Table 4.

Fixed system variables

Data variable number	Data variable name	Type of data	Data variable categories or values	Definition of data variable
1	Population	Continuous	Number	Population count in the primary response area of the EMS
2	Area	Continuous	Number	Area in sq km or sq miles of primary response area of the EMS
3	Rural, urban, split	Nominal	1 = Urban 2 = Rural 3 = Split	Urban area defined as: "De facto population living in areas classified as urban according to the criteria used by each area or country. Data refer to 1 July of the year indicated and are presented in thousands". Rural area defined as: "De facto population living in areas classified as rural. Data refer to 1 July of the year indicated and are presented in thousands".
4	Usual tiered response	Free text	Free text	Describe briefly
5	Time intervals collected	Free text	Free text	Describe briefly
6	Service mission types	Free text	Free text	Describe briefly; e.g., mainly trauma or mixed patient population
7	Times available	Free text	Free text	Describe briefly
8	Established airway management protocols	Free text	Free text	Describe briefly
9	Airway management techniques available	Free text	Free text	Describe briefly
10	Describe type of training in airway management	Free text	Free text	Describe briefly
11	Type of tracheal tube confirmation technique	Nominal	1 = Auscultation 2 = Colorimetry 3 = Capnometry 4 = Capnography 5 = none
12	Type of available ventilator	Free text	Free text	Describe briefly

EMS: Emergency Medical Service