Validation of low-acuity emergency medical services dispatch codes

Area of Science:

• Emergency Medical Services
• Prehospital Care
• Public Health

Background:

• Computer-aided dispatch (CAD) systems categorize 9-1-1 calls to determine emergency medical services (EMS) response levels.
• Low-acuity codes are defined as requiring advanced life support (ALS) intervention in less than 10% of cases.
• This study evaluates previously validated low-acuity codes in a new community.

Purpose of the Study:

• To assess the accuracy of pre-defined low-acuity dispatch codes in a specific community.
• To determine the actual rate of advanced life support (ALS) interventions for these codes.
• To identify the need for redefining patient subsets benefiting from prehospital treatments.

Main Methods:

• Analysis of 1,597 9-1-1 medical calls assigned low-acuity dispatch codes between January and July 2004.
• Definition of ALS care included interventions like pulse oximetry, glucose measurement, defibrillation, medication administration, airway maneuvers, or IV catheter placement.
• A more restrictive definition of ALS care was also calculated.

Main Results:

• None of the 26 evaluated dispatch codes met the low-acuity definition (less than 10% ALS intervention).
• Fifty-six percent of patients received ALS care, with IV catheter placement (45%) and pulse oximetry (32%) being most common.
• Using a restrictive definition, 7 of 28 categories were high-acuity (13-36% ALS intervention).

Conclusions:

• Pre-defined low-acuity dispatch codes were not accurate in this community.
• Clinical practice variations may stem from a precautionary approach and increased analgesic use.
• Optimal subsets of prehospital patients benefiting from specific treatments require further definition.