Unilateral Ventilation on Cardiopulmonary Bypass During Cardiac Surgery

N/ANot Yet RecruitingNCT07612709

Medical University of Vienna45 enrolled

Overview

This study investigates if single lung ventilation on cardiopulmonary bypass can mitigate postoperative lung water accumulation determined by lung ultrasound in the ventilated lung as compared to the non-ventilated lung in patients at high-risk for developing severe pulmonary complications after cardiac surgery.

Study Type

INTERVENTIONAL

Allocation

Purpose

SUPPORTIVE_CARE

Masking

NONE

Enrollment

Conditions

Lung Protective Ventilation Cardiopulmonary Bypass High-risk Cardiac Patients Lung Ultrasound Lung Water Assessment Pulmonary Complications in Surgical Patients

Interventions

Ventilated lungPROCEDURE

This lung will be ventilated during cardiopulmonary bypass using volume-controlled ventilation with a tidal volume of 3 mL/kg ideal body weight, a PEEP of 5 cmH2O, a respiratory rate of 10/min, and a fraction of inspired oxygen of 30%.

Non-ventilated lung.PROCEDURE

The contralateral lung will not be ventilated during cardiopulmonary bypass and will be allowed to collapse.

Eligibility

Sex: ALLMin age: 65 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Patients at increased risk for postoperative pulmonary complications * Major elective cardiac surgery * Prolonged duration of cardiopulmonary bypass * Patients older than 65 years of age * Informed consent Exclusion Criteria: * Emergency * Urgent procedures * Patients with implanted pacemakers * Patients with internal cardioverter/defibrillators * Decompensated cardiac disease * Pulmonary disease * Recent pneumonia * Need for temporary perioperative mechanical support * Patients not willing to participate * Treatment with inhaled nitric oxide

Outcomes

Primary Outcomes

Lung aeration score of both lungs.

The aeration score of each lung is the sum of the aeration scores determined in each of six lung quadrants in each lung, which can range from 0 (normal ventilation) to 3 (atelectasis/consolidation).

Time frame: Lung ultrasound investigations will be performed at baseline, i.e., before surgery, on the day of surgery, and on day 1 and 2 after surgery in the intensive care unit.

Secondary Outcomes

Radiologic assessment of Kerley B lines as indicators of lung edema.

Number of Kerley B lines in both lungs determined by chest x-ray where stage 1 (no Kerley B lines) reflects best outcome, stage 2 (Kerley B lines become visible) indicates interstitial edema, and stage 3 (increased number of Kerley B lines also in non-dependent areas and partially obscured in dependent parts of the lung) are a sign of alveolar edema.

Time frame: Performed on the day of surgery and on day 1 and 2 after surgery on the intensive care unit.

Presence of pleural effusion in chest x-ray.

Severity assessment will be semi-quantitative with 0 = no effusion, 1 = small effusion (with blunting of the basal lung segments and the costophrenic angle), 2 = moderate effusion (fluid extents to the mid-hemithorax creating a "meniscus sign"), and 3 = massive effusion (the whole lung appears opaque with displacement of the heart to the contralateral side if located unilaterally).

Time frame: Performed on the day of surgery and on day 1 and 2 after surgery on the intensive care unit.

Determination of the Global Inhomogeneity (GI) index in both lungs separately by thoracic Electrical Impedance Tomography (EIT).

Global inhomogeneity is calculated as the sum of the absolute differences between the median value of tidal variation and every single pixel value, divided by the sum of all impedance values, to normalize the calculated values. A GI index closer to 0 represents highly homogeneous (even) ventilation. Higher values (i.e., \> 0.5) indicate that some parts of the lung are over-distended while others are poorly aerated or collapsed (atelectasis).

Time frame: On the day of surgery and on day 1 and 2 after surgery in the intensive care unit.

Worst oxygenation (Horowitz) index measured per day during routine blood gas checks.

The Horowitz index (HI) is calculated by diving arterial oxygen partial pressure determined in the blood gas by the fraction of inspired oxygen. It will be assessed after each blood gas check and the lowest HI during one day will be entered for further statistical analysis. The degree of impaired lung function will be determined as follows: HI \> 300 mmHg (healthy lung function), HI between 201-300 mmHg (mild lung injury), HI between 101-200 mmHg (moderately severely impaired lung function), and HI \< 100 mmHg (severe lung injury, ARDS).

Time frame: Assessed on the day of surgery and on day 1 and 2 after surgery.

Static lung compliance determined in each lung separately.

Static lung compliance of the ventilated and the non-ventilated lung will be determined twice for each patient. Static compliance in healthy adults ranges between 60 and 100 mL/cm H₂O. Values below 50 mL/cm H₂O would be considered abnormally low.

Time frame: On the day of surgery in the operating room before and after cardiac surgery on cardiopulmonary bypass when the patient is still ventilated via double lumen tube.

Amount of released immune modulators.

Serum levels for HSP70, MMP-8, MMP-9, TIMP-1, and Lipocalin-2 will be determined in patients' blood samples, with normal values ranging from 0.2-3 ng/mL for HSP70, 0.3-1.2 ng/mL for MMP-8, 14-100 ng/mL for MMP-9, 80-150 ng/mL for TIMP-1, and 20-130 ng/mL for Lipocalin-2, respectively.

Time frame: Determined on the day of surgery as well as on day 1, 2, 3, and 4 after surgery.

Central Contacts

Martin Dworschak, MD, MBA

CONTACT

+43-1-40400 martin.dworschak@meduniwien.ac.at

Edda M. Tschernko, MD, MBA