The authors believe that single-parameter calling adds value as it does not rely upon the
calculation of an EWS, can be easily indicated on the standardised vital sign chart, and,
over time, the values of the ‘blue zone’ parameters will become more familiar to medical &
nursing staff. In the authors’ own DHB, the attendance of the MET at the bedside of
patients breaching these parameters, has been a significant factor in the reduction of
patients progressing to cardiac arrest and death. Since the introduction of EWS with a
mandatory escalation pathway, the incidence of cardiac arrests have decreased by 30%
each year for the last 3 years; in-patient cardiac arrests are now a relatively rare event.