Accuracy of ECG Chest Electrode Placements by Paramedics; an observational study

Background The use of the 12-lead ECG is common in UK paramedic practice but its value depends upon accurate placement of the ECG-electrodes. Several studies have shown widespread variation in the placement of chest electrodes by other health professionals but no studies have addressed the accuracy of paramedics. The main objective of this study was to ascertain the accuracy of the chest lead placements by registered paramedics. Methods Registered paramedics who attended the Emergency Services Show in Birmingham in September 2018 were invited to participate in this observational study. Participants were asked to place the chest electrodes on a male model in accordance with their current practice. Correct positioning was determined against the Society for Cardiological Science & Technology’s Clinical Guidelines for recording a standard 12-lead electrocardiogram (2017) with a tolerance of 19mm being deemed acceptable based upon previous studies. Results 52 eligible participants completed the study. Measurement of electrode placement in the craniocaudal and mediolateral planes showed a high level of inaccuracy with 3/52 (5.8%) participants able to accurately place all chest leads. In leads V 1 - V 3 , the majority of incorrect placements were related to vertical displacement with most participants able to identify the correct horizontal position. In V 4 , the tendency was to place the lead too low and to the left of the pre-determined position whilst V 5 tended to be below the expected positioning but in the correct horizontal alignment. There was a less defined pattern of error in V 6 although vertical displacement was more likely than horizontal displacement. Conclusions Our study identified a high level of variation in the placement of chest ECG electrodes which could alter the morphology of the ECG. From a patient safety perspective, we would advocate that paramedics leave the chest electrodes in situ to allow hospital staff to assess the accuracy of the placements. Key messages What is already known on this subject The recording of a prehospital ECG has become increasingly common in sophisticated Emergency Medical Services across the world The accuracy of precordial ECG electrode placement has been studied with other health professionals and has highlighted varying degrees of accuracy. Inaccurate electrode placement can lead to aberrant ECG readings and application of unnecessary treatment or the withholding of indicated treatment What this study adds In this observational cohort study, we found significant variation in the placement of the precordial ECG electrodes by UK registered paramedics We recommend that paramedics leave the prehospital ECG electrodes in situ to allow hospital staff to assess the accuracy of the placements.