PCV vs VCV in Low-Flow Anesthesia

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

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.

Study Overview

• Status: Completed
• Conditions: Low Flow Anesthesia; General Anesthetic; ASA Class I/II Patients

Detailed Description

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.

• Study Type: Observational
• Enrollment (Actual): 40

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Çorum
    • Çorum, Çorum, Turkey (Türkiye), 19030
      • Hitit University Erol Olcok Training and Research Hospital

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Probability Sample

Study Population

Hitit University Erol Olçok Training and Research Hospital

Description

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.

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mean Ppeak (cmH₂O) at each time point; between-group difference.	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.	From post-intubation baseline until 30 minutes after initiation of low-flow anesthesia (approximately 45 minutes total).

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in inspiratory score (number of balls raised).	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.	Baseline to 30 minutes after initiation of low-flow anesthesia and Preoperative baseline and postoperative 1 hour

Collaborators and Investigators

• Sponsor: HULYA TOPCU, MD

Study record dates

Study Major Dates

• Study Start (Actual): July 1, 2023
• Primary Completion (Actual): July 15, 2024
• Study Completion (Actual): August 1, 2025

Study Registration Dates

• First Submitted: November 27, 2025
• First Submitted That Met QC Criteria: December 12, 2025
• First Posted (Actual): December 26, 2025

Study Record Updates

• Last Update Posted (Actual): December 26, 2025
• Last Update Submitted That Met QC Criteria: December 12, 2025
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Keywords: respiratory mechanics; pulmonary function; pressure-controlled ventilation; volume-controlled ventilation; low-flow anesthesia; peak inspiratory pressure
• Other Study ID Numbers: 2023-64; hulya topcu (Other Identifier: Erol Olcok Corum Training and Research Hospital); serhat ozciftci (Other Identifier: Erol Olcok Corum Training and Research Hospital)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

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