Aim: The overall aim of the thesis was to generate knowledge and understanding of clinical reasoning in the context of EMS from the perspective of EMS clinicians.

Method: Three different methodologies were employed to describe various aspects of clinical reasoning. In Study I, an integrative literature review was conducted to summarise the existing literature related to clinical reasoning in EMS. After conducting systematic searches and screening, 38 articles were identified and analysed through an inductive thematic analysis. Studies II and III were conducted as case studies within an EMS organisation to capture clinical reasoning as it takes place in the naturalistic environment. In total, 34 patient encounters were observed, and group and individual interviews were conducted with EMS clinicians and organisational representatives at various hierarchical levels within the EMS organization. The data were analysed through pattern matching and triangulation in a computerised software program for qualitative analysis. Study IV was conducted as a goal-directed task analysis which focused on what EMS clinicians need in terms of achieving situation awareness. An online survey was created and answered by 30 EMS subject matter experts, consisting of active EMS clinicians, academic teachers in specialist ambulance nursing programmes, and researchers in the field of EMS. The data were analysed using qualitative content analysis and descriptive statistics.

Main results: Clinical reasoning in EMS is a continuously ongoing, iterative, and fragmented process. Information is gathered, analysed, and utilised at any given point during the mission. This information is then reasoned against various goals or instructions provided by the EMS organisation or what is perceived as the most suitable action by the EMS clinician. In the reasoning process, the clinicians take the patients’ and their relatives’ points of interest into account, striving to fulfil these. The clinical reasoning process continues after and between the missions well, and clinicians constantly evaluate their decisions and care provision for future improvement. Even if medical and caring interventions are the focus of clinical reasoning, this process involves the consideration of other aspects as well, such as logistics and safety for everyone present. Nevertheless, there seems to be a vague mandate for decision making among EMS clinicians in relation to other collaborative partners. Furthermore, organisational support for clinical reasoning and development is lacking, often due to economic limitations.

Conclusion: This thesis contributes to the caring science field with an increased understanding of the complexity of clinical reasoning in EMS. EMS clinicians today need to rely on themselves or their partners to have sufficient knowledge or experience to handle the situation encountered and provide safe patient care. As the reasoning process involves more than the physical patient encounter, additional support is needed to inform clinicians in decisions related to logistics and safety. As the reasoning process involves more than the physical patient encounter, additional support is needed to inform clinicians in decisions related to logistics and safety. EMS clinicians today need to rely on themselves or their partner to have sufficient knowledge or experience to handle situations encountered and provide patient safe care.