Laerdal Manufacturing Corporation

Jonathan M Benson

Helge Fossan

A defibrillator utilizes at least one flash tube for switching electrical energy from an energy source to a heart patient. The flash tube has a high impedance state in which the patient is isolated from the energy. In response to a triggering pulse, the flash tube enters a low impedance state in which energy is delivered to the patient. An additional switching element in the defibrillator operates to interrupt energy delivery through the flash tube so that a truncated defibrillation pulse having a desired energy level is produced.

Truncated pulse defibrillator with flash tube switch

A pulse delivery control signal is applied to and removed from a master or pulse delivery electronic switch to respectively start and terminate the delivery of a trapezoidal waveform defibrillation pulse from charge storage capacitors to a patient. In one specific embodiment, a transfer charge storage circuit is coupled to a capacitor charging circuit for charging as the charge storage capacitors are charged. A transfer switch interconnects the transfer charge storage circuit to a first field-effect transistor switch. In response to a transfer signal, a transfer voltage signal is delivered from the transfer charge storage circuit, through the transfer switch and to the first field-effect transistor. In response, the first field-signal transistor applied the pulse delivery control signal to the master switch. A second field-effect transistor may be included for operating the master switch together with the first field-effect transistor. Voltage detection and energy selection circuits may be employed for detecting when the charge storage capacitors in the circuit are charged to a desired level and for establishing the level to which the capacitors are charged to thereby control the energy delivered by the defibrillation pulses.

Growing community of inventors

Oregon City, OR, United States of America

Jonathan M Benson