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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

Status
Completed
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT06736197
Enrollment
378
Registered
2024-12-16
Start date
2020-03-01
Completion date
2021-06-01
Last updated
2024-12-16

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Anaesthesia Induction, Non-invasive Positive Pressure Ventilation, Preoxygenation

Keywords

anaesthesia, preoxygenation, tidal volume, PSV, PEEP

Brief summary

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

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.

Interventions

PROCEDUREGroup 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.

PROCEDUREGroup PSV

Preoxygenation was continued by providing 6cmH2O pressure support to the patients included in this group.

PROCEDUREGroup 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.

Sponsors

Pamukkale University
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
SEQUENTIAL
Primary purpose
PREVENTION
Masking
NONE

Intervention model description

The study was performed in 200 patients planned for general anaesthesia for elective surgery, aged 18-65 years, ASA 1-2 physical status, without premedication and ETO2 \<90% at the end of the 3rd minute with spontaneous TVB of 100% oxygen. 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).

Eligibility

Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No

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.

Design outcomes

Primary

MeasureTime frameDescription
Adequate preoxygenation.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.The moment of ensuring adequate preoxygenation when the end-tidal oxygen value is 90 and above.

Secondary

MeasureTime frameDescription
Adverse effectsWithin 5 min until target preoxygenation is reached.Any adverse effects such as discomfort or gastric distension were noted.

Countries

Turkey (Türkiye)

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026