Columns, Communications & Dispatch, Patient Care

MPDS Reliably Predicts Low Acuity Categorization

Review of: Hinchey P, Myers B, Zalkin J, et al: “Low acuity EMS dispatch criteria can reliably identify patients without high-acuity illness or injury.” Prehospital Emergency Care. 11(1):42-48, 2007.

The Science
During a six-month period, the authors of this study examined the emergency medical dispatch records of almost 24,000 dispatches. Medical Priority Dispatch System (MPDS) was used to categorize the calls. 2,703 calls were recorded as Alpha (lowest priority) of which 582 were excluded because of missing data. Of the remaining calls, only 21 were felt to have high acuity signs or symptoms by the responding paramedics. Of those, only eight were transported emergently.

They concluded that MPDS reliably predicted low acuity categorization greater than 99% of the time.

The Street
There continues be great debate over the value of priority dispatch systems. Most of the concern centers around missing high acuity calls that are mislabeled as low acuity. This large study provides greater evidence that, when used properly, MPDS is an accurate tool. In fact, after examining the eight patients who had high acuity symptoms and were transported emergently, I could make the argument that emergent transport was of minimal clinical value. None of them received life-saving interventions or medications.

Inefficient use of emergency medical dispatch significantly impacts EMS system resources. Sending ALS crews to care for low acuity patients prevents them from being available for more appropriate patients.