Calories

Adults Much work has focused on developing an easy-to-apply formula for predicting the number of calories required to maintain weight in the severely burned patient. Many of these formulas are simply based on percentage burn area and body surface area, but others are complex—arrived at by regression analysis. Recent evaluations of these formulas, compared to indirect calorimetry, suggest that none perfectly predict a patient's true requirements. The most reliable are summarized in Table 2. Requirements vary considerably depending on multiple factors including time after burn injury, not all of which can be taken into consideration in the formulas used (Table 3). Because of major within- as well as between-patient variation, it is agreed that

Table 2 Formulas for predicting calorie requirements in adults that compare favorably with indirect calorimetric measurements (1.3 x REE)

Xie formula3

1000 + (25 x BSAB) kcal/m2/day or 4184 + (105 x BSAB) kJ/ m2/day

Zawacki formula''

1440 kcal/m2/day or 6025 kJ/ m2/day

Milner formulac

®Xie WG et al. Estimation of the calorie requirements of burned Chinese adults. Burns. 1993, 19: 146-9. 'Zawacki BE et al. Does increased evaporative water loss cause hypermetabolism in burned patients? Annals of Surgery. 1970, 171: 236-40.

cMilner EA, Cioffi WG, Mason AD, McManus WF, and Pruitt BA Jr. A longitudinal study of resting energy expenditure in thermally injured patients. [Journal Article] Journal of Trauma-Injury Infection & Critical Care. 37(2): 167-70. BSAB, body surface area burned; BMR, basal metabolic rate; DPB, days postburn.

Table 3 Factors that may alter total energy requirements in burns patients

Number of days after burn injury

Changes in environmental temperature and humidity

Changes in core body temperature, including sepsis, infection

Inhalation injury

Activity level

Surgical interventions; grafting Dressing changes Pain and anxiety Sedative drugs indirect calorimetry should be used to predict resting energy requirements (REEs) throughout the recovery period.

By measuring oxygen uptake and carbon dioxide production, the REE of the patient can be derived. Recent work has established that although body weight can be maintained on a regimen of a caloric intake of 1.3-1.5 times the REE, this reflects increasing fat accumulation despite persistent catabolism of skeletal protein. The catabolism appears to persist despite nutritional manipulation. It has been suggested that lean mass can only be maintained by pharmacological means with the use of insulin, insulin-like growth factor-1 (IGF-1), or anabolic steroids such as oxandrone.

Children Pediatric patients, who account for at least 35% of all burn injuries, are a challenge to nutritional support teams. Compared to adults, they have lower lean body mass and fat reserves and have a higher basal metabolic rate. Extra allowances are needed for growth and development, particularly during the infant and adolescent growth spurts. Many different pediatric formulas are used (Table 4). Indirect calorimetry indicates that those predicting lower calorie requirements may be more accurate.

For pediatric patients, for whom requirements have been particularly difficult to predict using formulas, indirect calorimetry has been of great importance in determining adequate calorie intake and measured energy expenditure should be multiplied by a factor of 1.5 to provide adequate calories for weight maintenance in children with burns.

Breaking Bulimia

Breaking Bulimia

We have all been there: turning to the refrigerator if feeling lonely or bored or indulging in seconds or thirds if strained. But if you suffer from bulimia, the from time to time urge to overeat is more like an obsession.

Get My Free Ebook


Post a comment