An Algorithmic Approach to Preoxygenation

An Algorithmic Approach to Preoxygenation: Stepwise Addition of Pressure Support and Positive End-expiratory Pressure When Tidal Volume Breathing is Inadequate. A Randomised Controlled Trial

The aim of this randomized controlled trial is to evaluate an algorithmic approach to gradually adding pressure-supported ventilation and end-tidal positive pressure when conventional tidal volume breathing is insufficient for adequate preoxygenation. The main question it aims to answer is:

• Will the proportion of patients receiving preoxygenation increase?
• Will the duration of preoxygenation decrease?

Participants will;

• 200 patients who were planned to undergo general anesthesia for elective surgeries
• aged between 18 and 65 years
• ASA 1-2 physical status
• ETO2 <90% at the end of the 3rd minute with spontaneous tidal volume breathing

Study Overview

• Status: Completed
• Conditions: Preoxygenation; Non-invasive Positive Pressure Ventilation; Anaesthesia Induction
• Intervention / Treatment: Procedure: Group TVB; Procedure: Group PSV; Procedure: Group PSV+PEEP

Detailed Description

The patients were randomly assigned to one of two groups (Group TVB and Group PSV) according to a computer-generated randomisation table. In the patients included in Group TVB, the tidal volume breathing was maintained for a further two minutes. Group PSV received inspiratory pressure support of 6 cm H2O for +1 min. At the end of four minutes, patients whose ETO₂ value had not reached a minimum of 90% were randomly divided once more into two groups. One group continued with PSV, while the other was administered 4 cm H₂O PEEP in addition to PSV (Group PSV+PEEP).

When adequate preoxygenation was achieved, the duration of preoxygenation, SpO2, end-tidal carbon dioxide (ETCO2), arterial blood pressures and heart rate values were recorded. Any adverse effects such as discomfort or gastric distension were noted.

• Study Type: Interventional
• Enrollment (Actual): 378
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Turkey
  • Denizli, Turkey
    • Pamukkale University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Elective surgeries general anaesthesia was planned for a patient aged 18-65 years with ASA 1-2 physical condition.

Exclusion Criteria:

• Haemodynamically unstable, preoperative oxygen support such as increased intracranial or intraocular pressure, to be operated on by thoracic surgery have conditions in which positive pressure ventilation may be indirectly harmful, BMI≥35 kg/m2, pregnant, undergoing emergency surgery and causing leakage in mask ventilation bearded male patients were not included in the study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Sequential Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Group TVB; Group TVB patients who could not reach 90% ETO2 at the end of the 3rd minute were continued with tidal volume breathing.	Procedure: Group TVB; Patients who could not reach ETO2 value 90 with tidal volume breathing for 3 min were included in Group TVB tidal volume breathing was continued for 2 min.; Other Names: Tidal volume breathing was continued.
Experimental: Group PSV; Group PSV received 6 cm H2O positive pressure ventilation.	Procedure: Group PSV; Preoxygenation was continued by providing 6cmH2O pressure support to the patients included in this group.
Experimental: Group PSV+PEEP; In addition to 6 cmH2O pressure support, 4 cmH2O end-expiratory positive pressure support was added to the patients included in Group PEEP.	Procedure: Group PSV; Preoxygenation was continued by providing 6cmH2O pressure support to the patients included in this group.; Procedure: Group PSV+PEEP; At the 4th minute, preoxygenation was continued by adding 4 cmH2O positive end-expiratory pressure to the same 6 cmH2O pressure support for 1 min in patients whose end-tidal O2 value still reached 90% and who were included in this group.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Adequate preoxygenation.	The moment of ensuring adequate preoxygenation when the end-tidal oxygen value is 90 and above.	The moment when the end-tidal oxygen value of patients with insufficient preoxygenation at the end of the third minute with spontaneous tidal volume breathing is 90 and above.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Adverse effects	Any adverse effects such as discomfort or gastric distension were noted.	Within 5 min until target preoxygenation is reached.

Collaborators and Investigators

• Sponsor: Pamukkale University

Study record dates

Study Major Dates

• Study Start (Actual): March 1, 2020
• Primary Completion (Actual): March 1, 2021
• Study Completion (Actual): June 1, 2021

Study Registration Dates

• First Submitted: November 14, 2024
• First Submitted That Met QC Criteria: December 12, 2024
• First Posted (Actual): March 25, 2025

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: December 12, 2024
• Last Verified: December 1, 2024

More Information

Terms related to this study

• Keywords: preoxygenation; anaesthesia; PEEP; tidal volume; PSV
• Other Study ID Numbers: PamukkaleUCTanriverdi-001

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: My first trial.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No