Australasian Emergency Care

Background: Patient with dizziness are challenging in prehospital care. The aim was to describe ﬁnal diagnosis among patients assessed by EMS as suffering from dizziness with focus on time-critical conditions. Methods: Consecutive patients assessed by an EMS clinician during 12 months in a single large EMS system in Gothenburg, Sweden (660,000 inhabitants), were assessed. The study comprised patients given ESS code 11 dizziness. The main end-point was the ﬁnal diagnosis (ICD code). Results: There were 58,575 primary missions, of which 2,048 (3.5%) were assessed as ESS code 11 (dizziness). Of these, 161 (8%) were excluded. Among the remaining 1887 cases, there were 230 different ICD codes and 96 (5%) had a time-critical condition. The majority (88%) had a cerebrovascular disease. The most typical symptoms among time-critical conditions were an acute onset (63%) and nausea, vomiting (61%). When compared with non-time-critical conditions, those with time-critical conditions were older and had a higher median systolic blood pressure at EMS arrival. Conclusion: Among primary missions by the EMS, 3.5% had dizziness. Of these, 5% had a time-critical condition and the majority had a cerebrovascular disease. Instruments to identify time-critical conditions among patients seen by EMS due to dizziness are required. © 2020 Published by Elsevier Ltd on behalf of College of Emergency Nursing Australasia.


Introduction
Dizziness is a relatively common symptom that may force patients to seek emergency care.Many of these patients dial the emergency number in Sweden (112) for ambulance transport to hospital.
Dizziness is a unifying concept for a number of different experiences which the patients often describe as feelings of bring on a carousel, off balance, near syncope or motion of the sea.It has been reported that about three per cent of all admissions to an emergency department (ED) are due to symptoms of dizziness [1].
A number of conditions can be associated with symptoms of dizziness.Damage to central or peripheral parts of the vestibular system will generate an acute vestibular syndrome.
When the damage is localised in the inner ear or in the vestibular nerve, there is a peripheral aetiology.Examples of peripheral aetiologies of an acute vestibular syndrome are benign paroxysmal positional vestibular neuritis, Ménière's disease, bacterial labyrinthitis and herpes zoster oticus [2].
In "central dizziness", the damage is localised in central parts of the vestibular system in the brain stem and/or cerebellum and the underlying aetiologies include stroke/TIA, migraine, tumour in the brain stem, encephalitis and multiple sclerosis [2].
However, it has been suggested that the majority of patients with acute vertigo have other aetiologies, which are not associated with damage to the vestibular system.Lam et al. reported that 63% of patients with acute dizziness had something other than damage to the vestibular system [3].The most common aetiologies were an upper airway infection (35%) and hypertension (18%).Time-critical conditions such as sepsis, bradycardia, AV block III and acute coronary syndrome accounted for about three per cent of all cases.
A further categorisation of vertigo was made by Newman-Toker et al., who included 9000 cases of vertigo in their survey [1].More than half the patients had an aetiology which was not related to the vestibular system.The study confirmed that there is often a medical disease behind symptoms of vertigo which is not related to the vestibular system.Time-critical conditions which are not related to the vestibular system but may still cause dizziness and include water-electrolyte imbalance, arrhythmias, cerebrovascular diseases, carbon monoxide poisoning and aortic dissection/aneurysm.
The variety of conditions that may exist behind symptoms of dizziness highlight the difficulties health-care providers experience in differentiating these symptoms into benign and malignant conditions at the first encounter with patients who present with these symptoms.
The burden on the emergency medical service (EMS) has increased markedly during the last few decades.This phenomenon is explained by a number of factors, including the development of an elderly population and the fact that more people nowadays tend to call for an ambulance due to less time-critical conditions.It has thus been shown that not all patients who dial 112 need to be transported to an ED but can preferably be handled at another level of care [4].This has increased the demand on health-care providers in the EMS who, already at an early stage, need to be able to distinguish patients with a time-critical condition from those without and do not require emergency care.
One symptom that may create difficulties in the early assessment on EMS arrival is dizziness.This is explained by the large number of possible underlying aetiologies of which some are time critical but the majority are not.A recent study of patients with TIA/stroke describing patients who were not directly transported to hospital after the assessment by EMS, due to failure in the early identification indicated that many of these patients had dizziness as the dominant symptom [5].
The aim of the present study is therefore to describe consecutive patients who call for the EMS due to symptoms of dizziness with the emphasis on the initial presentation to the EMS clinician and the final diagnosis, i.e. underlying condition.Particular attention will be paid to whether the patients were or were not suffering from a time-critical condition according to the final diagnosis.

Design
This was a retrospective, consecutive, observational, pilot study with a quantitative approach which was performed through an evaluation of the EMS and hospital medical records.

Study setting and population
The study was performed in Gothenburg, which is the second largest city in Sweden, located on the west coast, with 660,000 inhabitants and an area of 900 km [2].In the EMS system, there are 20 advanced life support (ALS) ambulances manned by at least one registered nurse (often with a specific education in prehospital emergency care).This education involves either postgraduate education or a programme in prehospital emergency care.There are also two so-called single-responder units manned by experienced registered nurses always with an education in prehospital emergency care.There is also one physician-manned unit with an anaesthesiologist and a registered nurse.
In 2016, there were 58,575 primary missions within the organisation of which 2048 (3.5%) received the Emergency Signs and Symptoms (ESS) code 11 (dizziness) from the nurse.This code included all types of dizziness.
"Primary mission" means that the EMS nurse makes the patient assessment on scene.

Patient recruitment
In 2016, all the primary missions in the catchment area with ESS code 11 (dizziness; n = 2048) were included in the study.
The inclusion criteria were thus: 1) Primary mission assessed by the EMS nurse 2) ESS code 11 (dizziness) The exclusion criteria were: 1) Age < 16 years.
2) Patient being assessed by another caregiver, i.e. a physician at an outpatient clinic.
3) The lack of an assessment by a physician at the ED. 4) The lack of a complete identification number.5) The patient was sent to another hospital outside the catchment area.

Data collection
Data were collected from the health-care provider's notification in the EMS records in the EMS data system, Ambulink.A simultaneous analysis of the hospital database, Melior, to which Ambulink is linked, was performed with the emphasis on the final diagnosis according to the International Statistical Classification of Diseases and Related Health Problems -Tenth Revision (ICD-10) code.
Patients were thus divided into two groups, i.e. those with a time-critical condition according to final diagnosis and those without.
A time-critical condition was defined according to Hagiwara et al. [6] and comprised the following diagnoses: myocardial infarction, unstable angina pectoris, transitory ischaemic attack (TIA)/stroke, unconsciousness, sepsis, aortic dissection/rupture, any form of shock, pulmonary embolism, heart failure including pulmonary oedema, bundle branch block, cardiac arrest, intoxication, water-electrolyte imbalance and high-energy trauma.
All cases that had any of the above as the final diagnosis were more carefully reviewed, addressing some variables that were not addressed in the remaining patients.

Prioritisation
Patients were prioritised at the dispatch centre at three priority levels.
Level 1) Life threatening and an ambulance dispatched with blue lights and sirens Level 2) Not life threatening; can accept 30-minute waiting time for the EMS Level 3) Normal waiting time for the EMS Patients were assessed and triaged at the scene by the EMS clinician based on patient severity according to the Rapid Emergency Triage and Treatment System (RETTS).This system is based on the vital signs of degree of consciousness, oxygen saturation, respiratory rate, heart rate, blood pressure and body temperature in combination with an ESS code.The latter defines the mode of complaint, i.e. chest pain, dizziness and so on.Each patient is categorised into one of five colours (red, orange, yellow, green and blue) and one ESS code that define the main symptom.Red is life threatening and orange is potentially life threatening.Both colors indicate that the patient should be monitored and seen by a physician at the ED as soon as possible.Yellow and green indicate non-life-threatening conditions, but patients need to be seen by a physician within a reasonable time.
Blue means that a lower level of care may be more appropriate than ED admission.At the time of the study, the blue level was not in use in the EMS.

Data analysis
The result is presented as numbers, percentages or the median with 25th and 75th percentiles.When continuous variables as well as ordered data (priority level) were compared, the Mann-Whitney U test was used and Fisher's exact test for dichotomous/categorical variables.All tests are two-sided and p-values below 0.05 were regarded as statistically significant.SPSS version 22 (IBM Corp, Armonk, NY) was used for data processing and statistical analysis.

Ethical considerations
This study has been conducted within the framework of a master's degree at the University of Borås.According to the Swedish law, SFS 2003:460 The law of ethical considerations in human trials, studies conducted by students are not judged by the Swedish ethical review boards.However, Borås University judges all its students' work according to the Helsinki Declaration.In all analyses, patients remained anonymous and, as a result, patient integrity was respected.

Results
In all, 2048 patients fulfilled the inclusion criteria (primary mission and assessed as dizziness), but 161 (8%) of them were excluded for the following reasons: the patient left the ED before being seen by a physician (n = 71); the patient was assessed by another caregiver (n = 33), the lack of a complete identification number (n = 26), the patient was sent to another hospital outside the catchment area (n = 24) and the patient was under the age of 16 (n = 7).
From now on, the results will only deal with the remaining 1887 patients.Of these patients, 96 (5%) had a time-critical condition according to the final diagnosis (ICD code).

Characteristics of patients with dizziness in relation to the ambulance population
Patients with dizziness were almost 10 years older compared to the overall ambulance population, and had a higher percentage of women (58%), were assessed at the dispatch centre with a lower priority level and triaged on-scene to lower levels more frequently (Table 1).

Characteristics of all patients in relation to gender
Of all patients with dizziness, 58% were women.Women were somewhat older than men and they were given a lower priority than men at the dispatch centre.
Women were also assessed to a lower triage colour (level) by the EMS nurse.Among both women and men, about 80% were taken to hospital and about 20% stayed at the scene.Among those who stayed at the scene, 44 (11%) attended the ED within 72 h.Among those who were transported to hospital, slightly more than 70% were transported directly by ambulance.In terms of final diagnosis (ICD code), 4% of women and 6% of men had a time-critical condition (p = 0.06) (Table 2).

Characteristics among women and men with a time-critical condition
Women were 10 years older than men.None of the patients was given the highest priority colour (red).Four per cent of women and eight per cent of men were not conveyed.All these patients attended the ED within 72 h.Among those who were taken to hospital, 96% of women and 92% of men were transported by ambulance (Table 3).

Findings associated with onset of symptoms in the critical conditions
The most frequent findings associated with onset of symptoms in time critical conditions were 1) an acute onset (63%), 2) nausea, vomiting (61%), 3) the patient had a tendency to bleed or was on treatment with anticoagulants (25%), 4) a history of head trauma (16%), 5) sudden onset of headache (11%) and 6) loss of consciousness (10%).

Comparison between time-critical and non-time-critical conditions in terms of age and vital parameters
Patients with a time-critical condition were older, had slightly lower oxygen saturation and had higher blood pressure than patients without a time-critical condition (Table 4).

Final diagnosis
In all, there were 230 different ICD codes.Among the patients with a time-critical condition, a cerebrovascular disease was by far the most frequent final diagnosis (Fig. 1), whereas, among the patients with a non-time-critical condition, dizziness/giddiness was the most frequent final diagnosis (Fig. 2).

Overall results
In this pilot study, we found that 3.5% of primary EMS missions were assessed by the arriving EMS crew as being caused by symptoms of dizziness.Among these patients, five per cent had a final diagnosis equivalent to a time-critical condition.The majority of these patients had a cerebrovascular disease.Compared to the average patient who calls for EMS, the patient with dizziness appears to be older and is given a lower priority by the EMS crew.
The finding that 3.5% of primary EMS missions are assessed by the EMS crew as dizziness is in agreement with a report by Hjälte et al. [7], who found that, among all calls to the dispatch centre, three per cent were due to dizziness.Furthermore, this finding is in good agreement with a previous report by Newman-Toker et al. [8], who reported that, among consecutive ED admissions, about 3% are caused by dizziness.We found that five per cent of patients with dizziness had a timecritical condition where the vast majority had a cerebrovascular disease.This is new information.However, it is in good agreement with a study in the ED by Kerber et al. [9], where it was found that three per cent of patients with dizziness had an underlying stroke.Doijiri et al. [10] found that, among patients who were hospitalised due to isolated dizziness, 11% had a stroke which was mainly located in the cerebellum.Similar findings were made by Navi et al. [11] and Ljunggren et al. [12], who both reported that five per cent of admissions to the ED due to dizziness were caused by a cerebrovascular disease.
The next time-critical condition in order of frequency was electrolyte imbalance.However, only five of 1887 patients (0.3%) fulfilled this criterion.In the study by Navi et al. [11], two per cent had an electrolyte imbalance.
Among the patients with a non-time-critical condition, a large proportion had an ICD code equivalent to a final diagnosis of dizziness/giddiness.This highlights the fact that many patients did not receive an adequate explanation of the aetiology behind their complaints.
We looked for characteristics among the patients with a timecritical condition.A very large proportion of these patients either had an acute onset of the dizziness or simultaneously suffered from nausea, vomiting.Unfortunately, we do not know the corresponding figure for patients without a time-critical condition.Tarnutzer et al. [13] reported that patients with symptoms of dizziness which was caused by a stroke more frequently had an acute onset of symptoms than patients with dizziness due to vestibular neuronitis.Simultaneous symptoms of nausea and vomiting have also been reported by others as frequently occurring among patients with dizziness caused by a stroke [9,11].However, in none of these studies was the risk of these symptoms more frequent among patients with stroke as compared with non-time-critical conditions.
The hypothesis that nausea vomiting may be a warning sign for a time-critical condition among patients with vertigo gets some support from the situation in other time critical conditions.Thus, among patients with acute chest pain assessed by EMS, was the presence of nausea, vomiting shown to be associated with an increased risk of an underlying acute myocardial infarction [14].
Patients with a time-critical condition were older than patients without one.This is in agreement with the findings reported by Navi et al. [11].We also found that patients with a time-critical condition more frequently had an elevation of their systolic and diastolic blood pressure, as compared with non-time-critical conditions.This is in agreement with the findings reported by Kerber et al. [9] and may be explained by the fact that an elevation of blood pressure is common in the acute phase of a stroke [15][16][17][18].
In terms of previous history, a high rate of hypertension and TIA/stroke was found among patients with a time-critical condition.A relatively high proportion of the patients with such a condition had a previous history of various heart diseases including atrial fibrillation which is a well-known risk factor for stroke [20].A history of diabetes, which is another risk factor for stroke [21] was also relatively common among these patients.Thus, information from the patient's comorbidity may give important information regarding the risk of a time critical condition.Such a hypothesis gets support from Navi et al. [11], who reported a higher rate of some of these previous diseases among patients who had dizziness caused by a stroke than among patients who had dizziness caused by other diseases.
There may therefore be some differences in terms of the initial clinical picture when patients with dizziness caused by a timecritical condition are compared with those without one.In the future, these differences could be used in a more systematic manner to create a decision support tool for the assessment of patients with dizziness by the EMS crew in the prehospital setting.
Thus, one may speculate that a decision support tool for the EMS crew triaging patients with vertigo may be based on specific information regarding the patient's age, previous history with focus on cardiovascular disease, the type of acute onset of symptoms and clinical findings on admission of the EMS crew.The aim of such a tool should primarily be to identify patients with a time critical etiology.A secondary aim may be to identify patients who do not need to be transported by EMS to a hospital but could instead be handled at a lower level of care.
None of the patients with a time-critical condition received the highest priority (red) when assessed by the EMS crew according to RETTS.This is best explained by the fact that there is no red level based on the ESS code for dizziness.So, in order to be triaged to level red, vital signs must be life threatening and a deviation of this kind obviously did not occur.

Strengths and limitations
This is a cohort, which represents consecutive patients from a single EMS system from an urban area.For this reason, our data cannot be extrapolated to rural areas with any degree of certainty.Furthermore, this is a retrospective, observational study with all its weaknesses, including a large proportion of cases with missing information.Finally, questions relating to different aspects of

Conclusion
Among primary missions by the EMS, 3.5% of patients were assessed as suffering from dizziness.Of them, 5% had a time-critical condition and the majority of these patients had a cerebrovascular disease.Further studies are required to develop instruments that can help to identify time-critical conditions at an early stage among patients who call for the EMS due to dizziness.
N. Packendorff et al. / Australasian Emergency Care xxx (2020) xxx-xxx symptoms and previous history were only addressed in cases with a time-critical condition.

Table 1
Characteristics of all ESS 11 cases in relation to all primary missions.
a 17 missing in ESS 11; 1776 in primary missions.b 17 missing in ESS 11; 2274 in primary missions.c Two prio 4 cases excluded (assessed as transport only by dispatch) in ESS 11; 99 in primary missions.d 6816 missing in primary missions.e Of patients transported to hospital.f PTS: non-emergency patient transport services.

Table 2
Characteristics of all ESS 11 cases in relation to gender.
a Two prio 4 cases excluded (assessed as transport only by dispatch).b Of patients initially assessed to stay at the scene.c Of patients transported to hospital.d PTS: non-emergency patient transport services.

Table 3
Characteristics of patients with a time-critical condition in relation to gender.
a Of patients initially assessed to stay at the scene.b Of patients transported to hospital.c PTS: non-emergency patient transport services.

Table 4
A comparison between patients (ESS 11) with and without a time-critical condition with regard to age and vital parameters.