No abstract

Background Calls for emergency medical assistance at the scene of a motor vehicle crash (MVC) substantially contribute to the demand on ambulance services. Triage by emergency medical dispatch systems is therefore important, to ensure the right care is provided to the right patient, in the right amount of time. A lights and sirens (L&S) response is the highest priority ambulance response, also known as a priority one or hot response. In this context, over triage is defined as dispatching an ambulance with lights and sirens (L&S) to a low acuity MVC and under triage is not dispatching an ambulance with L&S to those who require urgent medical care. We explored the potential for crash characteristics to be used during emergency ambulance calls to identify those MVCs that required a L&S response. Methods We conducted a retrospective cohort study using ambulance and police data from 2014 to 2016. The predictor variables were crash characteristics (e.g. road surface), and Medical Priority Dispatch System (MPDS) dispatch codes. The outcome variable was the need for a L&S ambulance response. A Chi-square Automatic Interaction Detector technique was used to develop decision trees, with over/under triage rates determined for each tree. The model with an under/over triage rate closest to that prescribed by the American College of Surgeons Committee on Trauma (ACS COT) will be deemed to be the best model (under triage rate of ≤ 5% and over triage rate of between 25–35%. Results The decision tree with a 2.7% under triage rate was closest to that specified by the ACS COT, had as predictors—MPDS codes, trapped, vulnerable road user, anyone aged 75 + , day of the week, single versus multiple vehicles, airbag deployment, atmosphere, surface, lighting and accident type. This model had an over triage rate of 84.8%. Conclusions We were able to derive a model with a reasonable under triage rate, however this model also had a high over triage rate. Individual EMS may apply the findings here to their own jurisdictions when dispatching to the scene of a MVC.

Tables and Figures:Number of tables: 3 Number of figures: 1 Number of appendices: none TitleMotor vehicle crash characteristics predictive of high acuity patients: an analysis of linked ambulance and crash data.

PurposeTraffic incidents vary considerably in their severity, and the dispatch categories assigned during emergency ambulance calls aim to identify those incidents in greatest need of a lights and sirens (L&S) response. The purpose of this study was to determine whether dispatch categories could discriminate between those traffic incidents that do/do not require an L&S response.Design/methodology/approachA retrospective cohort study of ambulance records was conducted. The predictor variable was the Traffic/Transportation dispatch categories assigned by call-takers. The outcome variable was whether each incident required an L&S response. Possible thresholds for identifying dispatch categories that require an L&S response were developed. Sensitivity and specificity were calculated for each threshold.FindingsThere were 17,099 patients in 13,325 traffic incidents dispatched as Traffic/Transportation over the study period. “Possible death at scene” ‘had the highest odds (OR 22.07, 95% CI 1.06–461.46) and “no injuries” the lowest odds (OR 0.28 95% CI 0.14–0.58) of requiring an L&S response compared to the referent group. The area under the ROC curve was 0.65, 95% CI [0.64, 0.67]. It was found that Traffic/Transportation dispatch categories allocated during emergency ambulance calls had limited ability to discriminate those incidents that do/do not require an L&S response to the scene of a crash.Originality/valueThis research makes a unique contribution, as it considers traffic incidents not as a single entity but rather as a number of dispatch categories which has practical implications for those emergency medical services dispatching ambulances to the scene.