hydroflouric acid poisoning or burns

see also:

• burns
• https://www.health.gov.au/resources/publications/australian-clinical-guidelines-for-acute-exposures-to-chemical-agents-of-health-concern?language=en
• https://www.rch.org.au/clinicalguide/guideline_index/Hydrofluoric_acid_exposure/
• StatPearls 2023

• hydrofluoric acid exposure can occur through oral, inhalation, ocular or dermal exposure.
• Industrial HF preparations may have concentrations of up to 100%.
• Domestic solutions contain generally less than 15% HF.
• Dermal exposure to any concentration of HF can cause severe, delayed pain and liquefactive necrosis.
• Ingestion can cause local corrosive effects to the GIT, and systemic fluorosis can manifest suddenly with refractory ventricular dysrhythmias and cardiac arrest.
• Life threatening fluorosis occurs with dermal exposure of 100% HF to 2.5% BSA, 70% HF to 8% BSA, 23% HF to 11% BSA and ingestion of 100ml or more of 6% HF or any quantity of higher concentrations.
• Children who ingest any quantity of HF are at risk of lethal toxicity.

• local corrosive activity (liquefactive necrosis)
• dissociated fluoride ions
  • fluoride ions will bind with calcium and magnesium ions causing profound hypocalcaemia and hypomagnesaemia with subsequent tetany and QT prolongation.
  • potassium channels are also affected causing potassium efflux out of cells leading to hyperkalaemia.
  • in conjunction, there may be cell lysis and release of intracellular potassium from the exposure site, contributing to existing metabolic acidosis and hyperkalaemia.
• hydrofluoric acid (HF) does not appear to have a direct effect on sodium channels.

• staff must don chemical protective PPE
• rapid assessment
  • assessment and management life-threating conditions such as airway compromise or cardiac arrythmias
    • burns larger than 160 square cm may result in serious systemic toxicity
    • inhalational injuries or those with burns greater than 25 square cm should be admitted to an intensive care unit and carefully monitored for 24 to 48 hours
    • in some cases, haemodialysis is necessary for fluoride removal and correction of hyperkalemia and recurrent hypocalcemi
  • high inhaled concentrations may cause glossitis (obstruction of the airway) and acute pulmonary edema
    • may need supplmental oxyufen, NIV, nebulised calcium gluconate and/or intubation or surgical airway
  • cardiac monitoring and ECGs
    • QT prolongation from hypocalcemia
    • peaked T waves/arrhythmias from hyperkalemia
    • polymorphic ventricular tachycardia (specifically Torsades de Pointes) from hypomagnesia
  • regularly check U&Es, Ca, Po4, flouride levels
• removal of contaminated clothing
  • as well as jewellery that could trap HF, should be immediately removed and double-bagged to prevent secondary exposure
• decontamination
  • copious amounts of water, saline or solution of soap and water
  • using a soft brush, moving in a downward motion (from head to toe) with household dish soaps (Dawn, Palmolive) and water, with a pH value of at least 8 and should not exceed a pH value of 10.5
  • thorough rinsing
  • initial treatment for eye exposure includes irrigation with large amount of gently flowing cool plain water or sterile 0.9 % saline solution for 15-30 minutes
    • topical ophthalmic anesthetic solution can be used
• neutralization
  • calcium gluconate
    • topical use of calcium gluconate gel (2.5%)
      • applied and rubbed into the affected area for 15 - 30 minutes and should be reapplied every 10 - 15 minutes
      • will turn white as the calcium binds to the fluoride ions creating calcium fluoride (CaF₂)
      • if used as a definitive treatment, should be applied 4 to 6 times daily, for 3 to 4 days.
      • if pain persists after 30 minutes of treatment, subcutaneous infiltration of calcium gluconate is generally recommended at a dose of 0.5 mL of a 5% solution per square centimeter of surface burn extending 0.5 cm beyond the margin of involved tissue
        • to minimise compartment syndrome issues, injections into the hand should be limited to 0.5 ml per phalanx with repeat injections as needed
      • ocular use
        • ofter initial decontamination of the eye, intermittent irrigation using a sterile 1% calcium gluconate solution via a Morgan lens for 20 minutes
        • consider also hexaflourine
      • 2.5% to 3% calcium gluconate nebulized solution
        • consider for those with inhalational injury
  • additional possible topical agents:
    • benzalkonium chloride
      • iced solution of benzalkonium chloride (Zephiran Chloride) concentration of (0.13%)
      • side effects include stinging pain or allergic reaction (urticaria, pruritus, dyspnea, chest tightness, swelling of the face, lips or tongue)
    • polyethelene glycol
    • magnesium oxide
    • Hexafluorine
      • developed by PREVOR laboratories was designed for active washing of hydrofluoric acid splashes
      • triple effect in that it has the same rinsing and diluting properties as water, can neutralize the hydrogen ions and chelate the fluoride ions