In this study we evaluated the outcome of cases through the assessment of abnormal physiological signs using the ABCD approach at a telephone triage. In this approach, the outcome of 31% of total cases was either moderate, severe, lethal, or dead. We transferred these cases to the hospital soon by ambulance without taking time to listen to the “patient’s other status indicators. The groupwise analysis found AD, BC, CD, ABD and ABCD groups have a significantly larger proportion of the cases with severity, while C and AB groups significantly smaller, as compared to that in the total cases. Therefore, cases having a combination of the factor D may be predicted to be severe cases. Each of older age, gender male and factor D was significantly associated with cases with severity.
We already showed that 33% of cases, who were assigned to category red by Step 3 (symptom-specific protocols) in the #7119 telephone triage were moderate, severe, lethal, and dead, as in cases with severity according to the definition of this study . Katayama et al. reported that 29.2% of patients transported by ambulance after telephone triage were hospitalized . We share almost the same protocol of telephone triage and prehospital emergency ambulance system as their study in Japan. Patients with our definition of severity will be hospitalized at least (Table 1). In the present study, 31% of the cases were triaged using the ABCD approach (Step 2 in #7119) were the cases with severity and were hospitalized. These facts suggest that, at the telephone triage system in Japan, about 30% of cases, who are assigned to the red category by telephone triage and transported to hospital by ambulance, would be hospitalized at least based on their severity.
Wouters et al reported that telephone triage nurses interpret the vocal - but not worded - elements in communication (paralanguage) such as tone of voice and shortness of breath and create a mental image to compensate for lack of visual information . Croskerry pointed that two fundamental approaches to clinical reasoning have been recognized at a diagnosis. This dichotomy is now widely recognized as dual process theory, as System 1 which is automatic, fast and intuitive, and System 2, which is deliberate, reliable and analytical . In the present study, triage nurses may assess patients with D to have abnormal paralanguage signs using tone of voice and shortness of breath, although they can’t see patients and can’t approach patient’s physical signs. It may indicate that triage nurses could pick up such severe patients by paralanguage signs with System 1 and could dispatch them by ambulance sooner. Further studies involving the analysis of the real records of each consultation are needed to revise the ABCD approach.
Haraldseide et al. reported that male sex was associated with a higher degree of urgent priority than female sex at the consultation, including by telephone and at primary healthcare centers. The urgent priority degree is a decision support tool used to determine response patterns and the degree of urgency at the consultation scene with the Norwegian Index of Emergency Medical Assistance. They discussed that consultation nurses generally perceive men as more urgent cases than women, partially because of symptom presentation . In the present study, male sex was associated with severe outcomes, decided by physicians even after transport to hospital, in cases with red category triaged by telephone triage nurses. Cases of male sex, assigned to the severe category by telephone triage, may be associated with severe medical situation. However, our data does not contain enough information to analyze these sex differences. Therefore, future studies should be conducted based on nurses’ triage decisions to elaborate on sex differences.
This study has a limitation. Unfortunately, we have not yet developed a standard to validate the acuity evaluated in the prehospital setting. Therefore, in order to check the validity of the “acuity,” we had to use a 5-category “severity” scale, including lethal, severe, moderate, mild, and dead upon admission in the ED categories. This is a limitation of this study. We need to discuss how to validate the outcomes of telephone triage referring to other criteria, such as the use of lifesaving interventions , guidelines for intensive care unit admission, discharge, and triage  or therapeutic intervention scoring system [28, 29].