Muscle deteriorations become prominent within 24 hours after admission in severely burned adults.

Background: Severe burn injury results in profound catabolic deterioration. Although burn-related catabolism has been well stated, it is unclear when the catabolic response begins. This study characterized acute changes of muscle protein breakdown at the admission and the day after in severely burned adults.

Methods: Twelve patients (43 ± 19 years old) with 40% ± 21% total body surface area burns were prospectively enrolled into an observational study approved by institutional review board. Urinary samples were collected on admission day and the day after (day 1). Patient demographic and clinical data of vital signs, blood gas and chemistry, and coagulation status were collected. Catabolic changes of muscle breakdown were quantified by urinary excretion of 3-methylhisitidine, determined by gas chromatography and mass spectrometry analysis.

Results: Compared with admission day, burned patients had elevated mean ± SD arterial pressure (from 90 ± 5 mm Hg to 108 ± 7 mm Hg) and heart rate (from 102 ± 7 beats per minute to 119 ± 4 beats per minute both p < 0.05) after 24 hours. Their 24-hour urinary output was 1,586 ± 813 mL at admission day to 1,911 ± 1,048 mL on day 1. The 24-hour urea excretion was elevated from 172 ± 101 mg/kg per day at admission day to 302 ± 183 mg/kg per day on day 1 (both p < 0.05), with no change in creatinine excretion. Urinary 3-methylhisitidine excretion increased from 0.75 ± 0.74 mg/kg per day at admission to 1.14 ± 0.86 mg/kg per day on day 1 (p < 0.05). The estimated skeletal muscle protein breakdown was increased from 1.1 ± 1.0 g/kg per day at admission day to 1.6 ± 1.2 g/kg per day on day 1 (p < 0.05). There were no changes in prothrombin time, activated partial thromboplastin time, or platelets.

Conclusion: In severely burned patients, catabolic muscle protein breakdown is elevated within 24 hours after admission and before changes in coagulation. These findings suggest that early interventions may be needed to effectively attenuate the catabolic responses in burn patients.

Level Of Evidence: Prospective and observational study, level II.