Abstract: A method for automatically optimizing ultrasonic frequency power applied by a transducer to human tissue while the transducer is energized with ultrasonic signals from an ultrasonic signal generator. The frequency of an ultrasonic energizing signal applied by the ultrasonic signal generator to the transducer is set. The frequency of the energizing signal applied to the ultrasonic signal generator to the transducer is scanned, at reoccurring intervals, through a sequence of frequencies. The optimum level of power from the transducer is monitored as the frequency is scanned. The frequency of the ultrasonic energizing signal applied by the ultrasonic signal generator is ultimately reset, substantially at the frequency that causes the optimum level of power, until the next reoccurring interval.

Abstract: A system is provided for applying ultrasound power to treat human tissue comprising a transducer driven by an oscillating signal from a power amplifier. The transducer and power amplifier have a power-conversion-efficiency characteristic which is a function of the frequency of the oscillating signal and the acoustic load on the transducer. Data sampling and frequency adjustment means are provided which continually monitor the current supplied to the crystal and adjust the frequency of the oscillating signal to maximize the power-conversion-efficiency of the transducer and power amplifier.

Abstract: A cardiac output computer which measures cardiac output by the indicator method involving the estimation of the area under either a thermodilution of a luminous transmission curve with automatic bolus detection. Evaluation of the area under the curve is made relative to a true baseline and is independent of, in the case of thermodilution, blood temperature as of the time the bolus is injected into the patient. A series of blood temperature samples are read and stored with the magnitude of each successive signal compared to the one received immediately before. As soon as a plurality of successive comparisons, preferably five, of six successively acquired blood temperatures indicate monotonically decreasing blood temperature values, a test for monotonicity is confirmed, with the highest temperature of the six being designated as the baseline. Once the test is confirmed the computer proceeds to evaluate the area under the curve.

Abstract: A thermodilution catheter assembly for use in determining cardiac output includes a special connector for joining the catheter to the output computer. Catheter size indicator links housed in the connector automatically communicate the size of the catheter to the computer when the connection is made. As an optional feature, the connector additionally includes means to automatically energize the computer when the connection is made.