Ambulance diversion reduction and elimination: the 3-2-1 plan.

Background: The diversion of ambulances from their intended emergency departments (EDs) occurs frequently, compromising patient care. Previously, we reduced ambulance diversion (AD) by 74% in a large urban area with 17 EDs.

Objectives: In this follow-up program, we sought to further reduce and eliminate AD by progressively reducing the duration of each AD event.

Methods: Using tight diversion criteria, AD at each ED was limited by protocol to 3h at a stretch, after which incoming ambulances had to be accepted at that ED for at least 1h. After 6 months, AD was limited to 2h per diversion event; after another 6 months, AD was limited to 1h. The monitoring for AD was programmed into a region-wide, Internet-based Emergency Medical Services (EMS) program.

Results: Total annual AD decreased from 8469 h in 2006 (pre-implementation) to 4592 h in 2007 (during implementation), and finally to 2439 h and 2306 h in 2008 and 2009 (post-implementation), respectively, an 87.4% (95% confidence interval 64.6-95.5%) reduction, and one county within the region eliminated AD altogether. From 2006 to 2009, overall increases were noted in EMS arrivals (7.8%), ED census (13.0%), hospital admissions (6.6%), Intensive Care Unit admissions (17.1%), and overall Sacramento population (1.9%).

Conclusions: By limiting the duration of AD events to progressively shorter periods of time using a region-wide, Internet-based EMS program, we reduced AD hours in 17 EDs by 87.4% and eliminated AD in one entire county. This original, collaborative 3-2-1 Plan may be readily reproduced across the country to progressively reduce and eliminate AD.