"Computer-assisted determination of fluid and nutritional needs for burn patients"

Sir:

We have designed a computer program which automates the process of calculating the requirements in fluids, calories and nutrients for the adult burned patient. The program was written in BASIC language[Microsoft(R)GW-BASIC(TM) Version 3.20] and it can run in any IBM compatible personal computer. This application program is subdivided into three programs which can be individually selected and run through the options screen. Necessary entries to run the programs are data relevant to the determination of fluid and nutritional needs such as the patient's weight in kilograms, the time of injury, the extent of burn %(TBSA) and the body surface area in m².

After the entry of data, the first program generates a schedule with the proposed resuscitation fluids during the first and the second 24 hour post burn. Resuscitation fluids in Ringer's lactate in the first 24 hours are calculated with the use of the Parkland formula. Half of these fluids are infused in the first 8 hours and the remaining 1/2 during the 2^nd and 3^rd 8hour post-burn period. The fluids during the second 24 hours are calculated in an amount equal to one half the first day's requirements. Colloid is given in the amount of 0.5 cc per kg body weight per % burn(fig.1). The post-resuscitation fluids after the first 48 hours post burn which are determined by the second program, are estimated by calculating wound evaporative loss (Body Surface Area X[25+%TBSA]X24) and adding the measured nasogastric losses plus maintenance requirements(fig.2).

The third application program calculates the caloric requirements in the burned patient according to the Curreri formula(25cal/Kgr*+40cal/%TBSA). The nitrogen requirements in grams are also estimated. For burns greater than 10% TBSA, a non-protein calorie to nitrogen ratio of 100:1 is required in order to achieve positive nitrogen balance[1]. The amount of glucose, fat and proteins in grams to meet the caloric requirements are also determined(fig.3).

There are several formulas to estimate the resuscitation fluids in the burned patient. The Parkland formula is the most commonly applied formula in the USA[2]and worldwide. Resuscitation with Ringer’s Lactate is as effective in restoring blood volume as the compound formulas which use colloid solutions. The Parkland formula is also a safe and inexpensive formula. It is well known that all formulae serve only as guidelines to fluid replacement therapy. Evaluation of the clinical condition of the patient and monitoring of urine output are important guides to adequate resuscitation. The administration of fluids should be adjusted to maintain a urine output of 0.5-1ml/Kgr/hr. As far as the caloric needs are concerned, all formulae yield good results in the clinical setting. The differences in estimated energy expenditure by the multiple formulae may be statistically significant, but rarely are clinically significant[3]. Therefore selection of formula should be based on simplicity. The Curreri formula is simple and estimates the caloric needs based on burn’s extent and body weight.

We have successfully used the program described above in our department since 1996 and we have found it reliable, flexible and user friendly. Advantages of the program are as follows: a. concurrent display of data and results b. easy modification or reinsertion of data c. faster execution time than similar calculations performed with the aid of electronic spreadsheet[4] or with the handwritten technique.

This simple BASIC program automates the process of routine handwritten calculations without the fear of mathematical errors. It also makes the memorization of formulas unnecessary. The results can be easily copied or printed and kept in the medical record of the patient. The program may be useful and can be applied in Burn Units. In addition it may be used in cases where calculations must be made rapidly and accurately such as mass burns and and/or in the emergency room where expert burn advise may not be immediately available.

Theodore C. Kononas MD

George Kofinas MD

Vaggelogiannis Katergiannakis MD,PHD, Assoc. Professor in Surgery, Medical School, University of Athens, Greece

"Hippokration" Gen. Hospital,

Vasilissis Sofias 114,

11527, Athens,

Greece

Papadiamantopulu 59

11527, Athens,

Greece

e-mail: Tkononas@yahoo.com

1. Matsuda, T., Kagan, R.J., Hanumandass, M., Jonnason, O. The importance of burn wound size in determining the optimal calorie:nitrogen ratio. Surgery 94:562,1983

2. Fakhry, S.M., Alexander, J., Smith, D., Meyer, A.A., Peterson, H.D. Regional and institutional variation in burn care. Burn Care Rehabil. 16:86,1995

3. Curreri, P.W. Assessing nutritional needs for the burned patient. J. Trauma 30:520,1990

4. Kibby, M.R. The electronic spreadsheet as a general-purpose programming tool. Comput. Appl. Biosci. 1:73,1985

FIG.1. The computer screen with the recommended resuscitation fluids schedule.

FIG.2. Example of the calculated post-resuscitation fluids after the first 48 hrs.

FIG.3. Sample screen displaying the calculated calories, nutrients and nitrogen requirements.

Αρχή  κειμένου