Many EMS providers learned that a palpable pulse at a specific anatomic location correlates to an estimated systolic blood pressure. Most commonly, providers are taught that a radial pulse means a systolic of at least 90 mm Hg, a femoral pulse 70 mm Hg and a carotid pulse 60 mm Hg.
This assumption was historically taught in certification courses including Advanced Trauma Life Support, but is not supported by peer-reviewed research. The assessment work-around has since been pulled out of most standard curricula, but the practice continues in EMS, likely as one of the all-too-persistent traditions within medicine that hangs around because "we’ve always done it that way".
While not a substitute for a complete blood pressure measurement, a present palpable pulse does inform the EMS provider of a few important conditions. First, a palpable pulse confirms that the patient has a heartbeat and some level of cardiac output. Additionally, presence of a radial pulse can generally infer adequate perfusion to the brain. Finally, comparison of pulse rate and quality between the left and right extremities can assist in identifying a vascular condition like an aortic aneurysm. What a palpable pulse cannot do is infer a systolic blood pressure measurement.
