Medical Information Only. Always consult your healthcare provider before enrolling in any clinical trial.
NCT05168501 · ClinicalTrials.gov registry record · NA
Assessing Variability of the Ventilatory Response to Duffin's Rebreathing Procedure
A NA study, sponsored by Food and Drug Administration (FDA).
- Completed
- Registry status
- NA
- Development phase
- 7
- Enrollment target
NCT05168501: Completed NA study, sponsored by Food and Drug Administration (FDA).
NCT05168501 is a NA study that has completed, run by Food and Drug Administration (FDA). The registered enrollment target is 7 participants, below the 1,404-participant average among 58,714 other NA trials with a reported enrollment target (100% lower). According to ClinicalTrials.gov, the official US trial registry.
The verdict
NCT05168501, a NA study, has completed, sponsored by Food and Drug Administration (FDA).
- COMPLETED
- Registry status
- NA
- Development phase
- 7 participants
- Enrollment target
Study Summary
This study will combine Duffin's rebreathing procedure with additional study procedures, such as quantitative pupillometry, that are planned for subsequent clinical studies in order to confirm feasibility and gather reproducibility data using the procedure. The reproducibility of Duffin rebreathing has been assessed previously by Mahamed and Duffin (2001) performing hyperoxic and hypoxic rebreathing procedures measured once daily for 14 consecutive days and then by Jensen et al. (2010) performing 4 pairs of hyperoxic and hypoxic rebreathing procedures in 1 day followed by 1 pair on 4 additional days separated by weeks to more than a month. The present study is an unblinded reproducibility assessment to assess variability of the ventilatory response to Duffin's rebreathing procedure. Subjects will report to the study site for screening between Days -28 to -2 and then will return to the site on Day -1 for baseline assessments and check-in. After check-in (Day -1), subjects will remain in study site for PD assessments on Day 1 and check out on Day 2. Paired rebreathing procedures (i.e., at two different isoxic end tidal PO2 \[partial pressure oxygen\] levels) will be performed on Day 1 at 0, 2, 4, and 6 hours. An additional pair of rebreathing procedures will be performed on Day 2 before checkout (approximately 24 hours). Subjects will not be administered any drugs in this study.
Primary Outcome
Minute ventilation during the rebreathing assessment when end tidal PCO2 (partial pressure carbon dioxide) is less than the ventilatory recruitment threshold (represents non-chemoreflex drives to breathe; 'flat' portion of minute ventilation versus end tidal PCO2 relationship). Data was analyzed using linear-mixed effects regression of baseline minute ventilation with random effects for between subject, between day, and between occasion variability. Reported value is the mean for the treatment g
Interventions
- OTHER Rebreathing procedure
Trial Details
| Field | Value |
|---|---|
| Enrollment Target | 7 participants |
| Start Date | 2021-12-27 |
| Est. Completion | 2022-02-18 |
| Phase | NA |
What the finished NCT05168501 record still lists
NCT05168501 is an interventional study that assigns participants to a tested intervention. The registry caps enrollment at 7 participants, a relatively small participant target, below the 1,404-participant average among 58,714 other NA trials with a reported enrollment target (100% lower).
The record links to 0 conditions, and to 1 intervention - of which Rebreathing procedure is the first listed.
NCT05168501 does not publish any study locations in the registry export this page uses.
Frequently Asked Questions
What is clinical trial NCT05168501 about?
NCT05168501 is a clinical study titled "Assessing Variability of the Ventilatory Response to Duffin's Rebreathing Procedure". This study will combine Duffin's rebreathing procedure with additional study procedures, such as quantitative pupillometry, that are planned for subsequent clinical studies in order to confirm feasibility and gather reproducibility data using the procedure. The reproducibility of Duffin rebreathing ...
What is the current status of trial NCT05168501?
This trial is currently completed. It is a NA study. The enrollment target is 7 participants. The study started on 2021-12-27. Estimated completion is 2022-02-18.
What interventions are being tested in trial NCT05168501?
The interventions under investigation include: Rebreathing procedure (OTHER).
Who is sponsoring clinical trial NCT05168501?
This trial is sponsored by Food and Drug Administration (FDA), which has 23 total clinical trials registered on ClinicalTrials.gov.
Learn More About Clinical Trials
How this trial's enrollment target compares
Where NCT05168501's enrollment target sits among peer trials
7 1982nd of 2000 higher than 18 of 2,000 other NA trials
participants (enrollment target), bucketed by value
Each bar is a band; taller bars hold more other NA trials. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source ClinicalTrials.gov registry export · 2026-08-08
Nationwide trials with similar profiles
Cross-condition peers matched on enrollment target and registry start date, not the same-condition list above.
Similar registry start date
- NCT05962346 · started 2026-12 · NA
Fetal Endoscopic Tracheal Occlusion for Congenital Diaphragmatic Hernia
- NCT07125183 · started 2026-12 · Phase 2
Study on Efficacy and Tolerability of Weekly Doxorubicin in Elderly Patients With Advanced or Metastatic Leiomyosarcoma
- NCT07292298 · started 2026-11 · Phase 2
Phase 2 Single-Arm Rectal Cancer Brachytherapy for Patients With Low-Lying Residual Adenocarcinoma After Total Neoadjuvant Therapy to Improve Organ Preservation Rates
- NCT04263285 · started 2026-10 · NA
Treatment of Depression Post-SCI