- Poster presentation
- Open Access
Understanding vital-sign abnormalities in critical care patients
© BioMed Central Ltd. 2010
- Published: 1 March 2010
- Respiratory Rate
- Vital Sign
- Critical Event
- Bivariate Gaussian Distribution
- Medical Emergency Team
We have previously shown how a data fusion index, based on the integration of vital signs continuously monitored in a step-down unit (SDU), can identify the cardiorespiratory instability that often precedes adverse events . We show how the correlations between vital signs, captured in a data fusion index based on a probabilistic model of normality , change during times of cardiorespiratory instability.
An observational study was carried out in a 24-bed SDU, in which vital signs from 326 patients were continuously recorded . The existing standard of care used single-channel Medical Emergency Team (MET) activation criteria to determine when individual vital signs became abnormal. Retrospective evaluation of the continuous vital sign data identified that MET criteria were exceeded on 238 nonartefactual occasions. One hundred and eleven of these were indicative of sufficient cardiorespiratory instability that they should have required an MET call (critical events). Vital-sign dynamics during these events were compared with data from stable periods, using order statistics and covariance analysis.
Dynamics and correlations that exist in vital signs during periods of stability change significantly during periods of abnormality. A statistical approach that integrates vital signs and captures correlations between them will be sensitive to cardiorespiratory deterioration.