Pulse saturation oxygen delivery system and method

A system for delivering oxygen to a passenger of an aircraft, comprising:

• a supply of oxygen;
• an oral-nasal mask;
• a controller for adjusting a flow of oxygen from the supply of oxygen to the oral-nasal mask, the controller configured to detect erroneous signals;
• a first sensor device for determining a user's blood oxygen saturation level, the first sensor device coupled to the oro-nasal mask piece to contact a bridge of a nose of the user, the first sensor device including a pulse oximeter;
• and
• a second sensor device on a mask strap of the aircraft passenger breathing mask, the second sensor device configured to detect a second value of the blood oxygen saturation level of the user from a back of a neck of the user;
• wherein the controller adjusts the flow of oxygen based on the determination of the user's blood oxygen saturation level by the first sensor device and the second sensor device and using a running average of user blood saturation levels in response to detecting erroneous signals.

An adaptive controller for delivering a small dosage amount of oxygen to a patient, said controller comprising:

• a non-invasive oximeter sensor system configured to measure blood hemoglobin saturation in the patient, said oximeter sensor system generating a plurality of blood hemoglobin saturation output signal values over a given period of time, sequentially representative of said blood hemoglobin saturation, the oximeter sensor, the oximeter sensor system including and operating in parallel:
• (1) a first oximeter coupled to an oro-nasal mask piece of an aircraft passenger breathing mask to contact a nose of the patient, the first oximeter configured to detect oxygen saturation of hemoglobin based on absorption of light of two different wavelengths;
• (2) a capnometer configured to measure carbon dioxide in gas expired by the patient;
• (3) a second, visible light spectroscopy (VLS) tissue oximeter configured to detect oxygen levels in microvascular tissues based on wavelengths shorter than the two different wavelengths used by the first oximeter, and (4) a second oximeter on a mask strap of the aircraft passenger breathing mask, the second sensor device configured to detect a second value of the blood oxygen saturation level of the user from a back of a neck of the user;
• and
• a processor configured to:
• generate and adjust a running average of said blood hemoglobin saturation output values;
• generate an output signal that is a function of said running average;
• identify possibly invalid output signal values in response to receiving the blood hemoglobin saturation output signal values to evaluate a plurality of said blood hemoglobin saturation output signal values;
• based on said evaluation, provide a processed output signal;
• and
• substitute respective output signals for each of said possibly invalid output signal values thereby forming a sequence of valid output signals;
• and
• adjust a flow of oxygen to the patient using the running average.

An adaptive controller for delivering a fractional amount of oxygen to a patient, said controller comprising:

• a sensor configured to be coupled to the patient and to measure blood oxygen level in the patient and for providing a plurality of output signal values, sequentially representative of said measured blood oxygen level, the sensor including and operating in parallel:
• (1) a first oximeter coupled to an oro-nasal mask piece, the first oximeter configured to be coupled to a nose of the patient and configured to detect oxygen saturation of hemoglobin based on absorption of light of two different wavelengths;
• (2) a capnometer configured to measure carbon dioxide in gas expired by the patient;
• (3) a second, visible light spectroscopy (VLS) tissue oximeter configured to detect oxygen levels in microvascular tissues based on wavelengths shorter than the two different wavelengths used by the first oximeter, and (4) a second oximeter on a mask strap of the aircraft passenger breathing mask, the second sensor device configured to detect a second value of the blood oxygen saturation level of the user from a back of a neck of the user;
• a processor coupled to the sensor and configured to generate a running average of said plurality of output signal values and for subtracting said running average from a target value, representing a desired blood oxygen level for the patient, to produce a difference signal;
• and
• a feedback controller configured to receive said difference signal and adjust the fractional amount of oxygen to be delivered to the patient to minimize said difference signal in magnitude, wherein the fractional amount of oxygen delivered is adjusted in response to detecting erroneous signals.

A method for adaptively controlling the fractional amount of oxygen delivered to a patient comprising the steps of:

• a) measuring the blood hemoglobin saturation in the patient during a plurality of intervals over a given period of time and providing said measured values as an output signal using a first oximeter sensor coupled to an oro-nasal mask piece and configured to contact a nose of the patient and a second oximeter sensor on a mask strap of the aircraft passenger breathing mask, the first oximeter sensor and the second oximeter sensor configured to detect oxygen saturation of hemoglobin based on absorption of light of two different wavelengths;
• b) evaluating each of the measured values of said output signal to identify possibly invalid output signal values;
• c) eliminating said identified possibly invalid output signal values from said output signal to produce a processed output signal;
• d) adjusting the fractional amount of oxygen delivered to the patient in a sense to minimize any difference between said processed output signal and a predetermined desired blood hemoglobin saturation signal.