Alarm system that processes both motion and vital signs using specific heuristic rules and thresholds

Patent metadata

Field	Value
Publication number	US-9566007-B2
Application number	US-201514738910-A
Country	US
Kind code	B2
Filing date	Jun 14, 2015
Priority date	May 20, 2009
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

The invention provides a body-worn monitor that measures a patient's vital signs (e.g. blood pressure, SpO2, heart rate, respiratory rate, and temperature) while simultaneously characterizing their activity state (e.g. resting, walking, convulsing, falling). The body-worn monitor processes this information to minimize corruption of the vital signs by motion-related artifacts. A software framework generates alarms/alerts based on threshold values that are either preset or determined in real time. The framework additionally includes a series of ‘heuristic’ rules that take the patient's activity state and motion into account, and process the vital signs accordingly. These rules, for example, indicate that a walking patient is likely breathing and has a regular heart rate, even if their motion-corrupted vital signs suggest otherwise.

First claim

What is claimed is:

1. A method for continuously monitoring a patient, comprising the following steps:
detecting a first time-dependent physiological waveform indicative of one or more contractile properties of the patient's heart with a first sensor comprising a first detector configured to be worn on an arm of the patient;
detecting a second time-dependent physiological waveform indicative of one or more contractile properties of the patient's heart with a second sensor comprising a second detector configured to be worn on the patient's body;
detecting sets of time-dependent motion waveforms with at least three motion-detecting sensors, a first of which is positioned on the arm of the patient at the forearm, a second of which is positioned on the arm of the patient at the upper arm, and a third of which is located on the patient's chest, wherein each set of motion waveforms is indicative of motion of the location on the patient's body to which it is affixed;
analyzing at least a portion of the sets of time-dependent motion waveforms obtained from the first and second motion-detecting sensors to determine a time-dependent arm height for the patient;
processing the first and second time-dependent physiological waveforms and a correction value determined from the time-dependent arm height to determine a time-dependent blood pressure for the patient;
analyzing at least a portion of the sets of time-dependent motion waveforms obtained from the third motion-detecting sensor with a motion-determining algorithm to determine a time-dependent posture state for the patient;
determining an alarm condition by comparing the blood pressure to a predetermined alarm criterion that is regulated according to the patient's time-dependent posture state, wherein if the patient has undergone a change in posture state that would result in an expected drop in blood pressure, the alarm criterion is altered to reflect the expected drop in blood pressure; and
continuously displaying an icon indicative of the patient's time-dependent posture state and alarm condition and the time-dependent blood pressure on a display monitor.

2. The method of claim 1 , wherein the first time-dependent physiological waveform is an ECG waveform.

3. The method of claim 1 , wherein the second time-dependent physiological waveform is a plethysmogram waveform.

4. The method of claim 1 , wherein the first time-dependent physiological waveform is an ECG waveform and the second time-dependent physiological waveform is a plethysmogram waveform.

Assignees

• Sotera Wireless Inc

Inventors

• Mccombie Devin
• Banet Matt
• Dhillon Marshal
• Moon Jim

Classifications

• A61B5/6824

  Arm or wrist · CPC title

• A61B5/1118

  Determining activity level · CPC title

• A61B5/145

  Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value {; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue} (non-radiation detecting or locating of foreign bodies in blood A61B5/06) · CPC title

• G16H50/50

  for simulation or modelling of medical disorders · CPC title

• G16H50/20

  for computer-aided diagnosis, e.g. based on medical expert systems · CPC title