According to statistics released by the National Emergency Medical Center in Korea in 2019, more than 10 million patients visited the emergency department (ED) during 2018, which was more than 20% higher than that in 2008 as a result, ED overcrowding is increasing [
1]. As the number of patients who visited the ED increases, ED overcrowding has been pointed out as one of the most important problems [
2]. One of the most important ways to relieve ED overcrowding is by reducing the length of stay of emergency patients [
3,
4]. The ED stay time can be reduced by appropriately classifying the severity of emergency through accurate initial assessment of patients who visit the ED [
5,
6].
Classifying the severity appropriately through initial assessment of patients visiting the ED is a process of determining where to receive treatment [
7]. Accurate patient classification is essential for identifying patients who do not require prior intervention and optimizing emergency medical resources for immediate treatment [
8]. Therefore, triage nurses in charge of initial assessment in the ED should quickly and appropriately categorize the severity of patients visiting the ED. This is one of the most important tasks of ED triage nurses [
9].
For initial assessment and classification tool of emergency patients in Korea, various classification tools were used in each hospital until recently [
10]. In 2012, the Korean Triage and Acuity Scale (KTAS) Committee affiliated with the Korean Society of Emergency Medicine developed KTAS as a Korean type emergency patient classification tool based on Canadian Triage and Acuity Scale (CTAS), Canada’s five-stage classification tool, by modifying and supplementing it to suit the domestic situation [
11]. Since 2016, the law on emergency medical care has been changed. All EDs have been using the KTAS to classify patients visiting the ED [
12]. This severity classification is performed by nurses in the United States [
12]. In most EDs in Korea, nurses perform patient classification through initial evaluation. However, there is a difference in the degree of agreement among triage nurses according to ED experience or clinical experience of nurses who perform the evaluation. Objective evaluation may be difficult in psychological and mental health areas, although respiratory diseases could be objectively evaluated [
9]. In addition, the severity classification may be different because different factors determine the degree of urgency [
13]. Even if there are clear criteria for classification, there might be differences in the severity classification results among evaluators. In one study determining the agreement between nurses and emergency doctors [
14], the Kappa coefficient was 0.659. In addition, there was a significant difference in classification between male and female nurses (
p = .003) [
14]. Another study has assessed the degree of agreement among nurses [
15] and found that the kappa coefficient is 0.79. The kappa coefficient was 0.721 in one study that determined the degree of agreement between nurses and medical students [
16]. In one study that determined the agreement between triage nurses and an expert group consisting of KTAS instructors, the weighted kappa coefficient was 0.77 [
17]. These results are interpreted by Landis & Koch, which shows a ‘substantial agreement’, but there are some differences among evaluators [
18]. As such, differences in severity classification results among triage nurses may occur, and the differences in classification results may cause patient dissatisfaction and threaten patient safety. The agreement of these classification results can be improved by training or applying an algorithm [
13].
Problem-based learning (PBL) is a small group of learning method that enables students to present problems and learn knowledge, skills, and attitudes to solve problems [
19]. This is a learning method that can develop not only knowledge acquisition, but also reasoning ability and critical thinking ability [
19]. In previous studies, after PBL was conducted, learning attitude [
20,
21], critical thinking skill [
22,
23], problem solving [
21,
24], and knowledge [
25,
26] of nursing students and medical students were improved. As such, it is believed that PBL, led by nurses, will help resolve the discrepancy in the severity classification results of ED patients and help improve the patient classification algorithm. However, previous studies that suggested a method to improve the agreement of the severity classification results through PBL were insufficient. It is necessary to confirm whether PBL led by triage nurses using actual patient cases helps to improve the agreement of classification results among triage nurses. Therefore, the purpose of this study is to investigate the effect of PBL led by a triage nurse on the consistency of KTAS classification results of patients who visited the ED.