Digital Endpoints: Respiratory

Real World Assessments of Respiratory Outcomes

Real World Assessments of  Respiratory Outcomes

Respiratory abnormalities characterize a variety of disorders. In addition to physical disorders, ventilation is profoundly affected by mental and psychophysiological states, including stress, anxiety, and panic disorder.

The measurement of respiratory outcomes in the real-world requires careful artifact management. VivoSense ensures high-quality respiratory data are captured via proper protocol design, signal processing, and data analysis procedures.

Wearable Technology

Thoraco-Abdominal Respiration - Dual-band respiratory inductance plethysmography (RP) sensors are the gold standard for continuous, unobtrusive respiratory monitoring. They are widely used in clinical and research settings, and particularly in polysomnography (sleep studies). Thoracic and abdominal bands allow measurements of both breathing compartments, providing accurate volume and phase relation measurements in addition to simple respiration metrics of rate and timing.

ECG Derived Respiration (EDR) – EDR allows for continuous measurement of respiration rates and timing and has been analytically validated during sleep. Long term monitoring of transient respiratory events is possible while simultaneously enabling ECG measures to be used in a clinical endpoint. E.g., EDR, and HR.

PPG – PPG may be used to determine resting pulse rate and derive continuous measures of respiratory rate. PPG may also be used to assess decompensation via derived SpO2.

Audio – Audio recordings from wearable or app-enabled devices are used to identify cough events. EMG recordings and or patient-reported outcomes (ePRO) of frequency and intensity can enhance cough count.

Outcome Measures

Cough Frequency and Intensity

Sensor Modalities: Audio, RP

Clinical Use Examples: Monitoring biomarker for assessing real-world disease manifestation and severity in a wide range of respiratory indications such as COPD and cystic fibrosis.

Resting Respiratory Rate

Sensor Modalities: ECG, PPG, RP

Clinical Use Examples: Monitoring biomarker to assess recovery time in patients receiving pulmonary rehabilitation.

Monitoring biomarker for identifying exacerbations in patients with COPD.

Phase Relation

(Phase Angle, %Rib Cage Contributions)

Sensor Modalities: RP

Clinical Use Examples: Response monitoring biomarker to assess progression severity in obstructive breathing in patients with spinal muscular atrophy (SMA).

Response biomarker to quantify the change in ratio of rib vs. abdomen contribution to breathing in patients with Rett syndrome (RTT).

Respiratory Timing

(Duty Cycle, Insp., Exp.)

Sensor Modalities: ECG, PPG, RP

Clinical Use Examples: Response biomarker for identifying breath holds in patients receiving treatment for Rett syndrome (RTT).

Response biomarker for patients receiving treatment for sleep apnea.

Orthopnea

Sensor Modalities: ECG, PPG, RP

Clinical Use Examples: Monitoring biomarker for aiding in early detection and diagnoses of patients exhibiting symptoms consistent with heart failure.

Apnea and Hypopnea

Sensor Modalities: RP

Clinical Use Examples: Monitoring biomarker to assess disease burden and severity in patients with obstructive sleep apnea.

RP data from a patient with Rett syndrome visualized in VivoSense

RP data from a patient with Rett syndrome visualized in VivoSense.

  • Top - Tidal Volume (Vt), Breath by Breath Maximums and Minimums (Vt(Max), Vt(Min)).
  • Middle - Time of Inspiration (Ti).
  • Bottom - Time of Expiration (Te).

In this example, apneas measured on inspiration (yellow) and expiration (red) comprised the digital endpoint.

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