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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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