Do doctors position defibrillation paddles correctly? Observational study

Defibrillation is necessary to restore normal sinus rhythm in a patient having a ventricular fibrillation arrest. Each minute of delay in restoring sinus rhythm increases mortality by 7-10%.¹ Successful defibrillation requires depolarisation of a critical mass of myocardium, which is most likely to be achieved if the defibrillation paddles are correctly placed. Recent guidelines from the European Resuscitation Council state that the sternal paddle should be placed “below the right clavicle in the mid-clavicular line” and that the apical paddle should be placed “over the left lower ribs in the mid/anterior axillary line.”² The limited literature available and our own observations suggest that these anatomical positions are not adhered to during defibrillation.³ We undertook an observational study to assess paddle positioning during defibrillation.

Methods and results

We recruited 101 doctors of all grades and acute specialties at Southampton General Hospital over a period of two weeks, who were unprepared and unaware of the nature of the study. They were shown an anatomically accurate male resuscitation manikin that they were told was in ventricular fibrillation. They were asked to defibrillate the manikin, which required the initial placement of sternal and apical defibrillation pads on the chest wall, on to which were placed the defibrillation paddles. The position of the centre of the defibrillation pads was recorded by using a grid placed over the chest wall. It was assumed that positions of the pad centre and the paddle centre were anatomically identical. Details of doctors' grade and specialty and the date of any previous instruction on defibrillation technique were also recorded.

Data were collected from 20 consultants, 2 staff grades, 38 registrars, 31 senior house officers, and 10 preregistration house officers. There was no significant difference (determined by analysis of variance) in paddle positioning between different grades or specialties or between those who had received defibrillation instruction within the past three years and those who had not.

Results are shown in the figure. The positions for the sternal and apical paddles specified by the European Resuscitation Council are shown. Sixty five per cent of sternal paddles were placed within 5 cm (approximate radius of a defibrillation paddle) of the position recommended in the guidelines.² Most apical paddles were placed too medially and too cranially, only 22% being placed within 5 cm of the position recommended by the guidelines.²

Comment

Adherence to European Resuscitation Council guidelines for defibrillation paddle position is poor, resulting in incorrect paddle placement, particularly of the apical paddle, by most doctors, irrespective of grade, specialty, or how recently they had been instructed on technique. Apical paddle placement is usually too medial, reducing the separation of the paddles.

Since this study was performed, the International Liaison Committee on Resuscitation (ILCOR) has published guidelines which supersede those of the European Resuscitation Council and which specify even more lateral placement of the apical defibrillation paddle, “to the left of the nipple with the center of the electrode in the mid-axillary line.”⁴ This is the position previously advocated by the American Heart Association.⁵

Incorrect paddle placement will result in a greater percentage of current passing through non-cardiac tissue and will reduce the chances of successful defibrillation through failure to depolarise a critical mass of myocardium. Teaching of advanced life support must place greater emphasis on paddle position if success of defibrillation is to be optimised.

Figure.

Anatomical position of the centre of apical and sternal defibrillation paddles placed by 101 doctors. Positions recommended by the European Resuscitation Council (ERC) and the International Liaison Committee on Resuscitation (ILCOR) are also shown.