US 8,180,440 B2 · Alarm system that processes both motion and vital signs using specific heuristic rules and thresholds · patentgrep

Loading patent…

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.

Claims12

Dependent claims

A system for processing at least one vital sign from a patient and generating an alarm, the system comprising:

a first sensor comprising a first detector configured to detect a first time-dependent physiological waveform indicative of one or more contractile properties of the patient's heart;
a second sensor comprising a second detector configured to detect a second time-dependent physiological waveform indicative of one or more contractile properties of the patient's heart;
at least two motion-detecting sensors configured to be positioned on locations selected from a forearm, upper arm, and a body location other than the forearm or upper arm of the patient, each of the motion-detecting sensors generating at least one motion waveform indicative of motion of the location on the patient's body to which the motion-detecting sensor is affixed;
a first processing component configured to receive the time-dependent physiological and motion waveforms and determine therefrom:
(i) at least one vital sign calculated using at least one of the first and second time-dependent physiological waveforms;
and (ii) at least one motion parameter selected from the patient's posture, activity state, and degree of motion calculated using at least one motion waveform generated by each of the motion-detecting sensors, wherein the motion parameter is calculated by processing a time-dependent component from at least one motion waveform, and a frequency-dependent component from at least one motion waveform;
and
a second processing component configured to receive the at least one vital sign and motion parameter and determine therefrom:
(i) a first alarm condition, calculated by comparing the at least one vital sign to an alarm threshold;
(ii) a second alarm condition, calculated from the at least one motion parameter;
and (iii) an alarm rule, determined by collectively processing the first and second alarm conditions with an alarm algorithm, the alarm rule indicating whether or not the system generates an alarm.

8 more elements

A system for processing at least one vital sign from a patient and generating an alarm, the system comprising:

a first sensor comprising a first detector configured to detect a first time-dependent physiological waveform indicative of one or more contractile properties of the patient's heart;
a second sensor comprising a second detector configured to detect a second time-dependent physiological waveform indicative of one or more contractile properties of the patient's heart;
at least two motion-detecting sensors configured to be positioned on locations selected from a forearm, upper arm, and a body location other than the forearm or upper arm of the patient, each of the motion-detecting sensors generating at least one motion waveform indicative of motion of the location on the patient's body to which the motion-detecting sensor is affixed;
a first processing component configured to receive the time-dependent physiological and motion waveforms and determine therefrom:
(i) at least one vital sign calculated using at least one of the first and second time-dependent physiological waveforms;
and (ii) at least one motion parameter selected from the patient's posture, activity state, and degree of motion calculated using at least one motion waveform generated by each of the motion-detecting sensors, wherein the motion parameter corresponds to walking, and the first processing component determines walking by:
calculating a frequency-dependent motion waveform from at least one of the motion waveforms;
and analyzing a band of frequency components from the frequency-dependent motion waveform to determine that the patient is walking;
and
a second processing component configured to receive the at least one vital sign and motion parameter and determine therefrom:
(i) a first alarm condition, calculated by comparing the at least one vital sign to an alarm threshold;
(ii) a second alarm condition, calculated from the at least one motion parameter;
and (iii) an alarm rule, determined by collectively processing the first and second alarm conditions with an alarm algorithm, the alarm rule indicating whether or not the system generates an alarm.

10 more elements

A system for processing at least one vital sign from a patient and generating an alarm, the system comprising:

a first sensor comprising a first detector configured to detect a first time-dependent physiological waveform indicative of one or more contractile properties of the patient's heart;
a second sensor comprising a second detector configured to detect a second time-dependent physiological waveform indicative of one or more contractile properties of the patient's heart;
at least two motion-detecting sensors configured to be positioned on locations selected from a forearm, upper arm, and a body location other than the forearm or upper arm of the patient, each of the motion-detecting sensors generating at least one motion waveform indicative of motion of the location on the patient's body to which the motion-detecting sensor is affixed;
a first processing component configured to receive the time-dependent physiological and motion waveforms and determine therefrom:
(i) at least one vital sign calculated using at least one of the first and second time-dependent physiological waveforms;
and (ii) at least one motion parameter selected from the patient's posture, activity state, and degree of motion calculated using at least one motion waveform generated by each of the motion-detecting sensors, wherein the motion parameter comprises convulsing, and the first processing component determines convulsing by:
calculating a frequency-dependent motion waveform from at least one of the motion waveforms;
and analyzing a band of frequency components from the frequency-dependent motion waveform to determine that the patient is convulsing;
and
a second processing component configured to receive the at least one vital sign and motion parameter and determine therefrom:
(i) a first alarm condition, calculated by comparing the at least one vital sign to an alarm threshold;
(ii) a second alarm condition, calculated from the at least one motion parameter;
and (iii) an alarm rule, determined by collectively processing the first and second alarm conditions with an alarm algorithm, the alarm rule indicating whether or not the system generates an alarm.

10 more elements

A system for processing at least one vital sign from a patient and generating an alarm, the system comprising:

a first sensor comprising a first detector configured to detect a first time-dependent physiological waveform indicative of one or more contractile properties of the patient's heart;
a second sensor comprising a second detector configured to detect a second time-dependent physiological waveform indicative of one or more contractile properties of the patient's heart;
at least two motion-detecting sensors configured to be positioned on locations selected from a forearm, upper arm, and a body location other than the forearm or upper arm of the patient, each of the motion-detecting sensors generating at least one motion waveform indicative of motion of the location on the patient's body to which the motion-detecting sensor is affixed;
a first processing component configured to receive the time-dependent physiological and motion waveforms and determine therefrom:
(i) at least one vital sign calculated using at least one of the first and second time-dependent physiological waveforms;
and (ii) at least one motion parameter selected from the patient's posture, activity state, and degree of motion calculated using at least one motion waveform generated by each of the motion-detecting sensors, wherein the motion parameter comprises falling, and the first processing component determines falling by:
i) calculating a time-dependent change in at least one of the motion waveforms;
ii) calculating a frequency-dependent motion waveform from at least one of the motion waveforms;
and iii) analyzing the time-dependent change in at least one of the motion waveforms and a band of frequency components from at least one of the frequency-dependent motion waveforms to determine that the patient has fallen;
and
a second processing component configured to receive the at least one vital sign and motion parameter and determine therefrom:
(i) a first alarm condition, calculated by comparing the at least one vital sign to an alarm threshold;
(ii) a second alarm condition, calculated from the at least one motion parameter;
and (iii) an alarm rule, determined by collectively processing the first and second alarm conditions with an alarm algorithm, the alarm rule indicating whether or not the system generates an alarm.

11 more elements

A system for processing at least one vital sign from a patient and generating an alarm, the system comprising:

a first sensor comprising a first detector configured to detect a first time-dependent physiological waveform indicative of one or more contractile properties of the patient's heart;
a second sensor comprising a second detector configured to detect a second time-dependent physiological waveform indicative of one or more contractile properties of the patient's heart;
at least two motion-detecting sensors configured to be positioned on locations selected from a forearm, upper arm, and a body location other than the forearm or upper arm of the patient, each of the motion-detecting sensors generating at least one motion waveform indicative of motion of the location on the patient's body to which the motion-detecting sensor is affixed;
a first processing component configured to receive the time-dependent physiological and motion waveforms and determine therefrom:
(i) at least one vital sign calculated using at least one of the first and second time-dependent physiological waveforms;
and (ii) at least one motion parameter selected from the patient's posture, activity state, and degree of motion calculated using at least one motion waveform generated by each of the motion-detecting sensors;
and
a second processing component configured to receive the at least one vital sign and motion parameter and determine therefrom:
(i) a first alarm condition, calculated by comparing the at least one vital sign to an alarm threshold;
(ii) a second alarm condition, calculated from the at least one motion parameter;
and (iii) an alarm rule, determined by collectively processing the first and second alarm conditions with an alarm algorithm, the alarm rule indicating whether or not the system generates an alarm,
wherein the first processing component is further configured to determine the motion parameter by comparing a parameter determined from the motion waveform to an ROC threshold value associated with a ROC curve, wherein both the ROC threshold value and the ROC curve are determined beforehand.

9 more elements

A system for continuously monitoring a patient, the system configured to be worn on the patient's body and comprising:

an optical sensor comprising a first light source, a second light source, and a light detector, the optical sensor configured to detect a first time-dependent optical waveform from radiation generated by the first light source, and a second time-dependent optical waveform from radiation generated by the second light source, wherein both the first and second time-dependent optical waveforms are indicative of one or more contractile properties of the patient's heart;
an electrical sensor comprising at least two electrodes and an electrical circuit, wherein each electrode is configured to attach to separate locations on the patient and measure an electrical signal, and the electrical circuit is configured to receive and process an electrical signal from each electrode to generate a first time-dependent electrical waveform indicative of one or more contractile properties of the patient's heart and a second time-dependent electrical waveform indicative of a respiratory rate;
at least two motion-detecting sensors configured to be positioned on two separate locations on the body of the patient, the locations selected from a forearm, upper arm, chest, and hand of the patient, wherein each of the motion-detecting sensors generates at least one motion waveform indicative of motion of a body location onto which the motion-detecting sensor is affixed;
and a processing component configured to receive the first and second time-dependent optical waveforms, the first and second time-dependent electrical waveforms, and the motion waveforms, and determine therefrom:
(i) a time difference between a feature in one of the first and second time-dependent optical waveforms and a feature in one of the first and second electrical waveforms;
(ii) a blood pressure value calculated from the time difference;
iii) an SpO2value calculated from both the first and second time-dependent optical waveforms;
(iii) a heart rate calculated from at least one of the time-dependent electrical waveforms;
(iv) a respiratory rate calculated from the second time-dependent electrical waveform;
(v) at least one motion parameter selected from the patient's posture, activity state, and degree of motion calculated using at least one motion waveform generated by each of the motion-detecting sensors;
and (vi) an alarm parameter calculated from at least one of the blood pressure value, SpO2 value, heart rate, respiratory rate, and the motion parameter.

8 more elements

A system for processing at least one vital sign from a patient and generating an alarm, the system comprising:

a first sensor comprising a first detector configured to be worn on the patient's body and configured to detect a first time-dependent physiological waveform indicative of one or more contractile properties of the patient's heart;
a second sensor comprising a second detector configured to be worn on the patient's body and configured to detect a second time-dependent physiological waveform indicative of one or more contractile properties of the patient's heart;
a first motion-detecting sensor configured to be positioned on a first location on the patient's body, the motion-detecting sensor configured to generate a first set of motion waveforms indicative of motion of the location on the patient's body to which it is affixed;
a processing component configured to be worn on the patient's body, the processing component comprising:
a second motion-detecting sensor configured to be positioned on a second location on the patient's body, the second motion-detecting sensor configured to generate a second set of motion waveforms indicative of motion of the location on the patient's body to which the processing component is affixed;
and
a microprocessor configured to receive the time-dependent physiological waveforms and at least of portion of the first and second set of motion waveforms and determine therefrom:
(i) at least one vital sign calculated using at least one of the first and second time-dependent physiological waveforms;
(ii) at least one motion parameter selected from the patient's posture, activity state, and degree of motion, the motion parameter calculated by comparing at least one of the following components to a predetermined threshold value:
(a) a component calculated from a time-dependent waveform generated by the motion-detecting sensor;
(b) a component calculated from a frequency-dependent waveform calculated from the time-dependent waveform;
and (c) a component determined from an ROC curve;
and (iii) an alarm, determined by collectively processing the at least one vital sign and the motion parameter with an alarm algorithm.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/469,182Filed 20 May 2009
Published: US 2010/0298656 A125 Nov 2010
Granted: 15 May 2012
Term ends: Not estimatedThe source records don’t support an estimate.

Classification40 codes

A61B 5/0205
Detecting, measuring or recording for evaluating the cardiovascular system, e.g. pulse, heart rate, blood pressure or blood flow: simultaneously…
A61B 5/0022
Characterised by features of the telemetry system: monitoring a patient using a global network, e.g. telephone networks, internet
A61B 5/02028
Detecting, measuring or recording for evaluating the cardiovascular system, e.g. pulse, heart rate, blood pressure or blood flow: determining…
A61B 5/02055
Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition:…

Family

US 2010/0298656 A1Pre-grant publication · published 25 Nov 2010
US 8,180,440 B2This patent

From the US filing history. Foreign family members aren’t listed.

Timeline

Citations

Open elsewhere