The effect and associated factors of dispatcher recognition of stroke: A retrospective observational study

The effect and associated factors of dispatcher recognition of stroke: A retrospective observational study

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Journal of the Formosan Medical Association (2017) xx, 1e7

Available online at www.sciencedirect.com

ScienceDirect journal homepage: www.jfma-online.com

Original Article

The effect and associated factors of dispatcher recognition of stroke: A retrospective observational study Ming-Ju Hsieh a,1, Kuo-Liong Chien b,1, Jen-Tang Sun c, Sung-Chun Tang d, Li-Kai Tsai d, Wen-Chu Chiang a, Yu-Chun Chien e, Jiann-Shing Jeng d,**, Matthew Huei-Ming Ma a,b,*, the Taipei EMS Stroke Collaborative Group a

Department of Emergency Medicine, National Taiwan University Hospital, Taipei, Taiwan Institute of Epidemiology and Preventive Medicine, National Taiwan University, Taipei, Taiwan c Department of Emergency Medicine, Far Eastern Memorial Hospital, New Taipei City, Taiwan d Stroke Center and Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan e Taipei City Fire Department, Taiwan b

Received 6 September 2017; accepted 31 October 2017

KEYWORDS Stroke; Dispatch; Thrombolytic therapy

Background/purpose: Details of the communication between the caller and dispatcher have not been reported previously in Taiwan. This study aimed to: (1) understand the details of the communication between the caller and dispatcher among the calls for stroke patients, (2) identify factors associated with stroke recognition by dispatchers, and (3) evaluate the association between stroke recognition by dispatchers and stroke management. Methods: We conducted a retrospective observational study involving patients with stroke or transient ischemic stroke transported by the emergency medical service, and arriving at 9 hospitals in Taipei within 3 h of symptom onset from January 1, 2013 to February 28, 2014. Patients were excluded if tape-recording data or prehospital information were not available. Data of the enrolled patients were reviewed. We used stroke dispatch determination as the surrogate for stroke recognition by dispatchers. Multivariable logistic regression was used to identify the factors associated with stroke dispatch determination. Results: A total of 507 patients were included. In approximately 50% of cases, callers were close family members. Ninety-one patients (17.9%) had stroke dispatch determination. After adjustment, stroke reported spontaneously, any symptom included in the Cincinnati

* Corresponding author. Department of Emergency Medicine, National Taiwan University Hospital, No. 7, Chung-Shan South Rd, Taipei 100, Taiwan. Fax: þ886 2 23418395. ** Corresponding author. Department of Neurology, National Taiwan University Hospital, No. 7, Chung-Shan South Road, Taipei 100, Taiwan. E-mail addresses: [email protected] (J.-S. Jeng), [email protected], [email protected] (M. Huei-Ming Ma). 1 The authors contributed equally. https://doi.org/10.1016/j.jfma.2017.10.008 0929-6646/Copyright ª 2017, Formosan Medical Association. Published by Elsevier Taiwan LLC. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Please cite this article in press as: Hsieh M-J, et al., The effect and associated factors of dispatcher recognition of stroke: A retrospective observational study, Journal of the Formosan Medical Association (2017), https://doi.org/10.1016/j.jfma.2017.10.008

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M.-J. Hsieh et al. Prehospital Stroke Scale reported spontaneously, and dispatcher adherence to the protocol, were associated with stroke dispatch determination significantly. Stroke dispatch determination was associated with receiving pre-arrival notification, shorter door-to-computed tomography time, and thrombolytic therapy. Conclusions: The dispatchers should spend more time identifying stroke patients by following the dispatch protocol. Recognition of stroke by dispatchers was associated with improved stroke care. Copyright ª 2017, Formosan Medical Association. Published by Elsevier Taiwan LLC. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/bync-nd/4.0/).

Introduction Thrombolytic therapy has been proven to be effective for ischemic stroke patients when administered within 3e4.5 h of symptom onset.1,2 In addition, previous studies have found that the sooner thrombolytic therapy is given, the better the functional outcome.3e5 The American Heart Association (AHA) suggests that the public should contact the emergency medical service (EMS) for help as soon as a suspected case of stroke is witnessed, to allow for prompt arrival to hospital for thrombolytic therapy and to expedite stroke management.6 The dispatcher is the first person contacted by the public when they attempt to activate the EMS system, and the decision of the dispatcher influences prehospital care of stroke patients. One study showed that patients recognized by dispatchers as having a stroke had an increased chance of receiving prehospital care with advanced life support (ALS) and hospital arrival was earlier compared to patients where stroke remained unrecognized.7 However, the sensitivity for stroke detection by dispatchers was far from ideal, ranging from 31% to 61%.8e11 In Taiwan, there are no available studies evaluating communication between caller and dispatcher based on calls to activate EMS for stroke patients. In addition, there is no available research on the sensitivity of dispatcher identification of stroke. Furthermore, few studies in the literature have evaluated factors associated with correct recognition of stroke by dispatchers. Therefore, the aims of our study were: (1) to understand the characteristics of the communication between the caller and the dispatcher among calls regarding stroke patients, (2) to identify the factors associated with dispatcher recognition of stroke, and (3) to evaluate the association between dispatcher recognition of stroke and stroke management.

Methods

The patients included in our study were treated in 9 hospitals in a metropolitan city in collaboration with the local EMS system. The participating hospitals receive approximately 55% of the 80,000 to 90,000 patients served by the EMS system in Taipei city annually, and provide thrombolytic therapy for stroke patients, if feasible. The EMS system is a two-tier fire-based system, consisting of 41 basic life support units and 4 ALS units. There is only one dispatch center in Taipei city. All dispatchers in the dispatch center were qualified as emergency medical technician (EMT)-intermediates after they receiving a 280h course. Before commencing their dispatch career, they received an additional 8-h training course for dispatch. The dispatch protocol for stroke patients is as follows. Initial investigation involves ascertaining patient details, the timing of the event, and details of the development of events. If, according to the initial investigation, the patient is suspected as having a stroke, the dispatcher asks a series of key questions, included in the stroke card of the dispatch manual to callers. The following are the key questions: (1) Does he/she respond to you? (2) Does he/she have respiratory difficulty? (3) Does he/she have facial asymmetry? (4) Does he/she move his/her hands and legs normally? (5) Can he/she say a whole sentence normally? (6) Does he/she have severe headache? A patient will be recognized as having a stroke if he/she has facial asymmetry, difficulty in moving hands and legs on one side, speech abnormality, or severe headache. When the dispatcher recognizes a patient as having a stroke after communicating with the caller, the dispatcher will immediately dispatch the EMTs to the scene with stroke dispatch determination and, at the same time, inform them by telephone that a stroke is suspected. In view of the large demand for ambulance service, the relatively small number of ALS units, and the short transportation time in the city, there are no strict rules requesting the dispatcher to dispatch an ALS unit for patients with a suspected stroke, except when the patients are identified as having a lifethreatening condition.

Study design and setting Inclusion and exclusion criteria This was a retrospective observational study, including stroke patients served by EMS systems. The study was approved by the institutional review board of the National Taiwan University Hospital. We conducted and reported the study in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology statement.12

The study period was between January 1, 2013 and February 28, 2014. The inclusion criteria for the study were as follows: (1) patients aged 20 years with a discharge diagnosis of stroke or transient ischemic attack (TIA), and (2) patients who arrived at the emergency department (ED)

Please cite this article in press as: Hsieh M-J, et al., The effect and associated factors of dispatcher recognition of stroke: A retrospective observational study, Journal of the Formosan Medical Association (2017), https://doi.org/10.1016/j.jfma.2017.10.008

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Dispatcher recognition of stroke within 3 h of symptom onset via EMS. Patients were excluded from our study when data of the dispatcher call tape recording or prehospital management were not available. Furthermore, if one patient was served by EMS on more than one occasion, only the data of the first service were included in the final analysis.

Study protocol The Taipei EMS stroke registry was established in September 2012 to measure, track, and improve stroke care. All 9 participating hospitals are affiliated with the registry. Trained hospital staff prospectively identified stroke patients aged 20 years who arrived at the ED within 3 h of symptom onset via EMS and all patients arriving with pre-arrival notification. Staff then collected data on demographic characteristics, prehospital and in-hospital quality indicators, and stroke management, by using a standardized, web-based data collection tool. For this study, the Taipei EMS stroke registry was connected to the tape recording and computerized dispatch systems. Therefore, telephone recordings, prehospital, and inhospital data of the study participants could be collected. Before we obtained the patients’ data from the dataset during the study period, the data were processed so that patient could not be identified. From the registry, we collected data regarding age, sex, underlying diseases, prehospital and in-hospital management time, prehospital notification, and thrombolysis. One physician and one study nurse collected data for each communication between dispatchers and callers, by independently listening to tape recordings and noting the findings on a pre-specified recording form. We collected the communication time, identity of the callers, symptoms reported by the callers, whether the callers stayed calm during the communication, and dispatch determination by dispatchers. If the results noted on the recording form differed between the physician and the study nurse, they listened to the tape recording together to achieve agreement. To protect the confidentiality of the study participants, all data were collected and managed in the dispatch center of Taipei city and there was no authorization to remove data from the center. The dispatcher adherence to the protocol was defined as the dispatcher asking all key questions in the stroke card.

Outcome measurement We used stroke dispatch determination as a surrogate for stroke recognition by dispatchers. We performed a descriptive analysis to evaluate the identity and complaints made by callers, factors associated with stroke dispatch determination, and the association between stroke dispatch determination and stroke management. The sensitivity of stroke dispatch determination among patients with stroke and TIA was also evaluated. The total prehospital time included the time from the receipt of the call by the EMS to patient arrival at hospital. In-hospital management time included door-to-computed tomography (CT) time and door-to-needle (DTN) time. The door-to-CT time was defined as the time interval between ED arrival and CT

3 completion. The DTN time was defined as the time interval between ED arrival and administration of the first bolus of tissue plasminogen activator.

Sample size estimation There are no studies in the literature evaluating factors associated with correct recognition of stroke by dispatchers. However, studies that assessed the sensitivity of dispatcher recognition of stroke involved 104 to 482 participants.8e11 Therefore, we planned to collect the data of 500 participants for our study before our study was executed.

Statistical analysis The chi-square test, Student t test, and Wilcoxon rank-sum test were used to compare the differences between variables for patients with and those without stroke dispatch determination. Multivariable logistic regression was used to search the variables associated with stroke dispatch determination. In the literature, complaints of stroke, facial droop, weakness/falling, and impaired communication from the callers were associated with an increased chance of a final diagnosis of stroke.13 Facial droop, weakness and impaired communication were items derived from the Cincinnati Prehospital Stroke Scale (CPSS). Therefore, data input for multivariable logistic regression analysis was as follows: stroke reported spontaneously, any one CPSS symptom reported spontaneously, and dispatcher adherence to the protocol. Before the multivariable logistic regression analysis was performed, we tested the correlation and interaction between the variables. We defined a high correlation between two dichotomous variables when the phi coefficient was >0.4. The SAS software (Version 9.3, SAS Institute Inc., Cary, NC) was used for the statistical analyses. A two-tailed p value of <0.05 was defined as statistically significant.

Results During the study period, 64,078 patients were admitted to the EDs of the participating hospitals via the EMS. Of these, 523 patients (0.8%) had a stroke or TIA within 3 h of symptom onset (Fig. 1). Tape recordings for 16 patients within 3 h after stroke and TIA could not be found. No prehospital data were missing. There were no patients with stroke or TIA 3 h served by EMS more than once, after excluding patients lacking tape recording data. Finally, 507 patients were included in our study. Of these, 91 were determined as having a stroke by the dispatcher and 416 patients were assessed as non-stroke dispatches. The characteristics of patients in the group with and without stroke dispatch determination were comparable. The sensitivity of the stroke dispatch determination was 17.9%. The median communication time between the callers and dispatchers was 46.0 s (Table 1). Of the 507 calls, approximately 50% were from close family members, including spouses (17.8%), daughters (17.0%), and sons (14.8%). The remaining groups of callers were storekeepers or security service personnel (9.5%), strangers (8.1%), and policemen

Please cite this article in press as: Hsieh M-J, et al., The effect and associated factors of dispatcher recognition of stroke: A retrospective observational study, Journal of the Formosan Medical Association (2017), https://doi.org/10.1016/j.jfma.2017.10.008

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M.-J. Hsieh et al.

Fig. 1

Table 1

Flowchart of the study subjects. EMS: emergency medical service; TIA: transient ischemic attack.

Table 2 Proportions of complaints reported spontaneously by the caller (n Z 507).

Characteristics of the callers.

Callers (N Z 507) Total communication time (seconds), median (q1eq3) Male, n (%) Identity of caller, n (%) Patient Spouse Daughter Son Storekeepers or security service personnel Stranger Policeman Grandson or granddaughter Friend Colleague Other family member living with the patient Daughter-in-law Neighbor Medical personnel Mother Other family members not living with the patient Unknown Caller remained calm during communication

46.0 (36.0e59.0)

Problem Stroke suspected

244 (48.1%) 4 (0.8%) 90 (17.8%) 86 (17.0%) 75 (14.8%) 48 (9.5%) 41 28 26 22 20 13

(8.1%) (5.5%) (5.1%) (4.3%) (3.9%) (2.6%)

10 (2.0%) 8 (1.6%) 8 (1.6%) 7 (1.4%) 6 (1.2%) 15 (3.0%) 357 (70.4%)

(5.5%). Fewer than 1% of callers were the patients themselves. Approximately 70% of callers remained calm when communicating with the dispatchers. Of 507 callers, 207 (40.8%) spontaneously reported that they suspected a stroke. This was the leading reported complaint among study participants (Table 2). Extremity

n (%)

Problem

207 (40.8%) Numbness or sensory abnormality Extremity weakness 86 (17.0%) Blood pressure problem Generally malaise 85 (16.8%) Aphasia Unilateral 55 (10.8%) Vertigo extremity weakness Collapse 52 (10.3%) Seizure Coma 52 (10.3%) Headache Falling 43 (8.5%) Injury Slurred speech 40 (7.9%) Respiratory abnormality Facial weakness 27 (5.3%) Chocking Confusion 23 (4.5%) Heart attack Dizziness 16 (3.2%) Lethargy Walking difficulty 15 (3.0%) Othera No description 11 (2.2%)

n (%) 10 (2.0%)

10 (2.0%) 9 (1.8%) 9 (1.8%)

7 6 6 6

(1.4%) (1.2%) (1.2%) (1.2%)

3 (0.6%) 3 (0.6%) 3 (0.6%) 16 (3.2%)

a

Included hypoglycemia (2), vomiting (2), deviation of the eyes (2), chills (1), cold sweating (1), drunkenness (1), foaming at the mouth (1), generalized tremor (1), hematemesis (1), hypothermia (1), poor expectoration (1), shock (1), lip twitching (1).

weakness (17.0%), and general malaise (16.8%) were the second and third most frequent complaints reported spontaneously. Other spontaneously reported complaints included unilateral extremity weakness (10.8%), collapse (10.3%), and coma (10.3%). When comparing patients with and those without stroke dispatch determination, the patients with stroke dispatch determination had a longer duration of communication with

Please cite this article in press as: Hsieh M-J, et al., The effect and associated factors of dispatcher recognition of stroke: A retrospective observational study, Journal of the Formosan Medical Association (2017), https://doi.org/10.1016/j.jfma.2017.10.008

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Dispatcher recognition of stroke

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the dispatcher and a higher percentage of alcohol intake; increased rates of spontaneously reported stroke; spontaneously reported CPSS symptoms, dispatcher adherence to the protocol, ALS dispatch, and pre-arrival notification; and shorter door-to-CT time (Table 3). The patients with stroke dispatch determination were also more likely to receive thrombolytic therapy (p Z 0.07). However, total prehospital time and DTN time was comparable in patients with stroke dispatch determination and in those without stroke dispatch determination. During a search for the factors associated with stroke dispatch determination, interaction was noted between stroke reported spontaneously and any one CPSS symptom reported spontaneously (p Z 0.004). Analysis of subgroups of stroke reported spontaneously and of stroke not reported spontaneously were performed, and the results are shown in Table 4. In the subgroup of stroke reported

Table 3

spontaneously, the only significant association with stroke dispatch determination found in this study was dispatcher adherence to the protocol, with an adjusted odds ratio (aOR) of 4.5 and a 95% confidence interval (CI) of 2.4e8.4. Nevertheless, in the subgroup of stroke not reported spontaneously, both dispatcher adherence to the protocol (aOR, 4.3, 95% CI, 1.2e16.0) and spontaneous reporting of any one CPSS symptom (aOR, 11.3, 95% CI, 2.8e46.3) were independently and significantly associated with stroke dispatch determination. Analyses for subgroups of any one symptom included in the CPSS reported spontaneously and of any one symptom included in the CPSS not reported spontaneously were also performed. Both stroke reported spontaneously and dispatcher adherence to the protocol were independently and significantly associated with stroke dispatch determination in these two subgroups (Table 5).

Comparisons of the basic characteristics between patients with and those without stroke dispatch determination. All patients (N Z 507)

Total communication 46.0 (36.0e59.0) time (seconds), median, q1eq3 Characteristics of patients Male (%) 312 (61.5%) Age (years), mean  SD 69.3  15.2 History, n (%) Transient ischemic attack 11 (2.2%) Cerebral vascular disease 77 (15.2%) Hypertension 289 (57.0%) Hypercholesterolemia 57 (11.2%) Hypertriglyceridemia 35 (6.9%) Peripheral arterial occlusive 9 (1.8%) disease Heart disease 139 (27.4%) Renal disease 10 (2.0%) Diabetes mellitus 100 (19.7%) Malignancy 30 (5.9%) Alcohol intake 27 (5.3%) Current smoking 47 (9.3%) Complaints reported by the caller Stroke reported spontaneously 207 (40.8%) Any CPSS reported spontaneously 120 (23.7%) Protocol adherence by the dispatcher 103 (20.3%) ALS dispatch 105 (20.7%) Pre-arrival notification 379 (74.8%) Stroke type Hemorrhagic 181 (35.7%) Ischemic 290 (57.2%) Transient ischemic attack 36 (7.1%) Thrombolytic therapy received 89 (17.6%) Total prehospital time (min), 21.5 (18.0e25.5) median (q1eq3) In-hospital management time (min), median (q1eq3) Door-to-CT time 15.0 (11.0e22.0) DTN time 62.0 (46.0e78.0)

Stroke dispatch determination (n Z 91)

Non-stroke dispatch determination (n Z 416)

p value

52.0 (41.0e69.0)

44.0 (35.0e57.0)

<0.001

58 (63.7%) 70.1  15.5

254 (61.1%) 69.1  15.2

0.63 0.54

3 (3.3%) 14 (15.4%) 56 (61.5%) 5 (5.5%) 6 (6.6%) 1 (1.1%)

8 (1.9%) 63 (15.1%) 233 (56.0%) 52 (12.5%) 29 (7.0%) 8 (1.9%)

0.43 0.95 0.34 0.06 0.90 1.00

26 (28.6%) 1 (1.1%) 16 (17.6%) 5 (5.5%) 9 (9.9%) 8 (8.8%)

113 (27.2%) 9 (2.2%) 84 (20.2%) 25 (6.0%) 18 (4.3%) 39 (9.4%)

0.79 1.00 0.32 0.85 0.041 0.86

79 40 49 66 84

128 (30.8%) 80 (19.2%) 54 (13.0%) 39 (9.4%) 295 (70.9%)

<0.001 <0.001 <0.001 <0.001 <0.001

27 (29.7%) 58 (63.7%) 6 (6.6%) 22 (24.2%) 23 (18.5e25.5)

154 (37.0%) 232 (55.8%) 30 (7.2%) 67 (16.1%) 21.5 (18.0e25.8)

0.37

0.07 0.36

14.0 (10.0e20.0) 55.5 (45.0e71.0)

15.5 (11.0e23.0) 63.0 (46.0e80.0)

0.024 0.24

(86.8%) (44.0%) (53.8%) (72.5%) (92.3%)

SD: standard deviation; CPSS: Cincinnati Prehospital Stroke Scale; ALS: advanced life support; CT: computed tomography; DTN: Door-toneedle.

Please cite this article in press as: Hsieh M-J, et al., The effect and associated factors of dispatcher recognition of stroke: A retrospective observational study, Journal of the Formosan Medical Association (2017), https://doi.org/10.1016/j.jfma.2017.10.008

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M.-J. Hsieh et al. Table 4 Multivariable analyses of variables associated with stroke dispatch determination in subgroups with and without stroke reported spontaneously. Stroke reported spontaneously (n Z 207)

Stroke not reported spontaneously (n Z 300)

Odds ratio 95% confidence p-value c-statistics Odds 95% confidence p-value c-statistics interval ratio interval Any symptom included in the 1.2 CPSS reported spontaneouslya Dispatcher adherence 4.5 to the protocol

0.6e2.3

0.52

0.677

2.4e8.4

<0.001

11.3

2.8e46.3

<0.001 0.816

4.3

1.2e16.0

0.027

Interaction was found between stroke reported spontaneously and spontaneous reporting of any one CPSS symptom (p Z 0.004). There was no high correlation between any two variables. a CPSS: Cincinnati Prehospital Stroke Scale.

Table 5 Multivariable analyses of variables associated with stroke dispatch determination in subgroups with and without any one symptom included in the Cincinnati Prehospital Stroke Scale (CPSS) reported spontaneously. Any one symptom included in the CPSS reported spontaneously (n Z 120)

Stroke reported spontaneously Dispatcher adherence to the protocol

Any one symptom included in the CPSS not reported spontaneously (n Z 387)

Odds ratio

95% confidence interval

p-value

c-statistics

Odds ratio

95% confidence interval

p-value

c-statistics

3.8

1.5e9.6

0.005

0.786

34.8

10.5e115.4

<0.001

0.866

6.5

2.7e15.6

<0.001

3.4

1.6e7.1

0.002

Interaction was found between stroke reported spontaneously and any one symptom included in the CPSS reported spontaneously (p Z 0.004). There was no high correlation between any two variables.

Discussion Our study showed that stroke reported by callers spontaneously and dispatcher adherence to the protocol were associated with stroke dispatcher determination in all subgroups. These results highlight that, strategies for the education of the public on the identification of stroke patients is important. The International Liaison Committee on Resuscitation advised that first aid providers use the FAST or CPSS stroke assessment instrument to identify stroke patients.14 The AHA recommends that public stroke education should include the FAST stroke assessment instrument and convey the message of calling the ambulance promptly when a stroke is suspected.6 When a stroke is suspected, reporting the stroke to the dispatcher increases the possibility of recognition of stroke by the dispatcher and increases the chances of delivering ALS care to the patient. In our study, approximately 50% of callers were close family members who lived with the patient, not the patients themselves. This finding suggests that the target of stroke education should include not only patients but also family members. Furthermore, dispatchers should follow the protocol in order to increase the sensitivity of recognizing stroke patients, because both compliance with dispatch protocol and the sensitivity of recognizing stroke patients were suboptimal. The sensitivity of stroke dispatch determination by dispatchers was less than 20% in our

study. In the literature, the sensitivity for stroke detection by dispatchers ranged from 31% to 61%.8e11 More efforts are required to improve dispatcher recognition of stroke. In the subgroup of cases of stroke not reported spontaneously, the caller reporting of any CPSS symptom was associated with stroke dispatch determination. This result may be explained by the fact that CPSS symptoms are typical stroke symptoms, and their reporting increased dispatcher recognition of stroke. Unlike other studies in which callers frequently reported stroke-related symptoms,8,9,15,16 such as altered mental status or speech problems, the most frequent clinical manifestations reported by callers in our study were extremity weakness and general malaise. Falling, collapse and coma were also frequent problems in our study. One possible explanation for this may be that communication time between callers and dispatchers was too short in our study for dispatchers to ascertain whether patients reported the aforementioned symptoms also had other stroke-related symptoms. As most callers remain calm and can communicate with the dispatchers successfully, dispatchers should be more aware of the existence of other stroke-related symptoms and spend more time clarifying whether these are present in order to achieve a higher stroke detection rate. One study showed that patients recognized as having a stroke by dispatchers had an increased chance of receiving

Please cite this article in press as: Hsieh M-J, et al., The effect and associated factors of dispatcher recognition of stroke: A retrospective observational study, Journal of the Formosan Medical Association (2017), https://doi.org/10.1016/j.jfma.2017.10.008

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Dispatcher recognition of stroke prehospital care from the ALS unit and arrived at hospitals earlier than those where stroke was not recognized by dispatchers.7 Nevertheless, in our study, although dispatchers dispatched ALS units for patients with stroke dispatch determination more frequently, the total prehospital time was similar to that of patients without stroke dispatch determination. The short transportation routes in the metropolitan city in our study may be the main explanation for this finding. In addition, admission of patients with stroke dispatch determination was more likely to occur with pre-arrival notification, and was associated with shorter door-to-CT time and DTN time. These results suggest that recognition of stroke by dispatchers was associated with improved stroke care. This study has some limitations. First, the study only included patients with stroke and TIA within 3 h of symptom onset and not all stroke patients, therefore generalizability is potentially limited. In addition, the proportion of patients with a stroke or TIA among all patients with stroke dispatch determination could not be evaluated during the study period. Nevertheless, because all study participants were within the therapeutic window for thrombolytic therapy, it was valuable to identify the characteristics of the calls activating the EMS system and to determine how the dispatchers responded to the calls. Secondly, our study only included patients admitted to 9 participating hospitals, rather than to all the hospitals in the city, and this may have resulted in bias. However, the 9 participating hospitals received over 50% of patients served by the EMS in the city. Therefore, we believe that any bias is limited. Finally, we used the stroke dispatch determination as a surrogate for dispatcher recognition of stroke and this may also have resulted in bias. In conclusion, among the calls activating the EMS system, approximately 50% were from close family members and in the majority of cases, and the callers remained calm. The sensitivity of dispatcher recognition of stroke patients was far from ideal. Therefore, dispatchers should spend more time differentiating stroke patients from patients with frequently reported problems by following dispatch protocol. Recognition of stroke by dispatchers was associated with improved stroke care.

Prior presentations A part of this study was presented as a poster in the International Stroke Conference in 2017.

Funding sources The article was supported by grant No. 105-M3261 from the National Taiwan University Hospital, and the Taiwan Ministry of Science and Technology (MOST105-2314-B-002-026).

Conflicts of interest The authors declare that they have no conflicts of interest.

Disclosures None.

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Acknowledgments We thank the Taipei City Fire Department for their administrative support and implementation of prehospital stroke care in the EMS system. We also thank the medical personnel who are devoted to providing the best possible stroke care at the participating hospitals.

References 1. The National Institute of Neurological Disorders and Stroke rtPA Stroke Study Group. Tissue plasminogen activator for acute ischemic stroke. N Engl J Med 1995;333:1581e7. 2. Hacke W, Kaste M, Bluhmki E, et al. Thrombolysis with alteplase 3 to 4.5 hours after acute ischemic stroke. N Engl J Med 2008;359:1317e29. 3. Hacke W, Donnan G, Fieschi C, et al. Association of outcome with early stroke treatment: pooled analysis of ATLANTIS, ECASS, and NINDS rt-PA stroke trials. Lancet 2004;363:768e74. 4. Lees KR, Bluhmki E, von Kummer R, et al. Time to treatment with intravenous alteplase and outcome in stroke: an updated pooled analysis of ECASS, ATLANTIS, NINDS, and EPITHET trials. Lancet 2010;375:1695e703. 5. Fonarow GC, Smith EE, Saver JL, et al. Timeliness of tissuetype plasminogen activator therapy in acute ischemic stroke: patient characteristics, hospital factors, and outcomes associated with door-to-needle times within 60 minutes. Circulation 2011;123:750e8. 6. Jauch EC, Saver JL, Adams Jr HP, et al. Guidelines for the early management of patients with acute ischemic stroke: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke 2013;44: 870e947. 7. Caceres JA, Adil MM, Jadhav V, et al. Diagnosis of stroke by emergency medical dispatchers and its impact on the prehospital care of patients. J Stroke Cerebrovasc Dis 2013;22: e610e4. 8. Rosamond WD, Evenson KR, Schroeder EB, Morris DL, Johnson AM, Brice JH. Calling emergency medical services for acute stroke: a study of 9-1-1 tapes. Prehosp Emerg Care 2005; 9:19e23. 9. Porteous GH, Corry MD, Smith WS. Emergency medical services dispatcher identification of stroke and transient ischemic attack. Prehosp Emerg Care 1999;3:211e6. 10. Handschu R, Poppe R, Rauss J, Neundorfer B, Erbguth F. Emergency calls in acute stroke. Stroke 2003;34:1005e9. 11. Ellison SR, Gratton MC, Schwab RA, Ma OJ. Prehospital dispatch assessment of stroke. Mo Med 2004;101:64e6. 12. von Elm E, Altman DG, Egger M, Pocock SJ, Gotzsche PC, Vandenbroucke JP. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies. J Clin Epidemiol 2008;61:344e9. 13. Reginella RL, Crocco T, Tadros A, Shackleford A, Davis SM. Predictors of stroke during 9-1-1 calls: opportunities for improving EMS response. Prehosp Emerg Care 2006;10:369e73. 14. Zideman DA, Singletary EM, De Buck ED, et al. Part 9: First aid: 2015 international consensus on first aid science with treatment recommendations. Resuscitation 2015;95:e225e61. 15. Leathley MJ, Jones SP, Gibson JM, et al. “Can you send an ambulance please?”: a comparison of callers’ requests for emergency medical dispatch in non-stroke and stroke calls. Emerg Med J 2014;31:e25e8. 16. Jones SP, Carter B, Ford GA, et al. The identification of acute stroke: an analysis of emergency calls. Int J Stroke 2013;8: 408e12.

Please cite this article in press as: Hsieh M-J, et al., The effect and associated factors of dispatcher recognition of stroke: A retrospective observational study, Journal of the Formosan Medical Association (2017), https://doi.org/10.1016/j.jfma.2017.10.008