Individualized PEEP and Pulmonary Complications in On-Pump CABG

Official title

Effect of Individualized PEEP Guided by Driving Pressure and Mechanical Power on Postoperative Pulmonary Complications in On-Pump CABG: A Randomized Controlled Trial

Overview

Postoperative pulmonary complications (PPCs) are an important cause of morbidity and mortality after major surgery and are frequently observed in cardiac surgery patients undergoing cardiopulmonary bypass (CPB). These complications are associated with prolonged mechanical ventilation, longer intensive care unit and hospital stays, increased healthcare costs, and higher mortality (1,2). Intraoperative lung-protective ventilation strategies have traditionally focused on individual parameters such as low tidal volume, positive end-expiratory pressure (PEEP), plateau pressure, and driving pressure. However, the effects of these parameters on postoperative pulmonary outcomes in cardiac surgery patients remain unclear. In particular, PEEP- and driving pressure-guided approaches are controversial in terms of feasibility and safety in patients undergoing CPB, who may be hemodynamically vulnerable. Mechanical power is a comprehensive parameter that reflects the total energy delivered to the respiratory system per unit of time by integrating ventilatory variables such as tidal volume, airway pressures, respiratory rate, and flow. Therefore, mechanical power may provide a more comprehensive assessment of the mechanical load applied to the lungs compared with individual ventilatory parameters. Previous studies have reported that higher mechanical power values may be associated with lung injury, postoperative pulmonary complications, and mortality (3). The aim of this study is to evaluate the effect of monitoring mechanical power during perioperative mechanical ventilation on postoperative pulmonary complications in patients undergoing cardiac surgery with cardiopulmonary bypass. The study hypothesis is that a mechanical power-based ventilation approach may reduce the incidence of PPCs compared with strategies based on conventional ventilation parameters.

Detailed description

Postoperative pulmonary complications (PPCs) are an important cause of morbidity and mortality after major surgery and are frequently observed in cardiac surgery patients undergoing cardiopulmonary bypass (CPB). These complications are associated with prolonged mechanical ventilation, longer intensive care unit and hospital stays, increased healthcare costs, and higher mortality (1,2).

Intraoperative lung-protective ventilation strategies have traditionally focused on individual parameters such as low tidal volume, positive end-expiratory pressure (PEEP), plateau pressure, and driving pressure. However, the effects of these parameters on postoperative pulmonary outcomes in cardiac surgery patients remain unclear. In particular, PEEP- and driving pressure-guided approaches are controversial in terms of feasibility and safety in patients undergoing CPB, who may be hemodynamically vulnerable.

Mechanical power is a comprehensive parameter that reflects the total energy delivered to the respiratory system per unit of time by integrating ventilatory variables such as tidal volume, airway pressures, respiratory rate, and flow. Therefore, mechanical power may provide a more comprehensive assessment of the mechanical load applied to the lungs compared with individual ventilatory parameters. Previous studies have reported that higher mechanical power values may be associated with lung injury, postoperative pulmonary complications, and mortality (3).

The aim of this study is to evaluate the effect of monitoring mechanical power during perioperative mechanical ventilation on postoperative pulmonary complications in patients undergoing cardiac surgery with cardiopulmonary bypass. The study hypothesis is that a mechanical power-based ventilation approach may reduce the incidence of PPCs compared with strategies based on conventional ventilation parameters.

Interventions

• Other Driving pressure-based personalized PEEP strategy
  After hemodynamic stability is achieved, the ventilator will be switched to volume-controlled mode with 6 ml/kg tidal volume , and a recruitment maneuver will be performed by gradually increasing PEEP to 20 cmH₂O. Subsequently, during the decremental PEEP trial, PEEP will be reduced by 2 cmH₂O every 20 seconds down to 6 cmH₂O, and ΔP (Pplat-PEEP) will be calculated at each step. The PEEP level associated with the lowest ΔP on the ΔP-PEEP curve will be identified, a second recruitment maneuver w
• Other Conventional lung protective mechanical ventilation strategy
  In volume-controlled mechanical ventilation, tidal volume will be set at 6 mL/kg and PEEP will be fixed at 5 cmH₂O. Ventilation will be maintained with these settings throughout the perioperative period, except during cardiopulmonary bypass. Mechanical power values will also be calculated and recorded during all these periods.

Primary outcome measures

• postoperative pulmonary complications [Time frame: postoperative day 1,3,7]

Secondary outcome measures (5)

• Inflammatory markers [Time frame: Postoperative 1., 24, 48,72 hour and day 7]
• İCU lenght of stay [Time frame: From postoperative ICU admission to ICU discharge, assessed up to 30 days]
• Duration of mechanical ventilation [Time frame: Time from intubation to successfull extubation]
• 30 day mortality [Time frame: postoperative 30 day mortality]
• Hospital lenght of stay [Time frame: From hospital admission to hospital discharge, assessed up to 30 days]

Eligibility criteria

Patients with ASA physical status II-III who are scheduled to undergo elective open-heart surgery via on-pump median sternotomy will be included in the study.

Patients scheduled for emergency surgery, those planned to undergo off-pump cardiac surgery, patients with a history of myocardial infarction within the last 3 months, patients with advanced COPD, patients with an ARISCAT score of 44 or higher, patients with a BMI of 35 kg/m² or higher, patients with NYHA class IV status, patients receiving preoperative immunotherapy, and patients with severe hepatic or renal failure will be excluded from the study.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Triple blind

Primary purpose

Treatment

Study locations

Turkey (Türkiye) · 1 center

• Bursa City Hospital — Bursa

Publications

• 1. Association between driving pressure and development of postoperative pulmonary complications in patients undergoing mechanical ventilation for general anaesthesia: a meta-analysis of individual patient data Neto, Ary Serpa et al. The Lancet Respiratory Medicine, Volume 4, Issue 4, 272 - 280 2. Jammer I, Wickboldt N, Sander M, Smith A, Schultz MJ, Pelosi P, Leva B, Rhodes A, Hoeft A, Walder B,

Identifiers

NCT: NCT07623109 · 25.03.2026 2026-6/7 · 26-AKD-57

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗