Emergency medical services.
D004632:Emergency Medical Services / Q000331:legislation & jurisprudence / Q000639:trends*; D006801:Humans; D007591:Joint Commission on Accreditation of Healthcare Organizations; D009493:Neurosurgery / Q000639:trends*; D010347:Patient Care Planning / Q000331:legislation & jurisprudence / Q000639:trends*; D012955:Societies, Medical; D014193:Trauma Centers; D014481:United States; D014483:United States Dept. of Health and Human Services