Validation of a physiological track and trigger score to identify developing critical illness in haematology patients

Summary 

Objective

To validate two physiological track and trigger systems; the early warning score (Morgan et al., 1997) and the trust observation chart on a haematology unit. The study aimed to determine whether either of these systems could be used to identify developing critical illness in haematology.

Research design

A prospective validation study where all patients’ physiological observations were recorded, the level of care they were receiving assessed and after data collection finished, the triggers and EWS calculated.

Setting

A haematology unit in an inner London hospital.

Results

71 patients took part in the study; 17 of these became critically ill. The sensitivity of both systems compared favourably with other studies. However, specificity was lower. This will mean a number of false negative results within this patient group.

Conclusion

The study concluded that the systems are useful adjuncts to identify developing critical illness in haematology patients but cannot be used in isolation due to the high number of false negative results that occur. Any plan to introduce either system should acknowledge the increase in workload that will result.

Keywords: Physiological track and trigger score, Early warning score, Validation, Sensitivity and specificity