Vascular filling

The vascular filling is a technique consisting with perfuser a “liquid of filling” via a venous way to fight against a fall of the flow Sang uin. The latter involves a arterial Hypotension being able to have fatal consequences.

Sometimes one speaks about volemic expansion in the same direction, the Volémie being the quantity of liquid contained in the blood-vessels.

Recall of physiology

The Blood circulation can be regarded as a closed circuit with a pump (the Cœur) and pipes constituting the Artère S and the Veine S.

A pressure decrease of filling of the heart involves:

a reduction in the general flow,
a fall of the blood Pressure causing problems of supply Blood of the Body S. If the “noble” bodies (Cœur, Poumon S, Cerveau) are relatively protected by the mechanisms from regulation, the “peripheral” bodies are sacrificed, and the deficit in Oxygène (Hypoxie) resulting from the deficit of contribution in blood (hypoperfusion) can cause the death of some cell S and thus the toxin emission.

In the worst case, it can cause a draining of the cardiac pump involving a state of Collapsus, even a cardio-circulatory Arrêt.

The vascular filling makes it possible to increase the pressure of filling of the heart and is useful only if the latter is low. In the contrary case, it can be extremely harmful, involving a Cardiac failure with a table of acute edema pulmonary.

Aqueous solutions of filling

A good aqueous solution of filling must remain in the vessels, without diffusing in fabrics.

the serum glucose brings only water and a little sugar. This water will diffuse quickly in the cells. It is thus completely unsuited to an effective vascular filling.

the ic aqueous solutions Ion ( physiological Solution ) contains water and ions. The latter however will end up diffusing in the cells. The effectiveness is thus of enough short duration.

aqueous solutions with Macromolecule S : these last increase the oncotic Pression (or osmotic pressure) of the liquid, contributing to keep this last in the vessels. They are the aqueous solutions of choice for an effective vascular filling. There exist some rare phenomena of Allergie S to the macromolecules. These last are degraded at the end of a few hours, but that leaves time to treat the cause of hypotension.

the Sang in transfusion allows a good vascular filling but does not have to be used to this end because of the cost and the risks. It is reserved for the cases where there is a proven loss of red globules.

the Blood plasma, and other products of blood (Serum, Albumin,…) , are less and less used in vascular filling because of their cost and of the risks of contamination.

Other methods of vascular filling

the simple fact of putting the patient in reclining position by raising the legs makes it possible to have a better vascular filling, the blood of the lower extremities being put at contribution.
the use of an elastic application of the members makes it possible in the same way to redirect the blood of the members towards the internal bodies.

These methods are naturally insufficient in the event of too important fall of the blood Pressure.

Indication

The vascular filling is necessary in all the cases of important Hypotension to condition of not having not a table of Cardiac failure. In this last case, the filling worsens the situation.

Within the framework of the Urgency S préhospitalières (urgent Medical assistance), the maintenance of a minimal blood pressure makes it possible to limit the problems involved in transport: if the blood pressure is insufficient, the Accélération S (in the broad sense: acceleration, braking, Centrifugal force, even assembled and descent in the case of a transport héliporté) can “attract” the blood on a side or other and thus cause a deficit of certain bodies, even a draining of the cardiac pump.

An early vascular filling is in particular indicated in the case of a severe Sepsis, as in the case of a Rhabdomyolyse (it makes it possible to limit the Impaired renal function).

Certain aqueous solutions of filling have privileged indications. The mechanism at the origin of the fall of blood volume or the individual to be treated is to be taken into account in the choice of an aqueous solution. For example, the Serum Albumin is used for the vascular filling among patients suffering from nephrotic Syndrome, or in the expectant mothers.

Precautions with the vascular filling

However, the vascular filling has also disadvantages:

if one waits too a long time that the pressure goes up, one increases the time before the admission within the structure of care and thus the time before the saving care in the case of a seriously injured (concept of Heure of gold). This argument is only theoretical, the filling which can be done during transport.
if the victim presents a hemorrhage, one “pushes” blood outside, one dilutes blood and thus one worsens the hypoxia. The vascular filling is in particular to carefully discuss into pre-hospital for the traumatisms penetrating the thorax (standard Firearm).

The vascular filling is limited in time. Apart from the aqueous solutions of human origins, there exist maximum amounts of perfusion not to be exceeded. In the macromolecules, the allowed quantity of Hydroxyéthylamidon maximum is of 33 ml/Kg/24 hours. The blood aqueous solutions, even apart from the incompatibilities of group or rhesus, can be noxious if they are managed in great quantity.

Realization

A perfusion is posed on a venous way ideally important (gross veins arm, veins fold of the elbow or if need be, center lane). The speed of perfusion is regulated by the height of this one compared to the plan of the patient, but especially by a serrated roller clampant (narrowing) more or less the pipe leading to the vein. In certain cases one can accelerate the perfusion:

by increasing the pressure in the Pocket of perfusion (compression of the latter by a inflatable Arm-band)
by installing a motorized system (electric pump) pushing the liquid with a constant flow.

Certain devices still help in difficult situations:

Pants Anti-g; Inflated to the level of the 2 legs, it limits vascular volume to fill with the other parts of the body.
Heightening of the legs compared to the plan of the body, mobilizes approximately 300ml blood volume immediately available. This gesture is useful in the very first seconds of a faintness vagal with loss of consciousness.

Control effectiveness

A regular monitoring (either manual, or by an electronic system of Monitoring) is essential:

heart rate
Blood-pressure
Volume of the Diuresis

In the more delicate cases, one can help by the direct or indirect evaluation pressures of filling by:

échocardiographie : cut ventricle right, cuts Vena cava and influences breathing on the latter.

the measurement of the central venous Pressure . A catheter, connected to a central vein, is installed against a graduated vertical scale. The water level read corresponds (in cm of water) to the central venous pressure.

the measurement of the pulmonary capillary Pressure , the most reliable method but most complex, since it requires the installation of a long catheter (Swan-Ganz) introduced by a central vein, crossing the right cardiac cavities and the pulmonary Artère and whose end is on the level of the pulmonary Capillaire.

List aqueous solutions of vascular filling

Crystalloids

Serum salted (isotonic, hypertonic)
Ringer Lactate
Serum glucose (5%, 10%,30%,50%)

Macromolecules

Hydroxyéthylamidon S
Dextran S
Serum human Albumin (4%, 20%)
blood Bases (concentrated globular)

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