Hydrofluoric Acid Burns

A 32 year old gentleman was welding stainless steel and sustained a 75% concentration hydrofluoric acid burn to the right hand.  Upon initial assessment, vital signs are unremarkable with a RR-12 @ 99% RA and BP 128/86.  On physical exam there are no visible signs of damage to the right hand and he seems to be neurovascularly intact.  Upon auscultation of the heart and lungs, diffuse expiratory wheezing is noted.  A 12 lead EKG is obtained and pictured below.  What are your initial management options and continuing concerns throughout treatment of this patient?

Hydrogen fluoride and its aqueous form, hydrofluoric acid, are utilized in many manufacturing processes.  Uses include: cleaning products, oil refining, Teflon production, aluminum production, and etching of carbon and stainless steels as well as ceramics.  Exposures most commonly seen involve explosions of Teflon containing compounds, deployment of automated fire suppression systems, and exposure to cleaning solutions.

The high lipid solubility of HF allows it to penetrate tissues rapidly.  Immediate exposure may result in a painless burn, as the substance interferes with nervous system function.  This could delay contact of emergency services and also mask the severity of exposures. Extreme pain ensues as the chemical begins to interact with ions in the tissues.  The fluoride ion in the compound has a high electronegativity.  This quality imparts a high affinity for positively charged ions in the body, allowing HF to readily interact with calcium and magnesium in the body.  The combination of hypocalcemia and hypomagnesemia promotes prolongation of the QT interval, ventricular arrhythmias, tetany, and seizures.  HF burns involving greater than 2% body surface area or HF with a concentration of greater than 20% have the highest likelihood of causing systemic toxicity and fatal arrhythmia.

As with most chemical exposures, copious irrigation is encouraged.  In addition to irrigation, literature has shown improved immediate pain relief and long-term outcomes with application of topical 2.5% calcium gluconate.  If calcium gel is not readily available, it can be made by mixing 3.5 g of calcium gluconate powder with approximately 5 ounces of water soluble surgical lubricant.  For continued pain after topical application, 5% calcium gluconate subcutaneous injections may be utilized for local infiltration.   The appropriate dose is 0.5 mL per cm² burn area.  Local infiltration is not recommended for digits.  Up to 40 mL of 10% calcium gluconate can be given intra-arterially or intravenously with an inflated blood pressure cuff to localize the treatment if infiltration is not effective or not an option.

In the case presented, cardiac monitoring and topical calcium application are the most important management factors in the pre-hospital setting.  A seemingly mild case of an HF burn to the hand could decompensate quickly due to cardiac dysrhythmia.  Keep in mind that 2% BSA can include a burn only involving the hand!  In a hospital setting, continuous cardiac and electrolyte monitoring guide management.  Calcium can be administered intravenously in a 1000 mg dose infused over 2 minutes.  Magnesium replacement of 4g IV given over 20 minutes is also recommended. 

References

1.         Nathanson L A, McClennen S, Safran C, Goldberger AL. ECG Wave-Maven: Self-Assessment Program for Students and Clinicians. http://ecg.bidmc.harvard.edu.  Accessed 16 December 2014.

2.         Höjer J, Personne M, Hultén P, Ludwigs U. Topical treatments for hydrofluoric acid burns: a blind controlled experimental study. J Toxicol Clin Toxicol. 2002;40(7):861-866. http://www.ncbi.nlm.nih.gov/pubmed/12507055.

3.         Lewis N, Lewand M, Howland N, Hoffman R, Goldfrank L, Flommenbaum L; Goldfrank’s Toxicologic Emergencies, Ninth Edition; 9^th ed; 2010. 787-803.

4.         Wu M-L, Yang C-C, Ger J, Tsai W-J, Deng J-F. Acute hydrofluoric acid exposure reported to Taiwan Poison Control Center, 1991-2010. Hum Exp Toxicol. 2014;33(5):449-454. doi:10.1177/0960327113499165.