What is the comparison of dynamic compliance and airway resistance in pressure-controlled ventilation (PCV) versus volume-controlled ventilation (VCV) in pediatric patients with left-to-right intra-cardiac shunt undergoing corrective surgery?

From the Guidelines

When comparing dynamic compliance and airway resistance in pressure-controlled ventilation (PCV) versus volume-controlled ventilation (VCV) for pediatric patients with left-to-right intracardiac shunts undergoing corrective surgery, PCV is the preferred ventilation mode due to its ability to provide better dynamic compliance and lower airway resistance, as supported by the principles outlined in the Paediatric Mechanical Ventilation Consensus Conference (PEMVECC) 1.

Key Considerations for Ventilation Mode Selection

• The choice between PCV and VCV should be guided by the patient's specific pathophysiology, including the presence of left-to-right intracardiac shunts and the potential for altered lung mechanics and increased pulmonary blood flow.
• PCV allows for a decelerating flow pattern that delivers the preset pressure more evenly throughout the respiratory cycle, which can help in better distribution of air to the alveoli and reduce peak airway pressures, thus preventing barotrauma and volutrauma while maintaining adequate gas exchange.
• The use of sufficient PEEP is crucial to maintain end-expiratory lung volume, although the specific level of PEEP cannot be universally recommended for cardiac children with or without lung disease, as emphasized by the PEMVECC guidelines 1.

Ventilation Settings

• Typical settings for PCV in pediatric patients with left-to-right intracardiac shunts might include a peak inspiratory pressure of 15-20 cmH2O and PEEP of 4-5 cmH2O, with respiratory rates adjusted according to age.
• The selection of ventilation mode and settings should be tailored to the individual patient's needs, taking into account factors such as lung mechanics, hemodynamic status, and the specific goals of ventilation.

Physiological Basis

• The improved compliance and reduced airway resistance seen with PCV can be attributed to its ability to accommodate the altered pulmonary vascular resistance and compliance characteristics in patients with left-to-right shunts, as suggested by the principles for mechanical ventilation in critically ill children 1.
• Assisted rather than controlled ventilation may be preferable in cardiac children, considering the potential benefits of maintaining spontaneous breathing efforts while providing adequate ventilatory support, as noted in the PEMVECC recommendations 1.

From the Research

Comparison of Dynamic Compliance and Airway Resistance

• The question of comparing dynamic compliance and airway resistance in pressure versus volume controlled ventilation among pediatric patients with left to right intra-cardiac shunt undergoing corrective surgery is a complex one.
• Studies have shown that left to right shunts can cause increased pulmonary blood flow, leading to dilatation of cardiac chambers, congestive heart failure, pulmonary artery hypertension, and eventually Eisenmenger's syndrome 2.
• In terms of ventilation strategies, research has focused on adult patients with acute lung injury and acute respiratory distress syndrome, with studies comparing pressure-controlled ventilation (PCV) and volume-controlled ventilation (VCV) 3, 4.
• These studies have found that PCV may reduce mortality and morbidity in intubated and ventilated adults, but the evidence is not conclusive, and more research is needed to determine the best approach 4.
• The use of recruitment maneuvers and positive end-expiratory pressure (PEEP) has also been explored, with some studies suggesting that these strategies can improve respiratory function and minimize ventilator-associated lung injury 5, 6.
• However, the application of these findings to pediatric patients with left to right intra-cardiac shunt undergoing corrective surgery is not clear, and further research is needed to determine the optimal ventilation strategy for this population.

Ventilation Strategies

• Pressure-controlled ventilation (PCV) and volume-controlled ventilation (VCV) are two common ventilation strategies used in critically ill patients.
• PCV involves delivering a set pressure to the airways, while VCV involves delivering a set volume of air to the lungs.
• Studies have compared these two strategies in adult patients with acute lung injury and acute respiratory distress syndrome, with mixed results 3, 4.
• The use of recruitment maneuvers and PEEP has also been explored, with some studies suggesting that these strategies can improve respiratory function and minimize ventilator-associated lung injury 5, 6.

Pediatric Patients with Left to Right Intra-Cardiac Shunt

• Pediatric patients with left to right intra-cardiac shunt undergoing corrective surgery require careful consideration of their ventilation strategy.
• The optimal ventilation strategy for this population is not clear, and further research is needed to determine the best approach.
• Studies have shown that left to right shunts can cause increased pulmonary blood flow, leading to dilatation of cardiac chambers, congestive heart failure, pulmonary artery hypertension, and eventually Eisenmenger's syndrome 2.
• The application of ventilation strategies used in adult patients with acute lung injury and acute respiratory distress syndrome to pediatric patients with left to right intra-cardiac shunt undergoing corrective surgery is not clear, and further research is needed to determine the optimal approach.