The "unclear problem" category: An analysis of its implications and effects on the emergency medical dispatch process in Copenhagen, Denmark

Objective: An effective emergency medical dispatch process is vital to provide appropriate prehospital care to patients. It increases patient safety and ensures the sustainable use of medical resources. Although Copenhagen has a sophisticated emergency medical services (EMS) system with a significant focus on public welfare, more than 10% of emergency calls are still being categorized as an "unclear problem" and are thus not categorized as "symptom-specific". Therefore, the objective of this research is to gain a better understanding of underlying implications that lead to the categorization of an emergency call as "unclear". This research investigates the effects of the "unclear problem" category (UPC) on the medical dispatching process at the emergency medical dispatch center in Copenhagen. Also, it explores the effectiveness of educating medical dispatchers about the use of the UPC to reduce its use. Methods: This was a register-based study based on medical emergency call data. Descriptive analyses were conducted to investigate the effect of using the UPC on the medical dispatching process and determine the impact of alerting medical dispatchers to reduce its use. Results: The UPC accounted for 11.4% of the calls. Elderly patients were most often dispatched with the UPC. The UPC could impact the medical dispatching process in several potentially harmful, ways. Namely, it could lead to under or over triage and lead to inefficient use of EMS resources. Sensitizing medical dispatchers about the use of the UPC could have contributed to the decrease in the use of the UPC. Conclusion: The use of the UPC could have negative implications on patients' outcomes and the efficient use of EMS resources due to its possible impact on over-or under triage. The UPC is mainly used when dispatching the elderly. Nonetheless, the use of the UPC decreased throughout the study period after the medical dispatchers were alerted about the implications of its use. Copenhagen


Introduction
The World Health Organization identifies emergency medical services (EMS) as an integral part of any effective and functional healthcare system. The emergency medical dispatch center (EMDC) is the first point of contact in the case of a life-threatening or medical emergency. In some settings, it acts as a gatekeeping system to subsequent medical services 1 . A prompt prehospital response is conducive to a better prognosis of patients and timely access to EMS 2 .
Denmark has a long tradition of focusing on public welfare, including the provision of health services. Denmark promotes society-wide health and social equity through tax-financed services, including universal health care 3 . Each region in Denmark has an EMDC center responsible for the EMS 4 .
Throughout Denmark, all emergency or 1-1-2 calls are first answered by the police, except the Capital Region of Denmark, where the Copenhagen fire brigade answers these calls. The calltaker assesses the situation according to the information provided via the call and locates the incident's site. As of 2011, a call of medical nature is then forwarded to a regional EMDC 4 .
At the EMDC, healthcare professionals, either nurses or paramedics, answer and handle the calls. They must then assess the situation using the criteria-based emergency medical dispatch (CBD) system, also referred to as the Danish Index for Emergency Care. This index is inspired by a system developed in Seattle, Washington, in 1990 and was adapted according to the Scandinavian context. The Danish Index, used by all regions in Denmark 4 , consists of 38 criteria, including the "unclear problem" category (UPC). These various criteria correspond to clinical signs, symptoms or incidents and it aids the professional decide the response based on the implicated level of urgency 5 .
While identifying a specific complaint is crucial, the UPC remains a common category used by dispatchers to classify emergency calls. The categorization of an emergency call as UPC discloses that the medical dispatcher cannot determine the exact medical cause of the case in Journal: Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine general formatting rules: Reference style: Vancouver Style Word count 3000-4000 question. Nonetheless, an assessment of the level of urgency is still performed based on the description of the caller 6 .
One of the most crucial problems resulting from the categorization of calls as "unclear" instead of symptom-specific is that a higher or even lower emergency priority level than required might be assigned to the case. This is also known as over-triage or under-triage. Over triage entails using EMS transport for non-acute cases or when the patient does not make use of alternative transportation available. The inappropriate use of EMS results in inefficient use of medical resources. It could even be considered unethical for paramedic personnel as it holds them back from getting their much-needed sleep, meals and education.
Moreover, it could cause delayed responses to other life-threatening incidents with a potentially higher level of urgency 7 . Under triage from EMDCs represents an inappropriately low response without priority signs in an acute case. This type of response may not meet patients' actual medical needs and delay their access to the appropriate level of care 8 . Medical dispatch accuracy is vital in optimizing the balance between patient needs and available prehospital resources 5 .
Møller et al. 5 found a higher mortality rate for emergency priority level B calls categorized as UPC.
Their research states that this might imply that a higher priority level should have been used in the medical dispatch process. There was a problem of under-triaging and a subsequent detrimental effect on patient outcomes. Moreover, they stated that it might pose issues regarding EMS resources' availability for situations that truly require these resources.
Medical dispatchers have been made more aware of the use of the UPC at the EMDC in Copenhagen during the specified study period with the attempt to reduce the use of the UPC in the categorization process. It is relevant to investigate whether this sensitization has had an impact on the use of the UPC in medical dispatching.
Although Copenhagen already has a sophisticated emergency care system with a significant focus on public welfare 3 , more than 10% of emergency calls remain categorized as UPC and further improvements in the system can thus be made. Considering the potentially harmful implications of using the UPC, their investigation is needed to improve the dispatching process further. Therefore, this study aims to create a structured overview of the effects that the use of Journal: Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine general formatting rules: Reference style: Vancouver Style Word count 3000-4000 the UPC has on the medical dispatching process at the EMDC in Copenhagen and investigate the results of sensitizing medical dispatchers to reduce the use of the UPC.
It is hypothesized that using the UPC will lead to a less efficient medical dispatching process, leading to either over or under triage, subsequently leading to a waste of resources or endangerment of patients.

Study design
A register-based study based on emergency medical call data over 3 years (January 1, 2017 -December 31, 2019) from the EMDC in Copenhagen was conducted. The research was done according to the framework of the EMDC Copenhagen, Denmark's quality assurance protocol.
The project was approved by the executive level of the EMDC and Maastricht University.

Categorization in emergency medical dispatching
The categorization is the first step in the emergency medical dispatching process. It leads to more specific questions that enable the medical dispatcher to initiate the appropriate and corresponding priority level (ranging from A-E). Level A includes life threatening/potentially life-threatening symptoms; B includes urgent, yet not life-threatening symptoms; C is for non-urgent conditions that still require an ambulance; D has non-urgent cases requiring supine patient transport; and E is for cases that merely require medical advice 5 . Simultaneously, a red response (an immediate response with lights and sirens), an orange response (an immediate response without lights and sirens), a yellow response (a non-urgent response with the needed resources available), a green response (non-urgent) and a blue response (merely medical advice, for instance referring the patient to their general practitioner) can be dispatched 5 .

Research population and data collection
The study period entailed data from January

Data analysis
Age and deployment area characteristics of the cases triaged with the UPC were identified through descriptive statistical analyses. Comparisons were made to patients that were allocated to any of the 38 categories.
Descriptive analyses with numbers and percentages were also used to discover how the categorization with "unclear problem" could impact the medical dispatching process and the trends about the EMS units sent out. Moreover, the usage of the UPC over time was explored, to investigate the effect after making medical dispatchers more aware of the implications related to the use of the UPC.
To describe the study population, descriptive analyses were done by the use of numbers and percentages. Table 1 (medical dispatch information based on all 1-1-2 calls) illustrates sociodemographic and medical dispatch information of all 1-1-2 calls in general (symptom-specific and the UPC combined) over the same study period, from 01-01-2017 to 31-12-2019. Table 1. Medical dispatch information of all 1-1-2 calls & UPC calls specifically registered at EMDC Copenhagen, Denmark. B3 = a car is dispatched within an hour and, the case could be related to the heart or a potential stroke, F = no response sent out, A3 = high urgency level, usually associated with the heart or a potential stroke.  The most common final responses of the incidents triaged as "unclear" were B3, F and A3. A B3response implies that a car is dispatched within an hour and that the case could be related to the heart or a potential stroke, an F-response means that no response is sent out. An A3-response implies a potentially life-threatening situation and thus results in a high urgency level. In most cases A3 is related to the heart or a potential stroke.

Register-based results of all 1-1-2 calls in general
The data showed that the most common number of EMS units sent out for a call assigned to the UPC was 1 (58.41% of the time), the second most common was 0 (30.36% of the time) and the third most common was 2 (9.74% of the time). After having been dispatched with the UPC, 28.62% of the calls ended up being cancelled. The most common reasons for the cancellation of the first transport were either due to the patient cancelling their transport, due to an assignment rerouted to a more important case or due to the transport no longer being necessary.
In 12% of the cases, the initial dispatch criteria registered at the dispatch center differed from the actual dispatch criteria reported when the paramedics arrived. During the emergency call, the initial response changed instead of the primary evaluation 14.02% of the time.
The histogram in Fig 5 below depicts the top dispatch criteria reported at the EMDC in Copenhagen during the study period. It can be seen that at the beginning of 2017, the most used dispatch criteria used by medical dispatchers were related to "unclear" cases. However, the trend is visibly declining and faster than any other symptom-specific dispatch criteria.
Journal: Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine general formatting rules: Reference style: Vancouver Style Word count 3000-4000

Discussion
This study aimed to create a structured overview of the effects that the use of the UPC has on the medical dispatching process at the EMDC in Copenhagen, as well as to investigate the effects of sensitizing medical dispatchers to reduce the use of the UPC.
The research demonstrated that the UPC was most often used for the elderly and its use showed an impact on over and under triage in medical dispatching. Moreover, the UPC's use has been declining over the years, demonstrating a possible effect of alerting medical dispatchers about the implications of using the UPC.
Sociodemographic determinants related to the use of the "unclear problem" category The average age of patients who were triaged with the UPC was higher than the age of those patients reported for the overall number of emergency medical services calls (55 vs. 61.22 years).
Journal: Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine general formatting rules: Reference style: Vancouver Style Word count 3000-4000 In line with these results, a study based on emergency medical patients in hospitals in Denmark and California has demonstrated that non-specific diagnoses such as "other symptoms" and "other factors" constituted large groups in the elderly patient population 10 . Although this study considered the patient population in hospitals, it correlates with the increased use of UPC in emergency medical calls for elderly patients.
The fact that a relatively large number of elderly patients are triaged with the UPC may be explained by their reduced capability to exchange information in a clear and precise way 5 .
Moreover, elderly patients often present with more difficult problems. Namely, a study conducted by Wachelder et al. 11 explained that elderly patients who visit the emergency room often have non-specific complaints due to numerous factors including comorbidities, cognitive and functional impairment and communication problems. This could similarly be an issue during the dispatching process at the EMDC. It has been shown that cardiac arrest, which frequently occurs in the elderly 12 , is a medical condition that is difficult to spot 13 . Related to this notion, the data in our study demonstrates that one of the most common final responses of the incidents triaged with the UPC were related to the heart.

The impact of the "unclear problem" category on under and over triage
The data demonstrated that 28.62% of the dispatched transports after triage with the UPC end up being cancelled. This number is higher than the amount cancelled for all 1-1-2 calls in general, which is 23%. These results could indicate that, in general, over-triage might be an issue in Copenhagen, and particularly when regarding the UPC, as it might suggest that in the first instance, more or higher-level emergency vehicles are sent out than necessary. However, it could also denote the oppositeif more cars are cancelled, it might mean that cases are more often under-triaged as vehicles could be cancelled in instances where they were essential.
This study's scope did not allow for the determination of the exact amount of under and over triage. However, a study conducted in Vaud, Switzerland, evaluated the accuracy of the criteriabased dispatch system. One of their aims was to investigate the amount of under and over triage.
They found an over-triage rate of 78% compared to an under-triage rate of merely 4.6%. In both cases of under and over triage, "undefined problem", was the most used criterion. This criterion represented 38 % of over triage and 83.6 % of under triage cases 8 . Considering the same dispatch system was used as in the EMDC, this could indicate that over triage occurs more often  13 , and often present with comorbidities or cognitive and functional impairment, as well as communication issues 11 .
A study conducted in France by Travers et al. 13 depicted the difficulties medical dispatchers face with detecting cardiac arrests and found that reasons of non-recognition were due to the bystander not being near the victim, the medical dispatcher not asking the right questions, too many calls arriving at the EMDC simultaneously, as well as the presence of agonal breathing.
This could explain why medical dispatchers often choose the UPC over more symptom-specific categories. They may not be fully confident or lack information to determine an explicit category for the patient. Reference style: Vancouver Style Word count 3000-4000 that patients calling with the UPC are more often under triaged, as there are more often no transports sent out, whilst transport might have been necessary in reality.
The effect of the use of the "unclear problem" category on patient outcomes The data demonstrates that the first message from the emergency center differs from the actual incident reported when the paramedic arrives in 12% of cases when the calls are dispatched with the UPC compared to 9.3% when it comes to all 1-1-2 calls in general. The medical dispatchers might have a wrong or even misguided understanding of the situation. This might cause an increased amount of either over or under triage. This could cause the paramedics and the acute medical teams in the hospital emergency departments to be less prepared or over-prepared for what they have to deal with, possibly negatively influencing patient outcomes or rather causing inefficient use of resources 5 .

The impacts of sensitizing medical dispatchers about the use of the UPC to reduce its use
As can be seen from the register-based results, the use of the UPC has been steadily decreasing Other studies have also shown positive effects after the implementation of a new protocol in EMDCs. The introduction of a new protocol in EMDCs to improve cardiac arrest identification by medical dispatchers and increase conduction of medical-dispatcher-assisted CPR to patients has shown to be effective 15 16. Although these studies were not related to the UPC, it further exemplifies that new protocols can have beneficial effects in the medical dispatching process, similarly to how the protocols implemented at the EMDC in Copenhagen have reduced the usage of the UPC.

Implications
This study shows that the UPC is most often registered for cases concerning elderly patients. It demonstrates that UPC usage could have an impact on either under or over triage, and therefore have negative effects on patient outcomes or the efficient use of resources. Moreover, this study other EMDCs in Europe could take note of this research. This report could be a stimulus for EMDC leaders to investigate their medical dispatching categorization system and the implications that come along with it, to make further improvements.

Conclusion
The usage of the UPC could negatively impact patient outcomes and the efficient use of EMS resources. It was found that the UPC is mainly used when dispatching the elderly. Nonetheless, the UPC has been decreasing over time after the medical dispatchers were alerted about the implications of using the UPC. Notably, this research has illustrated which aspects of the UPC need further research to make future improvements.