The Brigham and Women's Hospital, Inc.

Daniel B Raemer

Stephen A Raymond

James H Philip

Gary R Strichartz

Martyn A Vickers, Jr

David R Walt

Christianne Munkholm

An adaptive controller for delivering a fractional amount of oxygen to a patient. The controller utilizes an oximeter coupled by a non-invasive sensor to the patient for measuring the blood hemoglobin saturation in the patient. The oximeter generates a plurality of blood saturation output signals over a given period of time which are sequentially representative of the patient's blood hemoglobin saturation. A processing means evaluates a plurality of the oximeter output signals and, based on the evaluation, provides a pseudo blood saturation signal. A feedback control means responsive to the pseudo output signal sets the fractional amount of oxygen to be delivered to the patient. When deviations of the oximeter output signal are excessive, the pseudo output signals cause a gradual increase in the fractional amount of oxygen for the patient. Furthermore, the feedback control means is periodically disconnected, and the response of the patient to random changes in the fractional amount of oxygen delivered to the patient is used to adapt the response characteristics of the feedback control means in a manner tailored to the needs of the patient.

Closed-loop non-invasive oxygen saturation control system

The present invention is directed to a method and apparatus for locating and identifying the function of specific peripheral nerves. In one embodiment, the present invention takes the form of a nerve stimulator which is used to locate nerves to assist in the administration of regional anesthesia. In another embodiment, the nerve stimulator is used to locate, identify the function of, and guard against the inadvertent cutting of specific nerves during surgical procedures. The apparatus of the present invention includes a stimulus delivery means, a response-detecting means and a means for automatically modulating the magnitude of the stimulus.

Apparatus for locating a nerve and for protecting nerves from injury

Method for locating a nerve and for protecting nerves from injury during

The invention relates to a CO.sub.2 detector for the detection of CO.sub.2 in respiratory gases. In particular, the invention relates to medical devices which contain a CO.sub.2 detector disposed within the devices to allow detection of CO.sub.2 within respiratory gases. The invention also relates to a method for determining the proper placement of an intubation device comprising inserting a tracheal tube having a CO.sub.2 detector disposed within, and observing whether the CO.sub.2 detector changes color in response to the CO.sub.2 which is present in respiratory gases. The CO.sub.2 detectors of the invention comprise a pH sensitive dye and a solid phase support. The CO.sub.2 detectors of the invention may further comprise a phase transport enhancer which allows the CO.sub.2 detector to respond contemporaneously with the presence or absence of CO.sub.2 in a respiratory gas on a breath by breath basis.

CO.sub.2 indicator and the use thereof to evaluate placement of tracheal

An improved method and apparatus for apnea detection is disclosed which features an infrared source and detector pair disposed on opposite sides of a cuvette through which the gas stream inhaled and exhaled by a patient is passed. The amount of CO.sub.2 in the exhaled stream is compared with that in the inhaled stream. Where the difference is greater than a predetermined amount, a breath is taken to be detected, thus avoiding the necessity of calibration of the apparatus against any absolute reference standard. The apparatus is disclosed in an inexpensive, readily manufacturable embodiment which is nevertheless highly immune to noise and highly sophisticated in the signal processing circuitry employed in detection of breathing. The apparatus additionally provides signals indicating obstruction in or detachment of the lines connecting the patient to the apparatus.

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Brookline, MA, United States of America

Daniel B Raemer