Abstract: A method and apparatus for improving the calculation of oxygen saturation and other blood constituents by non-invasive pulse oximeters. The method and apparatus permit more accurate determination of blood flow by collecting time-measures of the absorption signal at two or more wavelengths and processing the collected time-measure to obtain composite pulsatile flow data from which artifacts have been filtered. The processing may occur in the time domain or in the frequency domain. In the preferred time domain embodiment, successive portions of periodic information are weighted and added together in synchrony to obtain the composite pulse information. In the preferred frequency domain embodiment, the time-measure is Fourier transformed into its spectral components to form the composite information.

Abstract: A method and apparatus for improving the calculation of oxygen saturation by non-invasive pulse oximeters during transient conditions. Transient conditions introduce artifactual errors into the detected optical signal because of changes in transmittance of the light with localized blood volume changes and as the average background oxygen saturation level of the patient's blood changes. The invention relates to correcting the detected optical pulses by linear interpolation and rate of change techniques or by selective frequency filtering and compensating the detected optical signal using the filtered signal to provide accurate estimates of oxygen saturation during transient conditions.

Abstract: A sensor for trans-illumination of a blood perfused portion of flesh to measure light extinction during trans-illumination is disclosed. The sensor is preferably mounted on a fingertip but any digit or blood perfused portion of flesh will work. The sensor includes a first end for disposition on one side of the trans-illuminated flesh and a second end for disposition on the opposite and opposed side of the trans-illuminated flesh. A light source is mounted to the first side and a photo-sensor is mounted to the second side. If an elongated flexible strip is used, it is provided with adhesive and is suitably windowed that light is allowed to take an optical path through the finger. If no flexible strip is used, the two ends are aligned and secured to the flesh such that the light emitted takes an optical path through the finger.

Abstract: A method and apparatus for measuring and correlating a patient's heart activity with optical detection of the patient's blood flow. The method and apparatus permit more accurate determination of blood flow characteristics such as oxygen saturation and pulse rate. In a preferred embodiment, the heart activity is detected by monitoring the patient's EKG waveform, and the blood flow is detected by a non-invasive pulse oximeter. The occurrence of the R wave portion of the EKG signal is detected and the time delay by which an arterial pulse follows the R wave is determined to establish a time window in which an arterial is to be expected. The established time window provides the oximeter with a parameter enabling the oximeter to analyze the blood flow only when it is likely to present an arterial blood pulse for waveform analysis. The invention also includes adjusting the polarity of the detected EKG signal to have a preselected uniform upgoing or downgoing polarity.

Abstract: A probe apparatus for use with an optical oximeter is disclosed. A pair of light emitting diodes emit light of known narrow wavelengths through an appendage of a patient onto a photosensor. A resistor of coded known resistance is used to enable the oximeter to calculate the co-efficient of extinction of the wavelengths of the LEDs. The resistor, LEDs and photosensor are mounted on self-attaching hook and eye tape for mounting the probe onto the appendage of the patient. The probe is detachably wired to the oximeter, rendering the probe completely disposable. The oximeter is programmed at the factory to calculate the co-efficients of extinction of any LEDs which may be encountered in a series of disposable probes. From the co-efficients of extinction, the pulse rate and degree of arterial oxygen saturation is computed and displayed by the oximeter.

Abstract: A probe apparatus for use with an optical oximeter is disclosed. A pair of light emitting diodes emit light of known narrow wavelengths through an appendage of a patient onto a photosensor. A resistor of coded known resistance is used to enable the oximeter to calculate the co-efficient of extinction of the wavelengths of the LEDs. The resistor, LEDs and photosensor are mounted on self-attaching hook and eye tape for mounting the probe onto the appendage of the patient. The probe is detachably wired to the oximeter, rendering the probe completely disposable. The oximeter is programmed at the factory to calculate the co-efficients of extinction of any LEDs which may be encountered in a series of disposable probes. From the co-efficients of extinction, the pulse rate and degree of arterial oxygen saturation is computed and displayed by the oximeter.

Abstract: A sensor for use with instruments that non-invasively measure blood constituents, particularly oxygen saturation of arterial blood from the patient's tissue. The sensor has two rigid housings adapted for arrangement in opposition and secured about a patient's tissue. Each housing has a deformable pad adapted for receiving, conforming to, and securely gripping the patient's tissue without significantly affecting arterial blood flow. In one embodiment, the housings are pivotally mounted and biased closed under tension, one pad contains a light source for illuminating the tissue in its tissue contacting surface, and the other pad contains the light detector for use in measuring the amount of light absorbed by the blood constituent. In a second embodiment one or the other pad contains both the light source and light detector. The detected light can then be correlated to the amount of blood constituent present in the blood.

Abstract: A display monitor is disclosed for a pulse oximeter of the type wherein light of two different wavelengths is passed through body tissue, such as a finger, an ear or the scalp, so as to be modulated by the pulsatile component of arterial blood therein and thereby indicate oxygen saturation. A tonal signal is emitted having a pitch proportional to the ratio of oxygen saturation and a sequential repetition proportional to pulse. A visual cue consisting of an array of strobed light emitting diodes is flashed having a total light output proportional to the magnitude of the pulse and a sequential flashing rate proportional to pulse rate. A systematic rejection of extraneous or irregular detected data prevents undue sounding of alarms.

Abstract: A probe apparatus for use with an optical oximeter is disclosed. A pair of light emitting diodes emit light of known narrow wavelengths through an appendage of a patient onto a photosensor. A resistor of coded known resistance is used to enable the oximeter to calculate the co-efficient of extinction of the wavelengths of the LEDs. The resistor, LEDs and photosensor are mounted on self-attaching hook and eye tape for mounting the probe onto the appendage of the patient. The probe is detachably wired to the oximeter, rendering the probe completely disposable. The oximeter is programmed at the factory to calculate the co-efficients of extinction of any LEDs which may be encountered in a series of disposable probes. From the co-efficients of extinction, the pulse rate and degree of arterial oxygen saturation is computed and displayed by the oximeter.