Does reducing pulmonary hyperciculation affect pulmonary capillary permeability in severe ARDS patients? - a pilot study.

It is assumed that acute respiratory distress syndrome (ARDS) is an alveolar
but also an endothelial disorder. Treatment modalities targeting alveolar
disruption focus on low tidal volume ventilation and the avoidance of
atelectasis and successfully decreased mortality. Activated protein C, heparin
inhalation and corticosteroids targeted endothelial inflammation, but these
therapies failed to reduce mortality.
ARDS is often accompanied by sepsis, which is characterized by a high cardiac
output. A high cardiac output might cause endothelial shear stress in the lung,
causing and/or aggravating ARDS. Experimental and retrospective data suggest
that reducing lung capillary flow has a beneficial effect on gas exchange.

To study the effect of reducing the pulmonary circulation to normal levels on
the pulmonary leak index in patients suffering from severe ARDS.

open label, randomized controlled trial

Titrating cardiac index to 2,5 -3,5 l/min.m2 with a minimal SvO2 of 65%.

Burden to the patient:
An (additional) arterial canule is placed in the femoral artery. Sedated
patients (most of the patients suffering from severe ARDS are deeply sedated)
have minimal burden during placement of this canule. Moreover, this canule can
also function as a routine invasive arterial pressure monitoring tool. Also, it
is possible to withdraw blood from this canule. This makes the standard
invasive canullation superfluous. To measure the pulmonary leak index, a small
amount of radioactive 67Ga will be given. The amount of radiation is considered
minimal.

Risks:
Asthma bronchiale
Bradycardia
hypotension

All patients are admitted on the intensive care unit, in a extensive monitoring
environment. The beta blocker that is used to down regulate cardiac index is
esmolol, known for its very short half-life. If complication occur, beta
blockade therapy is stopped and the complications will resolve.