Pathophysiology of Hypoventilation in Obesity and Effects of Bariatric Intervention

NCT04025528 | Unknown

• 1 other identifier: 258045
• Study Type: observational
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

Breathing is impacted by obesity. Early changes are characterised by significant breathing abnormalities during sleep (a condition called sleep disordered breathing, the most common of which is obstructive sleep apnoea). As the breathing changes worsen in severity, it may result in a rise in carbon dioxide levels during daytime causing a condition called obesity hypoventilation syndrome (OHS). The current treatment for obesity related breathing changes include supportive breathing therapy at night, optimisation of associated medical conditions and weight loss. Weight management is an important part of obesity treatment. Weight loss strategies such as life-style modification do not always work. Weight loss surgery (bariatric surgery) has been shown to be an effective weight management intervention with long-term results. This study aims to understand breathing changes that occurs due to obesity and their resolution after weight loss surgery. The investigators are aiming to recruit participants with sleep disordered breathing who are currently awaiting bariatric surgery. In particular, the investigators are interested in comparing breathing changes in participants with OHS, who have abnormal regulation of their carbon dioxide levels, and participants with sleep disordered breathing with normal CO2 regulation. Participants will be recruited through outpatient clinics for sleep disordered breathing. The participants will undergo comprehensive breathing assessments on enrolment including an overnight sleep study. Participants will undergo further daytime breathing assessments before and after their bariatric surgery. End of study will be 6 months after surgery - participants will have a final comprehensive breathing assessment including an overnight sleep study to review resolution of their breathing changes. Depending on the wait list time for the bariatric surgery, it is anticipated that participants will be enrolled in the study for 2 years.

Conditions

Obesity Hypoventilation Syndrome (OHS)

Outcome Measures

Primary Outcomes (2)

• Expiratory flow limitation as measured by forced oscillation testing

  Measurement of expiratory flow limitation at different position including upright, 45 degrees and supine. We will explore whether expiratory flow limitation can differentiate hypercapnic and eucapnic patients

  Measurements on enrolment into study; measurements prior to bariatric surgery (once patients has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery

• Degree of change in expiratory flow limitation

  Explore whether the degree of positional change in expiratory flow limitation can differentiate between eucapnic and hypercapnic patients

  Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery

Secondary Outcomes (27)

• Closing capacity

  Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery

• Degree of change in closing capacity

  Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery

• Correlation between closing capacity and expiratory flow limitation

  Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery

• Intra-abdominal pressure

  Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery

• Correlation between intra-abdominal pressure, closing capacity and expriatory flow limitation

  Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery

Other Outcomes (2)

• Spectrum of sleep disordered breathing

  Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery

• Choice of bariatric surgery

  Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery

Study Arms (2)

Hypercapnic

Obese patients with daytime hypercapnia

Procedure: Bariatric Surgery

Eucapnic

Obese patients with normal daytime carbon dioxide levels

Procedure: Bariatric Surgery

Interventions

Bariatric Surgery PROCEDURE

Weight loss surgery with either gastric sleeve or gastric bypass surgery

Eucapnic; Hypercapnic

Eligibility Criteria

• Age: 18 Years - 80 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Obese patients who are considering bariatric surgery intervention

You may qualify if:

• Patients 18 years or older
• BMI \> 40
• Patients with significant sleep disordered breathing requiring treatment
• Patient is being assessed for bariatric surgery for either gastric sleeve or gastric bypass surgery

You may not qualify if:

• Patients with decompensated hypercapnic respiratory failure (pH\< 7.3)
• Chronic hypercapnic respiratory failure due to a cause other than obesity such as neuromuscular, chest wall or airway disease
• Unstable cardiac disease including coronary artery disease and heart failure
• Significant co-morbid psychiatric disease requiring anti-psychotic medications
• Chronic pain syndrome on high dose opioid medications
• Treatment for drug or alcohol addiction
• Cognitive impairment that would prevent informed consent
• Pregnancy
• Need for long-term renal replacement therapy
• Patients who undergo bariatric intervention with gastric balloon or gastric band.

Sponsors & Collaborators

• Guy's and St Thomas' NHS Foundation Trust: lead

Study Sites (1)

Guy's and St Thomas' NHS Trust

London, SE17EH, United Kingdom

RECRUITING

MeSH Terms

Conditions

Obesity Hypoventilation Syndrome

Interventions

Bariatric Surgery

Condition Hierarchy (Ancestors)

Sleep Apnea, Obstructive; Sleep Apnea Syndromes; Apnea; Respiration Disorders; Respiratory Tract Diseases; Hypoventilation; Respiratory Insufficiency; Sleep Disorders, Intrinsic; Dyssomnias; Sleep Wake Disorders; Nervous System Diseases; Obesity; Overweight; Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases

Intervention Hierarchy (Ancestors)

Bariatrics; Obesity Management; Therapeutics; Surgical Procedures, Operative

Study Officials

• Joerg Steier, PhD

  Guy's and St Thomas NHS Trust

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Michael Cheng, MBBS

CONTACT

+44 02071888070; michael.cheng@gstt.nhs.uk

Study Design

• Study Type: observational
• Observational Model: CASE CONTROL
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: June 21, 2019
• First Posted: July 19, 2019
• Study Start: June 20, 2019
• Primary Completion: July 1, 2024
• Study Completion: July 1, 2024
• Last Updated: March 23, 2023

Record last verified: 2023-03

Locations

GB (1)