Doig, Christopher JamesLang, Eddy S.Blanchard, Ian2020-01-202020-01-202020-01-14Blanchard, I. (2020). Optimally Linking Prehospital and Health System Data: The Association between Emergency Medical Services Offload Time, Response Time and Mortality (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.http://hdl.handle.net/1880/111521INTRODUCTION: Delays in offloading Emergency Medical Services (EMS) patients in the hospital may impact timely response to emergencies, but no published studies are available. Little research has been conducted on the potential for bias when EMS data are linked to health system outcome and on the optimal EMS response time for survival of critically injured or ill patients. METHODS: Three years of EMS data from a large urban system were used to create hourly estimates of median hospital time and response time, and linked to health system outcome. Multivariable modelling and descriptive statistics were used to: 1. Explore the association between paramedic hospital time and response time while controlling for the effects of system volume, time of day, and season; 2. Describe the linkage rate between the standard strategy and one designed to optimize linkage; and 3. Explore the association between response time and mortality in critically injured or ill patients who did not experience an out-of-hospital cardiac arrest while controlling for age and sex. RESULTS: Depending on the time of day, there was between a one and three minute increase in predicted median response time when the system was experiencing a median hospital time of 90 minutes, during the winter in heavy system volume, compared to a 30 minute median hospital time, during the summer in light system volume. The optimized strategy increased the linkage rate from 88% to 97.1%, and reduced linkage failure in key clinical sub-groups. There was no significant association between response time and mortality except in one secondary analysis subgroup, which suggested longer response decreased mortality. CONCLUSIONS: There is an association between EMS hospital time and response time, but the relationship is complex and influenced by system level factors such as time of day, volume and season. An optimized strategy for linking EMS data to health system outcome improved the linkage rate and reduced the potential for bias. No consistent association between response time and mortality could be demonstrated. These analyses underscore the importance of research quality linked EMS data in the development of knowledge for EMS and paramedic practice.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.Emergency Medical ServicesParamedicResponse TimeMortalityOffload delayData LinkageBiophysics--MedicalEpidemiologydoctoral thesis10.11575/PRISM/37473