Flow-Controlled vs. Pressure-Controlled Ventilation in CABG: Effects on Lung Aeration and Diaphragm Function

NCT07800741 | Not Yet Recruiting DMC

• 1 other identifier: FCV-PCV-DTI-LUS
• Study Type: interventional
• Target: 154
• Locations: 1 country
• Sites: 1

Brief Summary

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).

Conditions

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

Keywords

Flow-Controlled Ventilation; Pressure-Controlled Ventilation; Lung Ultrasound; Diaphragm Ultrasonography; Diaphragm Excursion; Diaphragm Thickening Fraction; Lung-Protective Ventilation; Point-of-Care Ultrasound; Perioperative Pulmonary Complications; Cardiopulmonary Bypass; Cardiac Surgery

Outcome Measures

Primary Outcomes (1)

• Total Lung Ultrasound Score (LUS)

  Lung aeration assessed using a 12-zone bilateral ultrasonography protocol. Each zone scored 0-3 (0 = normal aeration with A-lines; 1 = multiple B-lines; 2 = coalescent B-lines; 3 = consolidation). Total score ranges from 0 to 36; higher scores indicate greater aeration loss

  Preoperatively (T0), within 30 minutes of sternal closure while intubated (T1), and 24 hours postoperatively after extubation (T2)

Secondary Outcomes (4)

• Diaphragm Thickening Fraction (TFdi)

  Preoperatively (T0), within 30 minutes of sternal closure while intubated (T1), and 24 hours postoperatively after extubation (T2)

• Diaphragm Excursion

  Preoperatively (T0), within 30 minutes of sternal closure while intubated (T1), and 24 hours postoperatively after extubation (T2)

• PaO₂/FiO₂ Ratio

  Preoperatively (T0), within 30 minutes of sternal closure while intubated (T1), and 24 hours postoperatively after extubation (T2)

• Postoperative Pulmonary Complications

  Up to 30 days postoperatively

Study Arms (2)

FCV (Flow-Controlled Ventilation)

EXPERIMENTAL

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%.

Procedure: Pressure-Controlled Ventilation (PCV)

PCV (Pressure-Controlled Ventilation)

ACTIVE COMPARATOR

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%.

Procedure: Flow-Controlled Ventilation

Interventions

Flow-Controlled Ventilation PROCEDURE

FCV delivers tidal ventilation via a continuous triangular flow waveform, maintaining constant inspiratory and expiratory flow rates throughout the entire respiratory cycle. PEEP and peak airway pressure are titrated independently, guided by dynamic respiratory system compliance. Tidal volume target is 6-8 mL/kg ideal body weight. This ventilation modality is distinct from pressure-controlled and volume-controlled modes, which generate decelerating inspiratory flow profiles and do not allow simultaneous independent titration of PEEP and peak airway pressure based on compliance.

PCV (Pressure-Controlled Ventilation)

Pressure-Controlled Ventilation (PCV) PROCEDURE

PCV is delivered using a standard anaesthesia workstation in pressure-controlled mode. Inspiratory pressure is set to achieve a tidal volume of 6-8 mL/kg ideal body weight. PEEP is titrated using the same compliance-guided algorithm applied in the FCV arm. Unlike FCV, the inspiratory flow profile is decelerating and PEEP and peak airway pressure are not independently optimised in a compliance-guided manner within the same ventilation mode

FCV (Flow-Controlled Ventilation)

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Koşuyolu Kartal Heart Training and Research Hospital: lead

Study Sites (1)

Kosuyolu Heart Training and Research Hospital

Istanbul, Kartal, 34862, Turkey (Türkiye)

Location

MeSH Terms

Conditions

Coronary Artery Disease; Pulmonary Atelectasis; Respiratory Insufficiency

Condition Hierarchy (Ancestors)

Coronary Disease; Myocardial Ischemia; Heart Diseases; Cardiovascular Diseases; Arteriosclerosis; Arterial Occlusive Diseases; Vascular Diseases; Lung Diseases; Respiratory Tract Diseases; Respiration Disorders

Study Officials

• Ebru GIRGIN DINC

  Koşuyolu Kartal Heart Training and Research Hospital

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Ebru GIRGIN DINC, M.D., DESAIC

CONTACT

905446948852; grgnebru@gmail.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: Complete blinding of the anaesthesia care provider is not achievable given the distinct operational characteristics of the FCV device versus a standard ventilator in PCV mode. Accordingly, a single-blind (outcomes assessor-blinded) design is employed. A dedicated assessor, unaware of group assignment, performs all lung and diaphragm ultrasound examinations at each time point (T0, T1, T2) and scores the images offline using coded identifiers. The assessor has no access to the ventilator display, the anaesthesia record, or any clinical documentation that could reveal group allocation. To quantify inter-rater reliability, the first ten subjects are independently scored by two blinded assessors; disagreements exceeding one point per zone are resolved by consensus before proceeding.
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: M.D., DESAIC

Model Details: This is a single-centre, prospective, randomised, parallel-group controlled trial comparing two intraoperative ventilation strategies - Flow-Controlled Ventilation (FCV) and Pressure-Controlled Ventilation (PCV) - in adults undergoing elective isolated on-pump coronary artery bypass graft (CABG) surgery. A parallel-group design was selected because the two ventilation modes are mutually exclusive within a single surgical procedure; crossover is not feasible.

Study Record Dates

• First Submitted: August 30, 2026
• First Posted: September 2, 2026
• Study Start: September 30, 2026
• Primary Completion (Estimated): September 30, 2028
• Study Completion (Estimated): December 30, 2028
• Last Updated: September 2, 2026

Record last verified: 2026-08

Locations

TU (1)