Physician-manned prehospital emergency care in tertiary emergency centers in Japan.

Use of a physician-manned prehospital emergency medical service (EMS) has recently become widespread in Japan. Understanding the epidemiology of critically ill patients is essential for planning national and regional physician-manned prehospital EMS systems. However, current knowledge on patients receiving physician-manned prehospital EMS is sparse. The present study aimed to determine the clinical features of critically ill patients with and without physician-manned prehospital EMS, using a national inpatient database in Japan. Using the Japanese Diagnosis Procedure Combination inpatient database, we identified all hospitalized patients transported to tertiary emergency centers by physician-manned EMS or EMS without a physician from April 2014 to March 2015. We collected data on patient characteristics, in-hospital mortality, admission diagnoses, advanced life support interventions, and incidence of critical illnesses. We identified 497,911 hospitalized patients transported to tertiary emergency centers by EMS. Of these, 15,507 (3%) patients were hospitalized by physician-manned EMS. The majority of admission diagnoses in the physician-manned EMS group were classified "diseases of the circulatory system" (45%) and "injury, poisoning and certain other consequences of external causes" (34%). The rates of in-hospital mortality, advanced life support interventions, and critical illnesses in the physician-manned EMS group were 22%, 51%, and 53%, respectively. The median incidences of hospitalized patients by physician-manned EMS, advanced life support interventions, and critical illnesses were 12, 137, and 205 per 100,000 persons per year in facilities with physician-manned EMS, respectively. Our study indicates that physician-manned EMS is dispatched to a relatively small proportion of critically ill patients in Japan.