ObesityNCT06675435
Inhaled Nitric Oxide in Severe Obesity
A study testing Nitric oxide in people with Obesity and Respiratory Insufficiency, run by Massachusetts General Hospital at 1 site in United States.
Trial summary
The goal of this clinical trial is to learn about the effects of inhaled nitric oxide on oxygenation and lung perfusion in participants with severe obesity who have acute hypoxemic respiratory failure and are on mechanical ventilation The main questions it aims to answer are: 1. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Obesity, Respiratory Insufficiency, Hypoxemic Respiratory Failure
- What is being tested?
- Nitric oxide
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 60 participants
- Where
- 1 siteUnited States
- Study dates
- Oct 2026to Dec 2028
- 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
- Acute hypoxemic respiratory failure, defined as persistent hypoxemia (PaO2/FiO2 ≤ 300 mmHg or SpO2/FiO2 ≤ 315) and on invasive mechanical ventilation for < 72 hours
- Presence of an arterial and central venous catheter (for blood gas measurement)
- Admitted to a participating MGH ICU
- Receiving invasive mechanical ventilation and do not have a diagnosis of acute hypoxemic respiratory failure (PaO2/FiO2 > 300 mmHg or SpO2/FiO2> 315)
- Presence of an arterial catheter
- Admitted to a participating MGH ICU
Who cannot join
- Age < 18 years
- Pregnancy or known active breastfeeding
- Prisoner or Incarceration
- Inability or unwillingness of subject or legal surrogate/representative to give written informed consent
- Use of inhaled or oral pulmonary vasodilatory therapy within the 24 hours preceding study enrollment
- Contraindication to inhaled NO
Show all 25Show fewer
- Baseline Methemoglobin ≥ 3%
- Known left ventricle ejection fraction < 20%
- Known history of G6PD deficiency or cytochrome issues
- Prior adverse reaction to inhaled nitric oxide
- Presence of pneumothorax or acute pulmonary embolism
- Chronic hypoxemia requiring home supplemental non-invasive oxygen (nasal cannula or positive pressure ventilation) or home mechanical ventilation
- Chronic pulmonary vascular disease on home chemical vasodilator support (e.g., sildenafil)
- History of lung resection or transplant
- Hemodynamic instability at the time of potential study enrollment defined as:
- Persistent systolic blood pressure < 90 mmHg or >180 mmHg despite the use of vasopressor or vasodilators or
- Requiring an increment in inotropic-vasopressors over the past two hours just before enrollment: more than 15 mcg/min for norepinephrine and dopamine, more than 10 mcg/min in epinephrine; and more than 50 mcg/ min for phenylephrine.
- EIT assessments of lung perfusion will only be performed in participants who are already receiving neuromuscular blocking agents (e.g., cisatracurium) at the time of study enrollment. EIT assessments of lung perfusion will not be performed in participants who have the following contraindications to EIT perfusion monitoring:
- Hypernatremia (serum sodium > 150 mEq/L)
- Usage of any devices with electric current generation such as pacemaker or internal cardiac defibrillator
- For controls without acute hypoxemic respiratory failure
- Age < 18 years
- Pregnancy or known active breastfeeding
- Prisoner or Incarceration
- Inability or unwillingness of subject or legal surrogate/representative to give written informed consent
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
Massachusetts General Hospital
Boston, Massachusetts, 02114
Timothy Gaulton, MD, Msc, 6177263030, tgaulton@mgh.harvard.edu
About this study
Official title: The Effect of Inhaled Nitric Oxide on Intrapulmonary Shunt in Acutely Hypoxemic Patients With Severe Obesity
The goal of this clinical trial is to learn about the effects of inhaled nitric oxide on oxygenation and lung perfusion in participants with severe obesity who have acute hypoxemic respiratory failure and are on mechanical ventilation
The main questions it aims to answer are:
Read more
- In acute hypoxemic respiratory failure, what are the effects of inhaled nitric oxide on oxygenation in participants with severe obesity compared to participants with normal body weight.
- In acute hypoxemic respiratory failure, what are the effects of inhaled nitric oxide on lung perfusion and heart function in participants with severe obesity compared to participants with normal body weight.
- In acute hypoxemic respiratory failure, does severe obesity impact nitric oxide signaling pathways?
Participants with acute hypoxemic respiratory failure will be exposed to inhaled nitric oxide (20 ppm) while being clinically monitored.
Read the detailed description
The study is a single-center, open-label clinical trial in mechanically ventilated participants with acute hypoxemic respiratory failure. The primary aim is to assess changes in intrapulmonary shunt (primary study outcome) to inhaled nitric oxide in participants with severe obesity and those with normal body weight. The secondary aims are to determine differences in regional lung perfusion (measured by electrical impedance tomography), right ventricular pressure (measured by transthoracic echocardiography), and biomarkers of nitric oxide signaling dysfunction (nitric oxide activity, pro-inflammatory cytokines, endothelial glycocalyx fragments)
The primary study intervention involves inhaled nitric oxide at 20 ppm for 15 minutes. The investigators will compare inhaled nitric oxide response in participants with severe obesity (defined by body mass index greater than or equal to 40) to participants with normal body weight (defined by body mass index 18.5-24.9). 40 participants with acute hypoxemic respiratory failure will be enrolled (20 with severe obesity and 20 with normal body weight). The investigators will enroll a separate cohort of mechanically ventilated participants who do not have acute hypoxemic respiratory failure (10 with severe obesity and 10 with normal body weight). In this cohort, investigators will collect additional blood at a single time point to compare levels of nitric oxide signaling pathways between patients with and without acute hypoxemia across body weight.
- Being tested
- Nitric oxide
- Keywords
- severe obesity, acute hypoxemic respiratory failure, intrapulmonary shunt, inhaled nitric oxide
- Medical subject headings
- Obesity, Respiratory Insufficiency, Obesity, Morbid
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Nitric oxideDevice
20ppm for 15 minutes delivered by INO max(Nitric Oxide) Company : INO therapeutics, Inc.
| Study group | Role | What they receive |
|---|---|---|
| Acute hypoxemic respiratory failure | Experimental | Participants (n = 40) with acute hypoxemic respiratory failure will receive inhaled nitric oxide (20 ppm) for 15 min. Receives: Device: Nitric oxide |
| Participants without acute hypoxemic respiratory failure | No intervention | Participants (n = 20) without acute hypoxemic respiratory failure will not receive inhaled nitric oxide |
What is being measured
The primary outcome is the main question the study is designed to answer.
Intrapulmonary shunt
Intrapulmonary shunt will be defined as the difference in intrapulmonary shunt (%) to inhaled nitric oxide. Intrapulmonary shunt will be defined using the modified Berggren equation based on central venous and arterial oxygen concentrations from a central venous and peripheral arterial catheter.
Measured: Intrapulmonary shunt will be assessed before inhaled nitric oxide, at 15 minutes after inhaled nitric oxide, and at 15 minutes after inhaled nitric oxide discontinuation.
Secondary outcomes (3)
Regional pulmonary perfusion
In participants who are already receiving neuromuscular blocking agents, regional pulmonary perfusion will be measured and defined as the % change to inhaled nitric oxide in 4 lung regions of interest (right upper, right lower, left upper, left lower)
Measured: Regional pulmonary perfusion will be assessed before inhaled nitric oxide, at 15 minutes after inhaled nitric oxide, and at 15 minutes after inhaled nitric oxide discontinuation.
Gas exchange
Measures of gas exchange be defined by Pa02/Fi02 and dead space fraction in response to inhaled nitric oxide
Measured: Gas exchange will be assessed before inhaled nitric oxide, at 15 minutes after inhaled nitric oxide, and at 15 minutes after inhaled nitric oxide discontinuation.
Right ventricular systolic pressure
The investigators will measure right ventricular systolic pressure, an ultrasound surrogate of pulmonary arterial pressure, in response to inhaled nitric oxide
Measured: Right ventricular systolic pressure will be assessed before inhaled nitric oxide, at 15 minutes after inhaled nitric oxide, and at 15 minutes after inhaled nitric oxide discontinuation.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Nov 2024
- Study startOct 2026 (estimated)
- Primary completionOct 2028 (estimated)
- Study completionDec 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for ObesityStudies of the same condition, open and under way.
- More trials run by Massachusetts General HospitalThe 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
- Diagnosis
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Model description
- In a prospective single center clinical study, participants with acute hypoxemic respiratory failure will receive inhaled nitric oxide for 15 minutes. Study outcomes will compare cardiopulmonary responses to inhaled nitric oxide (vs. no inhaled nitric oxide).
- Masking
- None (open label)
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Massachusetts General Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Timothy G. Gaulton, MD, Massachusetts General Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06675435
- Sponsor's protocol ID
- 2024p003089
- Status last verified
- May 2026
- First submitted
- 4 Nov 2024
- Last updated
- 20 May 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- Yes: IPD will be provided following review and approval of a research proposal and Statistical Analysis Plan (SAP) and execution of a Data Use Agreement (DUA). For more information or to submit a request, please contact the study investigators
Publications
Spina S, Marrazzo F, Morais CCA, Victor M, Forlini C, Guarnieri M, Bastia L, Giudici R, Bassi G, Xin Y, Cereda M, Amato M, Langer T, Berra L, Fumagalli R. Modulation of pulmonary blood flow in patients with acute respiratory failure. Nitric Oxide. 2023 Jul 1;136-137:1-7. doi: 10.1016/j.niox.2023.05.001. Epub 2023 May 10.
PubMed 37172929Borges JB, Suarez-Sipmann F, Bohm SH, Tusman G, Melo A, Maripuu E, Sandstrom M, Park M, Costa EL, Hedenstierna G, Amato M. Regional lung perfusion estimated by electrical impedance tomography in a piglet model of lung collapse. J Appl Physiol (1985). 2012 Jan;112(1):225-36. doi: 10.1152/japplphysiol.01090.2010. Epub 2011 Sep 29.
PubMed 21960654
Study at a glance
From the registry record, last updated by the sponsor on 20 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Inhaled Nitric Oxide on Intrapulmonary Shunt in Acutely Hypoxemic Patients With Severe Obesity
- ClinicalTrials.gov ID
- NCT06675435
- Acronym / sponsor ID
- 2024p003089
- Keywords
- severe obesity, acute hypoxemic respiratory failure, intrapulmonary shunt, inhaled nitric oxide
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- Massachusetts General HospitalUniversity, hospital or other
- Study start
- Oct 2026 (estimated)
- Primary completion
- Oct 2028 (estimated)
- Study completion
- Dec 2028 (estimated)
- First posted
- 5 Nov 2024 (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.
The goal of this clinical trial is to learn about the effects of inhaled nitric oxide on oxygenation and lung perfusion in participants with severe obesity who have acute hypoxemic respiratory failure and are on mechanical ventilation
The main questions it aims to answer are:
- In acute hypoxemic respiratory failure, what are the effects of inhaled nitric oxide on oxygenation in participants with severe obesity compared to participants with normal body weight.
- In acute hypoxemic respiratory failure, what are the effects of inhaled nitric oxide on lung perfusion and heart function in participants with severe obesity compared to participants with normal body weight.
- In acute hypoxemic respiratory failure, does severe obesity impact nitric oxide signaling pathways?
Participants with acute hypoxemic respiratory failure will be exposed to inhaled nitric oxide (20 ppm) while being clinically monitored.
Detailed description
The study is a single-center, open-label clinical trial in mechanically ventilated participants with acute hypoxemic respiratory failure. The primary aim is to assess changes in intrapulmonary shunt (primary study outcome) to inhaled nitric oxide in participants with severe obesity and those with normal body weight. The secondary aims are to determine differences in regional lung perfusion (measured by electrical impedance tomography), right ventricular pressure (measured by transthoracic echocardiography), and biomarkers of nitric oxide signaling dysfunction (nitric oxide activity, pro-inflammatory cytokines, endothelial glycocalyx fragments)
The primary study intervention involves inhaled nitric oxide at 20 ppm for 15 minutes. The investigators will compare inhaled nitric oxide response in participants with severe obesity (defined by body mass index greater than or equal to 40) to participants with normal body weight (defined by body mass index 18.5-24.9). 40 participants with acute hypoxemic respiratory failure will be enrolled (20 with severe obesity and 20 with normal body weight). The investigators will enroll a separate cohort of mechanically ventilated participants who do not have acute hypoxemic respiratory failure (10 with severe obesity and 10 with normal body weight). In this cohort, investigators will collect additional blood at a single time point to compare levels of nitric oxide signaling pathways between patients with and without acute hypoxemia across body weight.
Study design
- Primary purpose
- Diagnosis
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- In a prospective single center clinical study, participants with acute hypoxemic respiratory failure will receive inhaled nitric oxide for 15 minutes. Study outcomes will compare cardiopulmonary responses to inhaled nitric oxide (vs. no inhaled nitric oxide).
| Arm | Type | Receives |
|---|---|---|
| Acute hypoxemic respiratory failure | Experimental | Device: Nitric oxideParticipants (n = 40) with acute hypoxemic respiratory failure will receive inhaled nitric oxide (20 ppm) for 15 min. |
| Participants without acute hypoxemic respiratory failure | No intervention | –Participants (n = 20) without acute hypoxemic respiratory failure will not receive inhaled nitric oxide |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Acute hypoxemic respiratory failure, defined as persistent hypoxemia (PaO2/FiO2 ≤ 300 mmHg or SpO2/FiO2 ≤ 315) and on invasive mechanical ventilation for < 72 hours
- Presence of an arterial and central venous catheter (for blood gas measurement)
- Admitted to a participating MGH ICU
- Receiving invasive mechanical ventilation and do not have a diagnosis of acute hypoxemic respiratory failure (PaO2/FiO2 > 300 mmHg or SpO2/FiO2> 315)
- Presence of an arterial catheter
Key exclusion criteria (25 listed)
- Age < 18 years
- Pregnancy or known active breastfeeding
- Prisoner or Incarceration
- Inability or unwillingness of subject or legal surrogate/representative to give written informed consent
- Use of inhaled or oral pulmonary vasodilatory therapy within the 24 hours preceding study enrollment
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 |
|---|---|---|
| Nitric oxide20ppm for 15 minutes delivered by INO max(Nitric Oxide) Company : INO therapeutics, Inc. | Device | Acute hypoxemic respiratory failure |
Primary outcome
Intrapulmonary shunt
Time frame: Intrapulmonary shunt will be assessed before inhaled nitric oxide, at 15 minutes after inhaled nitric oxide, and at 15 minutes after inhaled nitric oxide discontinuation.
Intrapulmonary shunt will be defined as the difference in intrapulmonary shunt (%) to inhaled nitric oxide. Intrapulmonary shunt will be defined using the modified Berggren equation based on central venous and arterial oxygen concentrations from a central venous and peripheral arterial catheter.
3 secondary outcomes
Regional pulmonary perfusion
Time frame: Regional pulmonary perfusion will be assessed before inhaled nitric oxide, at 15 minutes after inhaled nitric oxide, and at 15 minutes after inhaled nitric oxide discontinuation.
Gas exchange
Time frame: Gas exchange will be assessed before inhaled nitric oxide, at 15 minutes after inhaled nitric oxide, and at 15 minutes after inhaled nitric oxide discontinuation.
Right ventricular systolic pressure
Time frame: Right ventricular systolic pressure will be assessed before inhaled nitric oxide, at 15 minutes after inhaled nitric oxide, and at 15 minutes after inhaled nitric oxide discontinuation.
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 20 May 2026.
- Background: PubMed 37172929Spina S, Marrazzo F, Morais CCA, Victor M, Forlini C, Guarnieri M, Bastia L, Giudici R, Bassi G, Xin Y, Cereda M, Amato M, Langer T, Berra L, Fumagalli R. Modulation of pulmonary blood flow in patients with acute respiratory failure. Nitric Oxide. 2023 Jul 1;136-137:1-7. doi: 10.1016/j.niox.2023.05.001. Epub 2023 May 10.
- Background: PubMed 21960654Borges JB, Suarez-Sipmann F, Bohm SH, Tusman G, Melo A, Maripuu E, Sandstrom M, Park M, Costa EL, Hedenstierna G, Amato M. Regional lung perfusion estimated by electrical impedance tomography in a piglet model of lung collapse. J Appl Physiol (1985). 2012 Jan;112(1):225-36. doi: 10.1152/japplphysiol.01090.2010. Epub 2011 Sep 29.
- Individual participant dataSharing planned: Yes. IPD will be provided following review and approval of a research proposal and Statistical Analysis Plan (SAP) and execution of a Data Use Agreement (DUA). For more information or to submit a request, please contact the study investigators
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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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Nitric oxide in people with Obesity and Respiratory Insufficiency, run by Massachusetts General Hospital 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 6 inclusion and 25 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: opening soon, as of the sponsor's last update on 20 May 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 Timothy Gaulton, MD, MSc (6177263030, tgaulton@mgh.harvard.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Intrapulmonary shunt (time frame: Intrapulmonary shunt will be assessed before inhaled nitric oxide, at 15 minutes after inhaled nitric oxide, and at 15 minutes after inhaled nitric oxide discontinuation.). 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 NCT06675435, which also lists 2 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 20 May 2026.