Influence of Lung Volume Optimization Maneuver on Cardiac Output and Lung Compliance in Ventilated Children With Congenital Heart Disease Undergoing Surgical Repair

Official title

Influence of Lung Volume Optimization Maneuver on Cardiac Output and Lung Mechanics in Children With Congenital Heart Disease

Overview

The aim of this randomized interventional multi-center clinical trial is to determine whether a standardized lung volume optimization maneuver (LVOM), including PEEP titration, improves outcomes in children undergoing biventricular repair for congenital heart disease (CHD) with cardiopulmonary bypass. The primary hypothesis is that optimizing end-expiratory lung volume through a standardized PEEP titration maneuver improves cardiac performance and lung function. Secondary objectives are to evaluate whether this strategy reduces duration of mechanical ventilation, improves hemodynamics and ventilation-perfusion matching, and decreases the need for vasopressor support.

Detailed description

Cardiopulmonary bypass is associated with interruption of ventilation, leading to atelectasis, reduced end-expiratory lung volume, and increased pulmonary vascular resistance (PVR), which may impair right ventricular (RV) performance and overall cardiac output.

This study investigates whether a structured LVOM strategy can mitigate these effects by improving lung mechanics and cardiopulmonary interactions.

Specific Aims

Aim 1:

To quantify changes in hemodynamics and lung mechanics induced by LVOM under standardized postoperative (closed-chest) conditions.

Aim 2:

To compare individualized PEEP titration versus standard ventilation in terms of effects on hemodynamics and lung mechanics, while maintaining consistent tidal volume targets across groups.

Hypotheses

LVOM will improve lung mechanics and hemodynamic parameters. No significant between-group differences are expected prior to intervention. After PEEP titration, the intervention group will demonstrate superior cardiopulmonary function at moderate PEEP levels, reflecting the U-shaped relationship between lung volume and pulmonary vascular resistance (PVR).

Scientific Rationale

Cardiopulmonary bypass commonly results in atelectasis and loss of end-expiratory lung volume, contributing to increased PVR and RV afterload, with subsequent reduction in cardiac output.

Adult studies suggest that lung volume optimization through PEEP titration after CPB can improve cardiac index and RV performance. However, prospective pediatric data evaluating the interaction between ventilatory strategy, lung mechanics, and hemodynamics remain limited.

Given the central role of the right ventricle in coupling pulmonary and systemic circulation, optimizing lung volume may reduce RV afterload and improve overall cardiac performance.

Importantly, pulmonary vascular resistance follows a U-shaped relationship with lung volume, with increased resistance at both low (atelectasis) and high (overdistension) lung volumes. Individualized PEEP titration may therefore identify an optimal range that minimizes PVR while preserving hemodynamic stability.

This study addresses a critical gap by systematically evaluating cardiopulmonary interactions under contemporary ventilation strategies in pediatric cardiac surgery.

Interventions

• Procedure End-expiratory lung volume optimization maneuver with PEEP titration
  PEEP titration (incremental/decremental) will be performed at the end of surgery to optimize lung volume and find levels of PEEP corresponding to the "best" lung compliance and "best" compromise of overdistension and collapse and "best" homogenization of tidal volume distribution assessed with EIT. PEEP levels will be applied based on individual response of patients' lung mechanics and EIT measures. Tidal volume will be kept constant at 6ml/kg in cases and controls. Driving pressures will be lim
• Procedure Standard Care (in control arm)
  Patients will receive pressure controlled ventilation with target tidal volume of 6ml/kg and PEEP of 5cmH2O. Driving pressures are limited to 15cmH2O. No LVOM will be applied.

Primary outcome measures

• Cardiac Index (L/min/BSA) [Time frame: perioperatively]

Secondary outcome measures (6)

• lung mechanics [Time frame: perioperatively]
• right ventricular performance [Time frame: perioperatively]
• ventilation distribution [Time frame: perioperatively]
• lung perfurision [Time frame: perioperatively]
• dead space fraction [Time frame: perioperatively]
• avDO2 [Time frame: perioperatively]

Eligibility criteria

Inclusion criteria

• Inclusion Criteria
• congenital heart disease
• surgery with cardiopulmonary bypass

Exclusion criteria

• single ventricle physiology
• ECMO/VAD
• <36weeks of gestational age
• chronic lung disease
• Endotracheal tube leak > 15%
• lack of informed consent from parents.

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

Single blind

Primary purpose

Treatment

Study locations

Germany · 1 center

• German Heart Center of the Charité — Berlin

Publications

• "Electrical impedance tomography during open heart surgery and on the cardiac icu is feasible to monitor ventilation in children with congenital heart disease" J.-C. Clausen, M. Emeis, M. Kleine-Brueggeney, M.-Y. Cho, M. Kneyber and O. Miera Intensive Care Medicine - Paediatric and Neonatal 2024 Vol. 2 Issue 1 Pages 19 DOI: 10.1007/s44253-024-00043-4
• Clausen JC, Emeis M, Hollander R, Miera O, Kleine-Brueggeney M, Blokpoel RGT, Garfias-Veitl T, Asendorf T, Vadiunec VV, Photiadis J, Berger F, Kneyber MCJ. Effect of Positive End-Expiratory Pressure on Cardiac Index and Right Ventricular Performance in Ventilated Children Post-Cardiac Surgery. Pediatr Crit Care Med. 2026 Feb 1;27(2):176-186. doi: 10.1097/PCC.0000000000003880. Epub 2025 Dec 19. PMID 41416857

Identifiers

NCT: NCT07486167 · EA 2025/06/10

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗