Worthing physiological scoring system: derivation and validation of a physiological early-warning system for medical admissions. An observational, population-based single-centre study

Background. Several physiological scoring systems (PSS) have been proposed for identifying those at risk of deterioration. However, the chosen specific physiological values chosen and the scores allocated have not been prospectively validated. In this study, we investigate the relative contributions of the ventilatory frequency, heart rate, arterial pressure, temperature, oxygen saturation, and conscious level to mortality in order to devise a robust scoring system. All data were collected on admission to the emergency unit. Precise 'intervention-calling scores' could then be derived to trigger interventions. Methods. Our observational, population-based single-centred study took place in a 602-bedded district general hospital. Patients admitted to the emergency care unit at Worthing general hospital during an initial study period between July and November 2003 (n=3184) and a further validation period between October and November 2005 (n=1102) were included. Results. Multivariate logistic regression analysis demonstrated that a ventilatory frequency > 20 min(-1), heart rate >= 102 min(-1), systolic blood pressure <= 99 mm Hg, temperature >= 35.3 degrees C, oxygen saturation <= 96%, and disturbed consciousness were associated with an increase in mortality. The Worthing PSS was developed from the regression coefficients associated with each variable. The model showed good discrimination with an area under the receiver operating characteristic curve, 0.74, excluding age as a variable. The discrimination of this system was significantly better than the early-warning scoring system. Conclusions. A simple validated scoring system to predict mortality in medical patients with precise 'intervention-calling scores' has been developed.