Cardiac Surgery, Mechanical Power, Postoperative Pulmonary Complications (PPCs)
Conditions
Keywords
cardica surgery, mechanical power, postoperative pulmonary complications
Brief summary
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
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 will be performed, and PEEP will then be fixed at this level. Before sternotomy, the minimum PEEP value that provides the lowest driving pressure will be determined, and this value will be maintained throughout the perioperative period, except during cardiopulmonary bypass.
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.
Sponsors
Study design
Eligibility
Inclusion 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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| postoperative pulmonary complications | postoperative day 1,3,7 | Postoperative pulmonary complications, including atelectasis, pneumonia, respiratory failure, pleural effusion, pneumothorax, and bronchospasm, will be assessed according to the EPCO(European Perioperative Clinical Outcome) criteria. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Inflammatory markers | Postoperative 1., 24, 48,72 hour and day 7 | Postoperative biochemical markers, including CRP, neutrophil count, lymphocyte count, procalcitonin, white blood cell count, IL-6, and TNF-α, will be evaluated. |
| İCU lenght of stay | From postoperative ICU admission to ICU discharge, assessed up to 30 days | Duration of İCU lenght of stay |
| Duration of mechanical ventilation | Time from intubation to successfull extubation | Duration of mechanical ventilation |
| 30 day mortality | postoperative 30 day mortality | 30 day mortality |
| Hospital lenght of stay | From hospital admission to hospital discharge, assessed up to 30 days | Hospital lenght of stay |
Countries
Turkey (Türkiye)
Contacts
Burs City Hospital