Changes in ventilation distribution during general anesthesia measured with EIT in mechanically ventilated small...

Area of Science:

• Anesthesiology
• Pediatric Critical Care
• Respiratory Physiology

Background:

• Atelectasis is a risk during general anesthesia, potentially leading to perioperative complications in children.
• Understanding ventilation distribution changes is crucial for managing pediatric patients under anesthesia.

Purpose of the Study:

• To investigate changes in ventilation distribution in healthy children during general anesthesia using electrical impedance tomography (EIT).
• To quantify ventilation distribution using the Global Inhomogeneity (GI) index.

Main Methods:

• EIT measurements were performed on 23 children (9 weeks-10 years) undergoing elective surgery.
• Ventilation distribution and end-expiratory lung volume (EELV) changes were assessed at three time points: start of pressure-controlled ventilation (PCV), pressure support ventilation (PSV), and spontaneous breathing (SB) after extubation.
• The Global Inhomogeneity (GI) index was calculated.

Main Results:

• Controlled ventilation led to increased ventral lung ventilation and dorsal atelectasis.
• With the onset of spontaneous breathing, end-expiratory lung volume significantly decreased (105 ml).
• The GI in healthy ventilated children was 47% (±4%), indicating presumed homogeneous ventilation distribution.

Conclusions:

• General anesthesia and mechanical ventilation alter lung ventilation distribution in children.
• Spontaneous breathing after anesthesia promotes dorsal lung recruitment, counteracting the ventral shift seen during controlled ventilation.
• EIT and GI index provide valuable insights into ventilation dynamics during pediatric anesthesia.