EMS non-conveyance: A safe practice to decrease ED crowding or a threat to patient safety?

Emergency Medical Services (EMSs) and emergency departments (EDs) have reported increased workload [1, 2], mainly due to an aging population and difficulties accessing primary care [2]. The role of the EMS has changed to include more non-critical emergency patients [3], and patients are increasingly assessed and treated at the scene by EMSs, avoiding unnecessary conveyance to EDs [4]. Reported non-conveyance rates substantially vary internationally, between 3.7 and 93.7% in the general population [5]; in Finland, the rate is approximately 40% [3, 6, 7].

The decision-making process for non-conveyance appears to be complex and multifactorial [5]. EMS care providers’ higher education level [3, 8], EMS arrival time in the evening or at night [3, 7, 9, 10], longer distance to a healthcare facility [7], rural area, younger patient age [3, 10, 11], low National Early Warning Score (NEWS2), and alcohol use increase the likelihood of non-conveyance [3]. A recent review showed that, after a non-conveyance decision, re-contact with the EMS or the ED, hospitalization and mortality rates varied a lot [5]. However, whether re-contact with EMS was for a similar reason as the initial EMS contact is unclear [5].

Assessment and triage are a central part of the EMS work process [4]. Under-triaging may put patients’ safety at risk, whereas over-triaging leads to inappropriate use of limited resources [12]. NEWS2 developed by the Royal College of Physicians is a simple, widely adopted scoring system [13]. NEWS2 may help identify patients at risk of deterioration who need to be treated and conveyed by the EMS, but whether it can be used as an indicator regarding EMS non-conveyance decisions is controversial [14, 15].

Patient safety is a priority of the EMSs. Decisions not to convey patients may represent a risk to patient safety. These safety factors are unclear in the prehospital setting [4, 16] and relevant studies are lacking [5, 17]. However, some studies indicate that EMSs are able to make accurate preliminary diagnoses [18]. In the EMS context, a great number of adverse outcomes are associated with difficulties in clinical judgement [16] and patient groups with non-specific reasons for care [19, 20]. Older age and abnormal vital signs are common predictors of adverse outcomes after non-conveyance and, therefore, pose a threat to patient safety [21]. Finally, from the patient safety perspective, little is known about non-conveyance decisions and related adverse outcomes [5, 17, 22].

The aim of this study was to identify the rate and predictors of adverse outcomes after non-conveyance by the EMSs to determine whether the current practice of non-conveyance ensures patient safety.

A total of 48,297 EMS missions were identified, with 35,250 EMS missions included for the first-phase analysis. Of these patients, 42% (n = 14,874) were treated and discharged at the scene. Of these non-conveyed patients, 11,861 met the final inclusion criteria for this study (Fig. 2, Table 1). The reasons for non-conveyance are given in Table 2. The median age of the included patients was 67 (IQR 44–80) years, and 52.6% were females. Regarding EMS contacts during the study period, 85% (n = 7887) had 1 contact, 14.4% (n = 1334) had 2–6 contacts, and 0.6% (n = 60) had at least 7 contacts. Overall, 16% of the patients were under the influence of alcohol. The NEWS2 score was low, with 54.5% of patients having zero points (Table 3).

After the non-conveyance decision, adverse event rates were as follows: EMS re-contact 0–24 h 6.3%, 24–48 h 2.6%; primary health care facility attendance 0–24 h 8.3%, 24–48 h 2.6%; ED attendance 0–24 h 4.4%, 24–48 h 0.8%; hospitalization after ED contact 0–24 h 1.6%, 24–48 h 0.3%; and death 0–24 h 0.1%, 24–48 h 0.03%, within 28 days 1.1%. Some of these patients had multiple types of adverse events, but 4 in 5 (83.9% in 0–24 h) did not have any (Table 4). Reasons for care (ICPC-2) are presented in Table 5.

In the case of EMS re-attendance in 0–24 h, the re-contact was related (same ICPC-2 code) to the initial mission in 36.1% of cases, for a different reason in 50.5%, and the ICPC2 code was missing in 13.4% of missions. The corresponding figures for EMS re-attendance in 24–48 h were 29.0, 55.0, and 16.0%, respectively. Of these EMS re-contacts in 0–24 h, in 4 of 5 cases (80.4%) the mission priority was non-urgent, ending in a new non-conveyance decision in 39.7%; the corresponding figures for 24–48 h are 79.5 and 50.6%, respectively. The NEWS2 points were as follows: at 0–24 h, 50.8% had zero points and 83.3% had 0–4 points, whereas at 24–48 h 53.0% had zero points and 85.5% had 0–4 points. The median duration of visits to primary health care was 15 min and 65% of the patients were discharged from the ED within 24 h. The majority of primary health care or ED ICD10 diagnoses were not mapped to the initial EMS ICPC2 codes. Among the non-conveyed patients, 0.3% were admitted to an intensive care unit in 0–24 h (0.03% in 24–48 h) and 0.5% to high dependency units (0.1% in 24–48 h; Table 6).

Predictors of adverse events are shown in Table 7. EMS arrival time at night and older patient age were common predictors of many events. Furthermore, EMS re-contact (0–24 h) was more likely when the patient had refused conveyance than when the EMS had treated the patient at the scene or there was no need for conveyance (aOR 1.79; 95% CI 1.37 to 2.34). The usage of alcohol (aOR 1.37; 95% CI 1.10 to 1.71) was also associated with EMS re-contact (0–24 h). Non-urgent mission (aOR 1.49; 95% CI 1.25 to 1.77), ALS unit attendance (aOR 1.43; 95% CI 1.16 to 1.77), and rural area (aOR 1.74; 95% CI 1.51 to 1.99) also increased the likelihood of subsequent visits to a primary health care facility. If the patient was handed over to the police, the likelihood of an ED visit (0–24 h) increased (aOR 2.16; 95% CI 1.34 to 3.49).

After exclusion of patients for whom an end of life decision had been made either before or during EMS attendance via telephone consultation with EMS physician (n = 55, median age 85 years), there were 126 patients who died within 28 days (Fig. 3). In this group, the mission leading to the non-conveyance decision occurred most often at home (61%, n = 77). The remaining missions occurred at health care or social service units (37%, n = 47) and public places (2%, n = 2). Among the deceased patients, the place of death was at home in 17% (n = 22), at health care or social service units in 81% (n = 102), and in public places in 2% (n = 2). Overall, 10 patients refused conveyance to the ED. The median age of the deceased patients was 83 years. Emergency physicians or primary care physicians were consulted in 51% of the cases. Based on clinical re-evaluation by JP, TI, and JK, 25% (n = 32) of the deaths were related to the initial non-conveyance mission. In four cases (0.03% of the initial non-conveyance missions), the non-conveyance decision was not appropriate according to the clinical re-evaluation. In the first case, the patient with symptoms of gastroesophageal reflux had ST-elevation myocardial infarction but a 12-lead ECG had not been recorded. In the three remaining cases, the patients had shortness of breath and swelling of the foot due to coronary disease leading to heart failure, non-specific symptoms due to pneumonia, and aortic dissection with typical back pain. In two of these four cases, a physician had been consulted. In addition, one patient who refused treatment and later died would have clearly benefited from conveyance to the ED.

The main findings of this study were as follows. Firstly, 4 in 5 (83.9% in 0–24 h) of non-conveyed patients had no adverse events after the non-conveyance mission. Secondly, patients were mainly in good condition; the NEWS2 scores were low and duration of visits to primary health care or EDs short. The reasons for the adverse events seem to be different than the reason for the initial EMS mission. Thirdly, 0.03% of the non-conveyance decisions seem to be related to a patient’s death, where re-evaluation showed poor clinical judgement and/or clinical treatment protocol violation.

From the perspective of patient safety, it is important that the majority of non-conveyed patients did not have any subsequent events during the follow-up period, which is in line with previous studies [21, 31]. We found that EMS re-contacts, visits to primary health care or ED and hospitalization were relatively rare after non-conveyance missions. Two previous reviews indicate that there are many studies focusing on specific populations in which the sample size is small or the follow-up is by telephone, which may lead to bias because the follow-up of a large number of patients may fail [5, 17]. Thus, comparisons with our findings are challenging. However, the subsequent event rates in this study were roughly the same as in other similar studies [21, 31].

Our study indicates that the 24-h period after an EMS visit seems to be critical. The highest incidence of all outcomes occurred within 0–24 h after the initial non-conveyance mission, which was noted previously [21]. A longer follow-up period could have provided more information, but the likelihood of an adverse event being due to some other reason would have increased.

Our study shows that, in the case of EMS re-contact, primary health care or ED attendance, and hospitalization, the patients were mainly in good condition. The new mission (EMS re-contact) was commonly non-urgent, the patients’ NEWS2 scores were low, and almost half of these cases ended in a new non-conveyance decision. The visits to primary health care facilities or EDs were mostly short. On the other hand, 32 patients (0.3%) needed intensive care and 62 patients (0.5%) were treated in high-dependency units after the initial non-conveyance case. These findings are similar to a Swedish study [10]. However, it is difficult to assess whether these patients’ critical condition was derived from the EMS’s poor clinical judgement and incorrect non-conveyance decision. When comparing the preliminary diagnosis (adjusted ICPC2) to new ICPC2 codes in case of EMS re-contact or discharge diagnoses (ICD10) from primary health care, ED, or after hospitalization, these adverse events were usually not related to the initial non-conveyance mission. In addition, we found that there were many subsequent visits to primary health care, which may be an indication of impaired access to primary health care, especially in the evening and at night.

Our logistic regression model (Table 7) and previous studies [21, 32] indicate that older age is a risk factor for adverse outcomes. This may be due to elderly patients’ complex symptoms and many comorbidities and medications. We also found that patients’ refusal of conveyance and the use of alcohol predicted an EMS re-contact in 0–24 h. One explanation may be that these patients do not know how to handle their problems and an EMS re-call is the easiest choice. Other studies have reported that the refusal is associated with ED visits [33] and alcohol increases the likelihood of non-conveyance [3].

Decision-making at night is challenging [34]. Our results show that EMS arrival at night increases the likelihood of 3 in 4 primary outcomes of this study. However, the end of a work shift was not associated with re-contacts, which may indicate that EMS providers consider the patient’s needs even though the shift is close to its end. However, EMS arrival at night, non-urgent mission, ALS unit, rural area, and longer distance to a health care facility or ED were related to subsequent visits to primary health care. There is a possibility that this demonstrates appropriate use of health care resources to avoid unnecessary conveyance to the ED. Geographic variation in the EMS context is high [35], but the impact of geography on a patient’s outcome is unclear. However, the on-scene time is reported to be high in rural areas [36] and in the case of non-conveyance [3]. Understandably, visits to primary health care were related to non-urgent missions. In contrast, it seems that EMSs can safely discharge urgent missions such as hypoglycemia and other chronic diseases at the scene after appropriate assessment and treatment. Previous studies have shown that non-conveyance is challenging and requires competence [5, 34]. Indeed, there are a number of factors that are related to non-conveyance decisions [3, 8, 37‐39]. Our study demonstrated that ALS units are associated with re-contact in primary health care. This may be due to the longer education of EMS care providers in ALS units, which may be associated with more appropriate decision-making related to the use of primary health care and ED resources. On the other hand, based on the univariate analyses, BLS units increased the risk of subsequent ED visits. This raises the question of whether these visits are related to the BLS units’ competence. However, more studies are needed.

Moreover, an Australian study indicated that, when the EMS discharged patients at the scene, there was an increased risk of adverse events compared to patients discharged from the ED [21]. Notably, subsequent contacts with health care do not automatically mean that patient safety is compromised [5, 30].

Abnormal vital signs have been found as a common predictor of adverse events after EMS non-conveyance [21]. We found that, if the patient’s NEWS2 score increases by 1 point or the score is high (> 7 points), the risk of EMS re-contact increases. Non-specific complaints lead to a number of adverse outcomes in both the EMS context and EDs [19, 20, 40]. Surprisingly, we did not find similar results. Based on univariate analyses, non-specific complaints were only related to EMS re-contact in 24–48 h.

Most non-conveyance patients did not have adverse events in the follow-up period. In the case of EMS re-contact or visits to a primary health care facility or ED and hospitalization, the patients were mainly in good condition and the reason was often something other than the initial non-conveyance mission. A small proportion of non-conveyed patients were later in critical condition; deaths were very infrequent. From a patient safety perspective, the subsequent 24 h after a non-conveyance decision are critical. EMS non-conveyance seems to be a safe and rational use of limited resources and, therefore, is a solution that reduces unnecessary patient conveyance to EDs.