Abstract: The method and system for detecting occlusion in a fluid line upstream of a pump concerns a fluid pump with a pump cycle in which the upstream pressure of the fluid line is communicated to the downstream portion of the fluid line. A pressure sensor located downstream of the pump is capable of measuring a relatively large negative-going pressure in the fluid line. A signal is generated to indicate occlusion based upon detection of negative-going pressure.

Abstract: An electronic method and apparatus for automatically determining systolic and diastolic blood pressures and heart rate by accurately detecting, verifying and evaluating the full stream of korotkoff sounds produced as electrical signals from a microphone in a cuff occluding the brachial artery of a patient and the corresponding blood pressure pulse signals which accompany and are precursors to genuine korotkoff sound signals. Blood pressure is measured with the aid of a programmed data processor such as a microprocessor.

Abstract: An improved method and apparatus for parenteral administration of medical fluids, wherein a normally shut-off intravenous feeding tube is selectively opened at a frequency and open period duration automatically regulated by a digital control system to establish a fluid flow rate at any selected rate over a wide dynamic range. Measured and desired flow rates are converted to digital electrical signals and compared, the electrical difference being used to vary a control voltage which establishes the width of energizing pulses controlling a member for opening the feeding tube. The frequency of the energizing pulses is preferably a non-integral multiple of the desired drop flow rate and varies from a very high ratio, e.g. 15.5, at very low flow rates to a much smaller ratio, e.g. 2.5, at very high flow rates.

Abstract: An electronic method and apparatus for automatically determining systolic and diastolic blood pressure and heart rate by accurately detecting, verifying and evaluating the full stream of korotkoff sounds produced as electrical signals from a microphone in a cuff occluding the brachial artery of a patient. Waveform analysis is first performed upon the incoming signal waveforms by an analog prescreening subsystem to initially separate true korotkoff sound signals from a variety of artifact and noise signals and to provide an output pulse stream correctly indicating korotkoff sound occurrences in the time and blood pressure domain, with each pulse proportional in amplitude to the amplitude of the corresponding korotkoff sound represented.

Abstract: A syringe pump operated by a stepping motor to repetitively fill and empty a syringe cartridge over a plurality of operational cycles of successive fill stroke and pump stroke periods. The motor is driven by drive pulses from a digital pulse generation and control system, the pulse frequency establishing a predetermined fixed rate of fill during the fill stroke and being preselected, in accordance with desired output flow rate, to establish the rate at which the syringe is emptied during the pump stroke. The drive pulse rate during a fill stroke exceeds the maximum pulse rate during a pump stroke and, in order to maintain a proportional relationship between the preselected pumping rate and the actual pumping rate over each complete cycle of successive fill and pump strokes, the drive pulse frequency during each pump stroke is automatically increased to compensate for the time lost during each fill stroke.

Abstract: A digital system wherein a wide variety of different electromechanical output control devices, e.g., stepping motor pump or solenoid actuated I.V. tube pincher, is driven by electrical output pulses of varible frequency and pulse width from a digital pulse generation and control system, the frequency and pulse width of the output pulses being selected and controlled by the system to establish drop flow rates with digital precision over an extremely wide dynamic range. Pulse width is determined by the relative states of a pair of digital counters in a digital memory, frequency being determined by a high, preferably non-integral, multiple of the desired drop flow rate. The equivalent of negative pulse width in the digital memory can be effectively utilized to expand the effective dynamic range of the memory for specified types of electromechanical output devices. A start up subsystem temporarily presets the initial pulse rate and speeds up early regulation.

Abstract: An electronic method and apparatus for measuring temperatures by means of a thermistor in one arm of an electrical bridge, bridge output being varied by the on and off duty cycle of a shunting impedance selectively switched into and out of the balancing arm of the bridge in accordance with the relative states of a counting display register and a cyclically scanned counting register, the display register state being altered by gated pulses, under the control of bridge output, to provide a digital indication of measured temperature. Bridges of both the nulling and non-nulling types are disclosed using either a dual ramp integrator or conventional detector acting upon bridge output to provide an impedance measurement subsystem independent of reference supply voltage and also enabling non-linear analog to digital conversion to compensate for a non-linear thermistor temperature vs. thermistor resistance characteristics, without sacrificing measurement sensitivity.