Alan Murray1, John Kellett2, Wendy Huang3, Simon Woodworth4, Fei Wang3. 1. Dundalk Institute of Technology, Dundalk, Ireland. 2. Thunder Bay Regional Health Sciences Center, Thunder Bay, Ontario, Canada. Electronic address: jgkellett@eircom.net. 3. Department of Mathematical Sciences, Lakehead University, Thunder Bay, Ontario, Canada. 4. Health Information Systems Research Center, University College Cork, Ireland.
Abstract
BACKGROUND: It is not known how often, to what extent and over what time frame any early warning scores change, and what the implications of these changes are. SETTING: Thunder Bay Regional Health Sciences Center, Ontario, Canada. METHODS: The averaged vital signs measured over different time periods of 44,531 consecutive acutely ill medical admissions were determined and then combined to calculate the averaged abbreviated version of the Vitalpac early warning score (AbEWS) during each time period examined. RESULTS: 18% of all in-hospital deaths within 30 days are in patients with a low AbEWS on admission. Those admitted with a low AbEWS are more likely to increase their score and those admitted with a high score are more likely to lower it. Paradoxically, patients who have an averaged score over the first 6h in hospital that is lower than on admission have increased in-hospital mortality. Thereafter patients with an increase in the averaged score have almost twice the mortality of those with a decreased score. 4.7% of patients have a low averaged score on the day they die. CONCLUSION: AbEWS, without clinical judgment, cannot be used to detect those patients who do not need to be admitted to hospital or are suitable for discharge. A period of observation of at least 12h is required before the trajectory of AbEWS is of prognostic value, and any "improvement" that occurs before this time may be illusory.
BACKGROUND: It is not known how often, to what extent and over what time frame any early warning scores change, and what the implications of these changes are. SETTING: Thunder Bay Regional Health Sciences Center, Ontario, Canada. METHODS: The averaged vital signs measured over different time periods of 44,531 consecutive acutely ill medical admissions were determined and then combined to calculate the averaged abbreviated version of the Vitalpac early warning score (AbEWS) during each time period examined. RESULTS: 18% of all in-hospital deaths within 30 days are in patients with a low AbEWS on admission. Those admitted with a low AbEWS are more likely to increase their score and those admitted with a high score are more likely to lower it. Paradoxically, patients who have an averaged score over the first 6h in hospital that is lower than on admission have increased in-hospital mortality. Thereafter patients with an increase in the averaged score have almost twice the mortality of those with a decreased score. 4.7% of patients have a low averaged score on the day they die. CONCLUSION: AbEWS, without clinical judgment, cannot be used to detect those patients who do not need to be admitted to hospital or are suitable for discharge. A period of observation of at least 12h is required before the trajectory of AbEWS is of prognostic value, and any "improvement" that occurs before this time may be illusory.