A medical device for providing guidance to administered cardiopulmonary resuscitation during cardiac arrest in a subject comprising a measuring probe to measure a hemodynamic property of blood flowing through a blood vessel of the subject, an interface element with reference indicia to guide the measuring probe to major blood vessels of the subject experiencing cardiac arrest, and a blood flow monitoring device comprising a data module to collect measured hemodynamic properties of the subject and a guidance module configured to display resuscitation guidance information for manipulating at least one hemodynamic property of the blood.