The German Version of the Manchester Triage System and its quality criteria--first assessment of validity and reliability

Abstract

Background: The German Version of the Manchester Triage System (MTS) has found widespread use in EDs across German-speaking Europe. Studies about the quality criteria validity and reliability of the MTS currently only exist for the English-language version. Most importantly, the content of the German version differs from the English version with respect to presentation diagrams and change indicators, which have a significant impact on the category assigned. This investigation offers a preliminary assessment in terms of validity and inter-rater reliability of the German MTS.

Methods: Construct validity of assigned MTS level was assessed based on comparisons to hospitalization (general / intensive care), mortality, ED and hospital length of stay, level of prehospital care and number of invasive diagnostics. A sample of 45,469 patients was used. Inter-rater agreement between an expert and triage nurses (reliability) was calculated separately for a subset group of 167 emergency patients.

Results: For general hospital admission the area under the curve (AUC) of the receiver operating characteristic was 0.749; for admission to ICU it was 0.871. An examination of MTS-level and number of deceased patients showed that the higher the priority derived from MTS, the higher the number of deaths (p<0.0001 / χ² Test). There was a substantial difference in the 30-day survival among the 5 MTS categories (p<0.0001 / log-rank test).The AUC for the predict 30-day mortality was 0.613. Categories orange and red had the highest numbers of heart catheter and endoscopy. Category red and orange were mostly accompanied by an emergency physician, whereas categories blue and green were walk-in patients. Inter-rater agreement between expert triage nurses was almost perfect (κ = 0.954).

Conclusion: The German version of the MTS is a reliable and valid instrument for a first assessment of emergency patients in the emergency department.

Figure 1. Receiver operating characteristic curves for MTS and general hospital admission.

Area under the curve 0.749 (95% CI 0.744 to 0.754).

Figure 2. Receiver operating characteristic curves for MTS and admission to an ICU.

Area under the curve 0.871 (95% CI 0.864 to 0.879).

Figure 3. ED length of stay by MTS category.

The box plots indicate the median (black line), the interquartile range (box), the smallest and largest values that are not considered outliers (whiskers, not farther away than 1.5 times the interquartile range from the first and third quartile, respectively), and values that are considered outliers (empty dots).

Figure 4. Hospital length of stay by MTS level.

The box plots indicate the median (black line), the interquartile range (box), the smallest and largest values that are not considered outliers (whiskers, not farther away than 1.5 times the interquartile range from the first and third quartile, respectively), and values that are considered outliers (empty dots).

Figure 5. Kaplan-Meier survival curve of 30-Day likelihood of survival.

Each line represents the Kaplan-Meier survival estimate for an MTS category.

Figure 6. Time dependent ROC-Curve for MTS and 30-day likelihood of survival.

Area under the curve 0.613.

Figure 7. Kaplan-Meier survival curve of 30-Day likelihood of survival (subgroup cardiac patients).

Each line represents the Kaplan-Meier survival estimate for an MTS category.

Figure 8. Kaplan-Meier survival curve of 30-Day likelihood of survival (subgroup surgical patients).

Each line represents the Kaplan-Meier survival estimate for an MTS category.

Figure 9. Patient allocation by MTS level.

Helicopter and NEF are specially equipped emergency vehicles accompanied by an emergency physician (German Notarzt). Less ill patients are brought to the ED by paramedics and ambulances (German KTW / RTW). Category red and orange were mostly associated with prehospital contact to a doctor.