Flow-Controlled vs. Pressure-Controlled Ventilation in CABG: Effects on Lung Aeration and Diaphragm Function (FCV-PCV-DTI-LU)

Koşuyolu Kartal Heart Training and Research Hospital

Status: Begins enrollment this month

Conditions: Postoperative Pulmonary Complications; Coronary Artery Disease; Pulmonary Atelectasis, Postoperative; Respiratory Insufficiency; Diaphragm Dysfunction

Treatments: Procedure: Flow-Controlled Ventilation; Procedure: Pressure-Controlled Ventilation (PCV)

Study type: Interventional

Funder types: Other

Identifiers

NCT07800741

FCV-PCV-DTI-LUS

Details and patient eligibility

About

Pulmonary atelectasis and loss of lung aeration are common complications following cardiac surgery with cardiopulmonary bypass (CPB) and are associated with impaired oxygenation and prolonged mechanical ventilation. Diaphragm dysfunction occurring in the perioperative period may further delay extubation and prolong intensive care unit (ICU) stay. Flow-Controlled Ventilation (FCV) is a novel ventilation modality that provides continuous, flow-based delivery of tidal breaths with a triangular flow profile, potentially offering superior dynamic compliance optimisation compared to conventional Pressure-Controlled Ventilation (PCV).

Full description

This single-centre, prospective, 1:1 randomised parallel-group controlled trial will compare intraoperative FCV with PCV in adults undergoing elective isolated on-pump coronary artery bypass graft (CABG) surgery. The primary outcome is total lung ultrasound (LUS) score change (0-36 scale) from baseline (T0) to 24 hours postoperatively (T2). Secondary outcomes include diaphragm thickening fraction (TFdi), diaphragm excursion, PaO₂/FiO₂ ratio, extubation time, and ICU/hospital length of stay. Lung and diaphragm ultrasonography will be performed by an assessor blinded to group allocation at three time points: preoperatively (T0), at end of surgery while intubated (T1), and at 24 hours postoperatively after extubation (T2).

Enrollment: 154 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Age ≥18 years
• Planned elective isolated on-pump coronary artery bypass graft (CABG) surgery
• ASA Physical Status Classification II-IV
• Written informed consent obtained
• Technically adequate acoustic window for lung and diaphragm ultrasonography

Exclusion criteria

• Emergency surgery
• Combined surgical procedures (e.g., valve repair/replacement + CABG)
• Preoperative requirement for invasive or non-invasive mechanical ventilation
• Known diaphragm paralysis or neuromuscular disease
• Severe COPD exacerbation or active pneumonia at time of surgery
• Body mass index ≥40 kg/m²
• Inability to obtain standard lung or diaphragm ultrasound images due to pleural effusion, thoracic deformity, or prior thoracic surgery

Trial design

Primary purpose: Prevention

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Triple Blind

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154 participants in 2 patient groups

FCV (Flow-Controlled Ventilation)

Experimental group

Description:

Intraoperative ventilation with a Flow-Controlled Ventilation device. Target tidal volume: 6-8 mL/kg ideal body weight (IBW). PEEP and peak airway pressure titrated to maximise dynamic compliance. Respiratory rate adjusted to maintain EtCO₂ 35-45 mmHg. FiO₂ targeted to SpO₂ ≥94%.

Treatment:

Procedure: Pressure-Controlled Ventilation (PCV)

PCV (Pressure-Controlled Ventilation)

Active Comparator group

Description:

Intraoperative pressure-controlled ventilation. Inspiratory pressure adjusted to deliver a tidal volume of 6-8 mL/kg IBW. PEEP titrated to maximise dynamic compliance, using the same algorithm as the FCV group. Respiratory rate adjusted to maintain EtCO₂ 35-45 mmHg. FiO₂ targeted to SpO₂ ≥94%.

Treatment:

Procedure: Flow-Controlled Ventilation