An evaluation of activation and implementation of themedical emergency team system

Abstract

Problem investigated:The activation and implementation of the Medical Emergency Team (MET)system.Procedures followed:The ability of the objective activation criteria to accurately identify patients atrisk of three serious adverse events (cardiac arrest, unexpected death andunplanned intensive care admission) was assessed using a nested, matchedcase-control study. Sensitivity, specificity and Receiver OperatingCharacteristic curve (ROC) analyses were performed.The MET implementation process was studied using two convenience samplesurveys of the nursing staff from the general wards of twelve interventionhospitals. These surveys measured the awareness and understanding of theMET system, level of attendance at MET education sessions, knowledge of theactivation criteria, level of intention to call the MET and overall attitude to theMET system, and the hospital level of support for change, hospital capabilityand hospital culture. The association of these measures with the intention tocall the MET and the level of MET utilisation was assessed using nonparametriccorrelation.Results obtained:The respiratory rate was missing in 20% of subjects. Using listwise deletion, theset of objective activation criteria investigated predicted an adverse eventwithin 24 hours with a sensitivity of 55.4% (50.6-60.0%) and specificity of93.7% (91.2-95.6%). An analysis approach that assumed the missing valueswould not have resulted in MET activation provided a sensitivity of 50.4% (45.7-55.2%) and specificity of 93.3% (90.8-95.3%). Alternative models with modifiedcut-off values provided different results.The MET system was implemented with variable success during the MERITstudy. Knowledge and understanding of the system, hospital readiness, and apositive attitude were all significantly positively associated with MET systemutilisation, while defensive hospital cultures were negatively associated withthe level of MET system utilisation.Major conclusions:The objective activation criteria studied have acceptable accuracy, butmodification of the criteria may be considered. A satisfactory trade-off betweenthe identification of patients at risk and workload requirements may be difficultto achieve.Measures of effectiveness of the implementation process may be associatedwith the level of MET system utilisation. Trials of the MET system shouldensure good knowledge and understanding of the system, particularly amongstnursing staff