PCV vs VCV in Low-Flow Anesthesia

The aim of this observational study is to investigate the effects of ventilation modes on intraoperative and postoperative lung functions in patients under general anesthesia.

This study aimed to compare the effects of low-flow anesthesia on intraoperative respiratory mechanics and early postoperative pulmonary function between PCV and VCV in ASA I-II adult patients.

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Key information

Conditions

ASA Class I/II Patients General Anesthetic Low Flow Anesthesia

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Hitit University Erol Olçok Training and Research Hospital

Çorum, 19030, Turkey (Türkiye)

About this study

Studies comparing the effects of pressure-controlled ventilation (PCV) and volume-controlled ventilation (VCV) on lung function under low-flow conditions are limited. In this study, the effects of PCV and VCV on intraoperative respiratory mechanics and early postoperative pulmonary function were investigated during low-flow anesthesia in ASA I-II adult patients undergoing routine anesthesia procedures.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

age 18-65 years and American Society of Anesthesiologists (ASA) physical status I-II.

Exclusion criteria

morbid obesity (BMI > 35 kg/m²),
scoliosis or thoracic deformity,
restrictive or obstructive lung disease,
prior thoracic or upper abdominal surgery,
history of major thoracic trauma or congenital chest wall anomaly,
active smoking or chronic use of corticosteroids,
β-agonists, bronchodilators, or antihistamines,
anticipated difficult airway
severe hypoxemia (SpO₂ < 90%) during induction.

Treatment and study plan

Primary outcomes

Mean Ppeak (cmH₂O) at each time point; between-group difference.

Time frame: From post-intubation baseline until 30 minutes after initiation of low-flow anesthesia (approximately 45 minutes total).

Peak inspiratory pressure will be measured using the anesthesia workstation's built-in pressure monitoring system. Ppeak (cmH₂O) values will be automatically recorded at predefined time points: baseline after intubation, before low-flow transition, and 5, 10, 15, and 30 minutes after transition to low-flow anesthesia. Group comparisons will be reported as mean ± SD and analyzed for intergroup differences.

Secondary outcomes

Change in inspiratory score (number of balls raised).

Time frame: Baseline to 30 minutes after initiation of low-flow anesthesia and Preoperative baseline and postoperative 1 hour

Mean airway pressure will be measured continuously by the anesthesia machine. Values will be recorded at the same predefined time points as Ppeak. Data will be reported as mean ± SD. Dynamic compliance (mL/cmH₂O) will be calculated using the ventilator's automated measurement system (tidal volume / (Ppeak - PEEP)). Values will be recorded at identical intraoperative time points. Data will be reported as mean ± SD. Inspiratory effort will be assessed using the Triflo incentive spirometer by recording the number of balls elevated on a single maximal inspiratory attempt (range: 0-3). Measurements will be taken preoperatively and 1 hour postoperatively in the recovery unit.

Sponsors and collaborators

Lead sponsor

HULYA TOPCU, MD

Other

Registry information

Official study title

Pressure-Controlled Versus Volume-Controlled Ventilation in Low-Flow Anesthesia: A Randomized Controlled Trial on Intraoperative Respiratory Mechanics and Postoperative Pulmonary Function

Important dates

Study start: 2023
Primary completion: 2024
Study completion: 2025
First posted: Dec 26, 2025
Registry last updated: Dec 26, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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