Body-worn monitor for measuring respiration rate

• US 9,339,211 B2
• Filed: 05/31/2014
• Issued: 05/17/2016
• Est. Priority Date: 09/14/2009
• Status: Active Grant

• Current Assignee: Sotera Wireless Incorporated
• Original Assignee: Sotera Wireless Incorporated
• Inventors: Banet, Matt, Dhillon, Marshal, McCombie, Devin
• Primary Examiner(s): Natnithithadha, Navin
• Assistant Examiner(s): WEARE, MEREDITH H
• Application Number:
  US14/292,872
• Publication Number:
  US 20140276175A1
• Time in Patent Office: 717 Days
• Field of Search: 600529-543
• US Class Current: 1/1
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/0535 Impedance plethysmography for measuring blood flow A61B5/0295
• CPC Class Codes: A61B 5/0809 by impedance pneumography
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• CPC Class Codes: A61B 5/1118 Determining activity level
• CPC Class Codes: A61B 5/113 occurring during breathing
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61B 5/6823 Trunk, e.g., chest, back, abdomen, hip
• CPC Class Codes: A61B 5/6824 Arm or wrist
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61B 5/746 Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B

Abstract

The invention provides a multi-sensor system that uses an algorithm based on adaptive filtering to monitor a patient'"'"'s respiratory rate. The system features an impedance pneumography sensor and a motion sensor (e.g., an accelerometer) configured to attach to the patient'"'"'s torso and measure therefrom a motion signal. The system further comprises a processing system, configured to operably connect to the impedance pneumography sensor and motion sensor, and to determine a respiration rate value by applying filter parameters obtained from the impedance pneumography sensor signals to the motion sensor signals.

Claims

1. A system for continuously monitoring a patient'"'"'s respiration rate comprising:

a combined impedance pneumography, electrocardiography (ECG), and motion sensor unit comprising a housing configured to be mounted on the patient'"'"'s torso and comprising;

an impedance pneumography circuit within the housing configured to generate an impedance pneumography waveform, an ECG circuit within the housing configured to generate an ECG waveform, and an accelerometer within the housing configured to generate a motion waveform;

a photoplethysmography sensor configured to be mounted on a finger of the patient and to generate a photoplethysmography waveform; and

a processing system configured to, on a continuous basis;

(i) receive the impedance pneumography waveform, the ECG waveform, the motion waveform, and the photoplethysmography waveform,

(ii) select using a metric of signal quality one of the received waveforms to provide an initial respiration rate,

(iii) determine the initial respiration rate from the waveform selected in (ii), and

(iv) process one or more of the received waveforms not selected in (ii) using an adaptive filtering algorithm that uses parameters determined from the initial respiration rate to obtain and report the respiration rate for the patient.