Comparison of Esophageal Manometry and CT Scan Measurements

Mass General Brigham

Status

Not yet enrolling

Conditions

Respiratory Failure

Morbid Obesity

Treatments

Device: insertion of esophageal balloon

Radiation: low-dose chest CT scan

Study type

Observational

Funder types

Other

Identifiers

NCT04213911

CTobese2020

Details and patient eligibility

About

The goal of this study is to determine the relationship between esophageal pressure (Pes) and superimposed pressure (SP) in subjects with morbid obesity.

Full description

In the clinical setting, Pes is a surrogate for pleural pressure, while SP is measured by means of chest CT scan images. The SP highly approximates the vertical pleural pressure gradient both in normal lungs and injured lungs in lean subjects. It is known that in the healthy obese patient the Pes is higher than that in normal lean patients, but there is no information about the relationship between high Pes with the SP in subjects with morbid obesity.

The investigators hypothesized that factors other than superimposed pressure determine the high Pes in subjects with morbid obesity. Hence, Pes should be high despite the low SP found in healthy obese individuals.

The investigators will test this hypothesis in a prospective observational cohort study.

In 12 subjects (6 with body mass index > 40kg/m2, and 6 with body mass index < 30kg/m2 ) with scheduled chest CT scan for clinical purposes:

The Pes will be measured during spontaneous breathing (baseline values at end-expiration and variations during tidal breathing). To achieve this purpose, an esophageal balloon (AVEATM Ventilator Esophageal Pressure Monitoring Tube Set, 8 FR, CareFusion, Yorba Linda, CA, USA) will be inserted after administration of local anesthesia (lidocaine spray 2%).
The SP will be determined by lung computed tomography imaging and the pleural pressure will be calculated in non-dependent lung regions as the difference between Pes and SP. For this purpose, an additional low-dose CT scan at the end-expiration will be taken after the scheduled CT scan.

During the research procedure, the Pes during the whole respiratory cycle, the CT image at the end-expiration, demographics, past and current medical history will be recorded.

There will be no follow-up phase in this study.

Enrollment

12 estimated patients

Sex

All

Ages

18 to 99 years old

Volunteers

Accepts Healthy Volunteers

Inclusion criteria

Patients who are scheduled to take a chest CT scan for the clinical purpose at MGH Radiology Department
6 adult subjects with BMI more than 40kg/m2
6 adult subjects with BMI less than 30kg/m2
More than 18 years old

Exclusion criteria

Presence of pneumothorax
History of spontaneous pneumothorax
Severe coagulopathy (INR ≥ 4)
Severe thrombocytopenia (Platelets count ≤ 5,000/mm3)
Usage of any devices with electric current generation such as pacemakers or internal cardiac defibrillator
Recent esophageal trauma or surgery
Other esophageal diseases, such as esophageal cancer, leak, varices, and hernia
Presence of hypoxemia, short of breath and dysphagia.
Presence or suspicion of pneumonia or lung fibrosis.