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

NCT07380425 | Completed

• 1 other identifier: PamukkaleUCTanriverdi-002
• Study Type: interventional
• Target: 75
• Locations: 1 country
• Sites: 1

Brief 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. 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

Keywords

Preoxygenation; obesity; Pressure Support Ventilation; Positive End-Expiratory Pressure; Gastric Antrum Area

Outcome Measures

Primary Outcomes (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.

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

Secondary Outcomes (7)

• Heart rate

  Periprocedural (baseline and pre-induction)

• Gastric antral cross-sectional area

  Periprocedural (baseline and pre-induction)

• Gastric distension score

  Periprocedural (baseline and pre-induction)

• Reflux, belching, and discomfort

  Periprocedural (baseline and pre-induction)

• Systolic Blood Pressure

  Periprocedural (baseline and pre-induction)

Study Arms (3)

DB (Deep Breathing)

EXPERIMENTAL

Deep breathing preoxygenation with 100% oxygen at 12 L/min using.

Procedure: Positive End-Expiratory Pressure

DB+PSV

EXPERIMENTAL

Preoxygenation 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%.

Procedure: Deep Breathing Preoxygenation

DB+PSV+PEEP

EXPERIMENTAL

Deep 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.

Procedure: Pressure Support Ventilation

Interventions

Deep Breathing Preoxygenation PROCEDURE

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

DB+PSV

Pressure Support Ventilation PROCEDURE

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

DB+PSV+PEEP

Positive End-Expiratory Pressure PROCEDURE

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

DB (Deep Breathing)

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

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

You may not qualify if:

• 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
• Beard (preventing adequate face mask seal)
• Previous gastric surgery
• Inability to visualize the gastric antrum by ultrasonography

Sponsors & Collaborators

• Pamukkale University: lead

Study Sites (1)

Pamukkale University

Denizli, Turkey (Türkiye)

Location

Related Publications (5)

• 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.

  PMID: 26716862 RESULT

• 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.

  PMID: 37077116 RESULT

• 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.

  PMID: 26225498 RESULT

• 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.

  PMID: 18931236 RESULT

• 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.

  PMID: 11323373 RESULT

MeSH Terms

Conditions

Obesity

Interventions

Positive-Pressure Respiration

Condition Hierarchy (Ancestors)

Overweight; Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Respiration, Artificial; Airway Management; Therapeutics; Respiratory Therapy

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: 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.

Study Record Dates

• First Submitted: January 11, 2026
• First Posted: February 2, 2026
• Study Start: December 1, 2021
• Primary Completion: July 25, 2022
• Study Completion: July 25, 2022
• Last Updated: February 2, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)