Reliability of the Cardiff Test of basic life support and automated external defibrillation version 3.1

The introduction of the European Resuscitation Guidelines (2000) for cardiopulmonary resuscitation (CPR) and automated external defibrillation (AED) prompted the development of an up-to-date and reliable method of assessing the quality of performance of CPR in combination with the use of an AED. The Cardiff Test of basic life support (BLS) and AED version 3.1 was developed to meet this need and uses standardised checklists to retrospectively evaluate performance from analyses of video recordings and data drawn from a laptop computer attached to a training manikin. This paper reports the inter- and intra-observer reliability of this test. Data used to assess reliability were obtained from an investigation of CPR and AED skill acquisition in a lay responder AED training programme. Six observers were recruited to evaluate performance in 33 data sets, repeating their evaluation after a minimum interval of 3 weeks. More than 70% of the 42 variables considered in this study had a kappa score of 0.70 or above for inter-observer reliability or were drawn from computer data and therefore not subject to evaluator variability. 85% of the 42 variables had kappa scores for intra-observer reliability of 0.70 or above or were drawn from computer data. The standard deviations for inter- and intra-observer measures of time to first shock were 11.6 and 7.7 s, respectively. The inter- and intra-observer reliability for the majority of the variables in the Cardiff Test of BLS and AED version 3.1 is satisfactory. However, reliability is less acceptable with respect to shaking when checking for responsiveness, initial check/clearing of the airway, checks for signs of circulation, time to first shock and performance of interventions in the correct sequence. Further research is required to determine if modifications to the method of assessing these variables can increase reliability.