Tuesday, April 8, 2014
Role of colloids in burn resuscitation...........
Doc, what is the role of albumin in
early burn resuscitation? Do we have to give it in all cases?
Jessie p,
Colorado, USA
When a patient suffers a burn injury
there is a temporary loss of the integrity of the capillaries as we have
discussed before. This loss leads to the leakage of plasma proteins like
albumin into the interstitial space. This
loss continues for the first eight hours following which the capillaries start
to regain their integrity. Therefore if one were to replace the colloids in the
first eight hours they would obviously leak out. It seems reasonable that one
may start to replace giving colloids in the 2nd eight hours of the burn.
Different types of colloids may be
used for resuscitation in burns: fresh frozen plasma, albumin and Dextran. Fresh
frozen plasma is often given at a rate of 0.5ml-1ml/kg %TBSA and has a
theoretical advantage - it replaces other plasma proteins besides albumin.
Dextran, another colloid used in burn
resuscitation increases capillary blood flow, reduces RBC aggregation and helps
to reduce tissue edema though this effect is limited to the time that Dextran
is being administered as the body will metabolize it eventually. Dextran is
composed of polymerized high molecular weight glucose chains and has double the
osmotic pressure of albumin.
Hypertonic saline (180-300 mEq/L) has
been used in some centers as it helps to shift extracellular fluids ( third
space fluid loss) back into the vascular space by osmosis resulting in a
reduction of fluid requirements. However there are some disadvantages:
hypernatremia and intracellular fluid depletion can occur and therefore serum
sodium levels should be closely monitored and maintained below 160mEq/L.
Albumin which is a regular component
of our plasma is a protein that maximally raises the intravascular oncotic
pressure. When it is given intravenously fifty percent of it remains intravascular,
when compared to other colloid solutions where only twenty to thirty percent
remains intravascular. Albumin is often infused as the rate of 0.3-1ml/kg /% burn
over 24 hours.
In many centers colloids are added in
the 2nd eight hours though Parkland formula advocates only crystalloids in the first 24
hours. Colloids help to reduce the fluid
load in the first 24 hours and they also help to increase the urine output
which often tends to go down during resuscitation. Colloid resuscitation is of
great benefit in geriatric patients, major burns (>40%), patients associated
with inhalation injury and those with cardiac disorders as it is difficult to
resuscitate them with limited fluids and they are constantly in the danger of
being overloaded. Fluid infusion should be tapered off after the first 24-32
hrs, when one finds that the patient has been adequately resuscitated. Fluid administration
should then be planned on the basis of requirements of albumin (keep>2) and
free water requirements (electrolyte free) to counter irreversible water loss. Free water
requirement is estimated as (25% + % burn) x BSA (m2) = ml/hr free water.
The maintenance of all the clinical parameters like the urine output at normal
levels is critical to the continuation of the resuscitation process to its
logical conclusion. Prudent use of fresh frozen plasma and albumin can be very helpful and safe when compared to other colloids in burn resuscitation.
(An original initiative in burn care and education from asktheburnsurgeon++)
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