Annals of the MBC - vol. 4 - n' 2 - June 1991

HYPERTONIC SOLUTIONS IN LARGE BURNS

Peled U.

Department of Plastic Surgery and Burns, Rambam Medical Center, Haifa, Israel


SUMMARY. The use of hypertonic solutions in large bums allows sodium replacement with a smaller quantity of flpio. It results in less oedema no escharatomy and fewer paralytic ileus and pulmonary complications. The advantages are obvious and with acute aggressive surgical treatment the prognosis of severe bums is improved.

In severe large burns, adequate fluid replacement in immediate treatment of shock is mandatory and vital, following cardiopulmonary resuscitation when necessary. There are still a number of approaches and looking back into history we have found frequent changes in the last century.
Reiss started using intravenous saline, and later on colloids and whole blood were added. Rosenthal (1) believed in the importance of so , dium administration as opposed to colloids and Moyer (2) accomplished post-bum shock resuscitation with electrolyte solution only.
In addition to the great number of differppt fluids there are multiple formulae for the assessment of the amount of fluid replacement, and this further shows that we still do not have the magic words.
Most of the formulae take into consideration the extent of the burned area and the patient's weight, their range being between 2 to 4 cc x % x kg. The patients who received larger amount of fluids developed important generalized oedema and other signs of hyperhydration, which raised the question of excess fluid replacement.
Monafo Q) understood that the single most important factor in resuscitation is sodium and therefore. suggested the use of hypertonic solutions in order to reduce volume.
Following Monafo, other authors reported the use of hypertonic solutions.
The benefits of relative fluid restriction in the resuscitation of large burns are worth taking into consideration.

Method

The hypertonic solution which we use was popularized by Jalenco (4). It has 240 mEq of sodium per litre, half as.chloride and half as Jactate, plus 12.5 g of albumin per litre of the electrolyte solution. The sodium deficit, following thermic injury is 0.5-0.6 mEq/kg/%. The aim of our immediate treatment is to replace the required sodium with minimum fluios.
The formula for the acute treatment is based on the amount of Na to be replaced in the first. 16 hours and is as follows: 0.444 x % BSA x weight/0.24 or, dividing the factors (0.444/0.24) in order to simplify, 1.85 x % x weight.
This amount is about 60% of most of the common formulae.
The amount of fluiO divided by 16 will give us the. hourly infusion rate which will be adjusted according to the following parameters:

  • hourly diuresis, which should be between 30 to 40 cc and have a specific Weight of 1Q20 or more
  • mean arterial pressure, 60 mm Hg or more
  • sodium in scrum, between 142 and 146 mEq per litre
  • potassium in serum, between 4 and 4.5 mEq per litre.

Blood tests for sodium and potassium are performed every hour. The hypertonic solution is sus 1 pended when the sodium reaches 150 mEq and it is then replaced by normotonic solutions. The rise of sodium in the scrum is sudden, and blood samples should therefore ' be taken frequently. In general, the critical figure of 150 mEq of sodium is reached between 14 and 26 hours after,replacement has begun.

Results

The bum casualties that received hypertonic resuscitation showed an increase of oxygen consumption with normal cardiac output as opposed to patients receiving Parkland's formula, in whom there was an increased cardiac output with low oxygen consumption. It seems that the primary event may be the change in oxygen consumption (5). In the overhydrated patients the oedema caused impairment of ox ' ygen diffusion and diminished its utilization at the cellular level and by reaction there was an increased cardiac output. Sodium plays a key role in the balance of the extracellular volume. Following bums we expect hyponatraemia and hypoalbuminaemia with a consequent unbalanced osmotic pressure and capillary leak(6). Hypertonic solutions improved the osmotic pressure and diminished the generalized oedema and the following advantages were found:

  • reduction or absence of oedema, as mentioned
  • no brain oedema, patient alert
  • almost no paralytic ileus, patient starts with oral feeding on the second day
  • fewer pulmonary complications
  • patient can be operated on very early, 36 to 48 hours following the thermal insult. The only disadvantage is thirst.

The clinical and laboratory tests are routine with no need of sophisticated monitoring.
Although we do not recommend the use of hypertonic solutions in specific eases where larger amounts of fluids are required, as in impending or established renal damage, the treatment of burn shock by this method offers ' a physiological way of treatment with special stress on less volume and adequate sodium and albumin replacement.

RESUME. L'emploi de solutions hypertoniques dans le traitement des br6lures &tendues permet la sostitution de sodium avec une quantit6 mineure de liquide. L'incidence d'oedcme est mineure, il n'y a pas besoin de escarrectomie, et l'il6us paralytique et les complications pulmonaires sont plus rares. Les avantages sont 6vidents et, avec un traitement chirurgical aggressif aigu, le pronostic des br6lures graves est plus favorable.


BIBLIOGRAPHY

  1. Rosenthal S.M., Tabore H.: Electrolytic changes and chemotherapy in experimental burn and traumatic shock and haemorrhage. Arch. Surg., 51: 244, 1945.
  2. Moyer C.A., Morgraft H.W., Monafo W.W.: Bum shock and extravascular sodium deficiency, treatment with Ringer solution with lactate. Arch. Surg., 90: 799, 1965.
  3. Monafo W.W., Chuntrasakul C., Ayvozion V.H.: Hypertonic solutions in the treatment of burn shock. Amer. J. Surg., 126: 778, 1973.
  4. Jalenco, A., Williams J.B., Wheeler M.L., Callaway B.D., Fackler V.K., Albers C.A., Berger A.A.: Studies in shock and resuscitation: use of a. hypertonic albumin containing fluid demand regimen (HALFD) in resuscitation. Crit. Care Med., 7. 157, 1979.
  5. Peled I.J., Kaplan H.Y., Wexler M.R.: Hypertonic solutions in the treatment of the post burn shock. Cir. Plast. lbero-Latinamer., 10: 65, 1984.
  6. Baxter C.R., Shires G.T.: Physiological response to crystalloid resuscitation of severe burns. Ann. N.Y. Acad. Sci., 150: 874, 1968.



 

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