Improving Trauma Systems and Emergency Care Act This bill reauthorizes through FY2027 and modifies activities of the Department of Health and Human Services related to trauma care. Specific changes include requiring the Office of the Assistant Secretary for Preparedness and Response to develop guidance for and otherwise support states (and consortia of states) to coordinate and improve emergency medical services and trauma care during declared emergencies. The bill also expands eligibility for and revises (1) grants for improving emergency medical services and trauma care in rural areas, and (2) competitive grants for improving regional emergency medical and trauma systems.