Effect of Ultra-Low Tidal Volume on Mechanical Power During Heart Bypass Surgery

Konya City Hospital

Status: Enrolling

Conditions: Coronary Artery Disease

Treatments: Other: Ultra-Low Tidal Volume Ventilation; Other: Apnea Group

Study type: Interventional

Funder types: Other

Identifiers

NCT07073885

CABGO-MP

Details and patient eligibility

About

The goal of this clinical trial is to evaluate whether ultra-low tidal volume (ULTV) ventilation during cardiopulmonary bypass (CPB) can reduce mechanical power (MP) and improve postoperative respiratory outcomes in adult patients undergoing elective coronary artery bypass graft (CABG) surgery.

The main questions it aims to answer are:

Does ULTV ventilation during CPB result in lower intraoperative mechanical power compared to apnea?

Can ULTV ventilation reduce extubation time and ICU (Intensive Care Unit) stay and improve the PaO₂/FiO₂ ratio (Partial Pressure of Arterial Oxygen / Fraction of Inspired Oxygen Ratio)?

Researchers will compare patients receiving ULTV ventilation to those undergoing apnea after aortic cross-clamping to assess the effects on mechanical power and postoperative outcomes.

Participants will:

Be randomized to either ULTV ventilation or apnea group

Undergo standard general anesthesia and CABG surgery

Have mechanical power measured at three time points (pre-CPB, post-CPB, and ICU pre-extubation)

Have arterial blood gases evaluated for PaO₂/FiO₂ ratios

Be monitored for extubation time and ICU length of stay

This study aims to generate evidence that could inform safer and more protective intraoperative ventilation strategies during cardiac surgery.

Full description

This is a prospective, randomized, assessor-blinded, single-center clinical trial designed to evaluate the effects of ultra-low tidal volume (ULTV) ventilation on intraoperative mechanical power (MP) and postoperative pulmonary outcomes in patients undergoing elective coronary artery bypass graft (CABG) surgery with cardiopulmonary bypass (CPB).

After obtaining informed consent, eligible adult patients (ASA II-IV) scheduled for elective CABG will be randomly assigned to one of two groups:

ULTV Group: Ventilation will be continued after aortic cross-clamping using volume-controlled ventilation with a tidal volume of 3-4 mL/kg ideal body weight, 12-14 breaths per minute, 5 cm H₂O PEEP, and 50% FiO₂.

Apnea Group: Mechanical ventilation will be discontinued after aortic cross-clamping, and patients will remain apneic during CPB.

Mechanical power will be calculated using a validated surrogate formula and measured at three key time points: pre-CPB (baseline), post-CPB (before ICU transfer), and at the 3rd postoperative hour in the ICU (before extubation). Arterial blood gases will be obtained to determine PaO₂/FiO₂ ratios at these time points and 24 hours post-extubation.

Secondary outcomes include extubation time and length of ICU stay.

This study aims to generate evidence supporting the potential protective effects of continued low-volume ventilation during CPB, with a focus on reducing ventilator-induced lung injury by limiting mechanical power and preserving alveolar integrity.

Enrollment: 60 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Patients of either sex aged over 18 years
• Patients classified as ASA II-IV
• Patients scheduled for elective CABG

Exclusion criteria

• Presence of severe COPD
• Uncontrolled bronchial asthma
• Decompensated heart failure (NYHA class III-IV)
• Pulmonary hypertension
• History of lung surgery
• Morbid obesity (BMI >35)
• Emergency surgery cases
• Patients who decline to participate in the study

Trial design

Primary purpose: Prevention

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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60 participants in 2 patient groups

Group ULTV

Experimental group

Description:

Participants in this group will continue to receive mechanical ventilation after aortic cross-clamping during cardiopulmonary bypass (CPB). Ventilation will be provided in volume-controlled mode with a tidal volume of 3-4 mL/kg ideal body weight, respiratory rate of 12-14 breaths/min, 5 cm H₂O PEEP (Positive End-Expiratory Pressure), and 50% FiO₂. .

Treatment:

Other: Ultra-Low Tidal Volume Ventilation

Apnea Group

Active Comparator group

Description:

After the application of the aortic cross-clamp, mechanical ventilation will be discontinued, and apnea will be maintained.

Treatment:

Other: Apnea Group