Comparison of a solid state versus balloon esophageal catheter for estimation of pleural pressure in surgical ICU patients

Measurements of esophageal pressure (Pes) as surrogate for pleural pressure are
routinely performed in selected mechanically ventilated intensive care patients
to facilitate lung-protective ventilation and assess breathing effort. Pes is
clinically measured via an esophageal catheter. Current techniques involve
balloon catheters. Unfortunately, the balloon has some important limitations
including that it could deflate over time, complex positioning/calibration and
the need for regularly checking the adequate filling volume and position. Using
a solid-state sensor esophageal pressure catheter for the measurement of Pes
may overcome these limitations.

Previous older studies have used solid state transducers,but concluded these
were not able to meet the requirements.These studies were, however, performed
decades ago and/or might have used pressure transducers that were not correctly
(temperature) calibrated. The solid-state catheter proposed for this study has
a state-of-the-art pressure transducer, allowing for temperature and ambient
pressure calibration.
Bench tests from the manufacturer as well as a previous investigation in
healthy volunteers as performed by this research team demonstrated positive
results (see IMDD). We now want to further test the accuracy of this
solid-state sensor in mechanically ventilated patients.

To evaluate the accuracy of Pes measurement with a solid-state catheter during
controlled and assisted ventilation.

This is a physiological validation study, with a duration of 1.5-2hours and
performed on a single day.

The aim of this study is to improve the technique for the measurements of
respiratory parameters, which could optimize mechanical ventilation management
of patients. We do not expect high risks for participants in this study.
Placement of the catheter may give some discomfort, but this is similar to
placing any nasogastric tube. The participant is still sedated at the time of
placing the catheter, therefore no discomfort is expected. Risks of this study
will be minimal, especially because high-risk participants (with
contra-indication for placing a nasogastric catheter) are excluded for
participation in the study and the catheter will be inserted by a trained
doctor, nurse or technical physician. The measurements will take place in the
intensive care unit where vital parameters are continuously monitored and the
clinical team (nurse/doctor) is continuously available, so that potential risks
can be anticipated immediately. Further observational study measurements are
non-invasive. Participants will not directly benefit from this study, but their
participation will contribute to more knowledge in the field of esophageal
pressure measurements. Insights may lead to future clinical implementation of a
catheter that can more accurately measure esophageal pressure, resulting in
clinical benefits.