Overcrowding in the emergency department is a growing concern, which negatively impacts patients and the medical system in general[1]. Input, throughput, and output are the three main causes of overcrowding[2]. From an input perspective, triage plays an important role in addressing overcrowding[3]. As the initial point of contact for patients in the emergency room, triage seeks to quickly assess the patient and deliver the proper medical resources in accordance with the patient's classification of conditions[4]. Additionally, by providing appropriate service for non-urgent patients, patient waiting time can be safely shortened and input pressures relieved[5], [6]. For instance, in proper collaboration with other medical institutions, transfer non-urgent patients to a community or uncrowded medical unit to ensure that urgent patients have access to restricted medical resources[7]. Streppa J et al developed diagnostic algorithms and nursing training programs for wrist fractures, authorizing triage nurses to request X-rays for patients with isolated wrist injuries, decreasing more than 90 min in waiting time[6]. As emergency triage nurses face unplanned and various patient scenarios, their decision-making accuracy impacts patients more than any other type of nursing procedure [8]. Under-triage may fail to recognize danger signs that could threaten their lives, putting the patients at risk of delayed treatment and potentially missing the best chance of rescuing their lives[9]. An increase in patient congestion and medical resource waste might arise from over-triaging patients[10]. Triage tools and triage nurses are primarily accountable for ensuring the quality of triage decision-making[11].

Firstly, several triage tools have gained wide recognition, including triage scales or triage guidelines, such as the Manchester Triage Scale(MTS), the Canadian Triage Acuity Scale(CTAS), and the Australasian Triage Scale(ATS)[12], [13]. Various patient conditions are categorized into five levels based on these triage scales, and with the increase in triage levels, a shorter waiting time is required by patients. Such as, MTS requires patients with levels Ⅰ-Ⅴ to contact their doctor within immediate/10/60/120/240 min, respectively.[13]The paper-based triage guidelines of the past are becoming increasingly replaced by intelligent triage systems as the smart era advances[14]. Automated patient classification and clinical outcome prediction are now the main goals of computer-based triage systems[15], [16]. In the United States, a computer-based electronic triage system (ETS) based on some outcomes (mortality, admission to the ICU, or direct transport to the operating room or cardiovascular catheterization suite) is used to more evenly distribute patients among lower-acuity levels compared to the Emergency Severity Index (ESI) while reducing subjectivity in triage evaluation (ETS distribution: Level 3: 30 %, Level 4: 30 %, Level 5: 29 % vs ESI distribution, respectively: 46 %, 34 %, and 7 %)[16].The triage nurse would be better able to make accurate decisions by entering the patient's vital signs following the system's procedure[17].

Notably, no unified triage guidelines have been developed at an early stage in mainland China regarding emergency triage[18]. Based on the national conditions in China, scholars developed a system for intelligent triage[19]. The Chinese government implemented a four-tier triage scale for emergency departments in 2012 to unify the work of emergency departments nationwide, but all levels of triage lack detailed evaluation indicators[20]. The first consensus of Chinese experts on emergency triage was formed in 2018, refining the evaluation indicators for patients at all levels, and dividing emergency patients into I、II、III、IV levels, corresponding to waiting times of immediate, 10 min, 30 min, and 240 min, respectively[21].

Secondly, the triage system is merely an auxiliary procedure[22]. Despite the fact that the triage system's validity and reliability range from satisfactory to very good, ensuring triage quality remains difficult[23]. The quality of triage decision-making is influenced by triage nurses' capacity to gather key information[24]. When the triage nurse cannot identify the patient's key information, it is difficult to enter this information into the triage system for determining the level of the patient[25]. Patients may not fully meet the guidelines for clinical triage. For instance, patients with borderline symptoms (symptoms that were in between two different categories)[24]. In addition, the triage system offers limited support to the triage nurse in circumstances involving mentally ill patients (suicide or danger to others' safety) or vagrants, alcoholics, etc[26], [27]. Hence, the skills of the emergency nurses participating considerably influence the quality of the triage decision-making [22]. Triage nurses need to have the ability to use critical thinking, clinical experience, and intuition to provide an accurate assessment of emergency patients, determine the priority of those requiring treatment, and modify the triage plan accordingly[28]. When uncertainty arises, such as when a patient's condition is between two triage levels or when there are multiple patients in the same triage level, emergency nurses tend to make decisions by intuitive means[23]. Intuition is a spontaneous, rapid, and specific judgment of triage nurses, which is more in accordance with the actual triage environment[29]. Study results show that emergency nurses perform better at triage decision-making when trained with scenarios, case discussions, and thinking aloud[30], [31]. Research on emergency nurses' triage decision-making in mainland China is scarce, and few studies have examined how triage is practiced[18], [32]. The practice of triage and the decision-making abilities of emergency nurses in the northern region remains unclear following the publication of the triage consensus in 2018. Thus, this study aimed to investigate the practice of emergency triage in eleven representative tertiary hospitals in northern China, as well as the current situation and the influencing factors of emergency nurses' triage decision-making ability, to formulate future triage training plans.