James M Pihl

US Patent:

47858125, Nov 22, 1988

Filed:

Nov 26, 1986

Appl. No.:

6/935248

Inventors:

James M. Pihl - Bothell WA
Denny C. Edwards - Bellevue WA

Assignee:

First Medical Devices Corporation - Bellevue WA

International Classification:

A61N 136

US Classification:

128419D

Abstract:

A protection circuit for a defibrillator that prevents a defibrillator pulse from being generated if the impedance between the defibrillator's electrode leads is not characteristic of the impedance between a pair of defibrillator electrodes properly connected to the defibrillator. The impedance measuring circuit applies a current to the electrode leads and the resulting voltage is measured to provide an indication of the electrode's impedance. The current is applied between the electrodes at about 33 kHz to approximate the impedance between a pair of defibrillator electrodes during a defibrillation pulse. The output of the measurement circuit is converted to an 8 bit word by an analog-to-digital converter and read by a microprocessor which compares the measured impedance to various impedance values in order to either generate an enable signal for the defibrillator or display messages indicative of open or short circuited electrode leads or a patient monitoring electrode connected to the electrode leads. the impedance measurement circuit operates in either of two ranges which are selected by the microprocessor on the basis of the measured impedance values.

US Patent:

48703419, Sep 26, 1989

Filed:

Aug 3, 1988

Appl. No.:

7/228330

Inventors:

James M. Pihl - Bothell WA
Denny C. Edwards - Bellevue WA

Assignee:

First Medical Devices Corporation - Bellevue WA

International Classification:

A61N 100
H05G 0000

US Classification:

324 57R

Abstract:

A protection circuit for a defibrillator that prevents a defibrillator pulse from being generated if the impedance between the defibrillator's electrode leads is not characteristic of the impedance between a pair of defibrillator electrodes properly connected to the defibrillator. The impedance measuring circuit applies a current to the electrode leads and the resulting voltage is measured to provide an indication of the electrode's impedance. The current is applied between the electrodes at about 33 kHz to approximate the impedance between a pair of defibrillator electrodes during a defibrillation pulse. The output of the measurement circuit is converted to an 8 bit word by an analog-to-digital converter and read by a microprocessor which compares the measured impedance to various impedance values in order to either generate an enable signal for the defibrillator or display messages indicative of open or short circuited electrode leads or a patient monitoring electrode connected to the electrode leads. The impedance measurement circuit operates in either of two ranges which are selected by the microprocessor on the basis of the measured impedance values.

US Patent:

57139253, Feb 3, 1998

Filed:

Jan 11, 1996

Appl. No.:

8/585159

Inventors:

Joseph L. Sullivan - Kirkland WA
Bret R. Warrick - Graham WA
James M. Pihl - Woodinville WA

Assignee:

Physio-Control Corporation - Redmond WA

International Classification:

A61N 136
A61N 139
A61N 1362

US Classification:

607 4

Abstract:

An adapter for connecting combination electrodes to a defibrillator/monitor/pacer. The adapter isolates the pacer from the defibrillator when a defibrillation pulse is applied over the combination electrodes. In a first embodiment of the adapter, the pacer is conductively connected to the combination electrodes only when the pacer's power supply is turned on. In a second embodiment of the adapter, the pacer is normally connected to the combination electrodes, but is disconnected when the defibrillator/monitor/pacer is analyzing a patient's ECG or when the defibrillator is charging to enable it to deliver a defibrillation pulse. Also provided in the adapter is a contact assembly for connecting the adapter to defibrillation paddles from the defibrillator.