Layperson positioning of defibrillation electrodes guided by pictorial instructions

Correct positioning of defibrillation electrodes is essential to achieve sufficient transmyocardial current to depolarize a critical mass of myocardium, and thus terminate ventricular fibrillation (VF).

To evaluate the pictures on the self-adhesive defibrillation electrodes in guiding laypersons to place the electrodes in the recommended position.

Defibrillation electrodes from five manufactures (Access Cardio Systems, Schiller, Medtronic, Cardiac Science and Philips) were included in the study and compared with electrodes with a lateral view picture, designed for the study, showing the placement of the apical electrode. A total of 150 laypersons without any experience or training in use of a defibrillator participated in the study. The participants placed randomly selected electrodes on the chest of a resuscitation manikin without any guidance apart from the pictures on the electrodes. The distances of the electrodes from the recommended positions were measured.

The proportion of participants who placed both electrodes within 5 cm from recommended position varied from 8% to 36% with the different electrodes. Usually, the apical electrode was placed too anteriorly. Electrodes placed with help of the lateral instruction picture, (designed for the study), showing the placement of the apical electrode were placed significantly more often within 5 cm than any of the others (64%, 95% confidence interval 44-80, P < 0.05).

The current practice in designing pictures on the electrodes does not seem to be optimal in showing the recommended position of the apical electrode as recommended by Guidelines 2000. It is suggested that by showing a lateral view in the instructions, success in placing the apical electrodes correctly can be improved.