Acoustic sensor and ventilation monitoring system
Inventors
Joseph, Jeffrey I • HELMOND, Noud Van • TORJMAN, Marc C • DEVINE, Denise L • DICCIANI, Nance K • LOEUM, Channy
Assignees
Thomas Jefferson University • RTM Vital Signs LLC
Publication Number
US-11529076-B2
Publication Date
2022-12-20
Expiration Date
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Abstract
A method of monitoring respiration with an acoustic measurement device, the acoustic measurement device having a sound transducer, the sound transducer configured to measure sound associated with airflow through a mammalian trachea, the method includes correlating the measured sound into a measurement of tidal volume and generating at least one from the group consisting of an alert and an alarm if the measured tidal volume falls outside of a predetermined range.
Core Innovation
One core idea is monitoring respiration with an acoustic measurement device that uses a sound transducer to capture airflow-related sounds in the trachea. The method correlates the measured sound energy into measurements of tidal volume and respiratory rate in real time. It supports generating an alert or alarm when the tidal volume falls outside a predetermined range. These features are combined to assign a risk-index score based on measured and derived parameters.
Another aspect is an acoustic ventilation monitoring system (AVMS) that includes a wearable Trachea Sound Device (TSD) with a housing, sound transducer(s), an accelerometer, and a wireless transmitter. The controller is configured to correlate measured sound energy into tidal volume and respiratory rate, and to calculate values such as absolute tidal volume, direction, and rate of change. The system can assign likelihood values, apply predetermined weighting factors, and generate alerts when the combined score exceeds a predefined risk threshold.
The disclosure addresses the inadequacy of continuous, non-invasive monitoring during ambulation in hospital and real-world settings. Conventional methods such as tight-fitting chest bands, impedance pneumography, nasal capnography, and pulse oximetry can be cumbersome, prone to false alarms, or delayed in detecting hypoventilation. The AVMS provides continuous real-time monitoring with diagnostic algorithms to quantify and analyze respiratory rate, tidal volume, airway patency, body activity, body position, heart rate, and temperature to update the RIS.
Claims Coverage
The patent includes two primary independent claims that define the main inventive features of an acoustic monitoring method and an acoustic monitoring method with noise filtering and alerting.
Acoustic measurement correlated to tidal volume and respiratory rate
Correlating the measured sound vibrations associated with airflow through a mammalian trachea into a measurement of tidal volume and respiratory rate; calculating, at a first time interval, at least one selected from the group consisting of an absolute tidal volume, a direction of tidal volume, a rate of change of tidal volume, and a duration of time that the measured tidal volume deviates from a predetermined range; and correlating the at least one selected to a risk score defined on a predefined scale.
Filtering and alert generation based on risk score from acoustic measurements
Correlating measured sound vibrations into a measurement of tidal volume and respiratory rate; filtering out a set of anomalous data and ambient noise from the measured sound vibrations; calculating at least one selected from the group consisting of absolute tidal volume, a direction of tidal volume, a rate of change of tidal volume, and a duration of time that the measured tidal volume deviates from a predetermined range; correlating the at least one selected to a risk score on a predefined scale; and generating an alert if the risk score deviates from a predetermined risk threshold.
The independent claims focus on using an acoustic measurement device to derive tidal volume and respiratory rate from tracheal sound, computing selected features (absolute value, direction, rate of change, duration), mapping those features to a risk score, applying noise filtering, and generating alerts or alarms when risk thresholds are exceeded.
Stated Advantages
Non-invasive real-time monitoring system that continuously quantifies and analyzes respiratory rate, tidal volume, upper airway patency, body activity, body position, heart rate, and temperature.
Continuous monitoring and diagnostic algorithms that update a Risk-Index Score (RIS) to detect and predict unstable patterns of minute ventilation and the onset/progression of hypoventilation or hyperventilation.
Capability to produce alerts and alarms and to communicate alerts to patients, caregivers, clinicians, and emergency services, including automatic calling and location transmission.
Detection and prediction of opioid induced respiratory depression (OIRD) with algorithms contoured to detect mild, moderate, and severe hypoventilation with stated high sensitivity and specificity.
Improved clinical outcomes and decreased costs through continuous real-time monitoring used by hospital clinicians and for outpatient/home monitoring after discharge.
Functionality as a fitness monitor to continuously measure and display respiratory rate, tidal volume (minute ventilation), heart rate, temperature, body position, and body activity level.
Documented Applications
Predicting and detecting opioid overdose by correlating measured tidal volume and respiratory rate and generating alerts/alarms when summed likelihood values fall outside a predetermined opioid risk range.
Predicting heat exhaustion or heat stroke by periodically measuring heart rate, respiratory parameters, and temperature, assigning likelihood values, and generating alerts/alarms when comparisons exceed a predetermined range.
Tracking fitness of an ambulatory mammal by measuring heart rate and sound-derived respiratory rate and tidal volume during exercise, calculating minute ventilation (MV), and comparing MV with a predetermined MV threshold to assess fitness.
Continuous monitoring of patients during monitored anesthesia care (MAC), operative room (OR), PACU, ICU, emergency room, radiology suite, and cardiac catheterization laboratory to monitor minute ventilation and airway patency.
Hospital and outpatient monitoring of patients taking opioids or other respiratory depressant medications, including post-discharge monitoring with data transmitted to a smartphone application and central monitoring station.
Use in diagnosis and monitoring of chronic and acute pulmonary and cardiovascular conditions including congestive heart failure (CHF), COPD, asthma, pneumonia, cystic fibrosis, and other diseases by detecting unstable patterns of minute ventilation, heart rate, activity level, and temperature.
Closed-loop integration with a wearable or implantable drug infusion pump or auto-injector to automatically deliver opioid reversal medication (e.g., naloxone) based on AVMS detection/prediction of high overdose risk.
Use by first responders and in industrial or hazardous environments to detect hyperventilation or hypoventilation conditions that may indicate presence of harmful gases or low oxygen situations.
Monitoring electrocardiogram, percent hemoglobin oxygen saturation, and pulse oximeter waveform for additional hemodynamic and respiratory assessment and optional pulse transit time blood pressure estimation.
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