Obstructive Sleep ApneaDISE-PulmNCT05350332
Effects of Lung Volume on Upper Airway Patency During Drug Induced Sleep Endoscopy
A study testing Negative Pressure Ventilator, Pulmonary Function Testing (PFT) and Transcutaneous Phrenic Nerve Stimulation in people with Obstructive Sleep Apnea, run by Emory University at 1 site in United States.
Trial summary
Obstructive sleep apnea (OSA) is a disorder where a person has recurrent choking episodes during sleep. Surgery can treat OSA and drug induced sleep endoscopy (DISE) is a procedure that surgeons use to evaluate the throat while a person is sedated, mimicking sleep, to help determine if surgery might be effective. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Obstructive Sleep Apnea
- What is being tested?
- Negative Pressure Ventilator, Pulmonary Function Testing (PFT) and Transcutaneous Phrenic Nerve Stimulation
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 151 participants
- Where
- 1 siteUnited States
- Study dates
- 30 Jun 2022to Jun 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Adult patients (≥ 18 yrs) willing and capable of providing informed consent
- Obstructive sleep apnea (AHI ≥ 5 events/hour)
- Must be willing and able to provide informed consent to participate in the study.
- Interested in surgical treatments of OSA and have consented for a DISE procedure as part of their routine clinical evaluation.
- Patients are evaluated and cleared by anesthesia prior to the procedure.
Who cannot join
- No significant uncontrolled medical co-morbidities (e.g., uncontrolled hypertension, unstable angina, uncompensated heart failure or COPD).
- Any medical comorbidity that would prevent the patient from receiving anesthesia or having surgery
- Inability to tolerate negative pressure ventilator or perform PFT (i.e. claustrophobia)
- No incapacitating disability that interferes with execution of the protocol
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Emory University Hospital Midtown
Atlanta, Georgia, 30308
About this study
Official title: Characterizing the Effects of Lung Volume on Upper Airway Patency During Drug Induced Sleep Endoscopy in Patients With Obstructive Sleep Apnea
Obstructive sleep apnea (OSA) is a disorder where a person has recurrent choking episodes during sleep. Surgery can treat OSA and drug induced sleep endoscopy (DISE) is a procedure that surgeons use to evaluate the throat while a person is sedated, mimicking sleep, to help determine if surgery might be effective. Lung volume can influence OSA severity but the relationship between lung function and throat collapse seen on DISE has not been well studied. This study aims to see if lung volume influences what is happening in the throat during DISE. Participants will be recruited from the sleep surgery clinic where they are being evaluated for surgery to treat their OSA. Participants will have a DISE that is performed as part of their routine surgical workup for treatment of OSA. Additionally, during the DISE, they will participate in one of two study groups. One group will have a negative pressure "turtle shell" ventilator placed over the participants chest during DISE to manipulate lung volumes to see if it can improve throat collapse. A second group will have phrenic nerve stimulation to contract the diaphragm to improve lung volumes to see if it can improve throat collapse. Both groups will also have a lung function test performed. The findings of this study will be important in improving pre-surgical evaluation of patients to better predict if surgery can help as well as potentially develop new surgical therapies for the treatment of OSA.
Read the detailed description
Obstructive sleep apnea (OSA) is a common disorder characterized by recurrent choking episodes during sleep. OSA affects over 25 million Americans and is associated with increased risks of hypertension, diabetes, cardiovascular disease, and stroke. The severity of OSA is measured by the number of complete or partial obstructive events per hour of sleep, and quantified for diagnostic and research purposes as the apnea-hypopnea index (AHI). Continuous positive airway pressure (CPAP) is the first line therapy for treating OSA, however, 20-40% of patients do not tolerate wearing a pressurized mask during sleep. Several surgeries can treat OSA, including pharyngeal soft tissue surgery, skeletal advancement surgery, and hypoglossal nerve stimulation which are deemed successful when surgery reduces the AHI to below 5 events per hour. Successful surgical treatment of OSA is highly variable with rates of success as low as 40% in early studies that looked at pharyngeal soft tissue surgery. Selecting OSA patients for surgery based on certain pathophysiologic characteristics has vastly improved surgical success rates, up to 60-80% depending on the surgery. However, the application of OSA pathophysiological assessment for surgical selection remains incomplete. This study will explore a wider range of pathophysiological factors to improve surgical outcomes and anticipate that further understanding of these relationships will support development of new surgical and non-surgical treatments for those who may not benefit from current treatment options.
Drug induced sleep endoscopy (DISE) is currently used to help determine appropriate patients for OSA surgery. During DISE, a fiber optic camera is placed through the nose into the throat to visualize airway collapse patterns during sedation mimicking natural sleep. The standardized method of describing airway collapse is known as the Velum, Oropharynx, Tongue Base, Epiglottis (VOTE) score which assesses the severity and pattern of collapse at four different anatomic sites of the upper airway. Previous studies have shown that airway collapse patterns visualized on DISE affect surgical outcomes.
Prior studies indicate that the phrenic nerve can be stimulated non-invasively to examine effects of diaphragmatic contraction on upper airway patency. Initial studies demonstrated that surface electrodes overlying the phrenic nerves in the lateral neck can be used to recruit the diaphragm and generate tidal breaths. Later studies demonstrated similar effects of transcutaneous stimulation with inductance coils on tidal airflow while modeling the effects of vigorous diaphragmatic contraction on pharyngeal patency. Finally, transcutaneous phrenic nerve stimulation has been applied during drug-induced sleep studies in patients to elucidate effects of lung volume on pharyngeal patency. This study demonstrated substantial reductions in upper airway obstruction in a dose-dependent fashion when phrenic nerve stimulation increased lung volume to varying levels. Of note, no untoward adverse events were noted in any of these prior studies. Taken together, these studies demonstrate that external transcutaneous stimulation is safe, can generate transient and sustained elevations in lung volume, and relieve upper airway obstruction in sedated individuals.
One overlooked pathophysiologic factor in the evaluation for OSA surgery is lung volume. Studies of lung physiology in OSA patients have found that lower functional residual capacity (FRC) and expiratory reserve volume (ERV) on pulmonary function testing, a commonly used procedure in pulmonary medicine, is associated with increased OSA severity. Experimental studies in OSA patients have shown that when negative pressure was used to expand the chest (e.g., iron lung) during sleep, the subsequent increased lung volume resulted in decreased upper airway collapsibility and reduced OSA severity. Transcutaneous phrenic nerve stimulation has also been applied during sedation studies in patients to elucidate effects of lung volume on pharyngeal patency demonstrating substantial reductions in upper airway obstruction in a dose-dependent fashion when phrenic nerve stimulation increased lung volume to varying levels. Despite this evidence, lung volume is not utilized as part of the evaluation for OSA surgery. The goal of this study is to determine if lung volume is useful in predicting surgical success and whether improving lung volumes via negative pressure ventilator or phrenic nerve stimulation can be used as an adjunctive therapy with surgery to treat OSA.
Patients will participate in DISE and be assigned either into a negative pressure ventilator or phrenic nerve stimulation cohort to evaluate each modality's effect on improving lung volume and altering upper airway collapsibility in DISE. Participants will also have a pulmonary function test to determine baseline lung volume measures.
- Conditions
- Obstructive Sleep Apnea
- Being tested
- Negative Pressure Ventilator, Pulmonary Function Testing (PFT), Transcutaneous Phrenic Nerve Stimulation, Percutaneous Phrenic Nerve Stimulation
- Medical subject headings
- Sleep Apnea, Obstructive
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Negative Pressure VentilatorDevice
Also called cuirass ventilator, Hayek turtle shell, iron lung
The negative pressure ventilator is an off-the-shelf FDA-approved device designed to treat respiratory patients with hypoventilation syndromes. This ventilator places the torso within a fixed container that is connected to a vacuum source, which inflates the lungs by pulling a negative pressure around the chest and abdomen. After the clinically routine DISE, a negative pressure ventilator will be placed on the participant's chest to increase lung volumes and the DISE evaluation will be repeated to observe changes.
Pulmonary Function Testing (PFT)Device
Also called MiniBox+
PFT is a routine standardized clinical test evaluating lung function, consisting of two parts: spirometry and body plethysmography. In spirometry, participants breathe through a mouthpiece that measures airflow and volume to determine normal and maximal volume of inspiration/expiration. Body plethysmography is performed to calculate residual lung volumes. Participants enter in an enclosed chamber where they breathe through a mouthpiece. Changes in pressure in the sealed chamber during breathing are used to calculate the volume of air that remains in the lung after expiration. A MiniBox+ device may be used. The MiniBox+ device derives total lung capacity (TLC) during tidal breathing by the analysis of gas pressures and airflows immediately preceding and immediately following airway occlusions to calculate the same measures as conventional PFT analysis.
Transcutaneous Phrenic Nerve StimulationDevice
Also called Digitimer DS8R Bipolar Constant Current Stimulator
Phrenic nerve stimulation (PNS) will be performed transcutaneously using a commercially available and FDA approved peripheral neurostimulator. (Digitimer DS8R Bipolar Constant Current Stimulator). The neurostimulator consists of a stimulation generating box connected to electrodes that will be placed over the skin of the neck bilaterally over both phrenic nerves where an bipolar electric current will be used to stimulate the phrenic nerve leading to diaphragm contraction.
Percutaneous Phrenic Nerve StimulationDevice
Also called Digitimer DS8R Bipolar Constant Current Stimulator, Stimulong Sono II
Under ultrasound guidance, a stimulating catheter (Stimulong Sono II) will be inserted into the right side of the neck and positioned adjacent to the phrenic nerve as it travels along the anterior scalene muscle. The catheter will be connected to a commercially available research neurostimulator. Unilateral phrenic nerve stimulation will be performed for no more than 30 minutes.
| Study group | Role | What they receive |
|---|---|---|
| Negative Pressure Ventilator | Experimental | Participants with obstructive sleep apnea (OSA) who are being evaluated for surgical treatment of their OSA and having a routine clinical DISE will have their lung volume increased with a non-invasive negative pressure ventilator. Participants will also have a pulmonary function test performed per routine clinical protocol, but for research purposes only (i.e., not part of usual care). Receives: Device: Negative Pressure Ventilator; Device: Pulmonary Function Testing (PFT) |
| Phrenic Nerve Stimulation | Experimental | Participants with obstructive sleep apnea (OSA) who are being evaluated for surgical treatment of their OSA and having a routine clinical DISE will have their lung volume increased with transcutaneous or percutaneous phrenic nerve stimulation. Participants will also have a pulmonary function test performed per routine clinical protocol, but for research purposes only (i.e., not part of usual care). Receives: Device: Pulmonary Function Testing (PFT); Device: Transcutaneous Phrenic Nerve Stimulation; Device: Percutaneous Phrenic Nerve Stimulation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Expiratory Reserve Volume (ERV)
ERV is the volume of extra air that can be forcefully breathed out after exhaling normally. ERV is impacted by body size and altitude and the normal range for adults is about 0.7 to 1.1 liters (L). ERV is obtained as part of the pulmonary function test.
Measured: During PFT
Functional Residual Capacity (FRC)
FRC is the amount of air remaining in the lungs after a normal exhalation. FRC is impacted by body size and altitude and the normal volume for adults is about 1.8 to 2.4 L. FRC is obtained during the pulmonary function test and is the sum of residual volume (RV; the volume of air remaining after maximum exhalation) and ERV.
Measured: During PFT
Change in VOTE Collapse Patterns - Degree of Obstruction
VOTE collapse patterns are obtained during the routine clinical DISE evaluation and during DISE with negative pressure ventilation. The VOTE classification codes degree of obstruction as 0 = no obstruction (no vibration), 1 = partial obstruction (vibration), and 2 = complete obstruction (collapse). Degree of obstruction is determined the velum, oropharynx lateral walls, tongue base, and epiglottis. The measurements obtained without and with negative pressure ventilation will be compared.
Measured: During clinical DISE and intervention DISE
Change in VOTE Collapse Patterns - Configuration of Obstruction
VOTE collapse patterns are obtained during the routine clinical DISE evaluation and during DISE with negative pressure ventilation. The VOTE classification codes configuration of obstruction for structures with a degree of obstruction greater than 0. The configuration of obstruction is categorized as anteroposterior (anterior structures moving posteriorly against pharyngeal wall), lateral (lateral structures moving towards airway center), or concentric (both anteroposterior and lateral movements). The measurements obtained without and with negative pressure ventilation will be compared.
Measured: During clinical DISE and intervention DISE
Change in Critical Closing Pressure (Pcrit)
Critical closing pressures are obtained during the routine clinical DISE evaluation and during DISE with negative pressure ventilation. Pcrit assessed pharyngeal collapsibility and is measured as centimeters of water (cm H2O). A Pcrit of less than -10 cm H2O indicates normal breathing. Patients with a Pcrit around -6cm H2O tend to snore but not have OSA. A Pcrit around or greater than 0 cm H2O is seen with obstructive sleep apnea.The measurements obtained without and with negative pressure ventilation will be compared.
Measured: During clinical DISE and intervention DISE
Change in Pharyngeal Opening Pressures
Pharyngeal opening pressures are obtained during the routine clinical DISE evaluation and during DISE with negative pressure ventilation. Opening pressures are obtained using a positive airway pressure (PAP) titration device. Pharyngeal opening pressures are defined as the minimally effective positive airway pressure that results in non-flow limited breathing. This is measured in cm H2O and ranges from 0 to 25 cm H2O, with 25 cm H2O being the maximum pressure the PAP machine is capable of generating. The measurements obtained without and with negative pressure ventilation will be compared.
Measured: During clinical DISE and intervention DISE
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Apr 2022
- Study start30 Jun 2022
- Primary completionJun 2027 (estimated)
- Study completionJun 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (16)Papers the sponsor has linked to this study.
- Other trials for Obstructive Sleep ApneaStudies of the same condition, open and under way.
- More trials run by Emory UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 151 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Emory University
- Sponsor type
- University, hospital or other
- Collaborators
- Lunair Medical
- Responsible party
- Principal investigator, Jason Yu, Emory University
- Investigators
- Jason Yu, MD, Principal investigator, Emory University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05350332
- Sponsor's protocol ID
- STUDY00003579
- Other IDs
- 2025P013290
- Acronym
- DISE-Pulm
- Status last verified
- Aug 2026
- First submitted
- 22 Apr 2022
- Last updated
- 26 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- Yes: All of the individual participant data collected during the trial after deidentification will be available to share to researchers who provide a methodologically sound proposal. Sharing will be available immediately following publication with no end date.
Publications
Peppard PE, Young T, Palta M, Skatrud J. Prospective study of the association between sleep-disordered breathing and hypertension. N Engl J Med. 2000 May 11;342(19):1378-84. doi: 10.1056/NEJM200005113421901.
PubMed 10805822Punjabi NM, Shahar E, Redline S, Gottlieb DJ, Givelber R, Resnick HE; Sleep Heart Health Study Investigators. Sleep-disordered breathing, glucose intolerance, and insulin resistance: the Sleep Heart Health Study. Am J Epidemiol. 2004 Sep 15;160(6):521-30. doi: 10.1093/aje/kwh261.
PubMed 15353412Drager LF, Bortolotto LA, Lorenzi MC, Figueiredo AC, Krieger EM, Lorenzi-Filho G. Early signs of atherosclerosis in obstructive sleep apnea. Am J Respir Crit Care Med. 2005 Sep 1;172(5):613-8. doi: 10.1164/rccm.200503-340OC. Epub 2005 May 18.
PubMed 15901608Yaggi HK, Concato J, Kernan WN, Lichtman JH, Brass LM, Mohsenin V. Obstructive sleep apnea as a risk factor for stroke and death. N Engl J Med. 2005 Nov 10;353(19):2034-41. doi: 10.1056/NEJMoa043104.
PubMed 16282178Punjabi NM. The epidemiology of adult obstructive sleep apnea. Proc Am Thorac Soc. 2008 Feb 15;5(2):136-43. doi: 10.1513/pats.200709-155MG.
PubMed 18250205Iber, Conrad, Ancoli-Israel, Sonia, Chesson, Andrew L, Quan, Stuart F. The AASM manual for the scoring of sleep and associated events: rules, terminology and technical specifications. Am Acad Sleep Med Westchest IL. 2007;1.
Richards D, Bartlett DJ, Wong K, Malouff J, Grunstein RR. Increased adherence to CPAP with a group cognitive behavioral treatment intervention: a randomized trial. Sleep. 2007 May;30(5):635-40. doi: 10.1093/sleep/30.5.635.
PubMed 17552379Weaver TE, Grunstein RR. Adherence to continuous positive airway pressure therapy: the challenge to effective treatment. Proc Am Thorac Soc. 2008 Feb 15;5(2):173-8. doi: 10.1513/pats.200708-119MG.
PubMed 18250209Veasey SC, Rosen IM. Obstructive Sleep Apnea in Adults. N Engl J Med. 2019 Apr 11;380(15):1442-1449. doi: 10.1056/NEJMcp1816152. No abstract available.
PubMed 30970189Pepin JL, Woehrle H, Liu D, Shao S, Armitstead JP, Cistulli PA, Benjafield AV, Malhotra A. Adherence to Positive Airway Therapy After Switching From CPAP to ASV: A Big Data Analysis. J Clin Sleep Med. 2018 Jan 15;14(1):57-63. doi: 10.5664/jcsm.6880.
PubMed 29198291Bakker JP, Weaver TE, Parthasarathy S, Aloia MS. Adherence to CPAP: What Should We Be Aiming For, and How Can We Get There? Chest. 2019 Jun;155(6):1272-1287. doi: 10.1016/j.chest.2019.01.012. Epub 2019 Jan 23.
PubMed 30684472Verse T, Kroker BA, Pirsig W, Brosch S. Tonsillectomy as a treatment of obstructive sleep apnea in adults with tonsillar hypertrophy. Laryngoscope. 2000 Sep;110(9):1556-9. doi: 10.1097/00005537-200009000-00029.
PubMed 10983961Series F, Cormier Y, Lampron N, La Forge J. Increasing the functional residual capacity may reverse obstructive sleep apnea. Sleep. 1988 Aug;11(4):349-53.
PubMed 2974620Heinzer RC, Stanchina ML, Malhotra A, Jordan AS, Patel SR, Lo YL, Wellman A, Schory K, Dover L, White DP. Effect of increased lung volume on sleep disordered breathing in patients with sleep apnoea. Thorax. 2006 May;61(5):435-9. doi: 10.1136/thx.2005.052084. Epub 2006 Feb 20.
PubMed 16490766Owens RL, Malhotra A, Eckert DJ, White DP, Jordan AS. The influence of end-expiratory lung volume on measurements of pharyngeal collapsibility. J Appl Physiol (1985). 2010 Feb;108(2):445-51. doi: 10.1152/japplphysiol.00755.2009. Epub 2009 Nov 25.
PubMed 19940097
Study at a glance
From the registry record, last updated by the sponsor on 26 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Characterizing the Effects of Lung Volume on Upper Airway Patency During Drug Induced Sleep Endoscopy in Patients With Obstructive Sleep Apnea
- ClinicalTrials.gov ID
- NCT05350332
- Acronym / sponsor ID
- DISE-Pulm / STUDY00003579
- Conditions
- Obstructive Sleep Apnea
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 151 participants (estimated)
- Lead sponsor
- Emory UniversityUniversity, hospital or other
- Collaborators
- Lunair Medical
- Study start
- 30 Jun 2022 (actual)
- Primary completion
- Jun 2027 (estimated)
- Study completion
- Jun 2027 (estimated)
- First posted
- 28 Apr 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Obstructive sleep apnea (OSA) is a disorder where a person has recurrent choking episodes during sleep. Surgery can treat OSA and drug induced sleep endoscopy (DISE) is a procedure that surgeons use to evaluate the throat while a person is sedated, mimicking sleep, to help determine if surgery might be effective. Lung volume can influence OSA severity but the relationship between lung function and throat collapse seen on DISE has not been well studied. This study aims to see if lung volume influences what is happening in the throat during DISE. Participants will be recruited from the sleep surgery clinic where they are being evaluated for surgery to treat their OSA. Participants will have a DISE that is performed as part of their routine surgical workup for treatment of OSA. Additionally, during the DISE, they will participate in one of two study groups. One group will have a negative pressure "turtle shell" ventilator placed over the participants chest during DISE to manipulate lung volumes to see if it can improve throat collapse. A second group will have phrenic nerve stimulation to contract the diaphragm to improve lung volumes to see if it can improve throat collapse. Both groups will also have a lung function test performed. The findings of this study will be important in improving pre-surgical evaluation of patients to better predict if surgery can help as well as potentially develop new surgical therapies for the treatment of OSA.
Detailed description
Obstructive sleep apnea (OSA) is a common disorder characterized by recurrent choking episodes during sleep. OSA affects over 25 million Americans and is associated with increased risks of hypertension, diabetes, cardiovascular disease, and stroke. The severity of OSA is measured by the number of complete or partial obstructive events per hour of sleep, and quantified for diagnostic and research purposes as the apnea-hypopnea index (AHI). Continuous positive airway pressure (CPAP) is the first line therapy for treating OSA, however, 20-40% of patients do not tolerate wearing a pressurized mask during sleep. Several surgeries can treat OSA, including pharyngeal soft tissue surgery, skeletal advancement surgery, and hypoglossal nerve stimulation which are deemed successful when surgery reduces the AHI to below 5 events per hour. Successful surgical treatment of OSA is highly variable with rates of success as low as 40% in early studies that looked at pharyngeal soft tissue surgery. Selecting OSA patients for surgery based on certain pathophysiologic characteristics has vastly improved surgical success rates, up to 60-80% depending on the surgery. However, the application of OSA pathophysiological assessment for surgical selection remains incomplete. This study will explore a wider range of pathophysiological factors to improve surgical outcomes and anticipate that further understanding of these relationships will support development of new surgical and non-surgical treatments for those who may not benefit from current treatment options.
Drug induced sleep endoscopy (DISE) is currently used to help determine appropriate patients for OSA surgery. During DISE, a fiber optic camera is placed through the nose into the throat to visualize airway collapse patterns during sedation mimicking natural sleep. The standardized method of describing airway collapse is known as the Velum, Oropharynx, Tongue Base, Epiglottis (VOTE) score which assesses the severity and pattern of collapse at four different anatomic sites of the upper airway. Previous studies have shown that airway collapse patterns visualized on DISE affect surgical outcomes.
Prior studies indicate that the phrenic nerve can be stimulated non-invasively to examine effects of diaphragmatic contraction on upper airway patency. Initial studies demonstrated that surface electrodes overlying the phrenic nerves in the lateral neck can be used to recruit the diaphragm and generate tidal breaths. Later studies demonstrated similar effects of transcutaneous stimulation with inductance coils on tidal airflow while modeling the effects of vigorous diaphragmatic contraction on pharyngeal patency. Finally, transcutaneous phrenic nerve stimulation has been applied during drug-induced sleep studies in patients to elucidate effects of lung volume on pharyngeal patency. This study demonstrated substantial reductions in upper airway obstruction in a dose-dependent fashion when phrenic nerve stimulation increased lung volume to varying levels. Of note, no untoward adverse events were noted in any of these prior studies. Taken together, these studies demonstrate that external transcutaneous stimulation is safe, can generate transient and sustained elevations in lung volume, and relieve upper airway obstruction in sedated individuals.
One overlooked pathophysiologic factor in the evaluation for OSA surgery is lung volume. Studies of lung physiology in OSA patients have found that lower functional residual capacity (FRC) and expiratory reserve volume (ERV) on pulmonary function testing, a commonly used procedure in pulmonary medicine, is associated with increased OSA severity. Experimental studies in OSA patients have shown that when negative pressure was used to expand the chest (e.g., iron lung) during sleep, the subsequent increased lung volume resulted in decreased upper airway collapsibility and reduced OSA severity. Transcutaneous phrenic nerve stimulation has also been applied during sedation studies in patients to elucidate effects of lung volume on pharyngeal patency demonstrating substantial reductions in upper airway obstruction in a dose-dependent fashion when phrenic nerve stimulation increased lung volume to varying levels. Despite this evidence, lung volume is not utilized as part of the evaluation for OSA surgery. The goal of this study is to determine if lung volume is useful in predicting surgical success and whether improving lung volumes via negative pressure ventilator or phrenic nerve stimulation can be used as an adjunctive therapy with surgery to treat OSA.
Patients will participate in DISE and be assigned either into a negative pressure ventilator or phrenic nerve stimulation cohort to evaluate each modality's effect on improving lung volume and altering upper airway collapsibility in DISE. Participants will also have a pulmonary function test to determine baseline lung volume measures.
Study design
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Negative Pressure Ventilator | Experimental | Device: Negative Pressure Ventilator, Device: Pulmonary Function Testing (PFT)Participants with obstructive sleep apnea (OSA) who are being evaluated for surgical treatment of their OSA and having a routine clinical DISE will have their lung volume increased with a non-invasive negative pressure ventilator. Participants will also have a pulmonary function test performed per routine clinical protocol, but for research purposes only (i.e., not part of usual care). |
| Phrenic Nerve Stimulation | Experimental | Device: Pulmonary Function Testing (PFT), Device: Transcutaneous Phrenic Nerve Stimulation, Device: Percutaneous Phrenic Nerve StimulationParticipants with obstructive sleep apnea (OSA) who are being evaluated for surgical treatment of their OSA and having a routine clinical DISE will have their lung volume increased with transcutaneous or percutaneous phrenic nerve stimulation. Participants will also have a pulmonary function test performed per routine clinical protocol, but for research purposes only (i.e., not part of usual care). |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Adult patients (≥ 18 yrs) willing and capable of providing informed consent
- Obstructive sleep apnea (AHI ≥ 5 events/hour)
- Must be willing and able to provide informed consent to participate in the study.
- Interested in surgical treatments of OSA and have consented for a DISE procedure as part of their routine clinical evaluation.
Key exclusion criteria (4 listed)
- No significant uncontrolled medical co-morbidities (e.g., uncontrolled hypertension, unstable angina, uncompensated heart failure or COPD).
- Any medical comorbidity that would prevent the patient from receiving anesthesia or having surgery
- Inability to tolerate negative pressure ventilator or perform PFT (i.e. claustrophobia)
- No incapacitating disability that interferes with execution of the protocol
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Negative Pressure VentilatorAlso: cuirass ventilator, Hayek turtle shell, iron lungThe negative pressure ventilator is an off-the-shelf FDA-approved device designed to treat respiratory patients with hypoventilation syndromes. This ventilator places the torso within a fixed container that is connected to a vacuum source, which inflates the lungs by pulling a negative pressure around the chest and abdomen. After the clinically routine DISE, a negative pressure ventilator will be placed on the participant's chest to increase lung volumes and the DISE evaluation will be repeated to observe changes. | Device | Negative Pressure Ventilator |
| Pulmonary Function Testing (PFT)Also: MiniBox+PFT is a routine standardized clinical test evaluating lung function, consisting of two parts: spirometry and body plethysmography. In spirometry, participants breathe through a mouthpiece that measures airflow and volume to determine normal and maximal volume of inspiration/expiration. Body plethysmography is performed to calculate residual lung volumes. Participants enter in an enclosed chamber where they breathe through a mouthpiece. Changes in pressure in the sealed chamber during breathing are used to calculate the volume of air that remains in the lung after expiration. A MiniBox+ device may be used. The MiniBox+ device derives total lung capacity (TLC) during tidal breathing by the analysis of gas pressures and airflows immediately preceding and immediately following airway occlusions to calculate the same measures as conventional PFT analysis. | Device | Negative Pressure Ventilator, Phrenic Nerve Stimulation |
| Transcutaneous Phrenic Nerve StimulationAlso: Digitimer DS8R Bipolar Constant Current StimulatorPhrenic nerve stimulation (PNS) will be performed transcutaneously using a commercially available and FDA approved peripheral neurostimulator. (Digitimer DS8R Bipolar Constant Current Stimulator). The neurostimulator consists of a stimulation generating box connected to electrodes that will be placed over the skin of the neck bilaterally over both phrenic nerves where an bipolar electric current will be used to stimulate the phrenic nerve leading to diaphragm contraction. | Device | Phrenic Nerve Stimulation |
| Percutaneous Phrenic Nerve StimulationAlso: Digitimer DS8R Bipolar Constant Current Stimulator, Stimulong Sono IIUnder ultrasound guidance, a stimulating catheter (Stimulong Sono II) will be inserted into the right side of the neck and positioned adjacent to the phrenic nerve as it travels along the anterior scalene muscle. The catheter will be connected to a commercially available research neurostimulator. Unilateral phrenic nerve stimulation will be performed for no more than 30 minutes. | Device | Phrenic Nerve Stimulation |
Primary outcome
Expiratory Reserve Volume (ERV)
Time frame: During PFT
ERV is the volume of extra air that can be forcefully breathed out after exhaling normally. ERV is impacted by body size and altitude and the normal range for adults is about 0.7 to 1.1 liters (L). ERV is obtained as part of the pulmonary function test.
Functional Residual Capacity (FRC)
Time frame: During PFT
FRC is the amount of air remaining in the lungs after a normal exhalation. FRC is impacted by body size and altitude and the normal volume for adults is about 1.8 to 2.4 L. FRC is obtained during the pulmonary function test and is the sum of residual volume (RV; the volume of air remaining after maximum exhalation) and ERV.
Change in VOTE Collapse Patterns - Degree of Obstruction
Time frame: During clinical DISE and intervention DISE
VOTE collapse patterns are obtained during the routine clinical DISE evaluation and during DISE with negative pressure ventilation. The VOTE classification codes degree of obstruction as 0 = no obstruction (no vibration), 1 = partial obstruction (vibration), and 2 = complete obstruction (collapse). Degree of obstruction is determined the velum, oropharynx lateral walls, tongue base, and epiglottis. The measurements obtained without and with negative pressure ventilation will be compared.
Change in VOTE Collapse Patterns - Configuration of Obstruction
Time frame: During clinical DISE and intervention DISE
VOTE collapse patterns are obtained during the routine clinical DISE evaluation and during DISE with negative pressure ventilation. The VOTE classification codes configuration of obstruction for structures with a degree of obstruction greater than 0. The configuration of obstruction is categorized as anteroposterior (anterior structures moving posteriorly against pharyngeal wall), lateral (lateral structures moving towards airway center), or concentric (both anteroposterior and lateral movements). The measurements obtained without and with negative pressure ventilation will be compared.
Change in Critical Closing Pressure (Pcrit)
Time frame: During clinical DISE and intervention DISE
Critical closing pressures are obtained during the routine clinical DISE evaluation and during DISE with negative pressure ventilation. Pcrit assessed pharyngeal collapsibility and is measured as centimeters of water (cm H2O). A Pcrit of less than -10 cm H2O indicates normal breathing. Patients with a Pcrit around -6cm H2O tend to snore but not have OSA. A Pcrit around or greater than 0 cm H2O is seen with obstructive sleep apnea.The measurements obtained without and with negative pressure ventilation will be compared.
Change in Pharyngeal Opening Pressures
Time frame: During clinical DISE and intervention DISE
Pharyngeal opening pressures are obtained during the routine clinical DISE evaluation and during DISE with negative pressure ventilation. Opening pressures are obtained using a positive airway pressure (PAP) titration device. Pharyngeal opening pressures are defined as the minimally effective positive airway pressure that results in non-flow limited breathing. This is measured in cm H2O and ranges from 0 to 25 cm H2O, with 25 cm H2O being the maximum pressure the PAP machine is capable of generating. The measurements obtained without and with negative pressure ventilation will be compared.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Aug 2026.
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- Background: PubMed 17552379Richards D, Bartlett DJ, Wong K, Malouff J, Grunstein RR. Increased adherence to CPAP with a group cognitive behavioral treatment intervention: a randomized trial. Sleep. 2007 May;30(5):635-40. doi: 10.1093/sleep/30.5.635.
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- Background: PubMed 30970189Veasey SC, Rosen IM. Obstructive Sleep Apnea in Adults. N Engl J Med. 2019 Apr 11;380(15):1442-1449. doi: 10.1056/NEJMcp1816152. No abstract available.
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- Individual participant dataSharing planned: Yes. All of the individual participant data collected during the trial after deidentification will be available to share to researchers who provide a methodologically sound proposal. Sharing will be available immediately following publication with no end date.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Jason Yu, MD principal investigator
Emory University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Negative Pressure Ventilator, Pulmonary Function Testing (PFT) and Transcutaneous Phrenic Nerve Stimulation in people with Obstructive Sleep Apnea, run by Emory University at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 26 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Jason Yu, MD (470-763-3887, jyu40@emory.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Expiratory Reserve Volume (ERV) (time frame: During PFT). The study lists 6 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05350332, which also lists 16 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 26 Aug 2026.