Why do patients use the emergency room.
D000293:Adolescent; D000328:Adult; D000368:Aged; D001294:Attitude to Health; D002648:Child; D002675:Child, Preschool; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009825:Oklahoma