Supporting Air Versus Ground Vehicle Decisions for Interfacility Medical Transport Using Historical Data

Abstract

Patients undergoing interfacility transfers are at potentially greater risk of adverse or critical events than those in hospital, and efficient transfers play a significant role in reducing mortality and morbidity. Medical dispatchers rely on accurate estimations of transfer time in determining the most appropriate method of transportation, often either a helicopter and/or land ambulance, in situations that are characterized by high time pressure and uncertainty. In this paper, we propose the design of a datadriven decision support tool to improve dispatcher transport mode decision making. We studied the dispatch process of the air and land medical transport system in Ontario, Canada through onsite observations and developed a tool which generates transfer time estimates based on historical data. We found that dispatchers have large estimation errors, and are biased toward higher degrees of underestimation for air transfers compared with land transfers. In contrast, the proposed tool produced estimates that had significantly less error than dispatcher estimates. The estimation error for the tool was on the average 21 min less: a practically significant difference in urgent patient care. Through onsite observations and the relevant literature, we also identified factors that may influence the collaboration between the dispatcher and the tool. This research is a first attempt to study how decisions are made for interfacility medical transfers and for evaluating the accuracy of human operator estimates of these transfer times. It is also the first to demonstrate a tool's utility in comparison to existing procedures for estimating transfer times.

Supporting dispatch decisions in interfacility medical transfers: Understanding the roles of uncertainty and reliability

“…Our previous work has shown that dispatchers tend to underestimate the time required to transfer patients (Giang, Donmez, Fatahi, Ahghari, & MacDonald, 2014). The underestimation also appeared to be greater for transfers made by air than those made by land, a bias that may have consequences when dispatchers need to choose the mode of transportation for completing an interfacility transfer.…”

“…The prototype decision support tool (Giang et al, 2014) was designed to support interfacility transfers and produces estimates of time to definitive care using historical transfer time data provided by Ornge. Users are required to input information about the requested transfer, including sending and receiving facilities, the 2015 International Symposium on Human Factors and Ergonomics in Health Care: Improving the Outcomes vehicles to be used (often a land and air vehicle for comparison), the Ornge base where the vehicles are located, and any landing sites required for the aircraft.…”

The Impact of Precipitation on Land Interfacility Transport Times

“…19 Fleischman et al built and validated a model of ambulance arrival times using historical data from Multnomah County, Oregon (USA). 2 The models presented in this study can be incorporated in similar aids and models to improve the accuracy of estimated times. However, presence of wet weather (any transfer that occurred during a day with more than 0.01 inches of precipitation) and patient-related conditions were not significant predictors.…”

“…2,12 In general, the lower resolution is expected to generate more conservative effects of precipitation. In particular, five weather stations located in five different cities covered most of the sending and receiving facility locations and were used for precipitation information.…”

“…1 By concentrating medical resources and expertise in a small number of centers of excellence, care can be standardized and costs can be reduced. [2][3][4] Furthermore, accurate estimates of transfer times can impact a patient's prehospital management plan. 1 For medical transport systems where dispatchers are responsible for planning these interfacility transfers, accurate estimates of transfer times play a crucial part in their medical triage and resource-allocation decisions.…”