Performance of the rapid triage conducted by nurses at the emergency entrance*

Objective: to compare the performance of the rapid triage conducted by nurses at the emergency entrance and of the Manchester Triage System (MTS) in identifying the priority level of care for patients with spontaneous demand and predicting variables related to hospitalization. Method: a cross-sectional study carried out in an Emergency Department (ED) of a university hospital in São Paulo. The priority levels established in the rapid triage performed by nurses were high priority (patients of spontaneous demand directed to the emergency room) or low priority (those referred to the institution’s usual flow). Diagnostic accuracy measures were calculated to assess the performance of the indexes. Results: of the 173 patients (52.0% female, with mean age of 60.4 ± 21.2 years old) evaluated, it was observed that rapid triage was more inclusive for high priority and had better sensitivity and worse specificity than the MTS. The probability of non-severe patients being admitted to the emergency observation unit was lower due to the rapid triage. For the prediction of the other variables, the systems presented unsatisfactory results. Conclusion: the nurses overestimated the classification of patients as high priority, and rapid triage performed better than MTS in predicting admission to the emergency observation unit.


Introduction
Overcrowding in emergency services is a reality in many institutions. In this scenario, the triage emerged as a tool to optimize care in emergencies and to identify patients who need to have priority in care and treatment, through a dynamic assessment process (1)(2) .
Among the different triage systems applied in emergency services, the Manchester Triage System (MTS) (3) stands out as one of the most used in Brazilian institutions. The MTS is based on the identification of the patient's main complaint and establishes, through decision flowcharts and discriminators, the maximum time for the first medical assessment (3) . Thus, patients classified as red (emergency) by the MTS need immediate care, as orange (very urgent) in up to 10 minutes, as yellow (urgent) in a maximum of 60 minutes, as green (not very urgent), as and blue (not urgent) in up between 120 and 240 minutes, respectively (3) .
Despite the proven importance of triage in the organization of the emergency services, the waiting time between the opening of the service record and the triage routine can vary according to the demand of the moment, making it possible to wait in queues, which, for some patients, it means serious health problems due to the delay in starting their treatments (2) . In addition, a study that analyzed patients classified in the red category according to the MTS identified in the sample the mean time between arrival at the institution and the end of the 8-minute classification, which may represent valuable time spent for this type of patient (1) .
Still in the case of patients classified in the red category, research shows that, in some emergency services, critically ill patients are generally seen even before opening the hospital registration form, and that triage routine is performed retroactively, after the patient's clinical stabilization (1,(4)(5) .
Therefore, it is noticeable that the implementation of a triage protocol does not guarantee care at the recommended times, thus it is essential to organize management and assistance flows that speed up the patients' access to the service, care and treatment at the appropriate times according to their level of severity (5) . This is the case of high priority patients (emergency and very urgent), for example, who often need a quick professional evaluation (in this study called "rapid triage"), still at the hospital's emergency entrance, so that it is possible to early detect their severity and proceed to the immediate care in the emergency room.
In the present study, rapid triage, applied only to patients who arrive at the service reporting severity at the emergency entrance, is performed empirically, without protocols and/or triage systems, that is, the nurse makes a quick assessment of the patients' general condition and complaint, still in the transportation vehicle, to determine if they are facing an emergency and need immediate care (referral to the emergency room) or if they can follow the normal flow of the institution (opening the hospital registration form and waiting for the triage routine in a non-critical sector).
It is worth noting that the objective of rapid triage at the emergency entrance is to identify, among patients of spontaneous demand, those with a potential life risk and, therefore, who require immediate decision-making by the health professional (physician or nurse) working in the emergency service, based on clinical data, subjective information and previous experience (6) , in addition to the use of cognitive and intuitive processes. This situation differs from those patients referred to the hospital by pre-hospital service vehicles or private ambulances, as they are assisted by a health professional and have already received initial care.
Finally, the correct identification of patients with high priority through rapid triage increases the chances of survival. On the other hand, the identification of low priority patients (urgent, little urgent or non-urgent) avoids overcrowding in the emergency sector, preventing human and material resources from being diverted to the care of those without real serious conditions and that could be assessed in less critical sectors (2) .
In view of the above, there was concern about the rapid triage performed by nurses in cases of patients coming from spontaneous demand and who arrive at the emergency entrance referring severity. Some questions guided this concern: If the same patients were screened by the MTS protocol, would they have the same classification? What is the performance of rapid triage compared to the MTS in predicting different variables related to patients' hospital admission?
In this sense, the objective of this research was to compare the performance of the rapid triage performed by nurses at the emergency entrance and of the MTS in identifying the priority level (high or low) of care for patients with spontaneous demand and the prediction of variables related to hospitalization.

Method
This is an observational, descriptive, and cross-     (Table 2).
However, when analyzing the results of the NPVs, it is noted that the probability of non-severe patients being admitted to the emergency observation unit was lower by rapid triage (100.0% -78.6% = 21.4%) than by the MTS (100.0% -66.0% = 34.0%) and this is due to the good NLR associated with the low priority classification by rapid triage. It is also noteworthy that rapid triage showed a lower rate of undertriage and a higher rate of overtriage than the MTS in all the scenarios evaluated.

Discussion
Triage is essential for any health service, especially With regard to the characteristics of the patients evaluated, the higher frequency of females corroborates with the majority of the findings of several studies carried out in emergency services (1,(8)(9)(10)(11)(12)(13) , while the mean age identified was higher than in the results of other research (1,4,(8)(9)(10)(11) .
Among the previous comorbidities presented by the patients, researchers who analyzed the performance of the MTS in a population of adults (2) (2) .
The mortality rate in the sample was substantially higher than those found in the literature (8,14) . However, it is worth noting that the sample was composed only of patients who reported severity when they arrived at the emergency service and, therefore, were potentially more serious than the general population seeking ED, frequently investigated in other studies.
The occurrence of a death among those who were screened as a low priority by nurses during the rapid triage is highlighted. For this case, the MTS was suffering/anguish (16) . There is also the insecurity of the professionals in relation to the possibility of deterioration of the clinical condition of the patient awaiting care and the tensions arising from hostile acts by patients and/or family members.
As for the performance of the two systems, rapid triage was more sensitive and less specific than the MTS in all the variables analyzed. It is difficult to say which level of sensitivity or specificity is acceptable to conclude that a given triage system is safe since, to achieve high sensitivity (i.e., an acceptable degree of undertriage), specificity must be so low that the potential to save resources would be insignificant (17) .
Regarding the length of hospital stay, the PPVs of the two systems are considered low. This can be justified by the effectiveness of the treatment performed and, thus, by the shorter hospital stay. As an example: if treated efficiently and quickly, a moderate or severe asthma attack (patient classified as high priority) can be solved promptly, not requiring a hospital stay longer than 24 hours. Or even a patient with a decrease in the level of consciousness due to hypoglycemia, after the intravenous correction of blood glucose levels, can in most cases be discharged from hospital only with the guidance of the team.
Thus, there are patients at high risk for clinical deterioration and who, if cared for in a timely manner, will be discharged in less than 24 hours -and, in some cases, will not even be admitted to the emergency observation unit. A Brazilian study (18)  In the analysis of the performance of rapid triage in the prediction of admission in the emergency observation unit, this system presented a higher rate of overtriage and a lower rate of undertriage than the MTS. For the MTS, these values were better than that found in a study that analyzed 900 trauma victims admitted to the ED (18) .
In this context, the inclusion of patients who are not really in a serious condition in the high priority category (overtriage) can lead to overcrowding in the critical care area and impair work dynamics, in addition to unnecessarily using resources (2) . In cases of undertriage (inclusion of critically ill patients at low priority), there is a longer time between the patient's arrival at the emergency service and the first medical care, which may result in the patient's clinical worsening and in a worse prognosis (2) . An American study (20) that analyzed 50,576 patients identified a significant number of patients who waited for more than 10 minutes for the triage routine, and the researchers reinforce the possible impact of this delay on the quality of care provided.
The NPVs for both systems were better than the PPVs, demonstrating that the systems were more assertive in assigning low priority than high priority for the admission in the emergency observation unit variable. In addition, patients who were classified as low priority by rapid triage (NLR = 0.2) were less likely to be admitted to the emergency observation unit than those classified as low priority by the MTS (NLR = 0.4). In this sense, it can be said that rapid triage performed by nurses at the emergency entrance performed better than the MTS in predicting the non-admission of low priority patients in the emergency observation unit.
As for the death outcome, the two systems showed similar values in most of the analyses performed.
Researchers who investigated the triage given by an institutional protocol with the outcomes of patients seen at an emergency unit in the inland of São Paulo identified that, among the patients considered severe, the death rate corresponded to 66.7% and, in the group of low priority of care, this rate was 1.7% (14) . There was also a group of patients who were not classified by the institutional protocol due to situations of extreme severity and, therefore, were referred directly to the emergency room, where they had a death rate of 31.4% (14) . Another study identified that patients classified as high priority for care by the MTS have a 5.58 times greater chance of progressing to death than those classified as low priority (8) . In the present study, both rapid Finally, the present study did not intend to indicate the best triage instrument (rapid triage or MTS), but rather to highlight findings that may contribute to the improvement of the triage process and of the organization of managerial and assistance flows in emergency services that speed up the access of critically ill patients to the service.
Some limitations of the research must be highlighted: the study was carried out in a single emergency center of a secondary level hospital, and this fact must be considered when generalizing the results.
Furthermore, there was difficulty in identifying a reliable gold standard to assess the performance of the systems, although different variables have been tested.

Conclusion
Rapid triage was more inclusive in identifying patients with high priority of care and performed better than the MTS in predicting admission in the www.eerp.usp.br/rlae 8 Rev. Latino-Am. Enfermagem 2020;28:e3378.
emergency observation unit in the case of patients with spontaneous demand who reported severity on arrival at the emergency service.
For nurses who perform rapid triage, the classification of patients as low priority appears to be clear (less undertriage), but they still overestimate others, classifying them as high priority (more overtriage).
Therefore, the results of this study can contribute to the organization of managerial and care flows aimed at the rapid triage process performed by nurses at the emergency entrance, as well as indicate the need for more evidence on the main signs and symptoms that reflect the real severity of the patients, contributing to the reduction of overtriage, to the optimization of the use of resources, and to safety in the classification of patients.