Figure 1: Study Inclusion and Exclusion Criteria.

¹Excluded primary symptoms (N): Bleeding (25), change in responsiveness (199), choking (15), death (1), device/equipment problem (1), diarrhea (2), drainage/discharge (4), fever (177), malaise (94), mass/lesion (1), mental/psych (44), nausea/vomiting (4), not known or missing (5,556), pain (137), palpitations (1), rash/itching (201), swelling (80), transport only (43), weakness (46), wound (1)

²Excluded primary impressions: Behavioral / psychiatric disorder (28), diabetic symptoms (1), cardiac arrest (5), airway obstruction (90), vaginal hemorrhage (1), altered level of consciousness (21), syncope/fainting (5), seizure (14), hyperthermia (12), hypothermia (1), chest pain (30), abdominal pain (42), respiratory arrest (28), sexual assault/rape (1), traumatic injury (11) poisoning/drug ingestion (1), inhalational injury (7), stings/venomous bites (1), allergic reaction (493), fever (50), general malaise (97), heart-related illness (12), intentional drug use (1), not known or missing (1423), other non-traumatic pain (541), sepsis (4)

³Childbirth (3), seizure (38), interfacility transfer (160) or trauma (240) as indicated by other EMS procedure or classification codes