Physio-control, Inc.

Other

Medtronic Physio-control Corp.

Robert Eugene Smith

Stephen J Prosser

Darrell Orvin Wagner

Karl F Gauglitz

Peter W Cheung

Scott W Hunsaker

Lee R Mason

Richard C Nova

Gregory Vincent Browne

David R Hampton

Ryan David Lee

Kathleen E Briscoe

A system capable of self-adjusting both sound level and spectral content to improve audibility and intelligibility of electronic device audible cues. Audible cues are stored as sound files. Ambient noise is detected, and the output of the audible cues is altered based on the ambient noise. Various embodiments include processed sound files that are more robust in noisy environments.

Variable sound system for audio devices

A system capable of self-adjusting both sound level and spectral content to improve audibility and intelligibility of medical device audible cues. Audible cues are stored as sound files. Ambient noise is detected, and the output of the audible cues is altered based on the ambient noise. Various embodiments include processed sound files that are more robust in noisy environments.

Variable sound system for medical devices

Embodiments of the present concept are directed to medical devices having features that prevent contaminants from infiltrating the housing of the device while providing a mechanism to provide clear auditory sounds to aid a rescuer in providing care to a patient. In one example, a medical device includes a housing having a transmission area associated with an enclosed voice coil. An exterior diaphragm formed integrally with the housing surrounds the transmission area and provides a watertight seal of the transmission area. In addition, the diaphragm is structured to generate a sound that can be heard by the rescuer from the voice coil.

Medical device with speaker having exterior diaphragm

An event reporting program ( ) is provided which electronically records information critical to reconstructing events occurring during an emergency incident. The event reporting program ( ) includes an event recording component ( ) for recording events as they occur during the incident, and a post-processing component ( ) for further processing the events recorded by the event recording component after completion of the incident. The event recording component ( ) enables an emergency service provider to input a plurality of event records ( ) describing each event as it occurs and the time at which each event takes place. The event recording component also enables an emergency service provider to input a predefined protocol of expected event records. Each expected event record ( ) identifies an event which is expected to occur during the incident and a time at which the event is expect to occur. Finally, the event recording component also includes a number of tools for providing and/or recording information in addition to the event records to the emergency service provider, e.g., an address book, drug guidelines, a narrative recorder, etc. The post-processing component ( ), on the other hand, enables the user to modify or add to the event records ( ) and other information previously recorded by the event recording component. In addition, the post-processing component ( ) exports event records ( ) to and imports event records ( ) from external devices, such as a remote computer or medical electronic device. Finally, the post-processing component ( ) generates a run report including the recorded event records ( ) and information related to the incident.

Method and apparatus for reporting emergency incidents

Under the present invention, a method and apparatus are provided for compensating for the effect temperature variations have on the wavelength of light emitted by the oximeter sensor light source (40, 42). In pulse oximetry, LEDs (40, 42) are typically employed to expose tissue to light at two different wavelengths. The light illuminating the tissue is received by a detector (38) where signals proportional to the intensity of light are produced. These signals are then processed by the oximeter circuitry to produce an indication of oxygen saturation. Because current oximetry techniques are dependent upon the wavelengths of light emitted by the LEDs (40, 42), the wavelengths must be known. Even when predetermined combinations of LEDs (40, 42) having relatively precise wavelengths are employed, variations in the wavelength of light emitted may result. Because the sensor (12) may be exposed to a significant range of temperatures while in use, the effect of temperature on the wavelengths may be significant. To compensate for this effect, a temperature sensor (50) is included in the sensor (12) to produce a signal indicative of sensor temperature. This signal is interpreted by the oximeter circuitry including, for example, a microcomputer (16), where the effect of temperature on wavelength is compensated for. In a preferred arrangement, this compensation takes the form of a computation of an alternative calibration curve from which the oxygen saturation is indicated, given a particular processing of signals from the detector (38).

Apparatus for the automatic calibration of signals employed in oximetry

Under the present invention, a method and apparatus are provided for compensating for the effect temperature variations have on the wavelength of light emitted by the oximeter sensor light sources (40, 42). In pulse oximetry, LEDs are typically employed to expose tissue to light at two different wavelengths. The light illuminating the tissue is received by a detector (38) where signals proportional to the intensity of light are produced. These signals are then processed by the oximeter circuitry to produce an indication of oxygen saturation. Because current oximetry techniques are dependent upon the wavelengths of light emitted by the LEDs (40-42), the wavelengths must be known. Even when predetermined combinations of LEDs (40-42) having relatively precise wavelengths are employed, variations in the wavelength of light emitted may result. Because the sensor (12) may be exposed to a significant range of temperatures while in use, the effect of temperature on the wavelengths may be significant. To compensate for this effect, a temperature sensor (50) is included in the sensor (12) to produce a signal indicative of sensor temperature. This signal is interpreted by the oximeter circuitry including, for example, a microcomputer (16), where the effect of temperature on wavelength is compensated for. In a preferred arrangement, this compensation takes the form of a computation of an alternative calibration curve from which the oxygen saturation is indicated, given a particular processing of signals from the detector (38).

Method and apparatus for the automatic calibration of signals employed

A feedback control system is disclosed for use in processing signals employed in pulse transmittance oximetry. The signals are produced in response to light transmitted through, for example, a finger at two different wavelengths. Each signal includes a slowly varying baseline component representing the relatively fixed attenuation of light produced by bone, tissue, skin, and hair. The signals also include pulsatile components representing the attenuation produced by the changing blood volume and oxygen saturation within the finger. The signals are processed by the feedback control system before being converted by an analog-to-digital (A/D) converter (72) for subsequent analysis by a microcomputer (16). The feedback control system includes a controllable offset subtractor (66), a programmable gain amplifier (68), controllable drivers (44) for the light sources (40, 42), and the microcomputer (16). The microcomputer (16) receives signals from the offset subtractor (66), gain amplifier (68), drivers (44) and A/D converter (72) to produce signals that control the function of the subtractor (66) and drivers (44) in the following manner. Normally, the drivers ( 44) are maintained within a predetermined current range. In the event the microcomputer (16) senses an output from the converter (72) that is not within a predetermined range, the drive signal is adjusted to produce an acceptable signal. The magnitude of the offset removed by the subtractor (66), as controlled by the microcomputer (16), is maintained at a constant level when the converter (72) output is within a first predetermined range and is a predetermined function of the converter (72) output when that output falls within a second predetermined range.

Method and apparatus for offsetting baseline portion of oximeter signal

The disclosed invention is for use in extracting more accurate information from signals employed in pulse oximetry. Basically, pulse oximetry involves the illumination of arterial blood flowing in tissue with light at two wavelengths. Upon emerging from the tissue the light is received by a detector (38) that produces signals that are proportional to the intensity of the light received at each of the wavelengths. Each signal includes a slowly varying baseline component representing the attenuation .beta.(t) of light produced by bone, tissue, skin, and hair. The signals also include pulsatile components representing the attenuation .alpha.(t) produced by the changing blood volume and oxygen saturation within the finger. The signals produced by the detector (38) are converted by an analog-to-digital (A/D) converter (72) for subsequent analysis by a microcomputer (16). The microcomputer (16) extracts the following information from the signal corresponding to each wavelength. V.sub.H is determined to be the signal magnitude at a second pulse diastole. V.sub.L is, similarly, the signal magnitude at systole of the same pulse. A term .DELTA.V is identified equal in value to the difference in signal magnitudes at the adjacent systoles. Finally, values are determined for .DELTA.ts and .DELTA.tp, being the interval between an adjacent systole and diastole and the pulse period, respectively. The microcomputer (16) then determines a value for R.sub.OS in accordance with the relationship: ##EQU1## Empirically derived oxygen saturation curves are used to develop an indication of the oxygen saturation from the value of R.sub.OS computed.

Multiple-pulse method and apparatus for use in oximetry

A feedback control system is disclosed for use in processing signals employed in pulse transmittance oximetry. The signals are produced in response to light transmitted through, for example, a finger at two different wavelengths. Each signal includes a slowly varying baseline component representing the relatively fixed attenuation of light produced by bone, tissue, skin, and hair. The signals also include pulsatile components representing the attenuation produced by the changing blood volume and oxygen saturation within the finger. The signals are processed by the feedback control system before being converted by an analog-to-digital (A/D) converter (72) for subsequent analysis by a microcomputer (16). The feedback control system includes a controllable offset subtractor (66), a programmable gain amplifier (68), controllable drivers (44) for the light sources (40,42), and the microcomputer (16). The microcomputer receives signals from the offset subtractor (66), gain amplifier (68), drivers (44) and A/D converter (72) to produce signals that control the function of the subtractor (66) and drivers (44) in the following manner. Normally, the drivers (44) are maintained within a predetermined current range. In the event the microcomputer (16) senses an output from the converter (72) that is not within a predetermined range, the drive signal is adjusted to produce an acceptable signal. The magnitude of the offset removed by the subtractor (66), as controlled by the microcomputer (16), is maintained at a constant level when the converter (72) output is within a first predetermined range and is a predetermined function of the converter (72) output when that output falls within a second predetermined range.

Feedback-controlled method and apparatus for processing signals used in

The present invention relates to the processing of signals containing information about the pulse rate and oxygen saturation of arterial blood flowing in tissue. These signals have a relatively periodic pulsatile component superimposed upon a varying baseline component. To determine the pulse rate and oxygen saturation from the signals, the positive peaks, negative peaks, and period of the signal must be determined. The present invention accomplishes this by first searching for a sustained positive sloping region of the signal. Then the first derivative of the signal with respect to time is analyzed and points on the signal before and after the occurrence of a slope reversal marked. If the slope at the first point is positive, the interval between the two points is searched for a maximum amplitude that is identified as a positive peak. After the occurrence of a negative sloping region of the signal, another pair of points are marked occurring before and after a subsequent slope reversal. The minimum amplitude of the signal between these points is then identified as a negative peak. For improved accuracy, these positive and negative peaks are then compared with waveform templates to determine whether the amplitude between the peaks falls within an allowable range and to determine whether the interval between the peaks likewise falls within an acceptable range. These ranges are adjustable in proportion to the amplitude and interval compared against them. In this manner, values for the positive peak, negative peak, and period of the signal can be determined with high reliability.

Growing community of inventors

Lynnwood, WA, United States of America

Robert Eugene Smith