Introduction: Acute chest pain in the prehospital setting demands rapid, guideline-based decision-making. However, ambulance nurses’ adherence remains inconsistent, which can lead to diagnostic delays and omitted treatment, compromising patient safety. Evidence on determinants of adherence among ambulance nurses is limited, whereas most research focuses on patient-related determinants. Moreover, reliable and valid instruments are essential for monitoring adherence to and attitudes towards guidelines. However, no validated, prehospital-specific measures are currently available. Therefore, the overall aim of this thesis was to investigate ambulance nurses’ adherence to acute chest pain guidelines by (i) exploring their experiences of using these guidelines, (ii) developing and evaluating instruments to measure adherence to and attitudes towards guideline use, and (iii) examining associations with background and professional characteristics, and (iv) the influence of perceived stress, self-efficacy, and attitudes with adherence.
Methods: Study I used semi-structured interviews with 22 purposively sampled ambulance nurses to explore their experiences of using acute chest pain guidelines. Transcripts were analysed using content analysis. Insights from Study I informed the development of the Adherence Instrument, which assesses adherence to and attitudes towards these guidelines. Study II developed and psychometrically evaluated the Adherence Instrument and Self-Reported Adherence instrument via cognitive interviews (n = 15), an expert review (n = 7), test–retest assessments (n = 63 at test; n = 46 at retest), and a cross-sectional design (n = 261). In parallel, the study also adapted and assessed the Attitudes Regarding Practice Guidelines instrument. Studies III–IV analysed the crosssectional dataset obtained in Study II (n = 261). Study III examined self-reported adherence through stepwise linear regression, following preliminary bivariate analyses including Pearson correlations, independent samples t-tests, and Pearson’s chi-square test. In Study IV, associations were examined using Pearson correlations and subsequently modelled with multiple linear regression. Group differences were analysed using an independent samples t-test and a one-way ANOVA.
Results: Study I showed two overarching categories. Sense of Professional Obligation captured role clarity, interprofessional collaboration, and the need for feedback. Clinical Challenges Using Guidelines captured ambiguous presentations, unclear protocols, and logistical constraints. Study II developed and evaluated the Adherence Instrument, comprising five attitudinal components: Professional Evidence-Based Practice, Assessment of Symptoms, Confidence in Skills, Clinical Autonomy, and Guideline Clarity & Education, with acceptable validity and reliability. Additionally, the adapted Attitudes Regarding Practice Guidelines and the Self-Reported Adherence instruments showed adequate psychometric properties, including validity and reliability. Study III showed that adherence to acute chest pain guidelines was not consistent, as only half of the ambulance nurses reported always giving aspirin to patients with suspected acute coronary syndrome. Older, more experienced ambulance nurses reported higher adherence, and those who prioritised and favoured the guidelines also had higher scores, whereas sex and specialist education were not associated with adherence. Predictors of adherence were age and the extent to which ambulance nurses prioritised the guidelines; mobile applications were the primary source of guideline information. Study IV found that adherence was associated with more positive attitudes towards the guidelines. The Adherence Instrument’s attitudinal components, Confidence in Skills and Professional Evidence-Based Practice, independently predicted adherence. Higher perceived stress was associated with less favourable attitudes, particularly in the attitudinal components of Assessment of Symptoms and Guideline Clarity & Education, whereas higher self-efficacy was associated with more favourable attitudes. However, neither stress nor self-efficacy demonstrated a significant direct association with adherence. Stress was more pronounced among younger ambulance nurses, women, and non-specialist ambulance nurses, whereas older age and specialist education were associated with higher self-efficacy, lower stress, and more positive attitudes.
Conclusion: This thesis demonstrates that key recommendations in prehospital acute chest pain care, especially early aspirin treatment, are not consistently followed, despite ambulance nurses expressing a strong commitment to providing safe and equal care. The Adherence Instrument was developed as a prehospitalspecific instrument assessing attitudinal components related to the use of acute chest pain guidelines. Ambulance nurses who had more positive attitudes towards guidelines, more often based their clinical decisions on guideline recommendations, felt more confident in managing acute chest pain, and were more likely to adhere to the guidelines. Perceived stress and lower self-efficacy appeared to influence adherence mainly indirectly, by affecting these attitudes. Variations in age, professional experience, and education imply that some groups of ambulance nurses might benefit from more targeted education and organisational support. Overall, these findings suggest that more consistent care, in line with prehospital acute chest pain guidelines, may be achieved by strengthening ambulance nurses’ attitudes towards guideline use, enhancing skills and confidence in managing acute chest pain, and improving organisational support and resources, together with systematic follow-up using the Adherence Instrument.