J. H. Henderson1, P. Attaluri1, E. He1, J. Kesey1, M. Tan1, J. Griswold1 1Texas Tech University School of Medicine,Department Of Surgery,Lubbock, TEXAS, USA
Intro: Electrical high-voltage contact injuries are the second leading cause of occupational death in the U.S. The electrical surge encounters muscle cells, causing sudden and intense myocyte contraction, releasing intracellular contents such as myoglobin and creatine kinase (CK). The released pigments cause obstruction of renal tubules leading to acute renal failure. Currently, the trauma literature supports use of elevated serum CK to indicate muscle and renal damage. While CK can be a reliable screening method for muscle injury, we believe myoglobin is a more sensitive and specific indicator of risk and severity of renal damage. Our study aims to determine whether elevated CK or elevated myoglobin is more sensitive in predicting the risk of renal injury for electrical burn patients and to define parameters of serum myoglobin for implementing renal protective therapies.
Methods: A retrospective, single institution review was conducted on all patients over the age of 18 years who suffered a high voltage electrical injury (>1,000 volts) admitted to the Burn Center from 2006 to 2017. Patients who had preexisting end stage renal disease, were on dialysis, or died within 48 hours of admission were excluded. Chi-Square Testing was used to compare means in serum myoglobin and serum CK levels collected daily and acute kidney injury (AKI) as defined by the RIFLE criteria, which breaks AKI into three categories Risk, Injury, and Failure. Urine output and fluid resuscitation therapies were collected daily to track the progression of AKI. A Pearson product-moment correlation coefficient was computed to assess the relationship between AKI and serum myoglobin and serum CK. An independent sample mean's test was performed on patients who developed AKI to determine a serum myoglobin threshold for initiation of treatment.
Results: A total of 207 patients were analyzed 2006-2017; 27.1% of patients developed AKI as defined by RIFLE criteria. Mean serum myoglobin in patients with AKI was found to be 2,336.9 vs. no AKI 1,140.14 (P=0.0001). Mean serum CK level in patients with AKI was found to be 10,926 vs. no AKI 8,174 (P=0.132). There was a positive correlation between serum myoglobin levels and developing AKI (r = 0.212, n = 120, p = 0.02), whereas there was no statistically significant correlation between serum CK levels and AKI. Patients with myoglobin level 1,449.52 or above are at high risk of developing AKI (P=0.053) and require renal protective measure.
Conclusion: Serum myoglobin is a more sensitive marker for predicting AKI when compared to serum CK in high-voltage electrical burns. A serum myoglobin threshold of >1500 was associated with increased risk of AKI, indicating the need to start renal protective therapies. Although trauma and rhabdomyolysis patients’ CK may be useful for indication of risk of renal damage, in electrical contact injuries myoglobin must be used to determine risk of renal damage and to direct renal protective therapy.