BACKGROUND: Effective prehospital care for acute chest pain critically relies on ambulance nurses' adherence to clinical guidelines. However, current adherence is inadequate, with no instruments available to improve the situation. Therefore, this study aimed to develop and psychometrically evaluate an instrument measuring ambulance nurses' adherence to and attitudes towards acute chest pain guidelines, and to adapt and test the Attitudes Regarding Practice Guidelines instrument for measuring general attitudes towards guidelines.

METHODS: An instrument development design was used. A 49-item Adherence Instrument was initially developed for measuring adherence to and attitudes towards acute chest pain guidelines and the 18-item Attitudes Regarding Practice Guidelines instrument was translated into Swedish. Both instruments were validated through cognitive interviews and expert reviews. To ascertain its reliability, a test‒retest was conducted. The construct validity of the Adherence Instrument was assessed via principal component analysis on the basis of a polychoric correlation matrix.

RESULTS: The developed Adherence Instrument was refined to 18 items and showed strong validity and reliability. Similarly, the Attitudes Regarding Practice Guidelines instrument, refined to 12 items, demonstrated strong validity and reliability. Principal component analysis of the Adherence Instrument identified five components: professional evidence-based practice, assessment of symptoms, confidence in skills, clinical autonomy, and guideline clarity and education. These components accounted for 64.5% of the total variance and demonstrated strong reliability, with an ordinal alpha of 0.84 for the entire scale.

CONCLUSION: The psychometric properties of the Adherence Instrument were satisfactory and will be useful in prehospital emergency care to measure attitudes and adherence towards acute chest pain guidelines.