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ObesityNCT07380425

Deep Breathing With and Without Pressure Support and PEEP for Preoxygenation in Obese Patients

A study testing Deep Breathing Preoxygenation, Pressure Support Ventilation and Positive End-Expiratory Pressure in people with Obesity, run by Pamukkale University at 1 site in Turkey (Türkiye).

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

Obese patients are at increased risk of low oxygen levels during the induction of general anesthesia. Preoxygenation with a face mask before anesthesia is routinely used to increase oxygen reserves. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Obesity
What is being tested?
Deep Breathing Preoxygenation, Pressure Support Ventilation and Positive End-Expiratory Pressure
Type of treatment
Surgery or procedure
Could I receive a placebo?
No, everyone receives an active treatment
How many people
75 participants
Where
1 siteTurkey (Türkiye)
Study dates
1 Dec 2021to 25 Jul 2022
Phase
Interventional
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 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Age ≥ 18 years
  • Obesity
  • Scheduled for elective surgery under general anesthesia
  • Able to cooperate with deep breathing during preoxygenation

Who cannot join

  • Hemodynamic instability
  • Poor cooperation
  • Preoperative oxygen therapy requirement
  • Conditions in which positive pressure ventilation may be harmful (e.g., increased intracranial or intraocular pressure)
  • Pregnancy
  • Emergency surgery
Show all 9Show fewer
  • Beard (preventing adequate face mask seal)
  • Previous gastric surgery
  • Inability to visualize the gastric antrum by ultrasonography

Trial locations and contacts

1 site in 1 country.

Turkey (Türkiye)1 site

  • Pamukkale University

    Denizli

Other trials in Turkey (Türkiye)

About this study

Official title: Effects of Pressure Support and Positive End-Expiratory Pressure Added to Deep Breathing Preoxygenation on Gastric Distension in Obese Patients: A Randomized Controlled Trial

Obese patients are at increased risk of low oxygen levels during the induction of general anesthesia. Preoxygenation with a face mask before anesthesia is routinely used to increase oxygen reserves. This study compares three preoxygenation techniques: deep breathing alone, deep breathing with pressure-supported ventilation, and deep breathing with pressure-supported ventilation plus positive end-expiratory pressure (PEEP).

The main goal of the study is to determine how quickly each technique allows patients to reach an adequate level of oxygen in the lungs. In addition, the study evaluates whether these techniques cause gastric distension, which could increase the risk of regurgitation. Gastric ultrasound is used to assess stomach size before and after preoxygenation.

The results of this study will help identify the most effective and safest method of preoxygenation in obese patients undergoing elective surgery.

Conditions
Obesity
Being tested
Deep Breathing Preoxygenation, Pressure Support Ventilation, Positive End-Expiratory Pressure
Keywords
Preoxygenation, obesity, Pressure Support Ventilation, Positive End-Expiratory Pressure, Gastric Antrum Area
Medical subject headings
Obesity

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Deep Breathing PreoxygenationProcedure or surgery

    Preoxygenation performed with deep breathing using a ventilator delivering 100% oxygen at a flow rate of 12 L/min.

  • Pressure Support VentilationProcedure or surgery

    Application of pressure support ventilation with a pressure support level of 12 cmH₂O during preoxygenation.

  • Positive End-Expiratory PressureProcedure or surgery

    Application of positive end-expiratory pressure at a level of 6 cmH₂O during preoxygenation.

Study groups in NCT07380425
Study groupRoleWhat they receive
DB (Deep Breathing)ExperimentalDeep breathing preoxygenation with 100% oxygen at 12 L/min using.
Receives: Procedure: Positive End-Expiratory Pressure
DB+PSVExperimentalPreoxygenation with deep breathing supported by pressure-supported ventilation (PSV-Pro) with 12 cmH₂O pressure support and 100% oxygen at 12 L/min until EtO₂ reached 90%.
Receives: Procedure: Deep Breathing Preoxygenation
DB+PSV+PEEPExperimentalDeep breathing preoxygenation supported by PSV-Pro (pressure support 12 cmH₂O) with the addition of PEEP 6 cmH₂O; 100% oxygen at 12 L/min. This arm differs from Arm 2 by the application of PEEP.
Receives: Procedure: Pressure Support Ventilation

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Time to reach an end-tidal oxygen concentration (EtO₂) of 90%

    The time, in seconds, from the start of preoxygenation until the end-tidal oxygen concentration (EtO₂) reached 90%. End-tidal oxygen was measured at 30-second intervals using the anesthesia machine gas analyzer. Reaching EtO₂ 90% was defined as the endpoint of the preoxygenation period.

    Measured: Periprocedural (during the preoxygenation period, prior to induction of anesthesia)

Secondary outcomes (7)

  1. Heart rate

    Heart rate was measured at baseline (before the start of preoxygenation) and at the end of the preoxygenation period, defined as the time point when end-tidal oxygen concentration (EtO₂) reached 90%.

    Measured: Periprocedural (baseline and pre-induction)

  2. Gastric antral cross-sectional area

    Gastric antral cross-sectional area measured by ultrasonography using a 2-5 MHz convex probe, calculated as (anteroposterior diameter × craniocaudal diameter × π)/4. Measurements were performed at baseline (before the start of preoxygenation) and at the completion of the preoxygenation period, defined as the time point when end-tidal oxygen concentration (EtO₂) reached 90%.

    Measured: Periprocedural (baseline and pre-induction)

  3. Gastric distension score

    Epigastric gastric distension assessed using a 4-point ordinal scale (0 = none, 1 = mild, 2 = moderate, 3 = marked). The score was recorded at baseline (before the start of preoxygenation) and at the completion of the preoxygenation period, defined as the time point when end-tidal oxygen concentration (EtO₂) reached 90%.

    Measured: Periprocedural (baseline and pre-induction)

  4. Reflux, belching, and discomfort

    Patient-reported occurrence of discomfort, symptomatic gastroesophageal reflux, or belching during the preoxygenation period. Events were assessed and recorded at the completion of the preoxygenation period, defined as the time point when end-tidal oxygen concentration (EtO₂) reached 90%.

    Measured: Periprocedural (baseline and pre-induction)

  5. Systolic Blood Pressure

    Systolic blood pressure measured noninvasively at baseline (before the start of preoxygenation) and at the completion of the preoxygenation period, defined as the time point when end-tidal oxygen concentration (EtO₂) reached 90%.

    Measured: Periprocedural (baseline and pre-induction)

  6. Diastolic Blood Pressure

    Diastolic blood pressure measured noninvasively at baseline (before the start of preoxygenation) and at the completion of the preoxygenation period, defined as the time point when end-tidal oxygen concentration (EtO₂) reached 90%.

    Measured: Pre-induction (baseline and at completion of preoxygenation, defined by EtO₂ reaching 90%)

  7. Peripheral Oxygen Saturation (SpO₂)

    Peripheral oxygen saturation (SpO₂) measured at baseline (before the start of preoxygenation) and at the completion of the preoxygenation period, defined as the time point when end-tidal oxygen concentration (EtO₂) reached 90%.

    Measured: Periprocedural (baseline and pre-induction)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted2 Feb 2026
  2. Study start1 Dec 2021
  3. Primary completion25 Jul 2022
  4. Study completion25 Jul 2022

Resources

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
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Model description
Three-arm parallel-group randomized trial comparing deep breathing alone, deep breathing with pressure support, and deep breathing with pressure support plus PEEP for preoxygenation.
Masking
None (open label)
Enrolment
75 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07380425
Sponsor's protocol ID
PamukkaleUCTanriverdi-002
Status last verified
Jan 2026
First submitted
11 Jan 2026
Last updated
2 Feb 2026
Results posted
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Publications

  • Abou-Arab O, Guinot PG, Dimov E, Diouf M, de Broca B, Biet A, Zaatar R, Bernard E, Dupont H, Lorne E. Low-positive pressure ventilation improves non-hypoxaemic apnoea tolerance during ear, nose and throat pan-endoscopy: A randomised controlled trial. Eur J Anaesthesiol. 2016 Apr;33(4):269-74. doi: 10.1097/EJA.0000000000000394.

    PubMed 26716862

  • Taxak S, Gupta M, Bala R, Govil V, Lallar A. A prospective randomized study to evaluate the efficacy of pressure support ventilation with and without positive end expiratory pressure for preoxygenation in adult patients. Med Gas Res. 2023 Oct-Dec;13(4):187-191. doi: 10.4103/2045-9912.372665.

    PubMed 37077116

  • Hanouz JL, Lammens S, Tasle M, Lesage A, Gerard JL, Plaud B. Preoxygenation by spontaneous breathing or noninvasive positive pressure ventilation with and without positive end-expiratory pressure: A randomised controlled trial. Eur J Anaesthesiol. 2015 Dec;32(12):881-7. doi: 10.1097/EJA.0000000000000297.

    PubMed 26225498

  • Delay JM, Sebbane M, Jung B, Nocca D, Verzilli D, Pouzeratte Y, Kamel ME, Fabre JM, Eledjam JJ, Jaber S. The effectiveness of noninvasive positive pressure ventilation to enhance preoxygenation in morbidly obese patients: a randomized controlled study. Anesth Analg. 2008 Nov;107(5):1707-13. doi: 10.1213/ane.0b013e318183909b.

    PubMed 18931236

  • Nimmagadda U, Chiravuri SD, Salem MR, Joseph NJ, Wafai Y, Crystal GJ, El-Orbany MI. Preoxygenation with tidal volume and deep breathing techniques: the impact of duration of breathing and fresh gas flow. Anesth Analg. 2001 May;92(5):1337-41. doi: 10.1097/00000539-200105000-00049.

    PubMed 11323373

Questions about this trial

What is this clinical trial studying?

A study testing Deep Breathing Preoxygenation, Pressure Support Ventilation and Positive End-Expiratory Pressure in people with Obesity, run by Pamukkale University at 1 site in Turkey (Türkiye).

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 4 inclusion and 9 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: finished, as of the sponsor's last update on 2 Feb 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 Turkey (Türkiye). 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 is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

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?

Time to reach an end-tidal oxygen concentration (EtO₂) of 90% (time frame: Periprocedural (during the preoxygenation period, prior to induction of anesthesia)). 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 NCT07380425, which also lists 5 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 2 Feb 2026.

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