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Is the orientation of the apical defibrillation paddle of importance during manual external defibrillation ? OBJECTIVE Transthoracic impedance ( TTI ) is a factor determining the magnitude of the transmyocardial current during external defibrillation . Minimising TTI increases the chances of successful defibrillation . Most external defibrillation paddles are rectangular in shape and can , therefore , be placed in a transverse or longitudinal orientation . The apical paddle is often placed in a transverse orientation . This may theoretically result in a higher TTI than a longitudinal orientation because of poorer contact at the lateral paddle edges . We compared TTI with the apical paddle in both a transverse and longitudinal orientation . MATERIALS AND METHODS Twenty sequential anaesthetised patients were studied . A pair of defibrillator paddles were instrumented to measure paddle force . TTI was recorded pre-operatively at end-expiration with the apical paddle in both longitudinal and transverse orientations . The sternal paddle was placed in a longitudinal orientation for all measurements . RESULTS TTI decreased in both transverse and longitudinal orientations as paddle force increased . Transverse paddle orientation resulted in a significantly ( P < 0.01 ) higher TTI than longitudinal orientation at all paddle forces below 12 kg force . CONCLUSION The longitudinal orientation of a rectangular defibrillation paddle provides a lower TTI than orientation horizontally .
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Intervention_Physical
manual external defibrillation
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Intervention_Physical
external defibrillation
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Intervention_Physical
defibrillator paddles
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Intervention_Physical
Transverse paddle orientation
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Outcome_Other
Transthoracic impedance ( TTI )
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Outcome_Other
paddle force .
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Outcome_Physical
TTI