Prospective combined validation of an algorithmic calculated mean systemic filling pressure with transpulmonary pressure measurements during thoracic drainage and 3D TOE measured hemodynamic parameters.

Volume-state in critically ill patients is a difficult parameter to determine,
and knowledge about it could make the difference between life or death
concerning proper treatment. Determination of volume state starts with adequate
3D transesophageal echocardiography (TOE) in the operation room, including with
non-invasive doppler carotid artery measures. TOE is a standardly used method
in cardiac surgery. Because echocardiography only gives information about
volume status at a certain timepoint, a real-time continuous value reflecting
volume-status is needed. "Mean systemic filling pressure (Pms)" appears to be a
promising value reflecting volume status. There are clinically and
patient-unfriendly methods available which to date serve as a gold standard to
determine Pms. However, these methods cannot be used in daily practice because
of the aforementioned reasons. Therefore there is a need for a non-invasive
methods measuring Pms, which could now be determined by an algorithm (PmsALG).
It is key to compare this PmsALG with its gold standards (inspiratory breath
hold; PmsINSP) and a more minimally invasive but certainly not patient-friendly
determination of Pms by blood pressure cuff measurement in an arm (PmsARM) in
order to establish a clinical validation for PmsALG.
While validating PmsALG, one has to consider the intrathoracic pressure by
performing esophageal pressure measurements (Ppl) using a esophageal balloon to
be able to calculate which pressure changes are exactly attributable to the Pms
measurement during an inspiratory breath hold. Coincidentally this gives
opportunity to determine what the clinical value of oesophageal pressure
measurements is during thoracic drainage in post cardiac surgery patients, for
this has never been investigated. By combining all these entities, the
investigators hope to be able to give a better estimation of intravascular
fluid status in order to prevent hyper/hypovolemia and eventually create a
better outcome for ICU-patients.

1. Is PmsALG comparable with PmsINSP, even with changing Ppl?
2. Is PmsARM comparable with PmsINSP and PmsALG?
3. Does thoracic drainage have influence on pleural pressures measured by
esophageal balloon catheter to determine transpulmonary pressure?
4. What is the difference between cardiac parameters and non-invasive
perioperative values determined by 3D transoesophageal echocardiography (TEE)
compared with PiCCO and carotid echo doppler?

Prospective observational cohort analysis.

Minimal burden for the patient, as all study procedures will take place under
full sedation.

Inspiratory breath hold:
Standard method without risks.

Esophageal balloon catheter:
No hazard, small risk of bleeding (in theory) which has never occurred in
practice.

PiCCO catheter:
Standard Intensive Care equipment. Small risk of bleeding or catheter-related
infection (in theory) which has never occurred in practice.