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

Abstract

Efficient transfer of patients between facilities is a key component of regionalized critical care systems, but interfacility transfers pose added risks to patients. We created a decision support tool for dispatchers in medical transportation systems which provides estimates of the time to definitive care, the time between receiving the transfer request and patient handoff, which is a key component of dispatch decisions. This tool provides point-estimates of transfer times that are more accurate than the dispatchers own estimates, to support resource allocation and medical triage decisions. However, additional information about the uncertainty of these estimates may further improve dispatcher decision making. This paper describes an observational study conducted with 2 expert and 2 novice dispatchers in a medical transportation service on usage of our prototype decision support tool. In particular, we focused on whether these dispatchers use uncertainty information in their decision process, and how this information should be presented in a tool. We found that uncertainty, as represented by of the spread of possible transfer times (i.e., variability of times), is not currently considered by dispatchers. However, our observations suggest that reliability information (i.e., the trustworthiness of the tool's estimates) would be used. Expert dispatchers would use information about the reliability of estimates to build their trust in the system, while novices should use reliability information to calibrate their trust.

Dispatch Decision Making in an Air Medical Transport System

“…Time to definitive care estimates were given to the other decision makers involved in the transfer process (e.g., the TMP) to assist in their medical triage and level of care decisions. Similar to our previous findings (Giang et al, 2015), we found that the planners rarely used the transfer time estimates provided by the CAD software, but instead relied on cues such as the distance, their knowledge of the vehicle speeds, and their own experience in determining the closest or fastest resource. Only in cases that they felt were close did they explicitly calculate the time to definitive care for the 'matching resource to transfer' goal state.…”

“…A follow-up observational study examined whether Ornge's dispatchers would use information about uncertainty and reliability of the time estimates in a proposed decision support tool. This study revealed that expert dispatchers wanted to see information about the reliability of time estimates in order to judge whether they should revert to alternative estimation methods (Giang, Donmez, Zakir, Ahghari, & MacDonald, 2015). However, the observations also showed that the transport mode decision was only one small aspect of the dispatch task.…”

Medical dispatch decision support for transfer time estimation: Individual operator differences in system use

“…Presentation of uncertainty information in addition to point estimates has been shown to enhance operator predictions in other domains, such as weather forecasting (Nadav-Greenberg & Joslyn, 2009). Within the medical dispatch context, observational studies and interviews with Ornge dispatchers have found that expert dispatchers would use information about the variability of time estimates to judge whether they should revert to alternative estimation methods (Giang, Donmez, Zakir, Ahghari, & MacDonald, 2015). Thus, historical transfer time data can be visualized to help users understand both the central tendency and the past variability (i.e., uncertainty) associated with the patient transfer being considered which may result in better patient transfer time estimates.…”

“…However, time estimation strategies can vary between different dispatchers, due to elements such as experience and knowledge of the situation (Giang, Donmez, Zakir, Ahghari, & MacDonald, 2015;Giang, Hui, Donmez, Ahghari, & Macdonald, 2016). Thus, it is also possible that individual dispatchers may use a tool meant to support and standardize time estimation in different ways.…”