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-10842416-B2
Publication Date
2020-11-24
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
The disclosure describes a method, device, and system for an acoustic ventilation monitoring system in which an acoustic measurement device having a sound transducer measures sound associated with airflow through a mammalian trachea, correlates the measured sound into a measurement of tidal volume, and generates at least one of an alert and an alarm if the measured tidal volume falls outside of a predetermined range.
The background identifies a problem in that continuous and accurate measurement of airflow into and out of the lungs during ambulation and in real-world environments has not been well established; existing methods such as tight-fitting chest bands, impedance pneumography, nasal cannula capnography, and pulse oximetry have limitations including cumbersome/dislodgable nasal cannulas, delayed alarm for hypoxemia with pulse oximetry, hard-wired monitoring, and nursing observations that are infrequent and prone to error.
The system (AVMS) continuously measures and analyzes patterns of variables such as respiratory rate, tidal volume, upper airway patency (talking/snoring), body activity level, body coordination, body position, heart rate, and temperature using a wearable Trachea Sound Device (TSD) that transmits data to a diagnostic software application; real-time diagnostic algorithms calculate a Risk-Index Score (RIS) and produce alerts and alarms when unstable patterns of minute ventilation or other variables are detected or predicted.
Claims Coverage
The independent claims (three identified) recite inventive features that (1) use tracheal sound measured by an acoustic transducer to derive tidal volume/respiratory metrics, (2) assign risk index values based on absolute values, direction, and rates of change, and (3) generate alerts/alarms when aggregated risk scores exceed predetermined thresholds.
Correlating tracheal sound to tidal volume
Correlating measured sound associated with airflow through a mammalian trachea into a measurement of tidal volume.
Calculating tidal volume absolute value, direction, and rate of change
Calculating an absolute tidal volume, a direction of tidal volume, and a rate of change of tidal volume.
Assigning risk index values to tidal volume metrics
Assigning a risk index value of a likelihood of the opioid overdose to each of the absolute tidal volume, the direction of tidal volume, and the rate of change of tidal volume, each risk index value being one selected from the group consisting of a positive score and a negative score based on a predefined scale.
Summing risk index values and threshold alerting
Calculating a sum of risk index values assigned to the measured metrics and generating at least one of an alert or an alarm if the calculated sum exceeds a predetermined risk score threshold.
Continual tracheal sound measurement with wearable affixable device
Continually or continually measuring sound waves emanating from airflow into and out of the mammalian trachea with an acoustic measurement device releasably affixable to the mammal's skin proximate the trachea and correlating the measured sound into measurements of respiratory rate and tidal volume.
Assigning risk index values to respiratory rate and tidal volume and summation
During a predetermined interval, assigning risk index values to (a) respiratory rate and tidal volume, (b) direction trend of the respiratory rate and tidal volume, and (c) rate of change of the respiratory rate and tidal volume, summing (a)-(c), and generating an alert or alarm if the sum falls outside of a predetermined opioid risk range.
Weighted multiplication of direction and rate risk values
Multiplying the assigned risk index value of at least one of the direction trend and the rate of change by a predetermined weighting value as part of the risk calculation.
Multi-transducer housing adhered with coupling component and wireless transmission
An acoustic measurement device including a housing with at least two sound transducers disposed within the housing opposite an opening, the housing sized and configured to be adhered to the mammal's trachea with a coupling component, and wirelessly communicating the measured sound to a remote controller.
Remote controller correlation and multi-factor risk scoring
A remote controller configured to correlate measured sound energy into measurements of respiratory rate and tidal volume, assign first and second risk index values based on measured respiratory rate and tidal volume, calculate rates of change, assign third and fourth risk index values based on rates of change, and generate an alert or alarm if the sum of the risk index values exceeds a predetermined threshold.
The independent claims focus on using tracheal acoustic measurements to derive tidal volume and respiratory metrics, assigning risk index scores to absolute values, direction trends, and rates of change (optionally weighted), aggregating those scores, and generating alerts/alarms when aggregated scores cross predetermined thresholds, implemented via a wearable device and a remote controller.
Stated Advantages
Continuous, non-invasive real-time monitoring and quantification of respiratory parameters (respiratory rate, tidal volume, minute ventilation) and related physiological variables in ambulatory and hospitalized patients.
Early detection and prediction of unstable ventilation patterns and the onset/progression of mild, moderate, and severe hypoventilation or hyperventilation via a Risk-Index Score to produce alerts and alarms prior to severe events.
Improved clinical management leading to improved clinical outcomes and decreased costs by enabling clinicians to use real-time minute ventilation, heart rate, activity, and temperature trend data.
Enhanced patient safety through automated notifications to patients, caregivers, clinicians, and emergency personnel and the potential for automated delivery of an opioid reversal medication via an auto-injector in response to detected high risk.
Utility as a fitness monitor and for detection/prediction of overheating/exhaustion in athletes and military personnel.
Documented Applications
Predicting an opioid overdose by measuring tracheal sound, correlating to respiratory rate and tidal volume, calculating trends and rates of change, assigning risk index values, and generating alerts/alarms when summed risk exceeds a threshold.
Predicting heat exhaustion or heat stroke by combining measured respiratory rate, tidal volume, and body temperature, assigning likelihood values, and generating alerts/alarms when comparisons exceed predetermined ranges.
Tracking fitness of an ambulatory mammal by measuring respiratory rate, tidal volume, calculating minute ventilation, comparing to a predetermined MV threshold, and assessing fitness based on the comparison.
Continuous monitoring of hospitalized patients' minute ventilation and airway patency during monitored anesthesia care, in the OR, PACU, ICU, emergency room, radiology suite, and cardiac catheterization laboratory.
Home monitoring of patients taking opioids after hospital discharge with data transmitted to a cell phone application for automated analysis and alerts to enhance safety and adherence.
Use in outpatient/inpatient drug rehabilitation clinics to monitor patients with opioid-use disorder for safety and compliance, including use as a condition for dispensing methadone.
Closed-loop combination with a wearable or implantable drug infusion pump to automatically infuse opioid reversal medication (e.g., naloxone) based upon real-time AVMS data.
Monitoring and early detection of decompensation in chronic cardiopulmonary conditions such as congestive heart failure (CHF), COPD, asthma, pneumonia, and other pulmonary and cardiovascular diseases by detecting unstable patterns of minute ventilation, heart rate, activity level, and temperature.
Use by athletes and the military to monitor fitness, optimize training, and detect/predict overheating/exhaustion with alerts and alarms prior to an adverse clinical event.
Non-medical applications for first responders to detect harmful gases or chemicals via detection of hyperventilation or hypoventilation, and for industrial scenarios to detect low oxygen situations (e.g., oil fields, breweries, chemical facilities, mining, refrigeration, aviation hypoxia, high altitude, and space applications).
Use as a wearable Trachea Sound Device (TSD) that transmits tracheal sound and accelerometer data to a smartphone application for recording, analysis, and transmission to a central monitoring station and electronic medical record.
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