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Effect of PEEP on lung aeration in pediatric patients after cardiac surgery: a CT-Based study
Solange C Gimenez1, Milene C Carrilho1, Isabela M Malbouisson1
1Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Divisão de Anestesia, São Paulo, SP, Brazil.
Insights
Pediatric cardiac surgery can cause lung aeration loss. Positive End-Expiratory Pressure (PEEP) improved lung gas volume but did not fully re-inflate collapsed lung areas in children after heart defect repair.
Area of Science:
- Pediatric Critical Care Medicine
- Cardiothoracic Surgery
- Respiratory Physiology
Background:
- Lung aeration changes post-cardiac surgery in children are not well understood.
- Adults often experience lung aeration loss after cardiopulmonary bypass.
- The impact of Positive End-Expiratory Pressure (PEEP) on pediatric lung aeration post-congenital heart defect repair remains unclear.
Purpose of the Study:
- To investigate changes in lung aeration in children undergoing congenital heart defect repair.
- To evaluate the effect of Positive End-Expiratory Pressure (PEEP) on lung aeration post-surgery.
Main Methods:
- Volumetric computed tomography (CT) used in 12 children with congenital acianogenic heart diseases.
- CT scans obtained preoperatively and postoperatively during mechanical ventilation with varying PEEP levels (0, 5, 10 cm H2O).
- Quantification of gas, tissue, non-aerated, poorly aerated, and normally aerated lung compartments.
Main Results:
- Postoperatively, the non-aerated lung compartment increased significantly at zero PEEP.
- Stepwise PEEP application (up to 10 cm H2O) restored normally aerated lung volume to preoperative levels.
- PEEP did not significantly reduce the non-aerated lung parenchyma.
Conclusions:
- Surgical correction of congenital heart defects leads to significant loss of lung aeration.
- Positive End-Expiratory Pressure (PEEP) effectively restored lung gas volume but failed to fully recruit collapsed lung tissue.
- Further strategies may be needed to address persistent lung atelectasis after pediatric cardiac surgery.
Background:
Loss of lung aeration is frequently observed in adult patients following cardiac surgery with cardiopulmonary bypass. Yet, in children, changes in lung aeration following surgical repair of congenital heart defects, and the effects of Positive End-Expiratory Pressure (PEEP), remain uncertain.
Methods:
Changes in lung aeration were investigated using volumetric computed tomography in 12 children with congenital acianogenic heart diseases and increased pulmonary flow who underwent total surgical repair under cardiopulmonary bypass. Computed tomography of the lungs was obtained preoperatively during spontaneous breathing and postoperatively during mechanical ventilation with positive end-expiratory pressure of 0, 5 and 10 cm H2O. Gas and tissue lung volume and mass, as well non-aerated, poorly aerated and normally aerated lung compartments were measured.
Results:
Median age of patients was 18.3 months, (4 to 24 months), weight was 9.3 ± 2.3 kg. Cardiopulmonary bypass duration was 77 ± 26 minutes. Preoperatively, pulmonary volume was 545 mL (237‒753 mL), whereby tissue and gas volumes were 48.4% (41.7%‒59.6%), and 51.6% (40.4%‒58.3%), respectively. Non-aerated and normally aerated compartments accounted for 15% and 47.9% of lung tissue, respectively. Postoperatively, at zero PEEP, the non-aerated compartment increased to 27%, while normally-aerated compared decreased to 38.5%. Stepwise PEEP application restored normally aerated lung volume to preoperative levels but did not significantly reduce non-aerated parenchyma.
Conclusion:
Loss of lung aeration was pronounced after surgical correction of congenital heart defects. PEEP up to 10 cm H2O restored gas volume but failed to recruit the collapsed parenchyma. Ethical Approval CAPPesq n° 854/01.
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