Abstract: An electronic interface module for use with patient monitoring equipment which allows use of the monitoring equipment at the same time that the patient is being treated through the application to his body of electrical stimulating pulses or the like. Body contacting leads used to pick up physiologically generated impulses from the body of the patient are coupled through a suitable amplifier to a sample and hold circuit. The interface module also includes means for generating a control pulse at the onset of a body stimulating impulse which control pulse persists for a predetermined time greater than the period of the stimulating impulse. This control pulse is also applied to the sample and hold circuit. The output from the sample and hold circuit (which may be analog or digital in nature) is, in turn, coupled through suitable matching circuitry to the patient monitoring equipment.

Abstract: An apparatus is disclosed which comprises a photoelectric probe for introducing light pulses into a measurement area and for producing a measurement signal representative of the light as modulated in the measurement area, such modulation including modulations characteristic of the circulatory system blood volume variations of the area. Demodulation circuitry is disclosed which demodulates the meaningful from the non-meaningful data of the measurement signal, and utilization devices responsive to various characteristics of the meaningful data are disclosed, which utilization devices include a pulse wave meter, pulse amplitude meter, pulse rate meter, and tissue perfusion meter.