PCV vs VCV in Low-Flow Anesthesia

HULYA TOPCU, MD40 enrolled

Overview

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.

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

Conditions

ASA Class I/II Patients General Anesthetic Low Flow Anesthesia

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 Years

Medical Language ↔ Plain English

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.

Locations (1)

Hitit University Erol Olçok Training and Research Hospital

Çorum, Çorum, Turkey (Türkiye)

Outcomes

Primary Outcomes

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.

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

Secondary Outcomes

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.

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

Data from ClinicalTrials.gov

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