Can triage correctly stratify cardiogenic syncope in patients admitted to the emergency department for a transitory loss of consciousness?

Abstract

Abstract Background The Manchester Triage System (MTS) is the most popular validated triage system in Europe. It allows the stratification of the large volume of patients admitted to the emergency department (ED) into five increasing risk categories, assigning higher priority to the most serious patients [1]. Purpose To evaluate the effectiveness of the MTS in stratifying patients admitted to the ED for syncopal transitory loss of consciousness (TLOC) and correctly identifying cardiogenic syncope. Methods All patients consecutively evaluated in the ED between 1 January 2017 and 1 July 2019 for a TLOC episode were retrospectively considered. TLOCs were retrospectively classified according to the guidelines of the European Society of Cardiology (ESC) [2]. Syncopal TLOCs were separated from non-syncopal TLOCs. Demographic and baseline characteristics of all patients were recorded. Patients were divided into two groups for comparison according to the MTS code assigned at triage: blue/green/yellow (low priority) versus orange/red (high priority). Considering only syncopal TLOCs, the primary study outcome was the presence of cardiogenic syncope as defined in the ESC guidelines. The performance of the MTS was evaluated using a 2x2 table, deriving sensitivity, specificity and accuracy, and through analysing receiver operating characteristic curves. Sensitivity analyses were also performed on patient subgroups. Results A total of 2,291 patients with TLOC were considered (83% low priority versus 17% high priority). Of these, 90.2% (2,066/2,291) presented syncopal TLOC. Among the patients with syncopal TLOC, 85.7% (1,770/2,066) were assigned a low priority code, while 14.3% (296/2,066) were given high priority. Patients with a high priority code were older (median age 66 versus 77 years; p<0.001), presented more altered vital signs (p<0.001), presented more associated symptoms (p<0.001) and presented more cardiac comorbidities (p<0.001). Overall, cardiogenic syncope was present in 7.5% (154/2,066) of patients with syncopal TLOC. Of these, 55.2% (85/154) were stratified with a low priority code, while 44.8% (69/154) were stratified with a high priority code (p<0.001). The MTS presented a sensitivity of 44.8%, a specificity of 88.1% and an accuracy of 84.9%. The area under the receiver operating characteristic curve for the prioritisation of cardiogenic syncope through MTS codes was 0.683. Sensitivity analyses on specific subgroups of patients, such as those with or without other associated symptoms in triage or major cardiac comorbidities, revealed comparable performance. Conclusions Syncopal TLOC is an insidious clinical condition. Currently, limited information is available about triage systems and the correct prioritisation of syncope. Although the MTS has demonstrated good performance for other cardiac symptoms, its performance is not acceptable for syncopal TLOC [3]. Improvements are needed to optimise triage systems for syncopal TLOC. Funding Acknowledgement Type of funding sources: None.