Morbid ObesityNCT03925610
Recovery of Ventilation After General Anesthesia in Morbidly Obese Patients
An observational study of Morbid Obesity and Opioid-Related Disorders, run by Stanford University at 1 site in United States.
Trial summary
This is an observational study of morbidly obese patients recovering from general anesthesia after weight-loss surgery. The investigators aim to assess ventilatory function and how this is influenced by the diagnosis of obstructive sleep apnea (OSA), baseline ventilatory status, as well as pharyngeal collapsibility of… Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Morbid Obesity, Opioid-Related Disorders, Surgery--Complications
- How many people
- 8 participants
- Where
- 1 siteUnited States
- Study dates
- 10 Apr 2019to 30 Mar 2020
- Phase
- Observational
- Are there results?
- None posted in the registry
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 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Morbidly obese patients who are eligible for weight-loss surgery.
Who may be able to join
- Body mass index (BMI) equal or greater than 35 kg/m2.
- American Society of Anesthesiologists (ASA) physical status I - III patients.
- Scheduled to undergo laparoscopic roux-en-Y gastric bypass or gastric sleeve placement surgery for weight loss.
Who cannot join
- Chronic obstructive pulmonary disorder (COPD).
- Treatment with continuous positive airway pressure (CPAP) in the past three months.
- Severe neurological, cardiopulmonary, psychiatric, or untreated thyroid disorder.
- Chronic pain condition that was being treated with opioids.
- Patients with a hematocrit lower than 35%.
Trial locations and contacts
1 site in 1 country.
United States1 site
Stanford University School of Medicine
Stanford, California, 94305
About this study
Official title: Recovery of Ventilation After General Anesthesia in Morbidly Obese Patients Who Are Treated With Opioids: A Preliminary Investigation
This is an observational study of morbidly obese patients recovering from general anesthesia after weight-loss surgery. The investigators aim to assess ventilatory function and how this is influenced by the diagnosis of obstructive sleep apnea (OSA), baseline ventilatory status, as well as pharyngeal collapsibility of patients who are recovering from anesthesia and treated for pain with opioids. The investigators hypothesize that patients with OSA, chronic (baseline) hypoventilation and increased pharyngeal collapsibility, will be more vulnerable to opioid-induced ventilatory depression.
Read the detailed description
Obstructive sleep apnea (OSA) increases the risk for pulmonary complications in the first 24 hours after surgery, by more than 3-fold, suggesting an enhanced sensitivity to opioid-induced ventilatory depression (OIVD), in this patient population. Obesity and OSA, two highly comorbid conditions, are common among victims of postoperative life-threatening or fatal OIVD and increased somnolence preceding the onset of a critical event, is an almost ubiquitous clinical finding.
These clinical observations are in agreement with recent evidence that decreased wakefulness is an important contributory mechanism of OIVD in OSA patients who receive opioid analgesia in the postoperative period. Studies that examined the effect of opioids on breathing in awake, sleeping, or anesthetized patients with OSA, support overall that OSA is not associated with increased sensitivity to OIVD in awake subjects. In contrast, diminished wakefulness has been shown to worsen, leave unaffected, or even slightly improve breathing and oxygenation in patients with OSA, who are treated opioids.
Decrease in the tonic activity of the pharyngeal muscles with the progression from wakefulness to sleep, contributes to increased airway resistance and the predisposition to airway occlusion. This effect of sleep on the patency of pharyngeal airway seems to be more pronounced in patients with OSA, who present with increased genioglossus muscle activity during wakefulness taken as evidence for a neural compensation to maintain adequate airflow in the presence of anatomical airway narrowing.
It can thus be suggested that during pharmacological suppression of consciousness, like when recovering from anesthesia, patients with OSA will experience more severe sleep-disordered breathing and consequently be more vulnerable to OIVD, compared to normal subjects.
Specific Aims
Specific Aim 1: To assess opioid-induced ventilatory depression in morbidly obese patients with OSA, who recover from general anesthesia and are treated for pain with fentanyl. We will develop a pharmacodynamic model for OIVD to assess the effect of OSA status (i.e., moderate-to-severe OSA vs. no or mild OSA) on the probability for TcPCO2 to exceed a pre-specified threshold during recovery from anesthesia.
Specific Aim 2: To assess the effect of baseline TcPCO2 on the probability for TcPCO2 to exceed a pre-specified threshold during recovery from anesthesia, independently of the OSA status.
Specific Aim 3: To assess the effect of the minimum positive airway pressure (minPAP) that prevents obstructive breathing during sleep (estimated during in-lab polysomnography) on the probability for TcPCO2 to exceed a pre-specified threshold, during recovery from anesthesia.
Hypotheses:
- Patients with moderate-to-severe OSA will demonstrate a higher probability for exceeding a pre-specified threshold for TcPCO2, compared to those with mild or no OSA, during recovery from general anesthesia.
- Patients who present with higher TcPCO2 at baseline, will present with a higher probability to exceed a pre-specified threshold for TcPCO2, independently of their OSA status, compared to those with normal ventilatory control at baseline, during recovery from anesthesia.
- Patients with higher therapeutic PAP level (hence more collapsible airway) will be more sensitive to fentanyl-induced ventilatory depression and will thus demonstrate a higher probability for exceeding a pre-specified threshold for TcPCO2 during recovery from anesthesia.
- Keywords
- Morbid obesity, Opioid-induced ventilatory depression, Bariatric surgery, Sleep apnea
- Medical subject headings
- Obesity, Morbid, Opioid-Related Disorders, Sleep Apnea Syndromes
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Morbidly obese patients with moderate-to-severe OSA | Morbidly obese patients recovering from general anesthesia after weight loss surgery (gastric bypass and sleeve placement) surgery. All patients will undergo preoperative and postoperative continuous transcutaneous and intermittent arterial blood PCO2 monitoring. Sedation depth and pain assessment will be performed in the post-anesthesia care unit (PACU). Fentanyl only will be administered during surgery and in PACU to provide analgesia (verbal numerical score ≤ 3). A total of 9, 10-mL blood samples (including a preoperative blank sample) will be obtained throughout the study period (1 preoperatively, 4 intraoperatively and 4 in the PACU) to measure fentanyl concentration in the plasma. Five 1-mL samples will be used to determine arterial PCO2. | |
| Morbidly obese patients with no or mild OSA | Morbidly obese patients recovering from general anesthesia after weight loss surgery (gastric bypass and sleeve placement) surgery. All patients will undergo preoperative and postoperative continuous transcutaneous and intermittent arterial blood PCO2 monitoring. Sedation depth and pain assessment will be performed in the post-anesthesia care unit (PACU). Fentanyl only will be administered during surgery and in PACU to provide analgesia (verbal numerical score ≤ 3). A total of 9, 10-mL blood samples (including a preoperative blank sample) will be obtained throughout the study period (1 preoperatively, 4 intraoperatively and 4 in the PACU) to measure fentanyl concentration in the plasma. Five 1-mL samples will be used to determine arterial PCO2. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Probability for TcPCO2 / PaCO2 to exceed a pre-specified threshold during recovery from anesthesia.
Probability for TcPCO2 / PaCO2 to exceed a pre-specified threshold during recovery from anesthesia.
Measured: PACU period (approximate duration of about 1.5h).
Secondary outcomes (2)
The effect of baseline ventilation on the primary outcome
Effect of baseline ventilation, expressed as transcutaneous and arterial PCO2, on the primary outcome.
Measured: PACU period (approximate duration of about 1.5h)
The effect of the minimum PAP on the primary outcome.
The effect of the minimum positive airway pressure (minPAP) that prevents obstructive breathing during sleep (estimated during in-lab polysomnography) on the probability for TcPCO2 /PaCO2 to exceed a pre-specified threshold
Measured: PACU period (approximate duration of 1.5h)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Apr 2019
- Study start10 Apr 2019
- Primary completion30 Mar 2020
- Study completion30 Mar 2020
Why it stopped: Lack of resources and COVID-related closure in 2020.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Morbid ObesityStudies of the same condition, open and under way.
- More trials run by Stanford 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
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 8 participants (actual)
Sponsor and investigators
- Lead sponsor
- Stanford University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Anthony Doufas, Stanford University
- Investigators
- Anthony Doufas, MD, PhD, Principal investigator, Stanford University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03925610
- Sponsor's protocol ID
- IRB-49407
- Status last verified
- Mar 2021
- First submitted
- 21 Apr 2019
- Last updated
- 22 Mar 2021
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 22 Mar 2021. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Recovery of Ventilation After General Anesthesia in Morbidly Obese Patients Who Are Treated With Opioids: A Preliminary Investigation
- ClinicalTrials.gov ID
- NCT03925610
- Acronym / sponsor ID
- IRB-49407
- Keywords
- Morbid obesity, Opioid-induced ventilatory depression, Bariatric surgery, Sleep apnea
- Study type
- Observational
- Recruitment status
- TerminatedReason stopped: Lack of resources and COVID-related closure in 2020.
- Enrolment
- 8 participants (actual)
- Lead sponsor
- Stanford UniversityUniversity, hospital or other
- Study start
- 10 Apr 2019 (actual)
- Primary completion
- 30 Mar 2020 (actual)
- Study completion
- 30 Mar 2020 (actual)
- First posted
- 24 Apr 2019 (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.
This is an observational study of morbidly obese patients recovering from general anesthesia after weight-loss surgery. The investigators aim to assess ventilatory function and how this is influenced by the diagnosis of obstructive sleep apnea (OSA), baseline ventilatory status, as well as pharyngeal collapsibility of patients who are recovering from anesthesia and treated for pain with opioids. The investigators hypothesize that patients with OSA, chronic (baseline) hypoventilation and increased pharyngeal collapsibility, will be more vulnerable to opioid-induced ventilatory depression.
Detailed description
Obstructive sleep apnea (OSA) increases the risk for pulmonary complications in the first 24 hours after surgery, by more than 3-fold, suggesting an enhanced sensitivity to opioid-induced ventilatory depression (OIVD), in this patient population. Obesity and OSA, two highly comorbid conditions, are common among victims of postoperative life-threatening or fatal OIVD and increased somnolence preceding the onset of a critical event, is an almost ubiquitous clinical finding.
These clinical observations are in agreement with recent evidence that decreased wakefulness is an important contributory mechanism of OIVD in OSA patients who receive opioid analgesia in the postoperative period. Studies that examined the effect of opioids on breathing in awake, sleeping, or anesthetized patients with OSA, support overall that OSA is not associated with increased sensitivity to OIVD in awake subjects. In contrast, diminished wakefulness has been shown to worsen, leave unaffected, or even slightly improve breathing and oxygenation in patients with OSA, who are treated opioids.
Decrease in the tonic activity of the pharyngeal muscles with the progression from wakefulness to sleep, contributes to increased airway resistance and the predisposition to airway occlusion. This effect of sleep on the patency of pharyngeal airway seems to be more pronounced in patients with OSA, who present with increased genioglossus muscle activity during wakefulness taken as evidence for a neural compensation to maintain adequate airflow in the presence of anatomical airway narrowing.
It can thus be suggested that during pharmacological suppression of consciousness, like when recovering from anesthesia, patients with OSA will experience more severe sleep-disordered breathing and consequently be more vulnerable to OIVD, compared to normal subjects.
Specific Aims
Specific Aim 1: To assess opioid-induced ventilatory depression in morbidly obese patients with OSA, who recover from general anesthesia and are treated for pain with fentanyl. We will develop a pharmacodynamic model for OIVD to assess the effect of OSA status (i.e., moderate-to-severe OSA vs. no or mild OSA) on the probability for TcPCO2 to exceed a pre-specified threshold during recovery from anesthesia.
Specific Aim 2: To assess the effect of baseline TcPCO2 on the probability for TcPCO2 to exceed a pre-specified threshold during recovery from anesthesia, independently of the OSA status.
Specific Aim 3: To assess the effect of the minimum positive airway pressure (minPAP) that prevents obstructive breathing during sleep (estimated during in-lab polysomnography) on the probability for TcPCO2 to exceed a pre-specified threshold, during recovery from anesthesia.
Hypotheses:
- Patients with moderate-to-severe OSA will demonstrate a higher probability for exceeding a pre-specified threshold for TcPCO2, compared to those with mild or no OSA, during recovery from general anesthesia.
- Patients who present with higher TcPCO2 at baseline, will present with a higher probability to exceed a pre-specified threshold for TcPCO2, independently of their OSA status, compared to those with normal ventilatory control at baseline, during recovery from anesthesia.
- Patients with higher therapeutic PAP level (hence more collapsible airway) will be more sensitive to fentanyl-induced ventilatory depression and will thus demonstrate a higher probability for exceeding a pre-specified threshold for TcPCO2 during recovery from anesthesia.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Morbidly obese patients with moderate-to-severe OSA | – | –Morbidly obese patients recovering from general anesthesia after weight loss surgery (gastric bypass and sleeve placement) surgery. All patients will undergo preoperative and postoperative continuous transcutaneous and intermittent arterial blood PCO2 monitoring. Sedation depth and pain assessment will be performed in the post-anesthesia care unit (PACU). Fentanyl only will be administered during surgery and in PACU to provide analgesia (verbal numerical score ≤ 3). A total of 9, 10-mL blood samples (including a preoperative blank sample) will be obtained throughout the study period (1 preoperatively, 4 intraoperatively and 4 in the PACU) to measure fentanyl concentration in the plasma. Five 1-mL samples will be used to determine arterial PCO2. |
| Morbidly obese patients with no or mild OSA | – | –Morbidly obese patients recovering from general anesthesia after weight loss surgery (gastric bypass and sleeve placement) surgery. All patients will undergo preoperative and postoperative continuous transcutaneous and intermittent arterial blood PCO2 monitoring. Sedation depth and pain assessment will be performed in the post-anesthesia care unit (PACU). Fentanyl only will be administered during surgery and in PACU to provide analgesia (verbal numerical score ≤ 3). A total of 9, 10-mL blood samples (including a preoperative blank sample) will be obtained throughout the study period (1 preoperatively, 4 intraoperatively and 4 in the PACU) to measure fentanyl concentration in the plasma. Five 1-mL samples will be used to determine arterial PCO2. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Morbidly obese patients who are eligible for weight-loss surgery.
Key inclusion criteria (3 listed)
- Body mass index (BMI) equal or greater than 35 kg/m2.
- American Society of Anesthesiologists (ASA) physical status I - III patients.
- Scheduled to undergo laparoscopic roux-en-Y gastric bypass or gastric sleeve placement surgery for weight loss.
Key exclusion criteria (5 listed)
- Chronic obstructive pulmonary disorder (COPD).
- Treatment with continuous positive airway pressure (CPAP) in the past three months.
- Severe neurological, cardiopulmonary, psychiatric, or untreated thyroid disorder.
- Chronic pain condition that was being treated with opioids.
- Patients with a hematocrit lower than 35%.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Probability for TcPCO2 / PaCO2 to exceed a pre-specified threshold during recovery from anesthesia.
Time frame: PACU period (approximate duration of about 1.5h).
Probability for TcPCO2 / PaCO2 to exceed a pre-specified threshold during recovery from anesthesia.
2 secondary outcomes
The effect of baseline ventilation on the primary outcome
Time frame: PACU period (approximate duration of about 1.5h)
The effect of the minimum PAP on the primary outcome.
Time frame: PACU period (approximate duration of 1.5h)
Results and safety
The study was stopped early (reason given: Lack of resources and COVID-related closure in 2020.). Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Mar 2021.
- Individual participant dataSharing planned: No
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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. This study is not recruiting at the moment.
Anthony Doufas, MD, PhD principal investigator
Stanford University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Morbid Obesity and Opioid-Related Disorders, run by Stanford 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 3 inclusion and 5 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: stopped early, as of the sponsor's last update on 22 Mar 2021. 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?
The study was stopped early (reason given: Lack of resources and COVID-related closure in 2020.). Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Probability for TcPCO2 / PaCO2 to exceed a pre-specified threshold during recovery from anesthesia. (time frame: PACU period (approximate duration of about 1.5h).). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 22 Mar 2021.