Respiratory Function in Ventilated Newborn Infants Nursed Prone and Supine

Area of Science:

• Neonatal Physiology
• Respiratory Medicine
• Critical Care

Background:

• Prone positioning is known to improve oxygenation in ventilated newborns.
• The underlying physiological mechanisms for this improvement require further investigation.

Purpose of the Study:

• To investigate the physiological basis of improved oxygenation in ventilated neonates placed in the prone position.
• To test the hypothesis that respiratory function, measured by composite physiological indices, improves in the prone versus supine position.

Main Methods:

• Prospective observational study in a tertiary neonatal unit.
• Ventilated newborns were studied in random prone and supine positions.
• Non-invasive calculation of ventilation to perfusion ratio (V_A/Q), right to left shunt, and arterial to end-tidal carbon dioxide (PaCO₂ - EtCO₂) gradient.

Main Results:

• Forty-six neonates were studied after a median of 5 hours of invasive ventilation.
• Significantly higher V_A/Q (p=0.001) and lower right to left shunt (p=0.003) were observed in the prone position.
• The PaCO₂ - EtCO₂ gradient, indicating alveolar dead space, was significantly lower in the prone position (p<0.001).

Conclusions:

• Prone positioning in ventilated neonates is associated with improved ventilation-perfusion matching.
• The prone position leads to reduced intrapulmonary shunting and alveolar dead space compared to the supine position.
• These findings provide physiological evidence supporting the use of prone positioning to enhance respiratory function in neonates.