Designing Iranian Pre-hospital Stroke Scale

BACKGROUND Various studies have shown that stroke morbidity and mortality could be decreased if patients receive early diagnosis and treatment. Iranian Pre-hospital Stroke Scale (IPSS) is designed based on other prehospital stroke scales available across the world as well as experiences of emergency medicine specialists and pre-hospital emergency technicians to improve the diagnostic accuracy of the stroke scale in Iran. METHODS Using a mixed method, the study was carried out in two main phases. In the first phase, concept elicitation was conducted based on the review of the literature. Related stroke diagnosis and usual instruments in pre-hospital emergency stroke centers were documented. The IPSS was designed based on semi- structured interviews with 35 neurologists, emergency medicine practitioners and physicians working in hospitals and emergency technicians in the pre-hospital field. In the second phase, the face and content validity, and reliability were checked. RESULTS According to results from the first phase of this study (items generation), three domains were introduced as the most important factors in detection of early signs and symptoms of stroke. In the second phase (items reduction), the face validity of the IPSS was checked based on the comments from participants (the experts and EMS technicians). The content validity was calculated based on Lawshe index. The IPSS scale content validity index (S-CVI/Ave) was calculated as 89%. To determine the criterion validity of the instrument, the IPSS scores were compared with the final diagnosis based on results from brain CT scan in hospital. CONCLUSION During this study we developed IPSS to be used by emergency technicians in pre-hospital field with a dichotomous items and simple and easy administration. It is recommended for future studies to apply this tool to emergency dispatch units as well as triage procedures in hospitals.