Internet-accessible emergency department workload information reduces ambulance diversion.

Objective: To determine the effect of pre-emptive ambulance distribution based on the implementation of a real-time, Internet-accessible emergency department (ED) workload schematic and prehospital Australasian Triage Scale (ATS) allocations on ambulance diversion in Western Australia.

Methods: Comparison of July-December 2002 and July-December 2003 metropolitan Perth ED cubicle occupancy, ambulance diversion, ambulance distribution, and ambulance unloading delays at four inner and four outer metropolitan EDs.

Results: Ambulance diversion fell from 1,788 hours in 2002 to 1,138 hours in 2003 (p < 0.001) despite an increase in mean weekly ED cubicle occupancy from 31 patients (95% confidence internal [CI] 29-33) in 2002 to 39 patients in 2003 (95% CI 36-43, p < 0.001). Inner metropolitan ED ambulance attendances fell 2.7% from 27,475 in 2002 to 26,743 in 2003, and outer metropolitan correspondingly rose from 5,877 to 6,628 ambulance attendances (p < 0.001). Unloading delays were similar in 2002 (219, 0.66%) and 2003 (223, 0.67%, p = 0.84); however, median duration of unloading delays increased from 38 minutes (interquartile range [IQR] 18-68) in 2002 to 50 minutes (IQR 25-108) in 2003 (p < 0.001).

Conclusions: The implementation of pre-emptive ambulance distribution using Internet-accessible ED information and prehospital ATS allocations was associated with reduced ambulance diversion, probably consequent upon the redistribution of ambulances from inner to outer metropolitan EDs. The rise in ED cubicle occupancy between the study periods suggests that this approach to reducing ambulance diversion should be viewed only as complementary to direct efforts to reduce ambulance diversion by improving hospital inpatient flow and the balance between acute and elective hospital inpatient accommodation.