effect of a higher bloodpressure on Right Ventricular Function

Right ventricular (RV) dysfunction in cardiac surgery is an independent risk
factor for morbidity and mortality. Raising the systemic blood pressure with
norepinephrine seems to have a positive influence on the function of the right
ventricle in several animal studies. The current study is designed to evaluate
the effect of a higher blood pressure on the RV function in post cardiac
surgery patients.

To demonstrate differences in RV function by raising the systemic blood
pressure with norepinephrine.

randomized controlled trial

Intervention:
* Group 1: (N=22): RVEF<20% and MAP<70mmHg. Intervention with norepinephrine to
reach a MAP of 85mmHg for a maximum duration of four hours.
* Group 2: (N=22): RVEF <20% and MAP<70mmHg. Control group: treatment according
to current standards. Hypotensive patients are treated with fluids and/or
vasopressors to gain a mean arterial pressure (MAP) of 65mmHg.
* Group 3: (N=17): RVEF between *20 and <30%. Intervention with norepinephrine
to reach a MAP of 85mmHg for a maximum duration of four hours.
* Group 4: (N=17): RVEF between *20 and <30%. Control group: treatment
according to current standards. Hypotensive patients are treated with fluids
and/or vasopressors to gain a mean arterial pressure (MAP) of 65mmHg.

Norepinephrine will be used to raise the systemic blood pressure to asses our
end-points. Since the use of Norepinephrine falls within therapeutic routine,
the potential risks are low. Furthermore, all patients will undergo
transoesophageal echocardiography in the postoperative setting. The expected
risk and disadvantages are small. Only minor discomfort is expected because all
patients are sedated during the investigation.