Abstract: Systems and methods are provided for simultaneously determining impedances of a plurality of electrophysiological electrodes. Signals are injected into a first electrophysiological electrode and a second electrophysiological electrode, the injected signals differing in at least one of magnitude and phase. A magnitude and phase of an output of a differential amplifier are evaluated, where the differential amplifier is responsive to outputs of the first electrophysiological electrode and the second electrophysiological electrode. An impedance of the first electrophysiological electrode and an impedance of the second electrophysiological electrode are determined based on the magnitude and the phase of the differential amplifier output.

Abstract: An apparatus includes an ultrasound imaging unit integrated into a patient monitoring system continuously generating ultrasound images from a patient and continuously extracting therefrom diagnostic data.

Abstract: An apparatus includes an ultrasound imaging unit integrated into a patient monitoring system continuously generating ultrasound images from a patient and continuously extracting therefrom diagnostic data.

Abstract: Ultrasound energy has been observed to rapidly destroy a large quantity of microbubbles. The duration and intensity of the contrast effect is greatly diminished by conventional imaging frame rates and power levels. Altering the imaging sequence by strategically shooting ultrasound image frames at various transmit powers and reducing the number of transmit lines per frame allows for enhancement of the contrast effect (increasing maximum intensity and duration).

Abstract: An ultrasound transducer apparatus for use with an ultrasound imaging system which includes signal transmission and signal receiving circuitry coupled to the transducer through a cable. The transducer apparatus includes a transducer for converting ultrasonic energy into electronic signals and a variable gain amplifier circuit having an input coupled to the transducer and an output coupled to the cable for amplifying the electronic signals at a gain determined by a gain control signal from the imaging system. The transducer apparatus is typically hand-held, and the variable gain amplifier circuit is preferably mounted in the hand-held unit in close proximity to the transducer element. The variable gain amplifier circuit preferably includes a preamplifier and a variable gain amplifier. Preferably, the transducer is a transducer array including a plurality of transducer elements, each having a preamplifier and a variable gain amplifier associated with it.

Abstract: The surface temperature of tissue adjacent to an ultrasound transducer in an ultrasound imaging probe is determined by a differential measurement technique. A first temperature representative of the temperature of the ultrasound transducer is measured with a first temperature sensor. A second temperature representative of the ambient temperature of the tissue in a region that is thermally isolated from the ultrasound transducer is measured with a second temperature sensor. The surface temperature of the tissue adjacent to the ultrasound transducer is calculated from the first measured temperature and the second measured temperature. The energy transmitted by the ultrasound transducer can be controlled in response to the calculated surface temperature, typically by reducing the transmitted ultrasound energy when the calculated surface temperature exceeds a temperature limit.

Abstract: A defibrillator is described having separate amplifiers for the paddles and the ECG electrodes and means for supplying cardiographic signals to an output amplifier from the amplifier associated with the ECG electrodes when they are properly attached to the patient and for automatically coupling cardiographic signals to the output amplifier from the amplifier associated with the paddles if any combination of the ECG electrodes become improperly attached.

Abstract: Displayed ECG waveforms are maintained within acceptable aspect ratios without rapid fluctuation in amplitude by rapidly decreasing the gain of the signal channel by discrete amounts as the peak-to-peak amplitude of the ECG signal increases through each of a number of levels and by increasing the gain of the signal channel only after the peak-to-peak amplitude of the ECG signals has dropped to a given fraction for a predetermined period of time.

Abstract: In order to lessen the time that the baseline of an oscilloscope is driven off scale after the discharge through the paddles of a defibrillator, means are provided for attenuating the low frequencies in the signals applied to the output amplifier for a short time after the discharge pulse is initiated.