Methods and devices for countering grativity induced loss of consciousness and novel pulse oximeter probes
Inventors
Melker, Richard J. • Banner, Michael J. • Fuehrlein, Brian S. • Worley, George E. • Euliano, Neil R.
Assignees
CONVERGENT ENGINEERING Inc • Beta Biomed Services Inc • University of Florida Research Foundation Inc
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Publication Number
US-8679028-B2
Publication Date
2014-03-25
Expiration Date
Abstract
Disclosed herein are methods and devices of obtaining plethysmograph readings and utilizing plethysomography to identify when pilots are about to experience GLOC. Furthermore, in other embodiments, the invention pertains to methods and devices designed to warn a pilot that he/she is about to enter GLOC and/or automatically averting catastrophic damage or injuries by directing a plane being piloted to take predetermined corrective actions. Specifically disclosed is a system embodiment for assisting in the prevention of gravity induced loss of consciousness. The system comprises at least one pulse oximeter probe 10 configured for securing to a central source site of a pilot and to generate signals indicative of blood flow at said central source site, an analyzer unit 58 communicatingly connected to said at least one pulse oximeter probe 10, said analyzer unit comprising at least one processing module 56 configured to determine whether said blood flow is approaching a predefined level, and an aircraft computer 51 communicatingly connected to said analyzer unit 58, said aircraft computer 51 comprising at least one processing module 59 configured to effect a predetermined reaction responsive to said blood flow falling below a predetermined level.
Core Innovation
The invention provides a method and system for monitoring blood flow status to the head of an individual by using a pulse oximeter probe secured to a central source site. A plethysmography signal stream indicative of blood flow at the central source site is generated and processed by a signal processor within an analyzer unit, and the signal processor isolates an AC component signal stream and a DC component signal stream from the plethysmography signal stream.
Changes in blood flow at the central source site are determined based on the DC component signal stream, and optionally the AC component signal stream, to identify when blood flow is approaching a predefined level and/or falling below a predefined level. A predetermined reaction is then effected with a computer responsive to the blood flow condition.
In the described aircraft context, the predetermined reaction may include generating an alarm and may further include a corrective flight maneuver intended to lessen or reverse a gravity force applied to a pilot. The document also specifies central source sites including nasal, pre-auricular, alar/fibro-areolar, post-auricular, and ear canal/tympanic artery sites, with analyzer processing based on AC/DC component separation.
The signal-processing behavior supports determining arterial flow and venous return during maneuvers, including observations described for carotid depression and valsava. The extraction of the DC component as an interpolated peak/trough midline and the AC component as the residual is described as reflecting arterial flow and venous return during maneuvers.
Claims Coverage
The document contains three independent claims that share a common inventive core: securing a pulse oximeter probe at a central source site, generating a plethysmography signal stream, isolating AC and DC components, determining blood-flow changes using the DC component, and effecting a predetermined reaction when blood flow falls below a predefined value.
Central source site probe for head blood-flow monitoring
Securing a pulse oximeter probe to a central source site of said individual and generating a plethysmography signal stream indicative of blood flow at said central source site.
AC/DC component isolation from plethysmography signal
Isolating an AC component signal stream and a DC component signal stream from said plethysmography signal stream with a signal processor.
DC-based determination of blood-flow changes
Determining changes in blood flow at said central source site based on said DC component signal stream, and optionally said AC component signal stream.
Computer-controlled predetermined reaction responsive to threshold crossing
Effecting with a computer a predetermined reaction responsive to said blood flow falling below a predefined value.
Analyzer unit with predefined-level blood-flow assessment
An analyzer unit communicatingly connected to at least one pulse oximeter probe configured to generate a plethysmography signal stream at a central source site, the analyzer unit configured to isolate an AC component signal stream and a DC component signal stream from said plethysmography signal stream and to determine whether blood flow is approaching a predefined level based on said DC component signal stream, and optionally, said AC component signal stream.
Aircraft computer and flight-control corrective maneuver response
A computer communicatingly connected to said analyzer unit wherein said computer comprises at least one processing module configured to effect a predetermined reaction responsive to said blood flow falling below a predetermined level, wherein the predetermined reaction directs an aircraft flight control system to perform a corrective flight maneuver to lessen or reverse the gravity force applied to the pilot.
AC/DC decomposition only for monitoring blood-flow changes
Isolating an AC component signal stream and a DC component signal stream from a plethysmography signal stream with a signal processor; and determining changes in blood flow to the head of an individual based on said DC component signal stream, and optionally said AC component signal stream, with said signal processor.
Across the independent claims, the main coverage centers on AC/DC separation of a plethysmography signal at a central source site and using the DC component, optionally with the AC component, to determine blood-flow changes, with a computer effecting a predetermined reaction when blood flow falls below a predefined value, including aircraft-specific alarm and corrective flight maneuver responses.
Stated Advantages
Enables monitoring of blood flow status to the head of an individual by using a pulse oximeter probe and processing plethysmography signals with AC/DC component isolation.
Provides a response when blood flow falls below a predefined value by effecting a predetermined reaction with a computer.
In aircraft operation, supports generating an alarm and directing an aircraft flight control system to perform a corrective flight maneuver to lessen or reverse gravity force applied to the pilot.
Allows determination of blood-flow changes based on the DC component signal stream, with optional contribution from the AC component signal stream.
Documented Applications
Monitoring blood flow status to the head of an individual using a pulse oximeter probe at a central source site and processing plethysmography signals.
Aircraft operation for monitoring a pilot and effecting a predetermined reaction responsive to head blood-flow threshold conditions, including alarms and corrective flight maneuvering through aircraft flight control to address gravity force.
Use of the described AC/DC component behavior to reflect arterial flow and venous return during maneuvers described in the document, including carotid depression and valsava.
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