Patent ID: 7738936

Claim:
A method for obtaining information regarding a patient's blood oxygen saturation for a period of time using an implantable device implanted within the patient and a non-implanted device external to the patient, while limiting the amount of data that need be stored by the implantable device, the method comprising: (a) using a light source of the implantable device to transmit light having a first wavelength and light having a second wavelength through body tissue; (b) using a light detector of the implantable device to receive a portion of the light having the first wavelength and a portion of the light having the second wavelength and to produce a first signal based on the received portion of light having the first wavelength, and a second signal based on the received portion of light having the second wavelength; (c) determining, within the implantable device using the first and second signals or data indicative thereof, histogram data indicative of various levels of blood oxygen saturation that occur over the period of time without determining actual values of blood oxygen saturation; (d) storing, within the implantable device, the histogram data indicative of the various levels of blood oxygen saturation that occur over the period of time; (e) transmitting the stored histogram data from the implantable device to the non-implanted device, when the relative locations of the patient and the non-implanted device allows for transmission of the histogram data; and (f) using the non-implanted device to analyze [and/or display the levels of blood oxygen saturation provided by] the histogram data.