Solid State vs. Balloon Esophageal Catheter for Estimation of Pleural Pressure

Measurements of esophageal pressure (Pes) as surrogate for pleural pressure are routinely performed in selected ICU patients to facilitate lung-protective ventilation and assess breathing effort. Pes is clinically measured via a nasogastric esophageal catheter. Current techniques involve balloon catheters but have some important disadvantages as they could deflate over time and require a very precise positioning and filling volume. A solid state sensor does not have disadvantages associated with balloon catheters and may therefore be a useful alternative in clinical practice.

This method-comparison study in adult mechanically ventilated ICU patients evaluates the accuracy of Pes measured using an esophageal catheter with a solid-state sensor as compared to a balloon catheter as reference standard.

Subjects will receive a standard balloon esophageal catheter and a solid-state pressure catheter for simultaneous measurements of Pes. Study population will be post-surgical ICU patients. Measurements will be performed during clinical mechanical ventilation settings which include a first phase of passive controlled ventilation (patient is still sedated after surgery) as well a phase of partially-assisted ventilation where the patient's breathing effort has resumed and is assisted by the ventilator. During both phases, 10-15 minutes of tidal breathing will be recorded.

Inclusion criteria

• Signed informed consent
• Patient requiring mechanical ventilation at the ICU following cardiothoracic or abdominal surgery
• Age ≥ 18 year

Exclusion criteria

• Pregnancy
• Upper airway/esophageal/mouth or face pathology (i.e. recent surgery, esophageal varices, diaphragmatic hernia)
• Nasal bleeding within the last <2 weeks
• Presence of pneumothorax
• Use of anticoagulants that increase the risk of catheter insertion