>> Overview:
Used in a variety of industries, including plastic, dye, semiconductor, and fertilizer manufacturing, beer fermentation, and in petroleum production
Also found in rust remover, various pesticides, refrigerants, car wash cleaning products, and detergents
Cutaneous exposures are most common
Dilute aqueous HF is a weak acid, but at concentrations > 20%, severe and potentially lethal burns can occur
HF is lipophilic and highly penetrative; causes deep tissue destruction via liquefactive necrosis
Once within the tissues, the fluoride ion complexes with calcium and magnesium, causing their depletion
Hyperkalemia results from increased cellular permeability
>> Clinical Presentation:
Pain out of proportion to the exam; discomfort often described as severe throbbing
Exposures to concentrations > 50% cause immediate pain and tissue damage
This may include erythema, blistering, ulceration, underlying bone damage, and tenosynovitis
Systemic toxicity develops more slowly
Can manifest as nausea, vomiting, abdominal pain, renal failure, hepatic failure, seizure, hypotension, dysrhythmia, or heart failure
Electrolyte abnormalities (hypocalcemia, hypomagnesemia, and hyperkalemia) are common
Coagulopathy may develop secondary to hypocalcemia
>> Work Up:
12-lead EKG to evaluate for dysrhythmia and interval abnormalities
Prolongation of the QTc interval is one of the best indicators of systemic HF toxicity
Pts with significant exposures require continuous cardiac monitoring
>> Management:
Irrigation:
Immediately irrigate with water for 15-30 minutes to remove and dilute the acid
Irrigation will not effectively remove HF that has already penetrated into deeper tissue
Calcium gluconate gel (topical):
Turns the fluoride into an insoluble salt, preventing further absorption
This reduces the amount of tissue destruction and systemic toxicity
Apply gel to affected areas every 30 minutes
Once pain is controlled, reduce frequency to every 4 hours
Gel can be prepared by combining 100 mL of water-based lubricant with 2.5 g of calcium gluconate
Calcium gluconate infiltration:
Allows for much greater skin penetration than topical application; its use should be considered for significant burns
Infiltration is performed with a small gauge needle (25- or 27-gauge)
Inject approximately 0.5 mL/cm2 of 5% calcium gluconate into the affected skin and subcutaneous tissue
For finger injuries, do not exceed 0.5 mL per phalanx to prevent an excessive rise in compartment pressure
Calcium gluconate, intravenous:
Should be administered intravenously following significant exposures and in cases of hypocalcemia
Intravenous calcium gluconate decreases pain and prevents extension of the burn to deeper tissues
For extremity burns, regional intravenous calcium gluconate may be administered via Bier block
Tourniquet is placed proximal to burn; calcium gluconate is administered intravenously distal to tourniquet
Can inject 10 mL of 10% calcium gluconate diluted in 30 - 40 mL of normal saline and maintain for 20 - 25 min
Calcium gluconate, arterial:
High incidence of complications (arterial spasm, necrosis, dysrhythmia, and vasculitis)
No demonstrable benefit when compared to intravenous calcium gluconate for most HF exposures
Intra-arterial calcium is theoretically advantageous in severe burns affecting tissues with clear arterial distribution and in small spaces that cannot accommodate large volumes of locally-infiltrated calcium
**Resolution of pain is a good indicator of treatment efficacy**
>> Non-Dermal Exposures:
Inhalation:
Consider the possibility of inhalational exposure in any patient with HF burns to the face, head, or neck, as well as in burns sustained in confined spaces
May cause fever, chills, pulmonary edema, hemorrhage, chest discomfort, cyanosis, and wheezing
Obtain chest radiography and provide supplemental oxygen
Consider nebulized calcium gluconate (2-3%), PPV, and intubation in severe cases
Ocular:
An ophthalmologic emergency; irrigation is the immediate priority
Consider administration of calcium gluconate (1-10%) eye drops
Instill 1-2 drops every 2-3 hours into the affected eye(s)
Fingernail:
HF easily penetrates the nail
Removal is generally required to apply calcium gluconate gel to affected nailbed
