Defibrillator With Impedance-Compensated Energy Delivery
AssigneeKoninklijke Philips Electronics N.V.
InventorDavid Snyder
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Abstract
An external defibrillator is described which maintains the durations of phases of a multiphasic shock waveform within or below desired limits. As the duration of a waveform increases for patients of increased patient impedance, the durations of the phases of a multiphasic shock waveform also increase. Before a maximum duration limit is exceeded, the defibrillator adds another phase to the multiphasic waveform which brings the durations of the phases within the desired range or below a maximum duration limit. Both the number of shock phases and the individual phase durations can be controlled in response to measured patient impedance.
Claims18
An external defibrillator comprising:
- an energy source;
- a high voltage circuit coupled to the energy source;
- a pair of patient electrodes coupled to the high voltage circuit;
- a patient characteristic detection circuit coupled to the patient electrodes;
- and
- a phase duration determination circuit, responsive to the patient characteristic detection circuit and coupled to the high voltage circuit which acts to determine the number of phases of the shock pulse produced by the high voltage circuit.
A method for determining the duration of a multiphasic shock waveform delivered by an external defibrillator comprising:
- determining that a shock is advised;
- measuring a patient characteristic;
- determining the number of phases of a shock waveform from the patient characteristic;
- and
- delivering a shock waveform with the determined number of shock waveform phases.
Dependencies are inferred from the claim text.