Hypermetabolism exacerbation with increased white blood cell counts in patients with severe burns.

Severe weight loss after large burns has been previously described when the hypermetabolic response is not met with adequate nutritional provisions. Clinically, we have been able to minimize this weight loss in most patients admitted to our burn center but have identified unexpected weight loss in some. The goal of this analysis was to identify predictors of this weight loss. This retrospective descriptive study included adult patients with at least 20% TBSA burns admitted between September 2017 and February 2023. There were 63 patients who met the criteria for this study: median of 35% TBSA burn (IQR: 27-51), 44 years old (IQR: 31-55), 21% women. These patients experienced a median weight loss of 3 kg (IQR: 1-8) over 31 days (IQR: 22-50). Most (78%) patients experienced ≤10% weight loss, whereas 2% sustained >20% weight loss. The final factors significant in the multivariate analysis evaluating weight loss included days from injury to lowest weight, average WBC x days, and caloric deficit (p <0.01). The resulting equation is: weight loss (in kg) = 1.1 + 0.0121 x average WBC in 103/uL x days + 0.0001 x caloric deficit - 0.1432 x days from injury to lowest weight (R2=0.54). This indicates a further increase in metabolism above the expected hypermetabolic response when there is an elevation in WBC, likely reflecting concurrent sepsis or other processes driving systemic inflammation. Further research should focus on frequent metabolic cart study measurements in patients with elevated WBC counts to further elucidate this relationship.