To the best of our knowledge, this is the first study to use the ROSIER to identify suspected stroke patients in the prehospital setting. The results of our study show that both the ROSIER and the CPSS have a good corresponding diagnostic performance in Chinese patients, and the ROSIER is more sensitive and specific, suggesting that the ROSIER scale could be a good stroke recognition tool for EMS providers’ use in a prehospital setting in China.
Time is brain. The early recognition and reaction to stroke warning signs is the first key step of “Stroke Chain of Survival” that links actions to maximize stroke recovery![6
] As the EMS system continues to undergo rapid development, more and more suspected stroke patients are likely to arrive at the hospital earlier. It may make them who meet thrombolytic therapy indications achieve good medical treatments and outcomes possible. However, the therapeutic time window for thrombolytic therapy is narrow and precious. It is a challenge for EMS providers to make rapid stroke assessment and effective management. Until now, there is not a recognized “paramedic” profession in China. It is common for newly graduated doctors who lack clinic experience to work in prehospital emergency care.[25
] In order to decrease delay, emergency physicians had better be familiar with some stroke recognition tools to help confirm their overall clinic impression of stroke.[26
] At present, there has been no uniform approach to the prehospital diagnosis and assessment of suspected stroke patients in China. Some stroke recognition tools were developed based on European and American characters; therefore, they need validation among the Chinese population.
By use of regression modeling, Nor and colleagues developed the ROSIER and validated it at the Newcastle Hospital ED. In their study, early use of ROSIER has very promising results - greater sensitivity 93% (95% CI 89-97%) and similar or better specificity 83% (95% CI 77-89%), which is better than the CPSS, FAST and LAPSS.[18
] It can help emergency physicians with less neurology expertise recognize stroke patients rapidly in the ED. In China, it is popular to use the physician-staffed ambulance system in the prehospital setting. Therefore, we trained our emergency physicians to perform the ROSIER scale among Chinese patients. Can the ROSIER be useful in the assessment of suspected stroke patients in the prehospital setting? However, it has not yet been studied.
Three key problems in Nor and colleagues’ study may limit the use of the ROSIER in a prehospital setting. Firstly, the paramedics referred suspected patients directly to the stroke unit, bypassing the local ED by using a rapid ambulance protocol for suspected stroke that incorporated FAST. Patients identified as having a possible acute stroke are transferred to the stroke unit and assessed by the stroke team on call. For these reasons, the ROSIER scale study was conducted in the stroke unit and not in the prehospital setting, where EMS providers routinely assess and treat patients. And, the ROSIER scale has been applied later in the diagnostic process in the ED where the level of suspicion for a diagnosis of stroke was higher.[27
] Secondly, before the delivery to the stroke unit, some suspected stroke patients might be missed and “excluded” due to the FAST incorrect assessment. Thirdly, after the selection of FAST assessment, the “including” patients, with almost half having had stroke in Nor and colleagues’ study, could not necessarily be representative of the types of patients seen in the prehospital setting.
Our previous study, with a limited sample size in the prehospital setting (only 41 patients cases), shows that the ROSIER scale was a sensitive, specific stroke recognition tool in our ED.[22
] Here, we increased the sample size and compared the performance of the ROSIER with the CPSS. Both of them had good corresponding diagnostic performance, but not 100%. Our data showed that if totally depending on the ROSIER, emergency physicians might miss patients with ischemic posterior or lacunar lesions (18/380, 4.74%), which indicates that a thorough examination is still necessary. And, the ROSIER could not distinguish TIA from stroke mimics in patients without neurological signs. In some cases (confusion, coma, etc.), patient's elements of history and physical examination are difficult to access. We scored patients without witness history as zero, and suggested emergency CT or MRI scan in order to exclude stroke mimics.[22
We also found that there were no statistical significance of positive rate between the ROSIER and the CPSS (P > 0.05). A useful stroke assessment tool should be sensitive to the diagnosis of stroke (i.e., miss very few patients with a treatable disease) and sufficiently specific to ensure only appropriate patients are referred to the stroke service (or sent for emergent brain scanning). As the CPSS and the ROSIER have a very similar positive rate, and the CPSS is easier to complete, these results suggest that the simpler CPSS may be more practicable than the ROSIER for the prehospital assessment of patients with suspected stroke on the scene. Thus, when it is difficult to objectively evaluate the patients’ scores of the ROSIER, the CPSS could replace it in the prehospital setting.
Our study was limited by the small size and the single-center setting. In our study, not all stroke patients who met thrombolytic therapy indications got the thrombolytic therapy for some reasons. Thus, whether using the ROSIER can improve stroke patients outcomes is still not clear. Patients who met the study criteria were based on overall clinic impressions. And, the experience of different emergency physicians on recognition of stroke could be a bias to perform the ROSIER or not. We might have missed some patients without signs and symptoms of a stroke.