Oesophageal pressure measurements in ventilated preterm babies.

Oesophageal pressure measured with an air-filled, thin latex balloon on a 6 French gauge catheter can accurately measure intraoesophageal pressures in ventilated preterm babies. Intraoesophageal pressures and intrapleural pressures are equivalent. Less than 10% of the applied positive ventilator pressure is transmitted to the oesophageal balloon and the intrapleural catheter (intercostal drain). The oesophageal traces show that ventilated babies breath independently of the ventilator. The largest deflections recorded from the oesophageal trace are from spontaneous inspiratory activity. During paralysis with pancuronium spontaneous respiration is inhibited, peristaltic waves are still recorded, and there is little transmitted pressure from the ventilator to the oesophagus or intercostal drain.