vital signs and the vital signs groups using chi-square or Fisher's exact test, with an alpha value of 0.05 considered significant.Results. Fourteen EMT-Ps and 16 EMT-Is completed both the no-vital signs and vital signs portions of the study, for a total of 1,160 hypothetical patient encounters. When vital signs were given, the EMT-Is were more likely to apply a cardiac monitor (65.2% vs 80.1%, p = 0.000), more likely to start at least one intravenous (IV) line (82.1% vs 87.8%, p = 0.038), and more likely to administer a medication (1.3% vs 5.6%, p = 0.003). The EMT-Ps were also more likely to apply a cardiac monitor (84.4% vs 90.3%, p = 0.041), more likely to run an IV at a “wide open” rate (9.5% vs 19.0%, p = 0.004), and less likely to identify patients as being hypotensive (39.9% vs 26.4%, p = 0.004).Conclusion. The presence or absence of vital signs information does influence some of the patient care decisions of EMS providers; however, the clinical implications of these decisions are unclear. Further studies are needed to determine whether ALS providers can adequately manage actual patients without obtaining vital signs.