Pre-clinical trial with external defibrillator

Abstract

AIMS: To evaluate the efficacy of defibrillation in response to induced ventricular fibrillation and to describe the macroscopic changes in porcine hearts after truncated exponential capacitive discharge shock applied by a prototype defibrillator produced in Brazil and a reference, international market leader defibrillator. METHODS: Sixteen pigs were divided into four groups of four animals each, to verify the effectiveness of the defibrillator in response to induced ventricular fibrillation by applying loads of 50 J to 100 J, and assess the safety of the defibrillator by macroscopic analysis of the skin and heart. Erythema, edema, blistering, fluid in the pericardial cavity, burns, and post-shock charred tissue were evaluated. RESULTS: All pigs, after one minute of inducing ventricular fibrillation, developed tachycardia and progressed to ventricular fibrillation. When used low energy, the prototype equipment obtained 25% of success, with one reversed pig, while the reference equipment has obtained a success rate of 50%, with two reversals. However, with energy 100 J, the prototype equipment reestablished sinus rhythm in three pigs (75%) and the reference product only made effective defibrillation in one (25%). The application of 100 J energy was associated with skin burns Grade II in only one pig with the prototype defibrillator and four pigs with the reference equipment. The heart tissue injuries occurred in equal numbers with both defibrillators. CONCLUSIONS: The prototype defibrillator, when applied with 100 J energy, was more effective in reversing ventricular fibrillation and showed less injury than the reference defibrillator with the same energy. This study may help to raise the technological standard and to increase the supply of qualified health equipment produced in Brazil, replacing and/or decreasing imports and providing a secure next-generation device.