Oxygen Savings With Administered Oxygen and High Flow Ambient Air At Rest

This study is meant to compare the amount of oxygen required for hypoxemia relief between current standard of care (oxygen only) and oxygen with the addition of high flow air for Chronic Obstructive Pulmonary Disease (COPD), Interstitial Lung Disease (ILD), and Pulmonary Hypertension (PH) patients during rest. Subjects will be titrated from 0 L/min until they maintain 95% SpO2 for each of the following delivery methods:

1. Pulses of pure oxygen (control)
2. Constant high flow air with pulses of pure oxygen
3. Out of phase pulses of high flow air and pure oxygen

Each participant will require (1) visit, which will last approximately 4-5 hours.

At start of visit:

1. Vitals are taken (temperature, heart rate, SpO2, respiration rate, blood pressure, Borg dyspnea score, Mmrc score) while participant is seated and using their normal oxygen prescription.
2. Patient will remain seated during the following procedure with SpO2 and heart rate continuously being monitored.

Pulsed Oxygen Control at Rest:

1. Participant's oxygen will be turned off for 10 minutes as a washout period.
2. Using the oxygen tank with the pulse regulator, the participant will be titrated to a pulse rate that maintains their SpO2 at an average of 95%.

   a. Increasing volumes of oxygen in 1 L(liter)/min increments every thirty seconds until an average of 95% SpO2 is maintained for 30 seconds.
3. Once the participant is titrated to the correct amount of oxygen, they will remain on the oxygen for an additional 3 minutes
4. Final oxygen flow rate, SpO2, Heart Rate, and Borg Dyspnea Score will be recorded in the last minute of the test.

   Mixed Continuous Air/Oxygen Efficacy at Rest:
5. Participant's oxygen will be turned off for 10 minutes as a washout period.
6. The participant will be delivered pulsed oxygen and high flow ambient air using the oxygen tank with the pulse regulator and Vapotherm setup, the participant will be titrated to a pulse rate that maintains their SpO2 at an average of 95%.

   1. High flow ambient air will be set to 15 L/min
   2. Increasing volumes of oxygen from in 1 L/min increments every thirty seconds until an average of 95% SpO2 is maintained for 30 seconds.
7. Once the participant is titrated the correct amount of oxygen, they will remain on the oxygen for an additional 3 minutes.
8. Final oxygen flow rate, SpO2, Heart Rate, and Borg Dyspnea Score will be recorded in the last minute of the test.
9. Steps 5-8 are then repeated two more times for pulsed oxygen plus continuous flow ambient air at flow rates of 20 and 25 L/min.

   Mixed Pulsed Air/Oxygen Efficacy at Rest:
10. Participant's oxygen will be turned off for 10 minutes as a washout period
11. The participant will be delivered the out-of-phase pulsed oxygen and high flow ambient air using the oxygen tank with the pulse regulator and Vapotherm setup, the participant will be titrated to a pulse rate that maintains their SpO2 at an average of 95%

    1. High flow ambient air will be set to 15 L/min
    2. Increasing volumes of oxygen from in 1L/min increments every thirty seconds until an average of 95% SpO2 is maintained for 30 seconds.
12. Once the participant is titrated the correct amount of oxygen, they will remain on the oxygen for an additional 3 minutes
13. Final oxygen flow rate, SpO2, Heart Rate, and Borg Dyspnea Score will be recorded in the last minute of the test.
14. Steps 10-13 are then repeated two more times for out-of phase pulsed oxygen plus pulsed high flow ambient air at flow rates of 20 and 25 L/min.

Eligibility Criteria:
Inclusion Criteria:

* Provision of signed and dated informed consent form
* Stated willingness to comply with all study procedures and availability for the duration of the study
* Male or female, aged greater or equal to 30 years old
* Require Long Term Oxygen Therapy between 1 L/min and 4 L/min while at rest
* Have a peripheral blood saturation level above 80% with room air while seated
* Tolerate breathing while seated in room air
* Diagnosed with one of the following respiratory diseases: COPD (40% \< Forced Expiratory Volume (FEV1) \< 80% confirmed from pulmonary function test (PFT) within the last year), ILD (Confirmed with radiographic imaging), PH (Confirmed with radiographic imaging)
* Normal heart rate and blood pressure (Resting Heart Rate \<120 bpm, Systolic BP \<180 mmHg, Diastolic BP \<100mmHg)
* PFT taken in the last three months

Exclusion Criteria:

* Pregnancy or lactation
* Exacerbation that has resolved within the past 28 days
* Treatment with another investigational drug or other intervention within three months
* Has any of the following: unstable angina, recent revascularization, recent history of cerebrovascular accident