[1] In 2004, Laidlaw sold EmCare and American Medical Response to Onex.

[2] Onex formed Emergency Medical Services Corporation as the parent of its two acquisitions.

[4] On June 11, 2013, EMSC changed names to Envision Healthcare and went public as EVHC.

This practice is particularly frequent in emergency room visits, in which the patient has little to no ability to choose their doctors.

[6][7] EmCare Holdings Inc., was purchased by Envision Physician Services and is no longer in business.